Fixes #19 by adding an alternative method for determining when the vi…

…ew has been laid out
jackpocket · Dec 15, 2023 · e2d409a · e2d409a
1 parent a10c0b4
commit e2d409a
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Showing 5 changed files with 73 additions and 29 deletions.
diff --git a/scratchoff-sample/build.gradle b/scratchoff-sample/build.gradle
@@ -12,7 +12,7 @@ android {
     defaultConfig {
         applicationId "com.jackpocket.scratchoff.test"
 
-        minSdkVersion 14
+        minSdkVersion 16
         targetSdkVersion rootProject.ext.targetSdkVersion
 
         versionCode 1

diff --git a/scratchoff-sample/src/main/java/com/jackpocket/scratchoff/test/MainActivity.kt b/scratchoff-sample/src/main/java/com/jackpocket/scratchoff/test/MainActivity.kt
@@ -31,6 +31,7 @@ class MainActivity: AppCompatActivity(), ScratchoffController.ThresholdChangedLi
                 .setClearAnimationEnabled(true)
                 .setClearAnimationDuration(1, TimeUnit.SECONDS)
                 .setClearAnimationInterpolator(LinearInterpolator())
+                .setUsePreDrawForLayoutEnabled(true)
                 // .setTouchRadiusPx(25)
                 // .setThresholdAccuracyQuality(Quality.LOW)
                 // .setThresholdTargetRegionsProvider({

diff --git a/scratchoff/build.gradle b/scratchoff/build.gradle
@@ -11,7 +11,7 @@ android {
     buildToolsVersion = rootProject.ext.buildToolsVersion
 
     defaultConfig {
-        minSdkVersion 14
+        minSdkVersion 16
         targetSdkVersion rootProject.ext.targetSdkVersion
 
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"

diff --git a/scratchoff/src/main/java/com/jackpocket/scratchoff/ScratchableLayoutDrawer.java b/scratchoff/src/main/java/com/jackpocket/scratchoff/ScratchableLayoutDrawer.java
@@ -6,7 +6,6 @@
 import android.graphics.Paint;
 import android.graphics.PorterDuff;
 import android.graphics.PorterDuffXfermode;
-import android.os.Build;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.ViewTreeObserver;
@@ -59,6 +58,8 @@ public interface Delegate {
 
     private Long activeClearTag = 0L;
 
+    private boolean usePreDrawForLayoutEnabled = false;
+
     public ScratchableLayoutDrawer(Delegate delegate) {
         this.delegate = new WeakReference<>(delegate);
     }
@@ -120,7 +121,7 @@ protected void enqueueViewInitializationOnGlobalLayout(final View scratchView, f
             return;
         }
 
-        addGlobalLayoutRequest(
+        deferRunnableUntilViewIsLaidOut(
                 behindView,
                 new Runnable() {
                     public void run() {
@@ -141,7 +142,7 @@ protected void performLayoutDimensionMatching(final View scratchView, final View
 
     @SuppressWarnings("WeakerAccess")
     protected void enqueueScratchableViewInitializationOnGlobalLayout(final View scratchView) {
-        addGlobalLayoutRequest(
+        deferRunnableUntilViewIsLaidOut(
                 scratchView,
                 new Runnable() {
                     public void run() {
@@ -345,31 +346,49 @@ protected void hideAndMarkScratchableSurfaceViewCleared() {
         visibilityController.showChildren(view);
     }
 
