Change visibility of FlutterView when onStop/onStart (flutter/engine#30897)

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

@@ -74,7 +74,7 @@ import java.util.Arrays;
   // to this FlutterActivityAndFragmentDelegate.
   @NonNull private Host host;
   @Nullable private FlutterEngine flutterEngine;
-  @Nullable private FlutterView flutterView;
+  @VisibleForTesting @Nullable FlutterView flutterView;
   @Nullable private PlatformPlugin platformPlugin;
   @VisibleForTesting @Nullable OnPreDrawListener activePreDrawListener;
   private boolean isFlutterEngineFromHost;
@@ -388,6 +388,12 @@ import java.util.Arrays;
     Log.v(TAG, "onStart()");
     ensureAlive();
     doInitialFlutterViewRun();
+    // This is a workaround for a bug on some OnePlus phones. The visibility of the application
+    // window is still true after locking the screen on some OnePlus phones, and shows a black
+    // screen when unlocked. We can work around this by changing the visibility of FlutterView in
+    // onStart and onStop.
+    // See https://github.com/flutter/flutter/issues/93276
+    flutterView.setVisibility(View.VISIBLE);
   }
 
   /**
@@ -574,6 +580,12 @@ import java.util.Arrays;
     Log.v(TAG, "onStop()");
     ensureAlive();
     flutterEngine.getLifecycleChannel().appIsPaused();
+    // This is a workaround for a bug on some OnePlus phones. The visibility of the application
+    // window is still true after locking the screen on some OnePlus phones, and shows a black
+    // screen when unlocked. We can work around this by changing the visibility of FlutterView in
+    // onStart and onStop.
+    // See https://github.com/flutter/flutter/issues/93276
+    flutterView.setVisibility(View.GONE);
   }
 
   /**

engine/src/flutter/shell/platform/android/test/io/flutter/embedding/android/FlutterActivityAndFragmentDelegateTest.java

@@ -21,6 +21,7 @@ import android.content.Intent;
 import android.graphics.Color;
 import android.graphics.drawable.ColorDrawable;
 import android.net.Uri;
+import android.view.View;
 import androidx.annotation.NonNull;
 import androidx.lifecycle.Lifecycle;
 import io.flutter.FlutterInjector;
@@ -484,6 +485,7 @@ public class FlutterActivityAndFragmentDelegateTest {
     // --- Execute the behavior under test ---
     // The FlutterEngine is set up in onAttach().
     delegate.onAttach(RuntimeEnvironment.application);
+    delegate.onCreateView(null, null, null, 0, true);
     // Emulate app start.
     delegate.onStart();
 
@@ -511,6 +513,7 @@ public class FlutterActivityAndFragmentDelegateTest {
     // --- Execute the behavior under test ---
     // The FlutterEngine is set up in onAttach().
     delegate.onAttach(RuntimeEnvironment.application);
+    delegate.onCreateView(null, null, null, 0, true);
     // Emulate app start.
     delegate.onStart();
 
@@ -538,6 +541,7 @@ public class FlutterActivityAndFragmentDelegateTest {
     // --- Execute the behavior under test ---
     // The FlutterEngine is set up in onAttach().
     delegate.onAttach(RuntimeEnvironment.application);
+    delegate.onCreateView(null, null, null, 0, true);
     // Emulate app start.
     delegate.onStart();
 
@@ -565,6 +569,7 @@ public class FlutterActivityAndFragmentDelegateTest {
     // --- Execute the behavior under test ---
     // The FlutterEngine is set up in onAttach().
     delegate.onAttach(RuntimeEnvironment.application);
+    delegate.onCreateView(null, null, null, 0, true);
     // Emulate app start.
     delegate.onStart();
 
@@ -590,6 +595,7 @@ public class FlutterActivityAndFragmentDelegateTest {
     // --- Execute the behavior under test ---
     // The FlutterEngine is set up in onAttach().
     delegate.onAttach(RuntimeEnvironment.application);
+    delegate.onCreateView(null, null, null, 0, true);
     // Emulate app start.
     delegate.onStart();
 
@@ -978,6 +984,26 @@ public class FlutterActivityAndFragmentDelegateTest {
         });
   }
 
+  @Test
+  public void itChangesFlutterViewVisibilityWhenOnStartAndOnStop() {
+    // ---- Test setup ----
+    // Create the real object that we're testing.
+    FlutterActivityAndFragmentDelegate delegate = new FlutterActivityAndFragmentDelegate(mockHost);
+
+    // --- Execute the behavior under test ---
+    delegate.onAttach(RuntimeEnvironment.application);
+    delegate.onCreateView(null, null, null, 0, true);
+    delegate.onStart();
+    // Verify that the flutterView is visible.
+    assertEquals(View.VISIBLE, delegate.flutterView.getVisibility());
+    delegate.onStop();
+    // Verify that the flutterView is not visible.
+    assertEquals(View.GONE, delegate.flutterView.getVisibility());
+    delegate.onStart();
+    // Verify that the flutterView is visible.
+    assertEquals(View.VISIBLE, delegate.flutterView.getVisibility());
+  }
+
   @Test
   public void itDoesNotDelayTheFirstDrawWhenRequestedAndWithAProvidedSplashScreen() {
     when(mockHost.provideSplashScreen())