[android] Fixes 'drawRenderNode called on a context with no surface' crash

When a memory pressure warning is received and the level equal {@code
ComponentCallbacks2.TRIM_MEMORY_COMPLETE}, the Android system release the underlying
surface. If we continue to use the surface (e.g., call lockHardwareCanvas), a crash
occurs, and we found that this crash appeared on Android8.1 and above system.

Here our workaround is to recreate the surface before using it.

Fixes flutter/flutter#103870

Author: 0xZOne

shell/platform/android/io/flutter/embedding/android/FlutterActivityAndFragmentDelegate.java

@@ -4,6 +4,7 @@
 
 package io.flutter.embedding.android;
 
+import static android.content.ComponentCallbacks2.TRIM_MEMORY_COMPLETE;
 import static android.content.ComponentCallbacks2.TRIM_MEMORY_RUNNING_LOW;
 import static io.flutter.embedding.android.FlutterActivityLaunchConfigs.DEFAULT_INITIAL_ROUTE;
 
@@ -844,6 +845,7 @@ void onTrimMemory(int level) {
         flutterEngine.getDartExecutor().notifyLowMemoryWarning();
         flutterEngine.getSystemChannel().sendMemoryPressureWarning();
       }
+      flutterEngine.getRenderer().onTrimMemory(level);
     }
   }
 
@@ -860,6 +862,7 @@ void onLowMemory() {
     ensureAlive();
     flutterEngine.getDartExecutor().notifyLowMemoryWarning();
     flutterEngine.getSystemChannel().sendMemoryPressureWarning();
+    flutterEngine.getRenderer().onTrimMemory(TRIM_MEMORY_COMPLETE);
   }
 
   /**

shell/platform/android/io/flutter/embedding/engine/renderer/FlutterRenderer.java

@@ -19,6 +19,8 @@
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Set;
+import java.util.concurrent.CopyOnWriteArraySet;
 import java.util.concurrent.atomic.AtomicLong;
 
 /**
@@ -44,6 +46,10 @@ public class FlutterRenderer implements TextureRegistry {
   private boolean isDisplayingFlutterUi = false;
   private Handler handler = new Handler();
 
+  @NonNull
+  private final Set<TextureRegistry.OnLowMemoryListener> onLowMemoryListeners =
+      new CopyOnWriteArraySet<>();
+
   @NonNull
   private final FlutterUiDisplayListener flutterUiDisplayListener =
       new FlutterUiDisplayListener() {
@@ -91,6 +97,19 @@ public void removeIsDisplayingFlutterUiListener(@NonNull FlutterUiDisplayListene
     flutterJNI.removeIsDisplayingFlutterUiListener(listener);
   }
 
+  /** Adds a listener that is invoked when a memory pressure warning was forward. */
+  public void addOnLowMemoryListener(@NonNull OnLowMemoryListener listener) {
+    onLowMemoryListeners.add(listener);
+  }
+
+  /**
+   * Removes a {@link OnLowMemoryListener} that was added with {@link
+   * #addOnLowMemoryListener(OnLowMemoryListener)}.
+   */
+  public void removeOnLowMemoryListener(@NonNull OnLowMemoryListener listener) {
+    onLowMemoryListeners.remove(listener);
+  }
+
   // ------ START TextureRegistry IMPLEMENTATION -----
   /**
    * Creates and returns a new {@link SurfaceTexture} managed by the Flutter engine that is also
@@ -114,20 +133,30 @@ public SurfaceTextureEntry registerSurfaceTexture(@NonNull SurfaceTexture surfac
         new SurfaceTextureRegistryEntry(nextTextureId.getAndIncrement(), surfaceTexture);
     Log.v(TAG, "New SurfaceTexture ID: " + entry.id());
     registerTexture(entry.id(), entry.textureWrapper());
+    addOnLowMemoryListener(entry);
     return entry;
   }
 
-  final class SurfaceTextureRegistryEntry implements TextureRegistry.SurfaceTextureEntry {
+  @Override
+  public void onTrimMemory(int level) {
+    for (TextureRegistry.OnLowMemoryListener listener : onLowMemoryListeners) {
+      listener.onLowMemory(level);
+    }
+  }
+
+  final class SurfaceTextureRegistryEntry
+      implements TextureRegistry.SurfaceTextureEntry, TextureRegistry.OnLowMemoryListener {
     private final long id;
     @NonNull private final SurfaceTextureWrapper textureWrapper;
     private boolean released;
-    @Nullable private OnFrameConsumedListener listener;
+    @Nullable private OnLowMemoryListener lowMemoryListener;
+    @Nullable private OnFrameConsumedListener frameConsumedListener;
     private final Runnable onFrameConsumed =
         new Runnable() {
           @Override
           public void run() {
-            if (listener != null) {
-              listener.onFrameConsumed();
+            if (frameConsumedListener != null) {
+              frameConsumedListener.onFrameConsumed();
             }
           }
         };
@@ -151,6 +180,13 @@ public void run() {
       }
     }
 
