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/*
* 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.android.internal.widget;
import android.compat.annotation.UnsupportedAppUsage;
import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.View;
import android.widget.LinearLayout;
import com.android.internal.R;
/**
* An extension of LinearLayout that automatically switches to vertical
* orientation when it can't fit its child views horizontally.
*/
public class ButtonBarLayout extends LinearLayout {
/** Amount of the second button to "peek" above the fold when stacked. */
private static final int PEEK_BUTTON_DP = 16;
/** Whether the current configuration allows stacking. */
private boolean mAllowStacking;
private int mLastWidthSize = -1;
private int mMinimumHeight = 0;
@UnsupportedAppUsage
public ButtonBarLayout(Context context, AttributeSet attrs) {
super(context, attrs);
final TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.ButtonBarLayout);
mAllowStacking = ta.getBoolean(R.styleable.ButtonBarLayout_allowStacking, true);
ta.recycle();
}
public void setAllowStacking(boolean allowStacking) {
if (mAllowStacking != allowStacking) {
mAllowStacking = allowStacking;
if (!mAllowStacking && getOrientation() == LinearLayout.VERTICAL) {
setStacked(false);
}
requestLayout();
}
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
final int widthSize = MeasureSpec.getSize(widthMeasureSpec);
if (mAllowStacking) {
if (widthSize > mLastWidthSize && isStacked()) {
// We're being measured wider this time, try un-stacking.
setStacked(false);
}
mLastWidthSize = widthSize;
}
boolean needsRemeasure = false;
// If we're not stacked, make sure the measure spec is AT_MOST rather
// than EXACTLY. This ensures that we'll still get TOO_SMALL so that we
// know to stack the buttons.
final int initialWidthMeasureSpec;
if (!isStacked() && MeasureSpec.getMode(widthMeasureSpec) == MeasureSpec.EXACTLY) {
initialWidthMeasureSpec = MeasureSpec.makeMeasureSpec(widthSize, MeasureSpec.AT_MOST);
// We'll need to remeasure again to fill excess space.
needsRemeasure = true;
} else {
initialWidthMeasureSpec = widthMeasureSpec;
}
super.onMeasure(initialWidthMeasureSpec, heightMeasureSpec);
if (mAllowStacking && !isStacked()) {
final int measuredWidth = getMeasuredWidthAndState();
final int measuredWidthState = measuredWidth & MEASURED_STATE_MASK;
if (measuredWidthState == MEASURED_STATE_TOO_SMALL) {
setStacked(true);
// Measure again in the new orientation.
needsRemeasure = true;
}
}
if (needsRemeasure) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
// Compute minimum height such that, when stacked, some portion of the
// second button is visible.
int minHeight = 0;
final int firstVisible = getNextVisibleChildIndex(0);
if (firstVisible >= 0) {
final View firstButton = getChildAt(firstVisible);
final LayoutParams firstParams = (LayoutParams) firstButton.getLayoutParams();
minHeight += getPaddingTop() + firstButton.getMeasuredHeight()
+ firstParams.topMargin + firstParams.bottomMargin;
if (isStacked()) {
final int secondVisible = getNextVisibleChildIndex(firstVisible + 1);
if (secondVisible >= 0) {
minHeight += getChildAt(secondVisible).getPaddingTop()
+ PEEK_BUTTON_DP * getResources().getDisplayMetrics().density;
}
} else {
minHeight += getPaddingBottom();
}
}
if (getMinimumHeight() != minHeight) {
setMinimumHeight(minHeight);
}
}
private int getNextVisibleChildIndex(int index) {
for (int i = index, count = getChildCount(); i < count; i++) {
if (getChildAt(i).getVisibility() == View.VISIBLE) {
return i;
}
}
return -1;
}
@Override
public int getMinimumHeight() {
return Math.max(mMinimumHeight, super.getMinimumHeight());
}
private void setStacked(boolean stacked) {
setOrientation(stacked ? LinearLayout.VERTICAL : LinearLayout.HORIZONTAL);
setGravity(stacked ? Gravity.END : Gravity.BOTTOM);
final View spacer = findViewById(R.id.spacer);
if (spacer != null) {
spacer.setVisibility(stacked ? View.GONE : View.INVISIBLE);
}
// Reverse the child order. This is specific to the Material button
// bar's layout XML and will probably not generalize.
final int childCount = getChildCount();
for (int i = childCount - 2; i >= 0; i--) {
bringChildToFront(getChildAt(i));
}
}
private boolean isStacked() {
return getOrientation() == LinearLayout.VERTICAL;
}
}
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