Merge changes I23901fe7,I0cde537b

* changes:
  Added functionality of recording and storing videos to the Camera2Sample application
  Added functionality of taking and storing pictures to the Camera2Sample application

Author: jbolinger

Camera2Sample/app/src/main/java/com/example/glass/camera2sample/AnimationManager.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.glass.camera2sample;
+
+import android.content.Context;
+import android.view.animation.AnimationUtils;
+import android.widget.ImageView;
+
+/**
+ * Helper class responsible for performing animations on the camera shutter during taking pictures
+ * and changing shutter icon to the camera icon and vice versa, depends on the current camera mode.
+ */
+public class AnimationManager {
+
+  /**
+   * Minimum alpha for animations.
+   */
+  private static final float ALPHA_MIN = 0F;
+
+  /**
+   * Maximum alpha for animations.
+   */
+  private static final float ALPHA_MAX = 0.8F;
+
+  /**
+   * Animates shutter action on the given {@link ImageView}.
+   */
+  public static void animateShutter(Context context, ImageView imageView) {
+    imageView.startAnimation(AnimationUtils.loadAnimation(context, R.anim.alpha));
+  }
+
+  /**
+   * Changes given {@link ImageView} image resource by the animation using alpha.
+   */
+  public static void changeImageByAlpha(final ImageView imageView, final int resource) {
+    imageView.animate().alpha(ALPHA_MIN).withEndAction(new Runnable() {
+      @Override
+      public void run() {
+        imageView.setImageResource(resource);
+        imageView.animate().alpha(ALPHA_MAX);
+      }
+    });
+  }
+}

Camera2Sample/app/src/main/java/com/example/glass/camera2sample/BackgroundThreadHandler.java

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+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.glass.camera2sample;
+
+import android.os.Handler;
+import android.os.HandlerThread;
+import android.util.Log;
+
+/**
+ * Helper class responsible for handling the background thread.
+ */
+public class BackgroundThreadHandler {
+
+  private static final String TAG = BackgroundThreadHandler.class.getSimpleName();
+
+  private final String threadName;
+  private HandlerThread handlerThread;
+  private Handler handler;
+
+  /**
+   * Constructor of this class needs a background thread name to be passed by an argument.
+   *
+   * @param threadName of the background thread to handle.
+   */
+  public BackgroundThreadHandler(String threadName) {
+    this.threadName = threadName;
+  }
+
+  /**
+   * Starts a background thread and its {@link Handler}.
+   */
+  public void startBackgroundThread() {
+    Log.d(TAG, "Starting thread " + threadName);
+    handlerThread = new HandlerThread(threadName);
+    handlerThread.start();
+    handler = new Handler(handlerThread.getLooper());
+  }
+
+  /**
+   * Stops the background thread and its {@link Handler}.
+   */
+  public void stopBackgroundThread() {
+    Log.d(TAG, "Stopping thread " + threadName);
+    handlerThread.quitSafely();
+    try {
+      handlerThread.join();
+      handlerThread = null;
+      handler = null;
+    } catch (InterruptedException e) {
+      Log.e(TAG, "Stopping thread " + threadName + " failed", e);
+    }
+  }
+
+  /**
+   * Returns {@link Handler} using the background thread.
+   */
+  public Handler getHandler() {
+    return handler;
+  }
+}