Address a few warnings and suggestions for Android sample app

Summary: ^

Reviewed By: LukeDefeo

Differential Revision: D39575170

fbshipit-source-id: 8be293fe31521531e634132e4ca454da32aad73f

android/sample/src/main/java/com/facebook/flipper/sample/AnimationsActivity.java

@@ -26,66 +26,36 @@ public class AnimationsActivity extends Activity {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.activity_animations);
 
-    btnBlink = (Button) findViewById(R.id.btnBlink);
+    btnBlink = findViewById(R.id.btnBlink);
-    btnRotate = (Button) findViewById(R.id.btnRotate);
+    btnRotate = findViewById(R.id.btnRotate);
-    btnMove = (Button) findViewById(R.id.btnMove);
+    btnMove = findViewById(R.id.btnMove);
-    btnBounce = (Button) findViewById(R.id.btnBounce);
+    btnBounce = findViewById(R.id.btnBounce);
-    btnSequential = (Button) findViewById(R.id.btnSequential);
+    btnSequential = findViewById(R.id.btnSequential);
-    txtBlink = (TextView) findViewById(R.id.txt_blink);
+    txtBlink = findViewById(R.id.txt_blink);
-    txtRotate = (TextView) findViewById(R.id.txt_rotate);
+    txtRotate = findViewById(R.id.txt_rotate);
-    txtMove = (TextView) findViewById(R.id.txt_move);
+    txtMove = findViewById(R.id.txt_move);
-    txtBounce = (TextView) findViewById(R.id.txt_bounce);
+    txtBounce = findViewById(R.id.txt_bounce);
-    txtSeq = (TextView) findViewById(R.id.txt_seq);
+    txtSeq = findViewById(R.id.txt_seq);
 
     animBlink = AnimationUtils.loadAnimation(getApplicationContext(), R.anim.blink);
-    // blink
     btnBlink.setOnClickListener(
-        new View.OnClickListener() {
+        v -> {
-          @Override
-          public void onClick(View v) {
           txtBlink.setVisibility(View.VISIBLE);
           txtBlink.startAnimation(animBlink);
-          }
         });
 
     animRotate = AnimationUtils.loadAnimation(getApplicationContext(), R.anim.rotate);
 
-    // Rotate
+    btnRotate.setOnClickListener(v -> txtRotate.startAnimation(animRotate));
-    btnRotate.setOnClickListener(
-        new View.OnClickListener() {
-          @Override
-          public void onClick(View v) {
-            txtRotate.startAnimation(animRotate);
-          }
-        });
     animMove = AnimationUtils.loadAnimation(getApplicationContext(), R.anim.move);
-    // Move
+
-    btnMove.setOnClickListener(
+    btnMove.setOnClickListener(v -> txtMove.startAnimation(animMove));
-        new View.OnClickListener() {
-          @Override
-          public void onClick(View v) {
-            txtMove.startAnimation(animMove);
-          }
-        });
 
     animBounce = AnimationUtils.loadAnimation(getApplicationContext(), R.anim.bounce);
-    // Slide Down
-    btnBounce.setOnClickListener(
-        new View.OnClickListener() {
-          @Override
-          public void onClick(View v) {
-            txtBounce.startAnimation(animBounce);
-          }
-        });
-    animSequential = AnimationUtils.loadAnimation(getApplicationContext(), R.anim.sequential);
-    // Sequential
-    btnSequential.setOnClickListener(
-        new View.OnClickListener() {
-          @Override
-          public void onClick(View v) {
 
-            txtSeq.startAnimation(animSequential);
+    btnBounce.setOnClickListener(v -> txtBounce.startAnimation(animBounce));
-          }
+    animSequential = AnimationUtils.loadAnimation(getApplicationContext(), R.anim.sequential);
-        });
+
+    btnSequential.setOnClickListener(v -> txtSeq.startAnimation(animSequential));
   }
 }

android/sample/src/main/java/com/facebook/flipper/sample/ButtonsActivity.java

@@ -26,11 +26,11 @@ public class ButtonsActivity extends FragmentActivity {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.activity_buttons);
 
-    text = (TextView) findViewById(R.id.count);
+    text = findViewById(R.id.count);
 
