Mercurial > dwindows

changeset 2502:b6319aed3298

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Android: Massive thread safety overhaul. Not quite back to fully functional. WebView is having many complaints about not being on the UI thread... better to get this figured out early... All UI calls will be wrapped in a waitOnUiThread() closure. This is our version of Android's runOnUiThread() except it waits for the closure to finish running so we can return results... and also so that our calls will be in the order desired in the application.
author bsmith@81767d24-ef19-dc11-ae90-00e081727c95
date Thu, 06 May 2021 09:55:32 +0000
parents 41984ffb5ca2
children 1c2a79313b04
files android/DWindows.kt android/dw.cpp
diffstat 2 files changed, 545 insertions(+), 435 deletions(-) [+]
line wrap: on
line diff
--- a/android/DWindows.kt	Thu May 06 00:05:32 2021 +0000
+++ b/android/DWindows.kt	Thu May 06 09:55:32 2021 +0000
@@ -31,6 +31,8 @@
 import com.google.android.material.tabs.TabLayout.OnTabSelectedListener
 import com.google.android.material.tabs.TabLayoutMediator
 import java.util.*
+import java.util.concurrent.locks.Lock
+import java.util.concurrent.locks.ReentrantLock
 
 
 class DWTabViewPagerAdapter : RecyclerView.Adapter<DWTabViewPagerAdapter.DWEventViewHolder>() {
@@ -55,6 +57,27 @@
 class DWindows : AppCompatActivity() {
     var firstWindow: Boolean = true
     var windowLayout: LinearLayout? = null
+    var threadLock = ReentrantLock()
+    var threadCond = threadLock.newCondition()
+
+    // Our version of runOnUiThread that waits for execution
+    fun waitOnUiThread(runnable: Runnable)
+    {
+          if(Looper.myLooper() == Looper.getMainLooper()) {
+              runnable.run()
+          } else {
+              threadLock.lock()
+              val ourRunnable = Runnable {
+                  threadLock.lock()
+                  runnable.run()
+                  threadCond.signal()
+                  threadLock.unlock()
+              }
+              runOnUiThread(ourRunnable)
+              threadCond.await()
+              threadLock.unlock()
+          }
+    }
 
     // We only want to call this once when the app starts up
     // By default Android will call onCreate for rotation and other
@@ -96,15 +119,17 @@
      */
     fun windowNew(title: String, style: Int): LinearLayout? {
         if (firstWindow) {
-            var dataArrayMap = SimpleArrayMap<String, Long>()
-            windowLayout = LinearLayout(this)
+            waitOnUiThread {
+                var dataArrayMap = SimpleArrayMap<String, Long>()
+                windowLayout = LinearLayout(this)
 
-            windowLayout!!.tag = dataArrayMap
-            setContentView(windowLayout)
-            this.title = title
-            // For now we just return our DWindows' main activity layout...
-            // in the future, later calls should create new activities
-            firstWindow = false
+                windowLayout!!.tag = dataArrayMap
+                setContentView(windowLayout)
+                this.title = title
+                // For now we just return our DWindows' main activity layout...
+                // in the future, later calls should create new activities
+                firstWindow = false
+            }
             return windowLayout
         }
         return null
@@ -138,34 +163,42 @@
     }
 
     fun windowSetEnabled(window: View, state: Boolean) {
-        window.setEnabled(state)
+        waitOnUiThread {
+            window.setEnabled(state)
+        }
     }
 
     fun windowSetText(window: View, text: String) {
-        if (window is TextView) {
-            var textview: TextView = window
-            textview.text = text
-        } else if (window is Button) {
-            var button: Button = window
-            button.text = text
-        } else if (window is LinearLayout) {
-            // TODO: Make sure this is actually the top-level layout, not just a box
-            this.title = text
+        waitOnUiThread {
+            if (window is TextView) {
+                var textview: TextView = window
+                textview.text = text
+            } else if (window is Button) {
+                var button: Button = window
+                button.text = text
+            } else if (window is LinearLayout) {
+                // TODO: Make sure this is actually the top-level layout, not just a box
+                this.title = text
+            }
         }
     }
 
     fun windowGetText(window: View): String? {
-        if (window is TextView) {
-            var textview: TextView = window
-            return textview.text.toString()
-        } else if (window is Button) {
-            var button: Button = window
-            return button.text.toString()
-        } else if (window is LinearLayout) {
-            // TODO: Make sure this is actually the top-level layout, not just a box
-            return this.title.toString()
+        var text: String? = null
+
+        waitOnUiThread {
+            if (window is TextView) {
+                var textview: TextView = window
+                text = textview.text.toString()
+            } else if (window is Button) {
+                var button: Button = window
+                text = button.text.toString()
+            } else if (window is LinearLayout) {
+                // TODO: Make sure this is actually the top-level layout, not just a box
+                text = this.title.toString()
+            }
         }
-        return null
+        return text
     }
 
     fun clipboardGetText(): String {
@@ -185,45 +218,52 @@
         cm.setPrimaryClip(clipdata)
     }
 
-    fun boxNew(type: Int, pad: Int): LinearLayout {
-        val box = LinearLayout(this)
-        var dataArrayMap = SimpleArrayMap<String, Long>()
+    fun boxNew(type: Int, pad: Int): LinearLayout? {
+        var box: LinearLayout? = null
+        waitOnUiThread {
+            box = LinearLayout(this)
+            var dataArrayMap = SimpleArrayMap<String, Long>()
 
-        box.tag = dataArrayMap
-        box.layoutParams =
+            box!!.tag = dataArrayMap
+            box!!.layoutParams =
                 LinearLayout.LayoutParams(
                     LinearLayout.LayoutParams.WRAP_CONTENT,
                     LinearLayout.LayoutParams.WRAP_CONTENT
                 )
-        if (type > 0) {
-            box.orientation = LinearLayout.VERTICAL
-        } else {
-            box.orientation = LinearLayout.HORIZONTAL
+            if (type > 0) {
+                box!!.orientation = LinearLayout.VERTICAL
+            } else {
+                box!!.orientation = LinearLayout.HORIZONTAL
+            }
+            box!!.setPadding(pad, pad, pad, pad)
         }
-        box.setPadding(pad, pad, pad, pad)
         return box
     }
 
