package com.roboo.like.netease.view;
import com.roboo.like.netease.R;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewConfiguration;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.Scroller;
import android.widget.Toast;
//public class OverScrollListView extends ListView implements OnScrollListener, View.OnTouchListener, android.widget.AdapterView.OnItemSelectedListener
//{
//
// protected static float BREAKSPEED = 4f, ELASTICITY = 0.67f;
// public Handler mHandler = new Handler();
// public int nHeaders = 1, nFooters = 1, divHeight = 0, delay = 10;
// private int firstVis, visibleCnt, lastVis, totalItems, scrollstate;
// private boolean bounce = true, rebound = false, recalcV = false, trackballEvent = false;
// private long flingTimestamp;
// private float velocity;
// private View measure;
// private GestureDetector gesture;
//
// public OverScrollListView(Context context)
// {
// super(context);
// initialize(context);
// }
//
// public OverScrollListView(Context context, AttributeSet attrs)
// {
// super(context, attrs);
// initialize(context);
// }
//
// public OverScrollListView(Context context, AttributeSet attrs, int defStyle)
// {
// super(context, attrs, defStyle);
// initialize(context);
// }
//
// @Override
// public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
// {
// firstVis = firstVisibleItem;
// visibleCnt = visibleItemCount;
// totalItems = totalItemCount;
// lastVis = firstVisibleItem + visibleItemCount;
// }
//
// @Override
// public void onScrollStateChanged(AbsListView view, int scrollState)
// {
// scrollstate = scrollState;
// if (scrollState != OnScrollListener.SCROLL_STATE_TOUCH_SCROLL)
// {
// rebound = true;
// mHandler.postDelayed(checkListviewTopAndBottom, delay);
// }
// }
//
// @Override
// public void onItemSelected(AdapterView<?> av, View v, int position, long id)
// {
// rebound = true;
// mHandler.postDelayed(checkListviewTopAndBottom, delay);
// }
//
// @Override
// public void onNothingSelected(AdapterView<?> av)
// {
// rebound = true;
// mHandler.postDelayed(checkListviewTopAndBottom, delay);
// }
//
// @Override
// public boolean onTrackballEvent(MotionEvent event)
// {
// trackballEvent = true;
// rebound = true;
// mHandler.postDelayed(checkListviewTopAndBottom, delay);
// return super.onTrackballEvent(event);
// }
//
// @Override
// public boolean onTouch(View v, MotionEvent event)
// {
// gesture.onTouchEvent(event);
// return false;
// }
//
// private class gestureListener implements OnGestureListener
// {
// @Override
// public boolean onDown(MotionEvent e)
// {
// rebound = false;
// recalcV = false;
// velocity = 0f;
// return false;
// }
//
// @Override
// public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)
// {
// rebound = true;
// recalcV = true;
// velocity = velocityY / 25f;
// flingTimestamp = System.currentTimeMillis();
// return false;
// }
//
// @Override
// public void onLongPress(MotionEvent e)
// {
// }
//
// @Override
// public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY)
// {
// return false;
// }
//
// @Override
// public void onShowPress(MotionEvent e)
// {
// }
//
// @Override
// public boolean onSingleTapUp(MotionEvent e)
// {
// rebound = true;
// recalcV = false;
// velocity = 0f;
// return false;
// }
// };
//
// private void initialize(Context context)
// {
// View header = new View(context);
// header.setMinimumHeight(((WindowManager) context.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay().getHeight());
// addHeaderView(header, null, false);
// addFooterView(header, null, false);
//
// gesture = new GestureDetector(new gestureListener());
// gesture.setIsLongpressEnabled(false);
// flingTimestamp = System.currentTimeMillis();
// setHeaderDividersEnabled(false);
// setFooterDividersEnabled(false);
// setOnTouchListener(this);
// setOnScrollListener(this);
// setOnItemSelectedListener(this);
// }
//
// public void initializeValues()
// {
// nHeaders = getHeaderViewsCount();
// nFooters = getFooterViewsCount();
// divHeight = getDividerHeight();
// firstVis = 0;
// visibleCnt = 0;
// lastVis = 0;
// totalItems = 0;
// scrollstate = 0;
// rebound = true;
// setSelectionFromTop(nHeaders, divHeight);
// }
//
// /**
// * Turns bouncing animation on/off.
// *
// * @param bouncing
// * Default is true (on)
// */
// public void setBounce(boolean bouncing)
// {
// bounce = bouncing;
// }
//
// /**
// * Sets how fast the animation will be. Higher value means faster animation.
// * Must be >= 1.05. Together with Elasticity <= 0.75 it will not bounce
// * forever.
