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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.setupwizardlib.view;
import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.RectF;
import android.os.Build;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowInsets;
import android.view.accessibility.AccessibilityEvent;
import android.widget.ListView;
import com.android.setupwizardlib.R;
/**
* 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.
*
* <p>There are a few things to note:
*
* <ol>
* <li>The two supported scenarios are StickyHeaderListView -> Header (stickyContainer) -> sticky,
* and StickyHeaderListView -> Header (sticky). The arrow (->) represents parent/child
* relationship and must be immediate child.
* <li>The view does not work well with padding. b/16190933
* <li>If fitsSystemWindows is true, then this will offset the sticking position by the height of
* the system decorations at the top of the screen.
* </ol>
*
* @see StickyHeaderScrollView
*/
public class StickyHeaderListView extends ListView {
private View sticky;
private View stickyContainer;
private int statusBarInset = 0;
private final RectF stickyRect = new RectF();
public StickyHeaderListView(Context context) {
super(context);
init(null, android.R.attr.listViewStyle);
}
public StickyHeaderListView(Context context, AttributeSet attrs) {
super(context, attrs);
init(attrs, android.R.attr.listViewStyle);
}
public StickyHeaderListView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(attrs, defStyleAttr);
}
private void init(AttributeSet attrs, int defStyleAttr) {
final TypedArray a =
getContext()
.obtainStyledAttributes(attrs, R.styleable.SuwStickyHeaderListView, defStyleAttr, 0);
int headerResId = a.getResourceId(R.styleable.SuwStickyHeaderListView_suwHeader, 0);
if (headerResId != 0) {
LayoutInflater inflater = LayoutInflater.from(getContext());
View header = inflater.inflate(headerResId, this, false);
addHeaderView(header, null, false);
}
a.recycle();
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
super.onLayout(changed, l, t, r, b);
if (sticky == null) {
updateStickyView();
}
}
public void updateStickyView() {
sticky = findViewWithTag("sticky");
stickyContainer = findViewWithTag("stickyContainer");
}
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
if (stickyRect.contains(ev.getX(), ev.getY())) {
ev.offsetLocation(-stickyRect.left, -stickyRect.top);
return stickyContainer.dispatchTouchEvent(ev);
} else {
return super.dispatchTouchEvent(ev);
}
}
@Override
public void draw(Canvas canvas) {
super.draw(canvas);
if (sticky != null) {
final int saveCount = canvas.save();
// The view to draw when sticking to the top
final View drawTarget = stickyContainer != null ? stickyContainer : sticky;
// The offset to draw the view at when sticky
final int drawOffset = stickyContainer != null ? sticky.getTop() : 0;
// Position of the draw target, relative to the outside of the scrollView
final int drawTop = drawTarget.getTop();
if (drawTop + drawOffset < statusBarInset || !drawTarget.isShown()) {
// ListView does not translate the canvas, so we can simply draw at the top
stickyRect.set(
0,
-drawOffset + statusBarInset,
drawTarget.getWidth(),
drawTarget.getHeight() - drawOffset + statusBarInset);
canvas.translate(0, stickyRect.top);
canvas.clipRect(0, 0, drawTarget.getWidth(), drawTarget.getHeight());
drawTarget.draw(canvas);
} else {
stickyRect.setEmpty();
}
canvas.restoreToCount(saveCount);
}
}
@Override
@TargetApi(Build.VERSION_CODES.LOLLIPOP)
public WindowInsets onApplyWindowInsets(WindowInsets insets) {
if (getFitsSystemWindows()) {
statusBarInset = insets.getSystemWindowInsetTop();
insets.replaceSystemWindowInsets(
insets.getSystemWindowInsetLeft(),
0, /* top */
insets.getSystemWindowInsetRight(),
insets.getSystemWindowInsetBottom());
}
return insets;
}
@Override
public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
super.onInitializeAccessibilityEvent(event);
// Decoration-only headers should not count as an item for accessibility, adjust the
// accessibility event to account for that.
final int numberOfHeaders = sticky != null ? 1 : 0;
event.setItemCount(event.getItemCount() - numberOfHeaders);
event.setFromIndex(Math.max(event.getFromIndex() - numberOfHeaders, 0));
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
event.setToIndex(Math.max(event.getToIndex() - numberOfHeaders, 0));
}
}
}
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