-    fun scrollBoxNew(type: Int, pad: Int) : ScrollView {
-        val scrollBox = ScrollView(this)
-        val box = LinearLayout(this)
-        var dataArrayMap = SimpleArrayMap<String, Long>()
+    fun scrollBoxNew(type: Int, pad: Int) : ScrollView? {
+        var scrollBox: ScrollView? = null
+
+        waitOnUiThread {
+            val box = LinearLayout(this)
+            scrollBox = ScrollView(this)
+            var dataArrayMap = SimpleArrayMap<String, Long>()
 
-        scrollBox.tag = dataArrayMap
-        box.layoutParams =
-            LinearLayout.LayoutParams(
-                LinearLayout.LayoutParams.MATCH_PARENT,
-                LinearLayout.LayoutParams.MATCH_PARENT
-            )
-        if (type > 0) {
-            box.orientation = LinearLayout.VERTICAL
-        } else {
-            box.orientation = LinearLayout.HORIZONTAL
+            scrollBox!!.tag = dataArrayMap
+            box.layoutParams =
+                LinearLayout.LayoutParams(
+                    LinearLayout.LayoutParams.MATCH_PARENT,
+                    LinearLayout.LayoutParams.MATCH_PARENT
+                )
+            if (type > 0) {
+                box.orientation = LinearLayout.VERTICAL
+            } else {
+                box.orientation = LinearLayout.HORIZONTAL
+            }
+            box.setPadding(pad, pad, pad, pad)
+            // Add a pointer back to the ScrollView
+            box.tag = scrollBox
+            scrollBox!!.addView(box)
         }
-        box.setPadding(pad, pad, pad, pad)
-        // Add a pointer back to the ScrollView
-        box.tag = scrollBox
-        scrollBox.addView(box)
         return scrollBox
     }
 
@@ -237,273 +277,315 @@
         vsize: Int,
         pad: Int
     ) {
-        var w: Int = LinearLayout.LayoutParams.WRAP_CONTENT
-        var h: Int = LinearLayout.LayoutParams.WRAP_CONTENT
-        var box: LinearLayout? = null
-
-        // Handle scrollboxes by pulling the LinearLayout
-        // out of the ScrollView to pack into
-        if(boxview is LinearLayout) {
-            box = boxview as LinearLayout
-        } else if(boxview is ScrollView) {
-            var sv: ScrollView = boxview
+        waitOnUiThread {
+            var w: Int = LinearLayout.LayoutParams.WRAP_CONTENT
+            var h: Int = LinearLayout.LayoutParams.WRAP_CONTENT
+            var box: LinearLayout? = null
 
-            if(sv.getChildAt(0) is LinearLayout) {
-                box = sv.getChildAt(0) as LinearLayout
-            }
-        }
+            // Handle scrollboxes by pulling the LinearLayout
+            // out of the ScrollView to pack into
+            if (boxview is LinearLayout) {
+                box = boxview as LinearLayout
+            } else if (boxview is ScrollView) {
+                var sv: ScrollView = boxview
 
-        if(box != null) {
-            if ((item is LinearLayout) or (item is ScrollView)) {
-                if (box.orientation == LinearLayout.VERTICAL) {
-                    if (hsize > 0) {
-                        w = LinearLayout.LayoutParams.MATCH_PARENT
-                    }
-                } else {
-                    if (vsize > 0) {
-                        h = LinearLayout.LayoutParams.MATCH_PARENT
-                    }
+                if (sv.getChildAt(0) is LinearLayout) {
+                    box = sv.getChildAt(0) as LinearLayout
                 }
             }
-            var params: LinearLayout.LayoutParams = LinearLayout.LayoutParams(w, h)
 
-            if (item !is LinearLayout && (width != -1 || height != -1)) {
-                item.measure(0, 0)
-                if (width > 0) {
-                    w = width
-                } else if (width == -1) {
-                    w = item.getMeasuredWidth()
+            if (box != null) {
+                if ((item is LinearLayout) or (item is ScrollView)) {
+                    if (box.orientation == LinearLayout.VERTICAL) {
+                        if (hsize > 0) {
+                            w = LinearLayout.LayoutParams.MATCH_PARENT
+                        }
+                    } else {
+                        if (vsize > 0) {
+                            h = LinearLayout.LayoutParams.MATCH_PARENT
+                        }
+                    }
                 }
-                if (height > 0) {
-                    h = height
-                } else if (height == -1) {
-                    h = item.getMeasuredHeight()
-                }
-            }
-            if (box.orientation == LinearLayout.VERTICAL) {
-                if (vsize > 0) {
-                    if (w > 0) {
-                        params.weight = w.toFloat()
-                    } else {
-                        params.weight = 1F
+                var params: LinearLayout.LayoutParams = LinearLayout.LayoutParams(w, h)
+
+                if (item !is LinearLayout && (width != -1 || height != -1)) {
+                    item.measure(0, 0)
+                    if (width > 0) {
+                        w = width
+                    } else if (width == -1) {
+                        w = item.getMeasuredWidth()
+                    }
+                    if (height > 0) {
+                        h = height
+                    } else if (height == -1) {
+                        h = item.getMeasuredHeight()
                     }
                 }
-            } else {
-                if (hsize > 0) {
-                    if (h > 0) {
-                        params.weight = h.toFloat()
-                    } else {
-                        params.weight = 1F
+                if (box.orientation == LinearLayout.VERTICAL) {
+                    if (vsize > 0) {
+                        if (w > 0) {
+                            params.weight = w.toFloat()
+                        } else {
+                            params.weight = 1F
+                        }
+                    }
+                } else {
+                    if (hsize > 0) {
+                        if (h > 0) {
+                            params.weight = h.toFloat()
+                        } else {
+                            params.weight = 1F
+                        }
                     }
                 }
-            }
-            if (pad > 0) {
-                params.setMargins(pad, pad, pad, pad)
+                if (pad > 0) {
+                    params.setMargins(pad, pad, pad, pad)
+                }
+                var grav: Int = Gravity.CLIP_HORIZONTAL or Gravity.CLIP_VERTICAL
+                if (hsize > 0 && vsize > 0) {
+                    params.gravity = Gravity.FILL or grav
+                } else if (hsize > 0) {
+                    params.gravity = Gravity.FILL_HORIZONTAL or grav
+                } else if (vsize > 0) {
+                    params.gravity = Gravity.FILL_VERTICAL or grav
+                }
+                item.layoutParams = params
+                box.addView(item, index)
             }
-            var grav: Int = Gravity.CLIP_HORIZONTAL or Gravity.CLIP_VERTICAL
-            if (hsize > 0 && vsize > 0) {
-                params.gravity = Gravity.FILL or grav
-            } else if (hsize > 0) {
-                params.gravity = Gravity.FILL_HORIZONTAL or grav
-            } else if (vsize > 0) {
-                params.gravity = Gravity.FILL_VERTICAL or grav
-            }
-            item.layoutParams = params
-            box.addView(item, index)
         }
     }
 
