| /* |
| * 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.os.Build; |
| import android.util.AttributeSet; |
| import android.view.View; |
| import android.view.WindowInsets; |
| |
| /** |
| * This class provides sticky header functionality in a scroll view, to use with |
| * SetupWizardIllustration. To use this, add a subview tagged with "sticky", or a subview 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 StickyHeaderScrollView -> subview (stickyContainer) -> |
| * sticky, and StickyHeaderScrollView -> container -> subview (sticky). The arrow (->) |
| * represents parent/child relationship and must be immediate child. |
| * <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. |
| * <li>For versions before Honeycomb, this will behave like a regular ScrollView. |
| * </ol> |
| * |
| * @see StickyHeaderListView |
| */ |
| public class StickyHeaderScrollView extends BottomScrollView { |
| |
| private View sticky; |
| private View stickyContainer; |
| private int statusBarInset = 0; |
| |
| public StickyHeaderScrollView(Context context) { |
| super(context); |
| } |
| |
| public StickyHeaderScrollView(Context context, AttributeSet attrs) { |
| super(context, attrs); |
| } |
| |
| public StickyHeaderScrollView(Context context, AttributeSet attrs, int defStyleAttr) { |
| super(context, attrs, defStyleAttr); |
| } |
| |
| @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(); |
| } |
| updateStickyHeaderPosition(); |
| } |
| |
| public void updateStickyView() { |
| sticky = findViewWithTag("sticky"); |
| stickyContainer = findViewWithTag("stickyContainer"); |
| } |
| |
| private void updateStickyHeaderPosition() { |
| // Note: for pre-Honeycomb the header will not be moved, so this ScrollView essentially |
| // behaves like a normal BottomScrollView. |
| if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) { |
| if (sticky != null) { |
| // 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() - getScrollY(); |
| if (drawTop + drawOffset < statusBarInset || !drawTarget.isShown()) { |
| // ScrollView translates the whole canvas so we have to compensate for that |
| drawTarget.setTranslationY(getScrollY() - drawOffset); |
| } else { |
| drawTarget.setTranslationY(0); |
| } |
| } |
| } |
| } |
| |
| @Override |
| protected void onScrollChanged(int l, int t, int oldl, int oldt) { |
| super.onScrollChanged(l, t, oldl, oldt); |
| updateStickyHeaderPosition(); |
| } |
| |
| @Override |
| @TargetApi(Build.VERSION_CODES.LOLLIPOP) |
| public WindowInsets onApplyWindowInsets(WindowInsets insets) { |
| if (getFitsSystemWindows()) { |
| statusBarInset = insets.getSystemWindowInsetTop(); |
| insets = |
| insets.replaceSystemWindowInsets( |
| insets.getSystemWindowInsetLeft(), |
| 0, /* top */ |
| insets.getSystemWindowInsetRight(), |
| insets.getSystemWindowInsetBottom()); |
| } |
| return insets; |
| } |
| } |