109 lines
4.4 KiB
Java
109 lines
4.4 KiB
Java
/*
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* Copyright (C) 2011 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.example.android.hcgallery;
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import android.content.Context;
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import android.util.AttributeSet;
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import android.view.View;
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import android.view.ViewGroup;
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/**
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* A simple layout that fits and centers each child view, maintaining aspect ratio.
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*/
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public class FitCenterFrameLayout extends ViewGroup {
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public FitCenterFrameLayout(Context context) {
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super(context);
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}
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public FitCenterFrameLayout(Context context, AttributeSet attrs) {
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super(context, attrs);
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}
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@Override
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protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
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// We purposely disregard child measurements.
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final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
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final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
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setMeasuredDimension(width, height);
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int childWidthSpec = MeasureSpec.makeMeasureSpec(width, MeasureSpec.UNSPECIFIED);
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int childHeightSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.UNSPECIFIED);
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int childCount = getChildCount();
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for (int i = 0; i < childCount; i++) {
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getChildAt(i).measure(childWidthSpec, childHeightSpec);
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}
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}
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@Override
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protected void onLayout(boolean changed, int l, int t, int r, int b) {
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final int childCount = getChildCount();
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final int parentLeft = getPaddingLeft();
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final int parentTop = getPaddingTop();
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final int parentRight = r - l - getPaddingRight();
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final int parentBottom = b - t - getPaddingBottom();
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final int parentWidth = parentRight - parentLeft;
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final int parentHeight = parentBottom - parentTop;
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int unpaddedWidth, unpaddedHeight, parentUnpaddedWidth, parentUnpaddedHeight;
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int childPaddingLeft, childPaddingTop, childPaddingRight, childPaddingBottom;
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for (int i = 0; i < childCount; i++) {
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final View child = getChildAt(i);
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if (child.getVisibility() == GONE) {
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continue;
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}
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// Fit and center the child within the parent. Make sure not to consider padding
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// as part of the child's aspect ratio.
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childPaddingLeft = child.getPaddingLeft();
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childPaddingTop = child.getPaddingTop();
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childPaddingRight = child.getPaddingRight();
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childPaddingBottom = child.getPaddingBottom();
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unpaddedWidth = child.getMeasuredWidth() - childPaddingLeft - childPaddingRight;
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unpaddedHeight = child.getMeasuredHeight() - childPaddingTop - childPaddingBottom;
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parentUnpaddedWidth = parentWidth - childPaddingLeft - childPaddingRight;
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parentUnpaddedHeight = parentHeight - childPaddingTop - childPaddingBottom;
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if (parentUnpaddedWidth * unpaddedHeight > parentUnpaddedHeight * unpaddedWidth) {
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// The child view should be left/right letterboxed.
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final int scaledChildWidth = unpaddedWidth * parentUnpaddedHeight
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/ unpaddedHeight + childPaddingLeft + childPaddingRight;
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child.layout(
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parentLeft + (parentWidth - scaledChildWidth) / 2,
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parentTop,
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parentRight - (parentWidth - scaledChildWidth) / 2,
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parentBottom);
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} else {
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// The child view should be top/bottom letterboxed.
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final int scaledChildHeight = unpaddedHeight * parentUnpaddedWidth
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/ unpaddedWidth + childPaddingTop + childPaddingBottom;
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child.layout(
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parentLeft,
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parentTop + (parentHeight - scaledChildHeight) / 2,
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parentRight,
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parentTop + (parentHeight + scaledChildHeight) / 2);
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}
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}
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}
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}
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