     fun boxUnpack(item: View) {
-        var box: LinearLayout = item.parent as LinearLayout
-        box.removeView(item)
+        waitOnUiThread {
+            var box: LinearLayout = item.parent as LinearLayout
+            box.removeView(item)
+        }
     }
 
     fun boxUnpackAtIndex(box: LinearLayout, index: Int): View? {
-        var item: View = box.getChildAt(index)
+        var item: View? = null
 
-        box.removeView(item)
+        waitOnUiThread {
+            item = box.getChildAt(index)
+
+            box.removeView(item)
+        }
         return item
     }
 
-    fun buttonNew(text: String, cid: Int): Button {
-        val button = Button(this)
-        var dataArrayMap = SimpleArrayMap<String, Long>()
+    fun buttonNew(text: String, cid: Int): Button? {
+        var button: Button? = null
+        waitOnUiThread {
+            button = Button(this)
+            var dataArrayMap = SimpleArrayMap<String, Long>()
 
-        button.tag = dataArrayMap
-        button.text = text
-        button.id = cid
-        button.setOnClickListener {
-            eventHandlerSimple(button, 8)
+            button!!.tag = dataArrayMap
+            button!!.text = text
+            button!!.id = cid
+            button!!.setOnClickListener {
+                eventHandlerSimple(button!!, 8)
+            }
         }
         return button
     }
 
-    fun entryfieldNew(text: String, cid: Int, password: Int): EditText {
-        val entryfield = EditText(this)
-        var dataArrayMap = SimpleArrayMap<String, Long>()
+    fun entryfieldNew(text: String, cid: Int, password: Int): EditText? {
+        var entryfield: EditText? = null
+
+        waitOnUiThread {
+            var dataArrayMap = SimpleArrayMap<String, Long>()
+            entryfield = EditText(this)
 
-        entryfield.tag = dataArrayMap
-        entryfield.id = cid
-        if (password > 0) {
-            entryfield.transformationMethod = PasswordTransformationMethod.getInstance()
+            entryfield!!.tag = dataArrayMap
+            entryfield!!.id = cid
+            if (password > 0) {
+                entryfield!!.transformationMethod = PasswordTransformationMethod.getInstance()
+            }
+            entryfield!!.setText(text)
         }
-        entryfield.setText(text)
         return entryfield
     }
 
     fun entryfieldSetLimit(entryfield: EditText, limit: Long) {
-        entryfield.filters = arrayOf<InputFilter>(LengthFilter(limit.toInt()))
+        waitOnUiThread {
+            entryfield.filters = arrayOf<InputFilter>(LengthFilter(limit.toInt()))
+        }
     }
 
-    fun radioButtonNew(text: String, cid: Int): RadioButton {
-        val radiobutton = RadioButton(this)
-        var dataArrayMap = SimpleArrayMap<String, Long>()
+    fun radioButtonNew(text: String, cid: Int): RadioButton? {
+        var radiobutton: RadioButton? = null
+
+        waitOnUiThread {
+            var dataArrayMap = SimpleArrayMap<String, Long>()
+            radiobutton = RadioButton(this)
 
-        radiobutton.tag = dataArrayMap
-        radiobutton.id = cid
-        radiobutton.text = text
-        radiobutton.setOnClickListener {
-            eventHandlerSimple(radiobutton, 8)
+            radiobutton!!.tag = dataArrayMap
+            radiobutton!!.id = cid
+            radiobutton!!.text = text
+            radiobutton!!.setOnClickListener {
+                eventHandlerSimple(radiobutton!!, 8)
+            }
         }
         return radiobutton
     }
 
-    fun checkboxNew(text: String, cid: Int): CheckBox {
-        val checkbox = CheckBox(this)
-        var dataArrayMap = SimpleArrayMap<String, Long>()
+    fun checkboxNew(text: String, cid: Int): CheckBox? {
+        var checkbox: CheckBox? = null
+
+        waitOnUiThread {
+            var dataArrayMap = SimpleArrayMap<String, Long>()
 
