Java tutorial
/* * 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 com.tr4android.support.extension.picker.date; import android.content.Context; import android.graphics.drawable.Drawable; import android.support.v4.view.ViewCompat; import android.util.AttributeSet; import android.view.View; import android.widget.ViewAnimator; import java.util.ArrayList; /** * ViewAnimator with a more reasonable handling of MATCH_PARENT. * Used for switching between DayPickerView and YearPickerView in AppCompatDatePicker */ public class DialogViewAnimator extends ViewAnimator { private final ArrayList<View> mMatchParentChildren = new ArrayList<>(1); public DialogViewAnimator(Context context) { super(context); } public DialogViewAnimator(Context context, AttributeSet attrs) { super(context, attrs); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { final boolean measureMatchParentChildren = MeasureSpec.getMode(widthMeasureSpec) != MeasureSpec.EXACTLY || MeasureSpec.getMode(heightMeasureSpec) != MeasureSpec.EXACTLY; int maxHeight = 0; int maxWidth = 0; int childState = 0; // First measure all children and record maximum dimensions where the // spec isn't MATCH_PARENT. final int count = getChildCount(); for (int i = 0; i < count; i++) { final View child = getChildAt(i); if (getMeasureAllChildren() || child.getVisibility() != GONE) { final LayoutParams lp = (LayoutParams) child.getLayoutParams(); final boolean matchWidth = lp.width == LayoutParams.MATCH_PARENT; final boolean matchHeight = lp.height == LayoutParams.MATCH_PARENT; if (measureMatchParentChildren && (matchWidth || matchHeight)) { mMatchParentChildren.add(child); } measureChildWithMargins(child, widthMeasureSpec, 0, heightMeasureSpec, 0); // Measured dimensions only count against the maximum // dimensions if they're not MATCH_PARENT. int state = 0; if (measureMatchParentChildren && !matchWidth) { maxWidth = Math.max(maxWidth, child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin); state |= ViewCompat.getMeasuredWidthAndState(child) & ViewCompat.MEASURED_STATE_MASK; } if (measureMatchParentChildren && !matchHeight) { maxHeight = Math.max(maxHeight, child.getMeasuredHeight() + lp.topMargin + lp.bottomMargin); state |= (ViewCompat.getMeasuredHeightAndState(child) >> ViewCompat.MEASURED_HEIGHT_STATE_SHIFT) & (ViewCompat.MEASURED_STATE_MASK >> ViewCompat.MEASURED_HEIGHT_STATE_SHIFT); } childState = ViewCompat.combineMeasuredStates(childState, state); } } // 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(ViewCompat.resolveSizeAndState(maxWidth, widthMeasureSpec, childState), ViewCompat.resolveSizeAndState(maxHeight, heightMeasureSpec, childState << ViewCompat.MEASURED_HEIGHT_STATE_SHIFT)); // Measure remaining MATCH_PARENT children again using real dimensions. final int matchCount = mMatchParentChildren.size(); for (int i = 0; i < matchCount; i++) { final View child = mMatchParentChildren.get(i); final MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams(); final int childWidthMeasureSpec; if (lp.width == LayoutParams.MATCH_PARENT) { childWidthMeasureSpec = MeasureSpec.makeMeasureSpec( getMeasuredWidth() - getPaddingLeft() - getPaddingRight() - lp.leftMargin - lp.rightMargin, MeasureSpec.EXACTLY); } else { childWidthMeasureSpec = getChildMeasureSpec(widthMeasureSpec, getPaddingLeft() + getPaddingRight() + lp.leftMargin + lp.rightMargin, lp.width); } final int childHeightMeasureSpec; if (lp.height == LayoutParams.MATCH_PARENT) { childHeightMeasureSpec = MeasureSpec.makeMeasureSpec( getMeasuredHeight() - getPaddingTop() - getPaddingBottom() - lp.topMargin - lp.bottomMargin, MeasureSpec.EXACTLY); } else { childHeightMeasureSpec = getChildMeasureSpec(heightMeasureSpec, getPaddingTop() + getPaddingBottom() + lp.topMargin + lp.bottomMargin, lp.height); } child.measure(childWidthMeasureSpec, childHeightMeasureSpec); } mMatchParentChildren.clear(); } @Override public boolean getMeasureAllChildren() { return true; } }