Add some null checks

Author: gspencergoog

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

@@ -581,7 +581,7 @@ public boolean onPreDraw() {
   void onResume() {
     Log.v(TAG, "onResume()");
     ensureAlive();
-    if (host.shouldDispatchAppLifecycleState()) {
+    if (host.shouldDispatchAppLifecycleState() && flutterEngine != null) {
       // This may notify in a redundant fashion with onWindowFocusChanged. The
       // lifecycle channel will deduplicate, but since the Android documentation
       // says that we shouldn't rely on any particular order between lifecycle
@@ -633,7 +633,7 @@ void updateSystemUiOverlays() {
   void onPause() {
     Log.v(TAG, "onPause()");
     ensureAlive();
-    if (host.shouldDispatchAppLifecycleState()) {
+    if (host.shouldDispatchAppLifecycleState() && flutterEngine != null) {
       // This may notify in a redundant fashion with onWindowFocusChanged. The
       // lifecycle channel will deduplicate, but since the Android documentation
       // says that we shouldn't rely on any particular order between lifecycle
@@ -660,7 +660,7 @@ void onStop() {
     Log.v(TAG, "onStop()");
     ensureAlive();
 
-    if (host.shouldDispatchAppLifecycleState()) {
+    if (host.shouldDispatchAppLifecycleState() && flutterEngine != null) {
       flutterEngine.getLifecycleChannel().appIsPaused();
     }
 
@@ -766,7 +766,7 @@ void onDetach() {
       platformPlugin = null;
     }
 
-    if (host.shouldDispatchAppLifecycleState()) {
+    if (host.shouldDispatchAppLifecycleState() && flutterEngine != null) {
       flutterEngine.getLifecycleChannel().appIsDetached();
     }
 
@@ -909,8 +909,8 @@ void onUserLeaveHint() {
    */
   void onWindowFocusChanged(boolean hasFocus) {
     ensureAlive();
-    Log.w(TAG, "Received onWindowFocusChanged: " + (hasFocus ? "true" : "false"));
-    if (host.shouldDispatchAppLifecycleState()) {
+    Log.v(TAG, "Received onWindowFocusChanged: " + (hasFocus ? "true" : "false"));
+    if (host.shouldDispatchAppLifecycleState() && flutterEngine != null) {
       // This may notify in a redundant fashion with onResume and onPause. The
       // lifecycle channel will deduplicate, but since the Android documentation
       // says that we shouldn't rely on any particular order between lifecycle

shell/platform/android/io/flutter/embedding/engine/systemchannels/LifecycleChannel.java

@@ -38,7 +38,6 @@ private void sendState(String state) {
     if (lastState == state) {
       return;
     }
-    Log.e(TAG, "Sending " + state + " message.");
     lastState = state;
     channel.send(state);
   }