-        checkbox.tag = dataArrayMap
-        checkbox.id = cid
-        checkbox.text = text
-        checkbox.setOnClickListener {
-            eventHandlerSimple(checkbox, 8)
+            checkbox = CheckBox(this)
+            checkbox!!.tag = dataArrayMap
+            checkbox!!.id = cid
+            checkbox!!.text = text
+            checkbox!!.setOnClickListener {
+                eventHandlerSimple(checkbox!!, 8)
+            }
         }
         return checkbox
     }
 
     fun checkOrRadioSetChecked(control: View, state: Int)
     {
-        if(control is CheckBox) {
-            var checkbox: CheckBox = control
-            checkbox.isChecked = state != 0
-        } else if(control is RadioButton) {
-            var radiobutton: RadioButton = control
-            radiobutton.isChecked = state != 0
+        waitOnUiThread {
+            if (control is CheckBox) {
+                var checkbox: CheckBox = control
+                checkbox.isChecked = state != 0
+            } else if (control is RadioButton) {
+                var radiobutton: RadioButton = control
+                radiobutton.isChecked = state != 0
+            }
         }
     }
 
     fun checkOrRadioGetChecked(control: View): Boolean
     {
-        if(control is CheckBox) {
-            var checkbox: CheckBox = control
-            return checkbox.isChecked
-        } else if(control is RadioButton) {
-            var radiobutton: RadioButton = control
-            return radiobutton.isChecked
+        var retval: Boolean = false
+
+        waitOnUiThread {
+            if (control is CheckBox) {
+                var checkbox: CheckBox = control
+                retval = checkbox.isChecked
+            } else if (control is RadioButton) {
+                var radiobutton: RadioButton = control
+                retval = radiobutton.isChecked
+            }
         }
-        return false
+        return retval
     }
 
-    fun textNew(text: String, cid: Int, status: Int): TextView {
-        val textview = TextView(this)
-        var dataArrayMap = SimpleArrayMap<String, Long>()
+    fun textNew(text: String, cid: Int, status: Int): TextView? {
+        var textview: TextView? = null
+
+        waitOnUiThread {
+            var dataArrayMap = SimpleArrayMap<String, Long>()
 
-        textview.tag = dataArrayMap
-        textview.id = cid
-        textview.text = text
-        if (status != 0) {
-            val border = GradientDrawable()
+            textview = TextView(this)
+            textview!!.tag = dataArrayMap
+            textview!!.id = cid
+            textview!!.text = text
+            if (status != 0) {
+                val border = GradientDrawable()
 
-            // Set a black border on white background...
-            // might need to change this to invisible...
-            // or the color from windowSetColor
-            border.setColor(-0x1)
-            border.setStroke(1, -0x1000000)
-            textview.background = border
+                // Set a black border on white background...
+                // might need to change this to invisible...
+                // or the color from windowSetColor
+                border.setColor(-0x1)
+                border.setStroke(1, -0x1000000)
+                textview!!.background = border
+            }
         }
         return textview
     }
 
-    fun notebookNew(cid: Int, top: Int): RelativeLayout
+    fun notebookNew(cid: Int, top: Int): RelativeLayout?
     {
-        val notebook = RelativeLayout(this)
-        val pager = ViewPager2(this)
-        val tabs = TabLayout(this)
-        var w: Int = RelativeLayout.LayoutParams.MATCH_PARENT
-        var h: Int = RelativeLayout.LayoutParams.WRAP_CONTENT
-        var dataArrayMap = SimpleArrayMap<String, Long>()
+        var notebook: RelativeLayout? = null
 
-        notebook.tag = dataArrayMap
-        notebook.id = cid
-        tabs.id = View.generateViewId()
-        pager.id = View.generateViewId()
-        pager.adapter = DWTabViewPagerAdapter()
-        TabLayoutMediator(tabs, pager) { tab, position ->
-            // This code never gets called?
-        }.attach()
+        waitOnUiThread {
+            val pager = ViewPager2(this)
+            val tabs = TabLayout(this)
+            var w: Int = RelativeLayout.LayoutParams.MATCH_PARENT
+            var h: Int = RelativeLayout.LayoutParams.WRAP_CONTENT
+            var dataArrayMap = SimpleArrayMap<String, Long>()
+
+            notebook = RelativeLayout(this)
+            notebook!!.tag = dataArrayMap
+            notebook!!.id = cid
+            tabs.id = View.generateViewId()
+            pager.id = View.generateViewId()
+            pager.adapter = DWTabViewPagerAdapter()
+            TabLayoutMediator(tabs, pager) { tab, position ->
+                // This code never gets called?
+            }.attach()
 
-        var params: RelativeLayout.LayoutParams = RelativeLayout.LayoutParams(w, h)
-        if(top != 0) {
-            params.addRule(RelativeLayout.ALIGN_PARENT_TOP)
-        } else {
-            params.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM)
+            var params: RelativeLayout.LayoutParams = RelativeLayout.LayoutParams(w, h)
+            if (top != 0) {
+                params.addRule(RelativeLayout.ALIGN_PARENT_TOP)
+            } else {
+                params.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM)
+            }
+            tabs.tabGravity = TabLayout.GRAVITY_FILL
+            tabs.tabMode = TabLayout.MODE_FIXED
+            notebook!!.addView(tabs, params)
+            params = RelativeLayout.LayoutParams(w, w)
+            if (top != 0) {
+                params.addRule(RelativeLayout.BELOW, tabs.id)
+            } else {
+                params.addRule(RelativeLayout.ABOVE, tabs.id)
+            }
+            notebook!!.addView(pager, params)
+            tabs.addOnTabSelectedListener(object : OnTabSelectedListener {
+                override fun onTabSelected(tab: TabLayout.Tab) {
+                    val adapter = pager.adapter as DWTabViewPagerAdapter
+
+                    pager.currentItem = tab.position
+                    eventHandlerNotebook(notebook!!, 15, adapter.pageList[tab.position])
+                }
+
+                override fun onTabUnselected(tab: TabLayout.Tab) {}
+                override fun onTabReselected(tab: TabLayout.Tab) {}
+            })
         }
-        tabs.tabGravity = TabLayout.GRAVITY_FILL
-        tabs.tabMode = TabLayout.MODE_FIXED
-        notebook.addView(tabs, params)
-        params = RelativeLayout.LayoutParams(w, w)
-        if(top != 0) {
-            params.addRule(RelativeLayout.BELOW, tabs.id)
-        } else {
-            params.addRule(RelativeLayout.ABOVE, tabs.id)
-        }
-        notebook.addView(pager, params)
-        tabs.addOnTabSelectedListener(object : OnTabSelectedListener {
-            override fun onTabSelected(tab: TabLayout.Tab) {
-                val adapter = pager.adapter as DWTabViewPagerAdapter
-
-                pager.currentItem = tab.position
-                eventHandlerNotebook(notebook, 15, adapter.pageList[tab.position])
-            }
-            override fun onTabUnselected(tab: TabLayout.Tab) {}
-            override fun onTabReselected(tab: TabLayout.Tab) {}
-        })
         return notebook
     }
 
     fun notebookPageNew(notebook: RelativeLayout, flags: Long, front: Int): Long
     {
-        var pager: ViewPager2? = null
-        var tabs: TabLayout? = null
         var pageID = 0L
 
