content: /*
   * Copyright (C) 2020 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 androidx.constraintlayout.motion.widget;
  
  import android.graphics.Canvas;
  import android.view.View;
  
  import java.util.HashMap;
  
  /**
   * This defined the interface for MotionLayout helpers
   * Helpers can be used to draw motion effects or modify motions
   */
  public interface MotionHelperInterface extends  Animatable, MotionLayout.TransitionListener {
      /**
       * Notify when view is visible
       * @return
       */
      boolean isUsedOnShow();
  
      /**
       * Notify when views are hidden
       * @return
       */
      boolean isUseOnHide();
  
      /**
       * is involved in painting
       * @return
       */
      boolean isDecorator();
  
      /**
       * Call before views are painted
       * @param canvas
       */
      void onPreDraw(Canvas canvas);
  
      /**
       * Called after views are painted
       * @param canvas
       */
      void onPostDraw(Canvas canvas);
  
      /**
       * Called after motionController is populated with start and end and keyframes.
       *
       * @param motionLayout
       * @param controllerMap
       */
      void onPreSetup(MotionLayout motionLayout, HashMap<View, MotionController> controllerMap);
  
      /**
       * This is called after motionLayout read motionScene and assembles all constraintSets
       * @param motionLayout
       */
      void onFinishedMotionScene(MotionLayout motionLayout);
  }
  