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/*
* Copyright (C) 2014 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.settings.widget;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowInsets;
import android.widget.ListView;
/**
* This class provides sticky header functionality in a list view, to use with
* SetupWizardIllustration. To use this, add a header tagged with "sticky", or a header tagged with
* "stickyContainer" and one of its child tagged as "sticky". The sticky container will be drawn
* when the sticky element hits the top of the view.
*
* There are a few things to note:
* 1. The two supported scenarios are StickyHeaderListView -> Header (stickyContainer) -> sticky,
* and StickyHeaderListView -> Header (sticky). The arrow (->) represents parent/child
* relationship and must be immediate child.
* 2. The view does not work well with padding. b/16190933
* 3. If fitsSystemWindows is true, then this will offset the sticking position by the height of
* the system decorations at the top of the screen.
*
* @see SetupWizardIllustration
* @see com.google.android.setupwizard.util.StickyHeaderScrollView
*
* Copied from com.google.android.setupwizard.util.StickyHeaderListView
*/
public class StickyHeaderListView extends ListView {
private View mSticky;
private View mStickyContainer;
private boolean mDrawScrollBar;
private int mStatusBarInset = 0;
private RectF mStickyRect = new RectF();
public StickyHeaderListView(Context context) {
super(context);
}
public StickyHeaderListView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public StickyHeaderListView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
public StickyHeaderListView(Context context, AttributeSet attrs, int defStyleAttr,
int defStyleRes) {
super(context, attrs, defStyleAttr, defStyleRes);
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
super.onLayout(changed, l, t, r, b);
if (mSticky == null) {
updateStickyView();
}
}
public void updateStickyView() {
mSticky = findViewWithTag("sticky");
mStickyContainer = findViewWithTag("stickyContainer");
}
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
if (mStickyRect.contains(ev.getX(), ev.getY())) {
ev.offsetLocation(-mStickyRect.left, -mStickyRect.top);
return mStickyContainer.dispatchTouchEvent(ev);
} else {
return super.dispatchTouchEvent(ev);
}
}
@Override
public void draw(Canvas canvas) {
mDrawScrollBar = false;
super.draw(canvas);
if (mSticky != null) {
final int saveCount = canvas.save();
// The view to draw when sticking to the top
final View drawTarget = mStickyContainer != null ? mStickyContainer : mSticky;
// The offset to draw the view at when sticky
final int drawOffset = mStickyContainer != null ? mSticky.getTop() : 0;
// Position of the draw target, relative to the outside of the scrollView
final int drawTop = drawTarget.getTop();
if (drawTop + drawOffset < mStatusBarInset || !drawTarget.isShown()) {
// ListView does not translate the canvas, so we can simply draw at the top
canvas.translate(0, -drawOffset + mStatusBarInset);
canvas.clipRect(0, 0, drawTarget.getWidth(), drawTarget.getHeight());
drawTarget.draw(canvas);
mStickyRect.set(0, -drawOffset + mStatusBarInset, drawTarget.getWidth(),
drawTarget.getHeight() - drawOffset + mStatusBarInset);
} else {
mStickyRect.setEmpty();
}
canvas.restoreToCount(saveCount);
}
// Draw the scrollbars last so they are on top of the header
mDrawScrollBar = true;
onDrawScrollBars(canvas);
}
@Override
protected boolean isVerticalScrollBarHidden() {
return super.isVerticalScrollBarHidden() || !mDrawScrollBar;
}
@Override
public WindowInsets onApplyWindowInsets(WindowInsets insets) {
if (getFitsSystemWindows()) {
mStatusBarInset = insets.getSystemWindowInsetTop();
insets.consumeSystemWindowInsets(false, true, false, false);
}
return insets;
}
}
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