content: /*
   * Copyright (C) 2015 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 android.widget;
  
  import android.content.Context;
  import android.graphics.drawable.Drawable;
  import android.util.AttributeSet;
  import android.view.View;
  
  import com.android.internal.widget.ViewPager;
  
  import java.util.ArrayList;
  import java.util.function.Predicate;
  
  /**
   * This displays a list of months in a calendar format with selectable days.
   */
  class DayPickerViewPager extends ViewPager {
      private final ArrayList<View> mMatchParentChildren = new ArrayList<>(1);
  
      public DayPickerViewPager(Context context) {
          this(context, null);
      }
  
      public DayPickerViewPager(Context context, AttributeSet attrs) {
          this(context, attrs, 0);
      }
  
      public DayPickerViewPager(Context context, AttributeSet attrs, int defStyleAttr) {
          this(context, attrs, defStyleAttr, 0);
      }
  
      public DayPickerViewPager(Context context, AttributeSet attrs, int defStyleAttr,
              int defStyleRes) {
          super(context, attrs, defStyleAttr, defStyleRes);
      }
  
      @Override
      protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
          populate();
  
          // Everything below is mostly copied from FrameLayout.
          int count = getChildCount();
  
          final boolean measureMatchParentChildren =
                  MeasureSpec.getMode(widthMeasureSpec) != MeasureSpec.EXACTLY ||
                          MeasureSpec.getMode(heightMeasureSpec) != MeasureSpec.EXACTLY;
  
          int maxHeight = 0;
          int maxWidth = 0;
          int childState = 0;
  
          for (int i = 0; i < count; i++) {
              final View child = getChildAt(i);
              if (child.getVisibility() != GONE) {
                  measureChild(child, widthMeasureSpec, heightMeasureSpec);
                  final LayoutParams lp = (LayoutParams) child.getLayoutParams();
                  maxWidth = Math.max(maxWidth, child.getMeasuredWidth());
                  maxHeight = Math.max(maxHeight, child.getMeasuredHeight());
                  childState = combineMeasuredStates(childState, child.getMeasuredState());
                  if (measureMatchParentChildren) {
                      if (lp.width == LayoutParams.MATCH_PARENT ||
                              lp.height == LayoutParams.MATCH_PARENT) {
                          mMatchParentChildren.add(child);
                      }
                  }
              }
          }
  
          // Account for padding too
          maxWidth += getPaddingLeft() + getPaddingRight();
          maxHeight += getPaddingTop() + getPaddingBottom();
  
          // Check against our minimum height and width
          maxHeight = Math.max(maxHeight, getSuggestedMinimumHeight());
          maxWidth = Math.max(maxWidth, getSuggestedMinimumWidth());
  
          // Check against our foreground's minimum height and width
          final Drawable drawable = getForeground();
          if (drawable != null) {
              maxHeight = Math.max(maxHeight, drawable.getMinimumHeight());
              maxWidth = Math.max(maxWidth, drawable.getMinimumWidth());
          }
  
          setMeasuredDimension(resolveSizeAndState(maxWidth, widthMeasureSpec, childState),
                  resolveSizeAndState(maxHeight, heightMeasureSpec,
                          childState << MEASURED_HEIGHT_STATE_SHIFT));
  
          count = mMatchParentChildren.size();
          if (count > 1) {
              for (int i = 0; i < count; i++) {
                  final View child = mMatchParentChildren.get(i);
  
                  final LayoutParams lp = (LayoutParams) child.getLayoutParams();
                  final int childWidthMeasureSpec;
                  final int childHeightMeasureSpec;
  
                  if (lp.width == LayoutParams.MATCH_PARENT) {
                      childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(
                              getMeasuredWidth() - getPaddingLeft() - getPaddingRight(),
                              MeasureSpec.EXACTLY);
                  } else {
                      childWidthMeasureSpec = getChildMeasureSpec(widthMeasureSpec,
                              getPaddingLeft() + getPaddingRight(),
                              lp.width);
                  }
  
                  if (lp.height == LayoutParams.MATCH_PARENT) {
                      childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(
                              getMeasuredHeight() - getPaddingTop() - getPaddingBottom(),
                              MeasureSpec.EXACTLY);
                  } else {
                      childHeightMeasureSpec = getChildMeasureSpec(heightMeasureSpec,
                              getPaddingTop() + getPaddingBottom(),
                              lp.height);
                  }
  
                  child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
              }
          }
  
          mMatchParentChildren.clear();
      }
  
      @Override
      protected <T extends View> T findViewByPredicateTraversal(Predicate<View> predicate,
              View childToSkip) {
          if (predicate.test(this)) {
              return (T) this;
          }
  
          // Always try the selected view first.
          final DayPickerPagerAdapter adapter = (DayPickerPagerAdapter) getAdapter();
          final SimpleMonthView current = adapter.getView(getCurrent());
          if (current != childToSkip && current != null) {
              final View v = current.findViewByPredicate(predicate);
              if (v != null) {
                  return (T) v;
              }
          }
  
          final int len = getChildCount();
          for (int i = 0; i < len; i++) {
              final View child = getChildAt(i);
  
              if (child != childToSkip && child != current) {
                  final View v = child.findViewByPredicate(predicate);
  
                  if (v != null) {
                      return (T) v;
                  }
              }
          }
  
          return null;
      }
  
  }
  