/*
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* Copyright (C) 2014 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License
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*/
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package com.android.systemui.statusbar.phone;
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import android.content.Context;
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import android.util.AttributeSet;
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import android.view.MotionEvent;
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import android.view.View;
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import android.widget.ScrollView;
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/**
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* A scroll view which can be observed for scroll change events.
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*/
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public class ObservableScrollView extends ScrollView {
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private Listener mListener;
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private int mLastOverscrollAmount;
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private boolean mTouchEnabled = true;
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private boolean mHandlingTouchEvent;
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private float mLastX;
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private float mLastY;
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private boolean mBlockFlinging;
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private boolean mTouchCancelled;
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public ObservableScrollView(Context context, AttributeSet attrs) {
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super(context, attrs);
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}
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public void setListener(Listener listener) {
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mListener = listener;
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}
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public void setTouchEnabled(boolean touchEnabled) {
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mTouchEnabled = touchEnabled;
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}
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public boolean isScrolledToBottom() {
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return getScrollY() == getMaxScrollY();
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}
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public boolean isHandlingTouchEvent() {
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return mHandlingTouchEvent;
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}
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private int getMaxScrollY() {
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int scrollRange = 0;
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if (getChildCount() > 0) {
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View child = getChildAt(0);
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scrollRange = Math.max(0,
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child.getHeight() - (getHeight() - mPaddingBottom - mPaddingTop));
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}
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return scrollRange;
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}
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@Override
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public boolean onTouchEvent(MotionEvent ev) {
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mHandlingTouchEvent = true;
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mLastX = ev.getX();
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mLastY = ev.getY();
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boolean result = super.onTouchEvent(ev);
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mHandlingTouchEvent = false;
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return result;
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}
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@Override
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public boolean onInterceptTouchEvent(MotionEvent ev) {
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mHandlingTouchEvent = true;
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mLastX = ev.getX();
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mLastY = ev.getY();
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boolean result = super.onInterceptTouchEvent(ev);
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mHandlingTouchEvent = false;
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return result;
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}
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@Override
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public boolean dispatchTouchEvent(MotionEvent ev) {
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if (ev.getAction() == MotionEvent.ACTION_DOWN) {
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if (!mTouchEnabled) {
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mTouchCancelled = true;
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return false;
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}
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mTouchCancelled = false;
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} else if (mTouchCancelled) {
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return false;
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} else if (!mTouchEnabled) {
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MotionEvent cancel = MotionEvent.obtain(ev);
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cancel.setAction(MotionEvent.ACTION_CANCEL);
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super.dispatchTouchEvent(cancel);
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cancel.recycle();
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mTouchCancelled = true;
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return false;
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}
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return super.dispatchTouchEvent(ev);
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}
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@Override
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protected void onScrollChanged(int l, int t, int oldl, int oldt) {
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super.onScrollChanged(l, t, oldl, oldt);
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if (mListener != null) {
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mListener.onScrollChanged();
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}
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}
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@Override
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protected boolean overScrollBy(int deltaX, int deltaY, int scrollX, int scrollY,
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int scrollRangeX, int scrollRangeY, int maxOverScrollX, int maxOverScrollY,
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boolean isTouchEvent) {
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mLastOverscrollAmount = Math.max(0, scrollY + deltaY - getMaxScrollY());
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return super.overScrollBy(deltaX, deltaY, scrollX, scrollY, scrollRangeX, scrollRangeY,
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maxOverScrollX, maxOverScrollY, isTouchEvent);
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}
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public void setBlockFlinging(boolean blockFlinging) {
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mBlockFlinging = blockFlinging;
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}
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@Override
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public void fling(int velocityY) {
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if (!mBlockFlinging) {
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super.fling(velocityY);
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}
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}
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@Override
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protected void onOverScrolled(int scrollX, int scrollY, boolean clampedX, boolean clampedY) {
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super.onOverScrolled(scrollX, scrollY, clampedX, clampedY);
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if (mListener != null && mLastOverscrollAmount > 0) {
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mListener.onOverscrolled(mLastX, mLastY, mLastOverscrollAmount);
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}
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}
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public interface Listener {
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void onScrollChanged();
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void onOverscrolled(float lastX, float lastY, int amount);
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}
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}
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