| /* |
| * Copyright (C) 2011 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.example.android.hcgallery; |
| |
| import android.content.Context; |
| import android.util.AttributeSet; |
| import android.view.View; |
| import android.view.ViewGroup; |
| |
| /** |
| * A simple layout that fits and centers each child view, maintaining aspect ratio. |
| */ |
| public class FitCenterFrameLayout extends ViewGroup { |
| public FitCenterFrameLayout(Context context) { |
| super(context); |
| } |
| |
| public FitCenterFrameLayout(Context context, AttributeSet attrs) { |
| super(context, attrs); |
| } |
| |
| @Override |
| protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { |
| // We purposely disregard child measurements. |
| final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec); |
| final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec); |
| setMeasuredDimension(width, height); |
| |
| int childWidthSpec = MeasureSpec.makeMeasureSpec(width, MeasureSpec.UNSPECIFIED); |
| int childHeightSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.UNSPECIFIED); |
| |
| int childCount = getChildCount(); |
| for (int i = 0; i < childCount; i++) { |
| getChildAt(i).measure(childWidthSpec, childHeightSpec); |
| } |
| } |
| |
| @Override |
| protected void onLayout(boolean changed, int l, int t, int r, int b) { |
| final int childCount = getChildCount(); |
| |
| final int parentLeft = getPaddingLeft(); |
| final int parentTop = getPaddingTop(); |
| final int parentRight = r - l - getPaddingRight(); |
| final int parentBottom = b - t - getPaddingBottom(); |
| |
| final int parentWidth = parentRight - parentLeft; |
| final int parentHeight = parentBottom - parentTop; |
| |
| int unpaddedWidth, unpaddedHeight, parentUnpaddedWidth, parentUnpaddedHeight; |
| int childPaddingLeft, childPaddingTop, childPaddingRight, childPaddingBottom; |
| |
| for (int i = 0; i < childCount; i++) { |
| final View child = getChildAt(i); |
| if (child.getVisibility() == GONE) { |
| continue; |
| } |
| |
| // Fit and center the child within the parent. Make sure not to consider padding |
| // as part of the child's aspect ratio. |
| |
| childPaddingLeft = child.getPaddingLeft(); |
| childPaddingTop = child.getPaddingTop(); |
| childPaddingRight = child.getPaddingRight(); |
| childPaddingBottom = child.getPaddingBottom(); |
| |
| unpaddedWidth = child.getMeasuredWidth() - childPaddingLeft - childPaddingRight; |
| unpaddedHeight = child.getMeasuredHeight() - childPaddingTop - childPaddingBottom; |
| |
| parentUnpaddedWidth = parentWidth - childPaddingLeft - childPaddingRight; |
| parentUnpaddedHeight = parentHeight - childPaddingTop - childPaddingBottom; |
| |
| if (parentUnpaddedWidth * unpaddedHeight > parentUnpaddedHeight * unpaddedWidth) { |
| // The child view should be left/right letterboxed. |
| final int scaledChildWidth = unpaddedWidth * parentUnpaddedHeight |
| / unpaddedHeight + childPaddingLeft + childPaddingRight; |
| child.layout( |
| parentLeft + (parentWidth - scaledChildWidth) / 2, |
| parentTop, |
| parentRight - (parentWidth - scaledChildWidth) / 2, |
| parentBottom); |
| } else { |
| // The child view should be top/bottom letterboxed. |
| final int scaledChildHeight = unpaddedHeight * parentUnpaddedWidth |
| / unpaddedWidth + childPaddingTop + childPaddingBottom; |
| child.layout( |
| parentLeft, |
| parentTop + (parentHeight - scaledChildHeight) / 2, |
| parentRight, |
| parentTop + (parentHeight + scaledChildHeight) / 2); |
| } |
| } |
| } |
| } |