-        if(notebook.getChildAt(0) is ViewPager2 && notebook.getChildAt(1) is TabLayout) {
-            pager = notebook.getChildAt(0) as ViewPager2
-            tabs = notebook.getChildAt(1) as TabLayout
-        } else if(notebook.getChildAt(1) is ViewPager2 && notebook.getChildAt(0) is TabLayout) {
-            pager = notebook.getChildAt(1) as ViewPager2
-            tabs = notebook.getChildAt(0) as TabLayout
-        }
+        waitOnUiThread {
+            var pager: ViewPager2? = null
+            var tabs: TabLayout? = null
 
-        if(pager != null && tabs != null) {
-            var adapter: DWTabViewPagerAdapter = pager.adapter as DWTabViewPagerAdapter
-            var tab = tabs.newTab()
+            if (notebook.getChildAt(0) is ViewPager2 && notebook.getChildAt(1) is TabLayout) {
+                pager = notebook.getChildAt(0) as ViewPager2
+                tabs = notebook.getChildAt(1) as TabLayout
+            } else if (notebook.getChildAt(1) is ViewPager2 && notebook.getChildAt(0) is TabLayout) {
+                pager = notebook.getChildAt(1) as ViewPager2
+                tabs = notebook.getChildAt(0) as TabLayout
+            }
+
+            if (pager != null && tabs != null) {
+                var adapter: DWTabViewPagerAdapter = pager.adapter as DWTabViewPagerAdapter
+                var tab = tabs.newTab()
 
-            // Increment our page ID... making sure no duplicates exist
-            do {
-                adapter.currentPageID += 1
-            }
-            while(adapter.currentPageID == 0L || adapter.pageList.contains(adapter.currentPageID))
-            pageID = adapter.currentPageID
-            // Temporarily add a black tab with an empty layout/box
-            if(front != 0) {
-                adapter.viewList.add(0, LinearLayout(this))
-                adapter.pageList.add(0, pageID)
-                tabs.addTab(tab, 0)
-            } else {
-                adapter.viewList.add(LinearLayout(this))
-                adapter.pageList.add(pageID)
-                tabs.addTab(tab)
+                // Increment our page ID... making sure no duplicates exist
+                do {
+                    adapter.currentPageID += 1
+                } while (adapter.currentPageID == 0L || adapter.pageList.contains(adapter.currentPageID))
+                pageID = adapter.currentPageID
+                // Temporarily add a black tab with an empty layout/box
+                if (front != 0) {
+                    adapter.viewList.add(0, LinearLayout(this))
+                    adapter.pageList.add(0, pageID)
+                    tabs.addTab(tab, 0)
+                } else {
+                    adapter.viewList.add(LinearLayout(this))
+                    adapter.pageList.add(pageID)
+                    tabs.addTab(tab)
+                }
             }
         }
         return pageID
@@ -511,218 +593,252 @@
 
     fun notebookPageDestroy(notebook: RelativeLayout, pageID: Long)
     {
-        var pager: ViewPager2? = null
-        var tabs: TabLayout? = null
+        waitOnUiThread {
+            var pager: ViewPager2? = null
+            var tabs: TabLayout? = null
 
-        if(notebook.getChildAt(0) is ViewPager2 && notebook.getChildAt(1) is TabLayout) {
-            pager = notebook.getChildAt(0) as ViewPager2
-            tabs = notebook.getChildAt(1) as TabLayout
-        } else if(notebook.getChildAt(1) is ViewPager2 && notebook.getChildAt(0) is TabLayout) {
-            pager = notebook.getChildAt(1) as ViewPager2
-            tabs = notebook.getChildAt(0) as TabLayout
-        }
+            if (notebook.getChildAt(0) is ViewPager2 && notebook.getChildAt(1) is TabLayout) {
+                pager = notebook.getChildAt(0) as ViewPager2
+                tabs = notebook.getChildAt(1) as TabLayout
+            } else if (notebook.getChildAt(1) is ViewPager2 && notebook.getChildAt(0) is TabLayout) {
+                pager = notebook.getChildAt(1) as ViewPager2
+                tabs = notebook.getChildAt(0) as TabLayout
+            }
 
-        if(pager != null && tabs != null) {
-            var adapter: DWTabViewPagerAdapter = pager.adapter as DWTabViewPagerAdapter
-            val index = adapter.pageList.indexOf(pageID)
-            val tab = tabs.getTabAt(index)
+            if (pager != null && tabs != null) {
+                var adapter: DWTabViewPagerAdapter = pager.adapter as DWTabViewPagerAdapter
+                val index = adapter.pageList.indexOf(pageID)
+                val tab = tabs.getTabAt(index)
 
-            if (tab != null) {
-                adapter.viewList.removeAt(index)
-                adapter.pageList.removeAt(index)
-                tabs.removeTab(tab)
+                if (tab != null) {
+                    adapter.viewList.removeAt(index)
+                    adapter.pageList.removeAt(index)
+                    tabs.removeTab(tab)
+                }
             }
         }
     }
 
     fun notebookPageSetText(notebook: RelativeLayout, pageID: Long, text: String)
     {
-        var pager: ViewPager2? = null
-        var tabs: TabLayout? = null
+        waitOnUiThread {
+            var pager: ViewPager2? = null
+            var tabs: TabLayout? = null
 
