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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.systemui.statusbar.phone;
import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ScrollView;
/**
* A scroll view which can be observed for scroll change events.
*/
public class ObservableScrollView extends ScrollView {
private Listener mListener;
private int mLastOverscrollAmount;
private boolean mTouchEnabled = true;
private boolean mHandlingTouchEvent;
private float mLastX;
private float mLastY;
private boolean mBlockFlinging;
private boolean mTouchCancelled;
public ObservableScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public void setListener(Listener listener) {
mListener = listener;
}
public void setTouchEnabled(boolean touchEnabled) {
mTouchEnabled = touchEnabled;
}
public boolean isScrolledToBottom() {
return getScrollY() == getMaxScrollY();
}
public boolean isHandlingTouchEvent() {
return mHandlingTouchEvent;
}
private int getMaxScrollY() {
int scrollRange = 0;
if (getChildCount() > 0) {
View child = getChildAt(0);
scrollRange = Math.max(0,
child.getHeight() - (getHeight() - mPaddingBottom - mPaddingTop));
}
return scrollRange;
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
mHandlingTouchEvent = true;
mLastX = ev.getX();
mLastY = ev.getY();
boolean result = super.onTouchEvent(ev);
mHandlingTouchEvent = false;
return result;
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
mHandlingTouchEvent = true;
mLastX = ev.getX();
mLastY = ev.getY();
boolean result = super.onInterceptTouchEvent(ev);
mHandlingTouchEvent = false;
return result;
}
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
if (ev.getAction() == MotionEvent.ACTION_DOWN) {
if (!mTouchEnabled) {
mTouchCancelled = true;
return false;
}
mTouchCancelled = false;
} else if (mTouchCancelled) {
return false;
} else if (!mTouchEnabled) {
MotionEvent cancel = MotionEvent.obtain(ev);
cancel.setAction(MotionEvent.ACTION_CANCEL);
super.dispatchTouchEvent(cancel);
cancel.recycle();
mTouchCancelled = true;
return false;
}
return super.dispatchTouchEvent(ev);
}
@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
super.onScrollChanged(l, t, oldl, oldt);
if (mListener != null) {
mListener.onScrollChanged();
}
}
@Override
protected boolean overScrollBy(int deltaX, int deltaY, int scrollX, int scrollY,
int scrollRangeX, int scrollRangeY, int maxOverScrollX, int maxOverScrollY,
boolean isTouchEvent) {
mLastOverscrollAmount = Math.max(0, scrollY + deltaY - getMaxScrollY());
return super.overScrollBy(deltaX, deltaY, scrollX, scrollY, scrollRangeX, scrollRangeY,
maxOverScrollX, maxOverScrollY, isTouchEvent);
}
public void setBlockFlinging(boolean blockFlinging) {
mBlockFlinging = blockFlinging;
}
@Override
public void fling(int velocityY) {
if (!mBlockFlinging) {
super.fling(velocityY);
}
}
@Override
protected void onOverScrolled(int scrollX, int scrollY, boolean clampedX, boolean clampedY) {
super.onOverScrolled(scrollX, scrollY, clampedX, clampedY);
if (mListener != null && mLastOverscrollAmount > 0) {
mListener.onOverscrolled(mLastX, mLastY, mLastOverscrollAmount);
}
}
public interface Listener {
void onScrollChanged();
void onOverscrolled(float lastX, float lastY, int amount);
}
}
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