content: /*
   * Copyright 2015 Google Inc. All Rights Reserved.
   *
   * 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.agenthun.readingroutine.utils;
  
  import android.annotation.TargetApi;
  import android.os.Build;
  import android.support.annotation.Nullable;
  import android.support.v4.app.SharedElementCallback;
  import android.util.Log;
  import android.util.TypedValue;
  import android.view.View;
  import android.widget.TextView;
  
  import java.util.List;
  
  /**
   * This callback allows a shared TextView to resize text and start padding during transition.
   */
  @TargetApi(Build.VERSION_CODES.LOLLIPOP)
  public class TextSharedElementCallback extends SharedElementCallback {
  
      private final int mInitialPaddingStart;
      private final float mInitialTextSize;
      private float mTargetViewTextSize;
      private int mTargetViewPaddingStart;
      private static final String TAG = "TextResize";
  
      public TextSharedElementCallback(float initialTextSize, int initialPaddingStart) {
          mInitialTextSize = initialTextSize;
          mInitialPaddingStart = initialPaddingStart;
      }
  
      @Override
      public void onSharedElementStart(List<String> sharedElementNames, List<View> sharedElements,
                                       List<View> sharedElementSnapshots) {
          TextView targetView = getTextView(sharedElements);
          if (targetView == null) {
              Log.w(TAG, "onSharedElementStart: No shared TextView, skipping.");
              return;
          }
          mTargetViewTextSize = targetView.getTextSize();
          mTargetViewPaddingStart = targetView.getPaddingStart();
          // Setup the TextView's start values.
          targetView.setTextSize(TypedValue.COMPLEX_UNIT_PX, mInitialTextSize);
          ViewUtils.setPaddingStart(targetView, mInitialPaddingStart);
      }
  
      @Override
      public void onSharedElementEnd(List<String> sharedElementNames, List<View> sharedElements,
                                     List<View> sharedElementSnapshots) {
          TextView initialView = getTextView(sharedElements);
  
          if (initialView == null) {
              Log.w(TAG, "onSharedElementEnd: No shared TextView, skipping");
              return;
          }
  
          // Setup the TextView's end values.
          initialView.setTextSize(TypedValue.COMPLEX_UNIT_PX, mTargetViewTextSize);
          ViewUtils.setPaddingStart(initialView, mTargetViewPaddingStart);
  
          // Re-measure the TextView (since the text size has changed).
          int widthSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
          int heightSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
          initialView.measure(widthSpec, heightSpec);
          initialView.requestLayout();
      }
  
      @Nullable
      private TextView getTextView(List<View> sharedElements) {
          TextView targetView = null;
          for (int i = 0; i < sharedElements.size(); i++) {
              if (sharedElements.get(i) instanceof TextView) {
                  targetView = (TextView) sharedElements.get(i);
              }
          }
          return targetView;
      }
  
  }
  