+    @Override
+    public void onLowMemory(int level) {
+      if (lowMemoryListener != null) {
+        lowMemoryListener.onLowMemory(level);
+      }
+    }
+
     private SurfaceTexture.OnFrameAvailableListener onFrameListener =
         new SurfaceTexture.OnFrameAvailableListener() {
           @Override
@@ -166,6 +202,10 @@ public void onFrameAvailable(@NonNull SurfaceTexture texture) {
           }
         };
 
+    private void removeListener() {
+      removeOnLowMemoryListener(this);
+    }
+
     @NonNull
     public SurfaceTextureWrapper textureWrapper() {
       return textureWrapper;
@@ -190,6 +230,7 @@ public void release() {
       Log.v(TAG, "Releasing a SurfaceTexture (" + id + ").");
       textureWrapper.release();
       unregisterTexture(id);
+      removeListener();
       released = true;
     }
 
@@ -200,34 +241,31 @@ protected void finalize() throws Throwable {
           return;
         }
 
-        handler.post(new SurfaceTextureFinalizerRunnable(id, flutterJNI));
+        handler.post(
+            new Runnable() {
+              @Override
+              public void run() {
+                if (!flutterJNI.isAttached()) {
+                  return;
+                }
+                Log.v(TAG, "Releasing a SurfaceTexture (" + id + ").");
+                unregisterTexture(id);
+                removeListener();
+              }
+            });
       } finally {
         super.finalize();
       }
     }
 
     @Override
     public void setOnFrameConsumedListener(@Nullable OnFrameConsumedListener listener) {
-      this.listener = listener;
-    }
-  }
-
-  static final class SurfaceTextureFinalizerRunnable implements Runnable {
-    private final long id;
-    private final FlutterJNI flutterJNI;
-
-    SurfaceTextureFinalizerRunnable(long id, @NonNull FlutterJNI flutterJNI) {
-      this.id = id;
-      this.flutterJNI = flutterJNI;
+      frameConsumedListener = listener;
     }
 
     @Override
-    public void run() {
-      if (!flutterJNI.isAttached()) {
-        return;
-      }
-      Log.v(TAG, "Releasing a SurfaceTexture (" + id + ").");
-      flutterJNI.unregisterTexture(id);
+    public void setOnLowMemoryListener(@Nullable OnLowMemoryListener listener) {
+      lowMemoryListener = listener;
     }
   }
   // ------ END TextureRegistry IMPLEMENTATION ----

shell/platform/android/io/flutter/plugin/platform/PlatformViewWrapper.java

@@ -4,6 +4,8 @@
 
 package io.flutter.plugin.platform;
 
+import static android.content.ComponentCallbacks2.TRIM_MEMORY_COMPLETE;
+
 import android.annotation.SuppressLint;
 import android.annotation.TargetApi;
 import android.content.Context;
@@ -56,7 +58,7 @@ class PlatformViewWrapper extends FrameLayout {
   @Nullable @VisibleForTesting ViewTreeObserver.OnGlobalFocusChangeListener activeFocusListener;
   private final AtomicLong pendingFramesCount = new AtomicLong(0L);
 
-  private final TextureRegistry.OnFrameConsumedListener listener =
+  private final TextureRegistry.OnFrameConsumedListener frameConsumedListener =
       new TextureRegistry.OnFrameConsumedListener() {
         @Override
         public void onFrameConsumed() {
@@ -66,12 +68,39 @@ public void onFrameConsumed() {
         }
       };
 
+  private boolean shouldRecreateSurfaceForLowMemory = false;
+  private final TextureRegistry.OnLowMemoryListener lowMemoryListener =
+      new TextureRegistry.OnLowMemoryListener() {
+        @Override
+        public void onLowMemory(int level) {
+          // When a memory pressure warning is received and the level equal {@code
+          // ComponentCallbacks2.TRIM_MEMORY_COMPLETE}, the Android system release the underlying
+          // surface. If we continue to use the surface (e.g., call lockHardwareCanvas), a crash
+          // occurs, and we found that this crash appeared on Android8.1 and above system.
+          //
+          // Here our workaround is to recreate the surface before using it.
+          if (level == TRIM_MEMORY_COMPLETE && Build.VERSION.SDK_INT >= 27) {
+            shouldRecreateSurfaceForLowMemory = true;
+          }
+        }
+      };
+
   private void onFrameProduced() {
     if (Build.VERSION.SDK_INT == 29) {
       pendingFramesCount.incrementAndGet();
     }
   }
 
