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/*
* Copyright 2014 Google Inc.
*
* 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.google.samples.apps.iosched.ui.widget;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v4.view.ViewCompat;
import android.util.AttributeSet;
import android.widget.ScrollView;
import com.google.samples.apps.iosched.R;
/**
* A layout that draws something in the insets passed to {@link #fitSystemWindows(Rect)}, i.e. the area above UI chrome
* (status and navigation bars, overlay action bars).
*/
public class ScrimInsetsScrollView extends ScrollView {
private Drawable mInsetForeground;
private Rect mInsets;
private Rect mTempRect = new Rect();
private OnInsetsCallback mOnInsetsCallback;
public ScrimInsetsScrollView(Context context) {
super(context);
init(context, null, 0);
}
public ScrimInsetsScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context, attrs, 0);
}
public ScrimInsetsScrollView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init(context, attrs, defStyle);
}
private void init(Context context, AttributeSet attrs, int defStyle) {
final TypedArray a = context.obtainStyledAttributes(attrs,
R.styleable.ScrimInsetsView, defStyle, 0);
if (a == null) {
return;
}
mInsetForeground = a.getDrawable(R.styleable.ScrimInsetsView_insetForeground);
a.recycle();
setWillNotDraw(true);
}
@Override
protected boolean fitSystemWindows(Rect insets) {
mInsets = new Rect(insets);
setWillNotDraw(mInsetForeground == null);
ViewCompat.postInvalidateOnAnimation(this);
if (mOnInsetsCallback != null) {
mOnInsetsCallback.onInsetsChanged(insets);
}
return true; // consume insets
}
@Override
public void draw(Canvas canvas) {
super.draw(canvas);
int width = getWidth();
int height = getHeight();
if (mInsets != null && mInsetForeground != null) {
int sc = canvas.save();
canvas.translate(getScrollX(), getScrollY());
// Top
mTempRect.set(0, 0, width, mInsets.top);
mInsetForeground.setBounds(mTempRect);
mInsetForeground.draw(canvas);
// Bottom
mTempRect.set(0, height - mInsets.bottom, width, height);
mInsetForeground.setBounds(mTempRect);
mInsetForeground.draw(canvas);
// Left
mTempRect.set(0, mInsets.top, mInsets.left, height - mInsets.bottom);
mInsetForeground.setBounds(mTempRect);
mInsetForeground.draw(canvas);
// Right
mTempRect.set(width - mInsets.right, mInsets.top, width, height - mInsets.bottom);
mInsetForeground.setBounds(mTempRect);
mInsetForeground.draw(canvas);
canvas.restoreToCount(sc);
}
}
@Override
protected void onAttachedToWindow() {
super.onAttachedToWindow();
if (mInsetForeground != null) {
mInsetForeground.setCallback(this);
}
}
@Override
protected void onDetachedFromWindow() {
super.onDetachedFromWindow();
if (mInsetForeground != null) {
mInsetForeground.setCallback(null);
}
}
/**
* Allows the calling container to specify a callback for custom processing when insets change (i.e. when
* {@link #fitSystemWindows(Rect)} is called. This is useful for setting padding on UI elements based on
* UI chrome insets (e.g. a Google Map or a ListView). When using with ListView or GridView, remember to set
* clipToPadding to false.
*/
public void setOnInsetsCallback(OnInsetsCallback onInsetsCallback) {
mOnInsetsCallback = onInsetsCallback;
}
public static interface OnInsetsCallback {
public void onInsetsChanged(Rect insets);
}
}
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