-        if(notebook.getChildAt(0) is ViewPager2 && notebook.getChildAt(1) is TabLayout) {
-            pager = notebook.getChildAt(0) as ViewPager2
-            tabs = notebook.getChildAt(1) as TabLayout
-        } else if(notebook.getChildAt(1) is ViewPager2 && notebook.getChildAt(0) is TabLayout) {
-            pager = notebook.getChildAt(1) as ViewPager2
-            tabs = notebook.getChildAt(0) as TabLayout
-        }
+            if (notebook.getChildAt(0) is ViewPager2 && notebook.getChildAt(1) is TabLayout) {
+                pager = notebook.getChildAt(0) as ViewPager2
+                tabs = notebook.getChildAt(1) as TabLayout
+            } else if (notebook.getChildAt(1) is ViewPager2 && notebook.getChildAt(0) is TabLayout) {
+                pager = notebook.getChildAt(1) as ViewPager2
+                tabs = notebook.getChildAt(0) as TabLayout
+            }
 
-        if(pager != null && tabs != null) {
-            val adapter: DWTabViewPagerAdapter = pager.adapter as DWTabViewPagerAdapter
-            val index = adapter.pageList.indexOf(pageID)
-            val tab = tabs.getTabAt(index)
+            if (pager != null && tabs != null) {
+                val adapter: DWTabViewPagerAdapter = pager.adapter as DWTabViewPagerAdapter
+                val index = adapter.pageList.indexOf(pageID)
+                val tab = tabs.getTabAt(index)
 
-            if (tab != null) {
-                tab.text = text
+                if (tab != null) {
+                    tab.text = text
+                }
             }
         }
     }
 
     fun notebookPagePack(notebook: RelativeLayout, pageID: Long, box: LinearLayout)
     {
-        var pager: ViewPager2? = null
-        var tabs: TabLayout? = null
+        waitOnUiThread {
+            var pager: ViewPager2? = null
+            var tabs: TabLayout? = null
 
-        if(notebook.getChildAt(0) is ViewPager2 && notebook.getChildAt(1) is TabLayout) {
-            pager = notebook.getChildAt(0) as ViewPager2
-            tabs = notebook.getChildAt(1) as TabLayout
-        } else if(notebook.getChildAt(1) is ViewPager2 && notebook.getChildAt(0) is TabLayout) {
-            pager = notebook.getChildAt(1) as ViewPager2
-            tabs = notebook.getChildAt(0) as TabLayout
-        }
+            if (notebook.getChildAt(0) is ViewPager2 && notebook.getChildAt(1) is TabLayout) {
+                pager = notebook.getChildAt(0) as ViewPager2
+                tabs = notebook.getChildAt(1) as TabLayout
+            } else if (notebook.getChildAt(1) is ViewPager2 && notebook.getChildAt(0) is TabLayout) {
+                pager = notebook.getChildAt(1) as ViewPager2
+                tabs = notebook.getChildAt(0) as TabLayout
+            }
 
-        if(pager != null && tabs != null) {
-            var adapter: DWTabViewPagerAdapter = pager.adapter as DWTabViewPagerAdapter
-            val index = adapter.pageList.indexOf(pageID)
+            if (pager != null && tabs != null) {
+                var adapter: DWTabViewPagerAdapter = pager.adapter as DWTabViewPagerAdapter
+                val index = adapter.pageList.indexOf(pageID)
 
-            // Make sure the box is MATCH_PARENT
-            box.layoutParams = LinearLayout.LayoutParams(
-                LinearLayout.LayoutParams.MATCH_PARENT,
-                LinearLayout.LayoutParams.MATCH_PARENT
-            );
+                // Make sure the box is MATCH_PARENT
+                box.layoutParams = LinearLayout.LayoutParams(
+                    LinearLayout.LayoutParams.MATCH_PARENT,
+                    LinearLayout.LayoutParams.MATCH_PARENT
+                );
 
-            adapter.viewList[index] = box
+                adapter.viewList[index] = box
+            }
         }
     }
 
     fun notebookPageGet(notebook: RelativeLayout): Long
     {
-        var pager: ViewPager2? = null
-        var tabs: TabLayout? = null
+        var retval: Long = 0L
+
+        waitOnUiThread {
+            var pager: ViewPager2? = null
+            var tabs: TabLayout? = null
 
-        if(notebook.getChildAt(0) is ViewPager2 && notebook.getChildAt(1) is TabLayout) {
-            pager = notebook.getChildAt(0) as ViewPager2
-            tabs = notebook.getChildAt(1) as TabLayout
-        } else if(notebook.getChildAt(1) is ViewPager2 && notebook.getChildAt(0) is TabLayout) {
-            pager = notebook.getChildAt(1) as ViewPager2
-            tabs = notebook.getChildAt(0) as TabLayout
+            if (notebook.getChildAt(0) is ViewPager2 && notebook.getChildAt(1) is TabLayout) {
+                pager = notebook.getChildAt(0) as ViewPager2
+                tabs = notebook.getChildAt(1) as TabLayout
+            } else if (notebook.getChildAt(1) is ViewPager2 && notebook.getChildAt(0) is TabLayout) {
+                pager = notebook.getChildAt(1) as ViewPager2
+                tabs = notebook.getChildAt(0) as TabLayout
+            }
+
+            if (pager != null && tabs != null) {
+                var adapter: DWTabViewPagerAdapter = pager.adapter as DWTabViewPagerAdapter
+                retval = adapter.pageList.get(tabs.selectedTabPosition)
+            }
         }
-
-        if(pager != null && tabs != null) {
-            var adapter: DWTabViewPagerAdapter = pager.adapter as DWTabViewPagerAdapter
-            return adapter.pageList.get(tabs.selectedTabPosition)
-        }
-        return 0L
+        return retval
     }
 
     fun notebookPageSet(notebook: RelativeLayout, pageID: Long)
     {
-        var pager: ViewPager2? = null
-        var tabs: TabLayout? = null
+        waitOnUiThread {
+            var pager: ViewPager2? = null
+            var tabs: TabLayout? = null
 
