Update PlatformPluginTest.java & PlatformPlugin.java

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

@@ -14,6 +14,7 @@ import android.view.HapticFeedbackConstants;
 import android.view.SoundEffectConstants;
 import android.view.View;
 import android.view.Window;
+import android.view.WindowManager;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.VisibleForTesting;
@@ -268,9 +269,11 @@ public class PlatformPlugin {
         window.setStatusBarColor(systemChromeStyle.statusBarColor);
       }
     }
-    if (systemChromeStyle.systemNavigationBarDividerColor != null) {
-      // Not available until Android P.
-      // window.setNavigationBarDividerColor(systemNavigationBarDividerColor);
+    if (systemChromeStyle.systemNavigationBarDividerColor != null
+        && Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
+      window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
+      window.clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);
+      window.setNavigationBarDividerColor(systemChromeStyle.systemNavigationBarDividerColor);
     }
     view.setSystemUiVisibility(flags);
     currentTheme = systemChromeStyle;

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

@@ -2,6 +2,7 @@ package io.flutter.plugin.platform;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
@@ -18,7 +19,9 @@ import android.net.Uri;
 import android.view.View;
 import android.view.Window;
 import io.flutter.embedding.engine.systemchannels.PlatformChannel;
+import io.flutter.embedding.engine.systemchannels.PlatformChannel.Brightness;
 import io.flutter.embedding.engine.systemchannels.PlatformChannel.ClipboardContentFormat;
+import io.flutter.embedding.engine.systemchannels.PlatformChannel.SystemChromeStyle;
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.io.InputStream;
@@ -110,4 +113,23 @@ public class PlatformPluginTest {
     clipboardManager.setPrimaryClip(clip);
     assertFalse(platformPlugin.mPlatformMessageHandler.clipboardHasStrings());
   }
+
+  @Config(sdk = 29)
+  @Test
+  public void setNavigationBarDividerColor() {
+    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);
+    PlatformChannel fakePlatformChannel = mock(PlatformChannel.class);
+    PlatformPlugin platformPlugin = new PlatformPlugin(fakeActivity, fakePlatformChannel);
+    SystemChromeStyle style =
+        new SystemChromeStyle(0XFF000000, null, 0XFFC70039, null, 0XFF006DB3);
+    platformPlugin.mPlatformMessageHandler.setSystemUiOverlayStyle(style);
+
+    assertEquals(0XFF006DB3, fakeActivity.getWindow().getNavigationBarDividerColor());
+    assertEquals(0XFFC70039, fakeActivity.getWindow().getStatusBarColor());
+    assertEquals(0XFF000000, fakeActivity.getWindow().getNavigationBarColor());
+  }
 }