// *
// * @param breakspead
// * Default is 4.0
// */
// public void setBreakspeed(final float breakspeed)
// {
// if (Math.abs(breakspeed) >= 1.05f)
// {
// BREAKSPEED = Math.abs(breakspeed);
// }
// }
//
// /**
// * Sets how much it will keep bouncing. Lower value means less bouncing.
// * Must be <= 0.75. Together with Breakspeed >= 1.05 it will not bounce
// * forever.
// *
// * @param elasticity
// * Default is 0.67
// */
// public void setElasticity(final float elasticity)
// {
// if (Math.abs(elasticity) <= 0.75f)
// {
// ELASTICITY = Math.abs(elasticity);
// }
// }
//
// public Runnable checkListviewTopAndBottom = new Runnable()
// {
// @Override
// public void run()
// {
//
// mHandler.removeCallbacks(checkListviewTopAndBottom);
//
// if (trackballEvent && firstVis < nHeaders && lastVis >= totalItems)
// {
// trackballEvent = false;
// rebound = false;
// return;
// }
//
// if (rebound)
// {
//
// if (firstVis < nHeaders)
// {
//
// // hack to avoid strange behaviour when there aren't enough
// // items to fill the entire listview
// if (lastVis >= totalItems)
// {
// smoothScrollBy(0, 0);
// rebound = false;
// recalcV = false;
// velocity = 0f;
// }
//
// if (recalcV)
// {
// recalcV = false;
// velocity /= (1f + ((System.currentTimeMillis() - flingTimestamp) / 1000f));
// }
// if (firstVis == nHeaders)
// {
// recalcV = false;
// }
// if (visibleCnt > nHeaders)
// {
// measure = getChildAt(nHeaders);
// if (measure.getTop() + velocity < divHeight)
// {
// velocity *= -ELASTICITY;
// if (!bounce || Math.abs(velocity) < BREAKSPEED)
// {
// rebound = false;
// recalcV = false;
// velocity = 0f;
// }
// else
// {
// setSelectionFromTop(nHeaders, divHeight + 1);
// }
// }
// }
// else
// {
// if (velocity > 0f)
// velocity = -velocity;
// }
// if (rebound)
// {
// smoothScrollBy((int) -velocity, 0);
// if (velocity > BREAKSPEED)
// {
// velocity *= ELASTICITY;
// if (velocity < BREAKSPEED)
// {
// rebound = false;
// recalcV = false;
// velocity = 0f;
// }
// }
// else
// velocity -= BREAKSPEED;
// }
//
// }
// else if (lastVis >= totalItems)
// {
//
// if (recalcV)
// {
// recalcV = false;
// velocity /= (1f + ((System.currentTimeMillis() - flingTimestamp) / 1000f));
// }
// if (lastVis == totalItems - nHeaders - nFooters)
// {
// rebound = false;
// recalcV = false;
// velocity = 0f;
// }
// else
// {
// if (visibleCnt > (nHeaders + nFooters))
// {
// measure = getChildAt(visibleCnt - nHeaders - nFooters);
// if (measure.getBottom() + velocity > getHeight() - divHeight)
// {
// velocity *= -ELASTICITY;
// if (!bounce || Math.abs(velocity) < BREAKSPEED)
// {
// rebound = false;
// recalcV = false;
// velocity = 0f;
// }
// else
// {
// setSelectionFromTop(lastVis - nHeaders - nFooters, getHeight() - divHeight - measure.getHeight() - 1);
// }
// }
// }
// else
// {
// if (velocity < 0f)
// velocity = -velocity;
// }
// }
// if (rebound)
// {
// smoothScrollBy((int) -velocity, 0);
// if (velocity < -BREAKSPEED)
// {
// velocity *= ELASTICITY;
// if (velocity > -BREAKSPEED / ELASTICITY)
// {
// rebound = false;
// recalcV = false;
// velocity = 0f;
// }
// }
// else
// velocity += BREAKSPEED;
// }
//
// }
// else if (scrollstate == OnScrollListener.SCROLL_STATE_IDLE)
// {
//
// rebound = false;
// recalcV = false;
// velocity = 0f;
// }
// mHandler.postDelayed(checkListviewTopAndBottom, delay);
// return;
// }
//
// if (scrollstate != OnScrollListener.SCROLL_STATE_IDLE)
// return;
//
// if (totalItems == (nHeaders + nFooters) || firstVis < nHeaders)
// {
// setSelectionFromTop(nHeaders, divHeight);
// smoothScrollBy(0, 0);