-        if(notebook.getChildAt(0) is ViewPager2 && notebook.getChildAt(1) is TabLayout) {
-            pager = notebook.getChildAt(0) as ViewPager2
-            tabs = notebook.getChildAt(1) as TabLayout
-        } else if(notebook.getChildAt(1) is ViewPager2 && notebook.getChildAt(0) is TabLayout) {
-            pager = notebook.getChildAt(1) as ViewPager2
-            tabs = notebook.getChildAt(0) as TabLayout
-        }
+            if (notebook.getChildAt(0) is ViewPager2 && notebook.getChildAt(1) is TabLayout) {
+                pager = notebook.getChildAt(0) as ViewPager2
+                tabs = notebook.getChildAt(1) as TabLayout
+            } else if (notebook.getChildAt(1) is ViewPager2 && notebook.getChildAt(0) is TabLayout) {
+                pager = notebook.getChildAt(1) as ViewPager2
+                tabs = notebook.getChildAt(0) as TabLayout
+            }
 
-        if(pager != null && tabs != null) {
-            val adapter: DWTabViewPagerAdapter = pager.adapter as DWTabViewPagerAdapter
-            val index = adapter.pageList.indexOf(pageID)
-            val tab = tabs.getTabAt(index)
+            if (pager != null && tabs != null) {
+                val adapter: DWTabViewPagerAdapter = pager.adapter as DWTabViewPagerAdapter
+                val index = adapter.pageList.indexOf(pageID)
+                val tab = tabs.getTabAt(index)
 
-            tabs.selectTab(tab)
+                tabs.selectTab(tab)
+            }
         }
     }
 
-    fun sliderNew(vertical: Int, increments: Int, cid: Int): SeekBar
+    fun sliderNew(vertical: Int, increments: Int, cid: Int): SeekBar?
     {
-        val slider = SeekBar(this)
-        var dataArrayMap = SimpleArrayMap<String, Long>()
+        var slider: SeekBar? = null
+
+        waitOnUiThread {
+            var dataArrayMap = SimpleArrayMap<String, Long>()
 
-        slider.tag = dataArrayMap
-        slider.id = cid
-        slider.max = increments
-        if(vertical != 0) {
-            slider.rotation = 270F
+            slider = SeekBar(this)
+            slider!!.tag = dataArrayMap
+            slider!!.id = cid
+            slider!!.max = increments
+            if (vertical != 0) {
+                slider!!.rotation = 270F
+            }
+            slider!!.setOnSeekBarChangeListener(object : OnSeekBarChangeListener {
+                override fun onStopTrackingTouch(seekBar: SeekBar) {
+                }
+
+                override fun onStartTrackingTouch(seekBar: SeekBar) {
+                }
+
+                override fun onProgressChanged(seekBar: SeekBar, progress: Int, fromUser: Boolean) {
+                    eventHandler(slider, null, 14, null, null, slider!!.progress, 0, 0, 0)
+                }
+            })
         }
-        slider.setOnSeekBarChangeListener(object : OnSeekBarChangeListener {
-            override fun onStopTrackingTouch(seekBar: SeekBar) {
-            }
-
-            override fun onStartTrackingTouch(seekBar: SeekBar) {
-            }
-
-            override fun onProgressChanged(seekBar: SeekBar, progress: Int, fromUser: Boolean) {
-                eventHandler(slider, null, 14, null, null, slider.progress, 0, 0, 0)
-            }
-        })
         return slider
     }
 
-    fun percentNew(cid: Int): ProgressBar
+    fun percentNew(cid: Int): ProgressBar?
     {
-        val percent = ProgressBar(this)
-        var dataArrayMap = SimpleArrayMap<String, Long>()
+        var percent: ProgressBar? = null
+
+        waitOnUiThread {
+            var dataArrayMap = SimpleArrayMap<String, Long>()
 
-        percent.tag = dataArrayMap
-        percent.id = cid
-        percent.max = 100
+            percent = ProgressBar(this)
+            percent!!.tag = dataArrayMap
+            percent!!.id = cid
+            percent!!.max = 100
+        }
         return percent
     }
 
     fun percentGetPos(percent: ProgressBar): Int
     {
-        return percent.progress
+        var retval: Int = 0
+
+        waitOnUiThread {
+            retval = percent.progress
+        }
+        return retval
     }
 
     fun percentSetPos(percent: ProgressBar, position: Int)
     {
-        percent.progress = position
+        waitOnUiThread {
+            percent.progress = position
+        }
     }
 
     fun percentSetRange(percent: ProgressBar, range: Int)
     {
-        percent.max = range
+        waitOnUiThread {
+            percent.max = range
+        }
     }
 
     fun htmlNew(cid: Int): WebView?
     {
-        val looper = Looper.myLooper()
+        var html: WebView? = null
 
-        // WebView requires an active Looper
-        if(looper == null) {
-            Looper.prepare()
+        waitOnUiThread {
+            var dataArrayMap = SimpleArrayMap<String, Long>()
+
+            html = WebView(this)
+            html!!.tag = dataArrayMap
+            html!!.id = cid
         }
-
-        var dataArrayMap = SimpleArrayMap<String, Long>()
-        val html = WebView(this)
-
-        html.tag = dataArrayMap
-        html.id = cid
         return html
     }
 
     fun htmlLoadURL(html: WebView, url: String)
     {
-        html.loadUrl(url)
+        waitOnUiThread {
+            html.loadUrl(url)
+        }
     }
 
     fun htmlRaw(html: WebView, data: String)
     {
-        val encodedHtml: String = Base64.encodeToString(data.toByteArray(), Base64.NO_PADDING)
-        html.loadData(encodedHtml, "text/html", "base64")
+        waitOnUiThread {
+            val encodedHtml: String = Base64.encodeToString(data.toByteArray(), Base64.NO_PADDING)
+            html.loadData(encodedHtml, "text/html", "base64")
+        }
     }
 
     fun htmlJavascriptRun(html: WebView, javascript: String, data: Long)
     {
-        html.evaluateJavascript(javascript) { value ->
-            // Execute onReceiveValue's code
-            eventHandlerHTMLResult(html, 18, value, data)
+        waitOnUiThread {
+            html.evaluateJavascript(javascript) { value ->
+                // Execute onReceiveValue's code
+                eventHandlerHTMLResult(html, 18, value, data)
+            }
         }
     }
 
     fun htmlAction(html: WebView, action: Int)
     {
-        when (action) {
-            0 -> html.goBack()
-            1 -> html.goForward()
-            2 -> html.loadUrl("http://dwindows.netlabs.org")
-            4 -> html.reload()
-            5 -> html.stopLoading()
+        waitOnUiThread {
+            when (action) {
+                0 -> html.goBack()
+                1 -> html.goForward()
+                2 -> html.loadUrl("http://dwindows.netlabs.org")
+                4 -> html.reload()
+                5 -> html.stopLoading()
+            }
         }
     }
 