+  private void recreateSurfaceIfNeeded() {
+    if (shouldRecreateSurfaceForLowMemory) {
+      if (surface != null) {
+        surface.release();
+      }
+      surface = createSurface(tx);
+      shouldRecreateSurfaceForLowMemory = false;
+    }
+  }
+
   private boolean shouldDrawToSurfaceNow() {
     if (Build.VERSION.SDK_INT == 29) {
       return pendingFramesCount.get() <= 0L;
@@ -87,7 +116,8 @@ public PlatformViewWrapper(@NonNull Context context) {
   public PlatformViewWrapper(
       @NonNull Context context, @NonNull TextureRegistry.SurfaceTextureEntry textureEntry) {
     this(context);
-    textureEntry.setOnFrameConsumedListener(listener);
+    textureEntry.setOnFrameConsumedListener(frameConsumedListener);
+    textureEntry.setOnLowMemoryListener(lowMemoryListener);
     setTexture(textureEntry.surfaceTexture());
   }
 
@@ -249,6 +279,10 @@ public void draw(Canvas canvas) {
       // If there are still frames that are not consumed, we will draw them next time.
       invalidate();
     } else {
+      // We try to recreate the surface before using it to avoid the crash:
+      // https://github.com/flutter/flutter/issues/103870
+      recreateSurfaceIfNeeded();
+
       // Override the canvas that this subtree of views will use to draw.
       final Canvas surfaceCanvas = surface.lockHardwareCanvas();
       try {

shell/platform/android/io/flutter/view/TextureRegistry.java

@@ -31,6 +31,13 @@ public interface TextureRegistry {
   @NonNull
   SurfaceTextureEntry registerSurfaceTexture(@NonNull SurfaceTexture surfaceTexture);
 
+  /**
+   * Callback invoked when memory is low.
+   *
+   * <p>Invoke this from {@link android.app.Activity#onTrimMemory(int)}.
+   */
+  default void onTrimMemory(int level) {}
+
   /** A registry entry for a managed SurfaceTexture. */
   interface SurfaceTextureEntry {
     /** @return The managed SurfaceTexture. */
@@ -45,6 +52,9 @@ interface SurfaceTextureEntry {
 
     /** Set a listener that will be notified when the most recent image has been consumed. */
     default void setOnFrameConsumedListener(@Nullable OnFrameConsumedListener listener) {}
+
+    /** Set a listener that will be notified when a memory pressure warning was forward. */
+    default void setOnLowMemoryListener(@Nullable OnLowMemoryListener listener) {}
   }
 
   /** Listener invoked when the most recent image has been consumed. */
@@ -55,4 +65,10 @@ interface OnFrameConsumedListener {
      */
     void onFrameConsumed();
   }
+
+  /** Listener invoked when a memory pressure warning was forward. */
+  interface OnLowMemoryListener {
+    /** This method will be invoked when a memory pressure warning was forward. */
+    void onLowMemory(int level);
+  }
 }

shell/platform/android/test/io/flutter/embedding/engine/renderer/FlutterRendererTest.java

@@ -1,5 +1,6 @@
 package io.flutter.embedding.engine.renderer;
 
+import static android.content.ComponentCallbacks2.TRIM_MEMORY_COMPLETE;
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 import static org.mockito.ArgumentMatchers.anyFloat;
@@ -339,4 +340,30 @@ public void onFrameConsumed() {
     // Verify behavior under test.
     assertEquals(1, invocationCount.get());
   }
+
+  @Test
+  public void itNotifySurfaceTextureEntryWhenMemoryPressureWarning() {
+    // Setup the test.
+    FlutterRenderer flutterRenderer = new FlutterRenderer(fakeFlutterJNI);
+
+    AtomicInteger invocationCount = new AtomicInteger(0);
+    final TextureRegistry.OnLowMemoryListener listener =
+        new TextureRegistry.OnLowMemoryListener() {
+          @Override
+          public void onLowMemory(int level) {
+            invocationCount.incrementAndGet();
+          }
+        };
+
+    FlutterRenderer.SurfaceTextureRegistryEntry entry =
+        (FlutterRenderer.SurfaceTextureRegistryEntry) flutterRenderer.createSurfaceTexture();
+    entry.setOnLowMemoryListener(listener);
+    flutterRenderer.addOnLowMemoryListener(entry);
+
+    // Execute the behavior under test.
+    flutterRenderer.onTrimMemory(TRIM_MEMORY_COMPLETE);
+
+    // Verify behavior under test.
+    assertEquals(1, invocationCount.get());
+  }
 }