content: /*
   * Copyright (C) 2018 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.widget;
  
  import android.content.Context;
  import android.content.res.TypedArray;
  import android.util.AttributeSet;
  import android.view.View;
  import android.view.ViewParent;
  
  /**
   *  <b>Added in 2.0</b>
   *  <p>
   *  </p>
   *
   */
  public abstract class VirtualLayout extends ConstraintHelper {
      private boolean mApplyVisibilityOnAttach;
      private boolean mApplyElevationOnAttach;
  
      public VirtualLayout(Context context) {
          super(context);
      }
  
      public VirtualLayout(Context context, AttributeSet attrs) {
          super(context, attrs);
      }
  
      public VirtualLayout(Context context, AttributeSet attrs, int defStyleAttr) {
          super(context, attrs, defStyleAttr);
      }
  
      @Override
      protected void init(AttributeSet attrs) {
          super.init(attrs);
          if (attrs != null) {
              TypedArray a = getContext().obtainStyledAttributes(attrs,
                      R.styleable.ConstraintLayout_Layout);
              final int count = a.getIndexCount();
              for (int i = 0; i < count; i++) {
                  int attr = a.getIndex(i);
                  if (attr == R.styleable.ConstraintLayout_Layout_android_visibility) {
                      mApplyVisibilityOnAttach = true;
                  } else if (attr == R.styleable.ConstraintLayout_Layout_android_elevation) {
                      mApplyElevationOnAttach = true;
                  }
              }
              a.recycle();
          }
      }
  
      /**
       * called to measure layout
       * @param layout
       * @param widthMeasureSpec
       * @param heightMeasureSpec
       */
      public void onMeasure(androidx.constraintlayout.core.widgets.VirtualLayout layout,
                            int widthMeasureSpec,
                            int heightMeasureSpec) {
          // nothing
      }
  
      /**
       *
       */
      @Override
      public void onAttachedToWindow() {
          super.onAttachedToWindow();
          if (mApplyVisibilityOnAttach || mApplyElevationOnAttach) {
              ViewParent parent = getParent();
              if (parent instanceof ConstraintLayout) {
                  ConstraintLayout container = (ConstraintLayout) parent;
                  int visibility = getVisibility();
                  float elevation = 0;
                  if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP) {
                      elevation = getElevation();
                  }
                  for (int i = 0; i < mCount; i++) {
                      int id = mIds[i];
                      View view = container.getViewById(id);
                      if (view != null) {
                          if (mApplyVisibilityOnAttach) {
                              view.setVisibility(visibility);
                          }
                          if (mApplyElevationOnAttach) {
                              if (elevation > 0
                                      && android.os.Build.VERSION.SDK_INT
                                      >= android.os.Build.VERSION_CODES.LOLLIPOP) {
                                  view.setTranslationZ(view.getTranslationZ() + elevation);
                              }
                          }
                      }
                  }
              }
          }
      }
  
      /**
       *
       */
      @Override
      public void setVisibility(int visibility) {
          super.setVisibility(visibility);
          applyLayoutFeatures();
      }
  
      /**
       *
       */
      @Override
      public void setElevation(float elevation) {
          super.setElevation(elevation);
          applyLayoutFeatures();
      }
  
      /**
       *
       * @param container
       */
      @Override
      protected void applyLayoutFeaturesInConstraintSet(ConstraintLayout container) {
          applyLayoutFeatures(container);
      }
  }
  