@@ -763,63 +879,70 @@
 
     fun messageBox(title: String, body: String, flags: Int): Int
     {
-        // make a text input dialog and show it
-        var alert = AlertDialog.Builder(this)
         var retval: Int = 0
 
-        alert.setTitle(title)
-        alert.setMessage(body)
-        if((flags and (1 shl 3)) != 0) {
-            alert.setPositiveButton(
-                "Yes",
-                DialogInterface.OnClickListener { _: DialogInterface, _: Int ->
-                    retval = 1
-                    throw java.lang.RuntimeException()
-                });
-        }
-        if((flags and ((1 shl 1) or (1 shl 2))) != 0) {
-            alert.setNegativeButton(
-                "Ok",
-                DialogInterface.OnClickListener { _: DialogInterface, _: Int ->
-                    retval = 0
-                    throw java.lang.RuntimeException()
-                });
-        }
-        if((flags and ((1 shl 3) or (1 shl 4))) != 0) {
-            alert.setNegativeButton(
-                "No",
-                DialogInterface.OnClickListener { _: DialogInterface, _: Int ->
-                    retval = 0
-                    throw java.lang.RuntimeException()
-                });
-        }
-        if((flags and ((1 shl 2) or (1 shl 4))) != 0) {
-            alert.setNeutralButton(
-                "Cancel",
-                DialogInterface.OnClickListener { _: DialogInterface, _: Int ->
-                    retval = 2
-                    throw java.lang.RuntimeException()
-                });
-        }
-        alert.show();
+        waitOnUiThread {
+            // make a text input dialog and show it
+            var alert = AlertDialog.Builder(this)
 
-        // loop till a runtime exception is triggered.
-        try {
-            Looper.loop()
-        } catch (e2: RuntimeException) {
+            alert.setTitle(title)
+            alert.setMessage(body)
+            if ((flags and (1 shl 3)) != 0) {
+                alert.setPositiveButton(
+                    "Yes",
+                    DialogInterface.OnClickListener { _: DialogInterface, _: Int ->
+                        retval = 1
+                        throw java.lang.RuntimeException()
+                    });
+            }
+            if ((flags and ((1 shl 1) or (1 shl 2))) != 0) {
+                alert.setNegativeButton(
+                    "Ok",
+                    DialogInterface.OnClickListener { _: DialogInterface, _: Int ->
+                        retval = 0
+                        throw java.lang.RuntimeException()
+                    });
+            }
+            if ((flags and ((1 shl 3) or (1 shl 4))) != 0) {
+                alert.setNegativeButton(
+                    "No",
+                    DialogInterface.OnClickListener { _: DialogInterface, _: Int ->
+                        retval = 0
+                        throw java.lang.RuntimeException()
+                    });
+            }
+            if ((flags and ((1 shl 2) or (1 shl 4))) != 0) {
+                alert.setNeutralButton(
+                    "Cancel",
+                    DialogInterface.OnClickListener { _: DialogInterface, _: Int ->
+                        retval = 2
+                        throw java.lang.RuntimeException()
+                    });
+            }
+            alert.show();
+
+            // loop till a runtime exception is triggered.
+            try {
+                Looper.loop()
+            } catch (e2: RuntimeException) {
+            }
         }
         return retval
     }
 
     fun dwindowsExit(exitcode: Int)
     {
-        this.finishAffinity()
-        System.exit(exitcode)
+        waitOnUiThread {
+            this.finishAffinity()
+            System.exit(exitcode)
+        }
     }
 
     fun dwindowsShutdown()
     {
-        this.finishAffinity()
+        waitOnUiThread {
+            this.finishAffinity()
+        }
     }
 
     /*
--- a/android/dw.cpp	Thu May 06 00:05:32 2021 +0000
+++ b/android/dw.cpp	Thu May 06 09:55:32 2021 +0000
@@ -90,11 +90,7 @@
     static int runcount = 0;
 
     /* Safety check to prevent multiple initializations... */
-#if defined(__arm__) || defined(__aarch64__)
     if(runcount == 0)
-#else
-    if(runcount == 1)
-#endif
     {
         char *arg = strdup(env->GetStringUTFChars((jstring) path, NULL));
 
@@ -110,9 +106,6 @@
 
         /* Launch the new thread to execute dwmain() */
         dw_thread_new((void *) _dw_main_launch, arg, 0);
-
-        /* Wait until dwmain() calls dw_main() then return */
-        dw_event_wait(_dw_main_event, DW_TIMEOUT_INFINITE);
     }
     runcount++;
 }
@@ -467,12 +460,6 @@
  */
 void API dw_main(void)
 {
-    /* Post the event so dwindowsInit() will return...
-     * allowing the app to start handling events.
-     */
-    dw_event_post(_dw_main_event);
-    dw_event_reset(_dw_main_event);
-
     /* We don't actually run a loop here,
      * we launched a new thread to run the loop there.
      * Just wait for dw_main_quit() on the DWMainEvent.
@@ -3178,7 +3165,7 @@
 {
     JNIEnv *env;
 
-    if((env = (JNIEnv *)pthread_getspecific(_dw_env_key)))
+    if(handle && (env = (JNIEnv *)pthread_getspecific(_dw_env_key)))
     {
         // Construct a String
         jstring jstr = env->NewStringUTF(text);