-    private void addGlobalLayoutRequest(final View view, final Runnable runnable) {
-        view.getViewTreeObserver()
-                .addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
-                    public void onGlobalLayout() {
-                        if(runnable != null)
-                            runnable.run();
-
-                        removeGlobalLayoutListener(view, this);
-                    }
-                });
-
-        view.requestLayout();
-    }
-
-    @SuppressWarnings({"deprecation", "RedundantSuppression"})
-    private void removeGlobalLayoutListener(View view, ViewTreeObserver.OnGlobalLayoutListener listener) {
-        if (Build.VERSION.SDK_INT < 16) {
-            view.getViewTreeObserver()
-                    .removeGlobalOnLayoutListener(listener);
-
-            return;
+    private void deferRunnableUntilViewIsLaidOut(final View view, final Runnable runnable) {
+        if (usePreDrawForLayoutEnabled) {
+            view
+                    .getViewTreeObserver()
+                    .addOnPreDrawListener(
+                            new ViewTreeObserver.OnPreDrawListener() {
+                                @Override
+                                public boolean onPreDraw() {
+                                    if (runnable != null) {
+                                        runnable.run();
+                                    }
+
+
+                                    view
+                                            .getViewTreeObserver()
+                                            .removeOnPreDrawListener(this);
+
+                                    return true;
+                                }
+                            }
+                    );
+        }
+        else {
+            view
+                    .getViewTreeObserver()
+                    .addOnGlobalLayoutListener(
+                            new ViewTreeObserver.OnGlobalLayoutListener() {
+                                @Override
+                                public void onGlobalLayout() {
+                                    if (runnable != null) {
+                                        runnable.run();
+                                    }
+
+
+                                    view
+                                            .getViewTreeObserver()
+                                            .removeOnGlobalLayoutListener(this);
+                                }
+                            }
+                    );
         }
 
-        view.getViewTreeObserver()
-                .removeOnGlobalLayoutListener(listener);
+        view.requestLayout();
     }
 
     @SuppressWarnings("WeakerAccess")
@@ -385,4 +404,11 @@ public ScratchableLayoutDrawer setClearAnimationInterpolator(Interpolator clearA
 
         return this;
     }
+
+    @SuppressWarnings("WeakerAccess")
+    public ScratchableLayoutDrawer setUsePreDrawForLayoutEnabled(boolean usePreDrawForLayoutEnabled) {
+        this.usePreDrawForLayoutEnabled = usePreDrawForLayoutEnabled;
+
+        return this;
+    }
 }
diff --git a/scratchoff/src/main/java/com/jackpocket/scratchoff/ScratchoffController.java b/scratchoff/src/main/java/com/jackpocket/scratchoff/ScratchoffController.java
@@ -79,6 +79,8 @@ public interface ThresholdChangedListener {
     private final LinkedBlockingQueue<ScratchPathPoint> history = new LinkedBlockingQueue<ScratchPathPoint>();
     private boolean stateRestorationEnabled;
 
+    private boolean usePreDrawForLayoutEnabled = false;
+
     /**
      * Create a new {@link ScratchoffController} instance targeting a scratchable layout.
      */
@@ -151,7 +153,8 @@ public ScratchoffController attach() {
     protected ScratchableLayoutDrawer createLayoutDrawer() {
         return new ScratchableLayoutDrawer(this)
                 .setClearAnimationDurationMs(clearAnimationDurationMs)
-                .setClearAnimationInterpolator(clearAnimationInterpolator);
+                .setClearAnimationInterpolator(clearAnimationInterpolator)
+                .setUsePreDrawForLayoutEnabled(usePreDrawForLayoutEnabled);
     }
 
     protected ScratchoffThresholdProcessor createThresholdProcessor() {
@@ -467,6 +470,20 @@ public ScratchoffController setStateRestorationEnabled(boolean stateRestorationE
         return this;
     }
 
+    /**
+     * Set whether or not to use the new {@link android.view.ViewTreeObserver.OnPreDrawListener}
+     * code paths to determine the layout sizing, instead of the original
+     * {@link android.view.ViewTreeObserver.OnGlobalLayoutListener} implementation.
+     * This is in attempt to fix #19 caused by the width or height of the View being
+     * zero when attempting to create the scratchable {@link Bitmap} instances.
+     * The default for this value is false for the original (crashing) behavior.
+     */
+    public ScratchoffController setUsePreDrawForLayoutEnabled(boolean usePreDrawForLayoutEnabled) {
+        this.usePreDrawForLayoutEnabled = usePreDrawForLayoutEnabled;
+
+        return this;
+    }
+
     public View getViewBehind() {
         return behindView.get();
     }