-    button = (Button) findViewById(com.facebook.flipper.sample.R.id.btn_inc);
+    button = findViewById(com.facebook.flipper.sample.R.id.btn_inc);
-    dialogOld = (Button) findViewById(R.id.dialog_old_api);
+    dialogOld = findViewById(R.id.dialog_old_api);
-    dialogFragment = (Button) findViewById(R.id.dialog_fragment);
+    dialogFragment = findViewById(R.id.dialog_fragment);
     button.setOnClickListener(view -> ButtonsActivity.this.text.setText(String.valueOf(++count)));
 
     dialogFragment.setOnClickListener(

android/sample/src/main/java/com/facebook/flipper/sample/FlipperSampleApplication.java

@@ -24,6 +24,8 @@ public class FlipperSampleApplication extends Application {
     Fresco.initialize(this);
 
     final FlipperClient client = AndroidFlipperClient.getInstance(this);
+    assert client != null;
+
     final FlipperInitializer.IntializationResult initializationResult =
         FlipperInitializer.initFlipperPlugins(this, client);
 

android/sample/src/main/java/com/facebook/flipper/sample/FragmentTestFragment.java

@@ -15,39 +15,39 @@ import android.widget.TextView;
 import androidx.fragment.app.Fragment;
 
 public class FragmentTestFragment extends Fragment {
-  View mView;
+  View view;
-  int mTicker;
+  int ticker;
 
   public FragmentTestFragment() {
-    mTicker = 0;
+    ticker = 0;
   }
 
   private void updateTicker() {
     try {
-      ViewGroup viewGroup = (ViewGroup) mView;
+      ViewGroup viewGroup = (ViewGroup) view;
       TextView textView = (TextView) viewGroup.getChildAt(1);
-      String text = String.valueOf(mTicker++);
+      String text = String.valueOf(ticker++);
 
       textView.setText(text);
     } finally {
       // 100% guarantee that this always happens, even if
       // your update method throws an exception
-      mView.postDelayed(
+      view.postDelayed(
           new Runnable() {
             @Override
             public void run() {
               updateTicker();
             }
           },
-          10000);
+          1000);
     }
   }
 
   @Override
   public View onCreateView(
       LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
-    mView = inflater.inflate(R.layout.fragment_test, container, false);
+    view = inflater.inflate(R.layout.fragment_test, container, false);
-    mView.postDelayed(
+    view.postDelayed(
         new Runnable() {
           @Override
           public void run() {
@@ -56,6 +56,6 @@ public class FragmentTestFragment extends Fragment {
         },
         1000);
 
-    return mView;
+    return view;
   }
 }

android/sample/src/main/java/com/facebook/flipper/sample/ListActivity.java

@@ -24,7 +24,7 @@ public class ListActivity extends Activity {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.activity_list);
 
-    listView = (ListView) findViewById(R.id.list);
+    listView = findViewById(R.id.list);
 
     list = new ArrayList<>();
     list.add("Apple");
@@ -33,7 +33,7 @@ public class ListActivity extends Activity {
     list.add("Orange");
     list.add("Lychee");
     list.add("Guava");
-    list.add("Peech");
+    list.add("Peach");
     list.add("Melon");
     list.add("Watermelon");
     list.add("Papaya");

android/sample/src/main/java/com/facebook/flipper/sample/MainActivity.java

@@ -29,7 +29,9 @@ public class MainActivity extends AppCompatActivity {
     final FlipperClient client = AndroidFlipperClient.getInstanceIfInitialized();
     if (client != null) {
       final ExampleFlipperPlugin samplePlugin = client.getPluginByClass(ExampleFlipperPlugin.class);
+      if (samplePlugin != null) {
         samplePlugin.setActivity(this);
       }
     }
   }
+}

android/sample/src/main/java/com/facebook/flipper/sample/TestDialogFragment.java

@@ -9,10 +9,12 @@ package com.facebook.flipper.sample;
 
 import android.app.Dialog;
 import android.os.Bundle;
+import androidx.annotation.NonNull;
 import androidx.appcompat.app.AlertDialog;
 import androidx.fragment.app.DialogFragment;
 
 public class TestDialogFragment extends DialogFragment {
+  @NonNull
   @Override
   public Dialog onCreateDialog(Bundle savedInstanceState) {
     // Use the Builder class for convenient dialog construction