Fix NPE in PlatformPlugin.getClipboardData() (#21189)

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

@@ -280,6 +280,9 @@ public class PlatformPlugin {
   private CharSequence getClipboardData(PlatformChannel.ClipboardContentFormat format) {
     ClipboardManager clipboard =
         (ClipboardManager) activity.getSystemService(Context.CLIPBOARD_SERVICE);
+
+    if (!clipboard.hasPrimaryClip()) return null;
+
     ClipData clip = clipboard.getPrimaryClip();
     if (clip == null) return null;
 

shell/platform/android/test/io/flutter/plugin/platform/PlatformPluginTest.java

 package io.flutter.plugin.platform;
 
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
 import android.app.Activity;
+import android.content.ClipData;
 import android.content.ClipboardManager;
 import android.content.Context;
 import android.view.View;
 import android.view.Window;
 import io.flutter.embedding.engine.systemchannels.PlatformChannel;
+import io.flutter.embedding.engine.systemchannels.PlatformChannel.ClipboardContentFormat;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.robolectric.RobolectricTestRunner;
@@ -38,6 +42,27 @@ public class PlatformPluginTest {
     platformPlugin.vibrateHapticFeedback(PlatformChannel.HapticFeedbackType.SELECTION_CLICK);
   }
 
+  @Test
+  public void platformPlugin_getClipboardData() {
+    ClipboardManager clipboardManager =
+        RuntimeEnvironment.application.getSystemService(ClipboardManager.class);
+
+    View fakeDecorView = mock(View.class);
+    Window fakeWindow = mock(Window.class);
+    when(fakeWindow.getDecorView()).thenReturn(fakeDecorView);
+    Activity fakeActivity = mock(Activity.class);
+    when(fakeActivity.getWindow()).thenReturn(fakeWindow);
+    when(fakeActivity.getSystemService(Context.CLIPBOARD_SERVICE)).thenReturn(clipboardManager);
+    PlatformChannel fakePlatformChannel = mock(PlatformChannel.class);
+    PlatformPlugin platformPlugin = new PlatformPlugin(fakeActivity, fakePlatformChannel);
+
+    ClipboardContentFormat clipboardFormat = ClipboardContentFormat.PLAIN_TEXT;
+    assertNull(platformPlugin.mPlatformMessageHandler.getClipboardData(clipboardFormat));
+    ClipData clip = ClipData.newPlainText("label", "Text");
+    clipboardManager.setPrimaryClip(clip);
+    assertNotNull(platformPlugin.mPlatformMessageHandler.getClipboardData(clipboardFormat));
+  }
+
   @Test
   public void platformPlugin_hasStrings() {
     ClipboardManager clipboardManager =
@@ -52,10 +77,12 @@ public class PlatformPluginTest {
     PlatformChannel fakePlatformChannel = mock(PlatformChannel.class);
     PlatformPlugin platformPlugin = new PlatformPlugin(fakeActivity, fakePlatformChannel);
 
-    clipboardManager.setText("iamastring");
+    ClipData clip = ClipData.newPlainText("label", "Text");
+    clipboardManager.setPrimaryClip(clip);
     assertTrue(platformPlugin.mPlatformMessageHandler.clipboardHasStrings());
 
-    clipboardManager.setText("");
+    clip = ClipData.newPlainText("", "");
+    clipboardManager.setPrimaryClip(clip);
     assertFalse(platformPlugin.mPlatformMessageHandler.clipboardHasStrings());
   }
 }