// }
// else if (lastVis == totalItems)
// {
// int offset = getHeight() - divHeight;
// measure = getChildAt(visibleCnt - nHeaders - nFooters);
// if (measure != null)
// offset -= measure.getHeight();
// setSelectionFromTop(lastVis - nHeaders - nFooters, offset);
// smoothScrollBy(0, 0);
// }
// }
// };
//}
public class OverScrollListView extends ListView
{
private static final int MAX_Y_OVERSCROLL_DISTANCE = 200;
private int mMaxYOverscrollDistance;
/**
* 当前滑动的ListView position
*/
private int slidePosition;
/**
* 手指按下X的坐标
*/
private int downY;
/**
* 手指按下Y的坐标
*/
private int downX;
/**
* 屏幕宽度
*/
private int screenWidth;
/**
* ListView的item
*/
private View itemView;
/**
* 滑动类
*/
private Scroller scroller;
private static final int SNAP_VELOCITY = 600;
/**
* 速度追踪对象
*/
private VelocityTracker velocityTracker;
/**
* 是否响应滑动，默认为不响应
*/
private boolean isSlide = false;
/**
* 认为是用户滑动的最小距离
*/
private int mTouchSlop;
/**
* 移除item后的回调接口
*/
private RemoveListener mRemoveListener;
/**
* 用来指示item滑出屏幕的方向,向左或者向右,用一个枚举值来标记
*/
private RemoveDirection removeDirection;
// 滑动删除方向的枚举值
public enum RemoveDirection
{
RIGHT, LEFT;
}
public OverScrollListView(Context context)
{
this(context, null);
}
public OverScrollListView(Context context, AttributeSet attrs, int defStyle)
{
super(context, attrs, defStyle);
init();
}
public OverScrollListView(Context context, AttributeSet attrs)
{
this(context, attrs, 0);
}
private void init()
{
final DisplayMetrics metrics = getContext().getResources().getDisplayMetrics();
final float density = metrics.density;
mMaxYOverscrollDistance = (int) (density * MAX_Y_OVERSCROLL_DISTANCE);
screenWidth = metrics.widthPixels;
scroller = new Scroller(getContext());
mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
}
protected boolean overScrollBy(int deltaX, int deltaY, int scrollX, int scrollY, int scrollRangeX, int scrollRangeY, int maxOverScrollX, int maxOverScrollY, boolean isTouchEvent)
{
// This is where the magic happens, we have replaced the incoming
// maxOverScrollY with our own custom variable mMaxYOverscrollDistance;
return super.overScrollBy(deltaX, deltaY, scrollX, scrollY, scrollRangeX, scrollRangeY, maxOverScrollX, mMaxYOverscrollDistance, isTouchEvent);
}
/**
* 设置滑动删除的回调接口
*
* @param removeListener
*/
public void setRemoveListener(RemoveListener removeListener)
{
this.mRemoveListener = removeListener;
}
/**
* 分发事件，主要做的是判断点击的是那个item, 以及通过postDelayed来设置响应左右滑动事件
*/
@Override
public boolean dispatchTouchEvent(MotionEvent event)
{
switch (event.getAction())
{
case MotionEvent.ACTION_DOWN:
{
addVelocityTracker(event);
// 假如scroller滚动还没有结束，我们直接返回
if (!scroller.isFinished())
{
return super.dispatchTouchEvent(event);
}
downX = (int) event.getX();
downY = (int) event.getY();
slidePosition = pointToPosition(downX, downY);
// 无效的position, 不做任何处理
if (slidePosition == AdapterView.INVALID_POSITION)
{
return super.dispatchTouchEvent(event);
}
// 获取我们点击的item view
itemView = getChildAt(slidePosition - getFirstVisiblePosition());
break;
}
case MotionEvent.ACTION_MOVE:
{
if (Math.abs(getScrollVelocity()) > SNAP_VELOCITY || (Math.abs(event.getX() - downX) > mTouchSlop && Math.abs(event.getY() - downY) < mTouchSlop))
{
isSlide = true;
}
break;
}
case MotionEvent.ACTION_UP:
recycleVelocityTracker();
break;
}
return super.dispatchTouchEvent(event);
}
/**
* 往右滑动，getScrollX()返回的是左边缘的距离，就是以View左边缘为原点到开始滑动的距离，所以向右边滑动为负值
*/
private void scrollRight()
{
removeDirection = RemoveDirection.RIGHT;
final int delta = (screenWidth + itemView.getScrollX());
// 调用startScroll方法来设置一些滚动的参数，我们在computeScroll()方法中调用scrollTo来滚动item
scroller.startScroll(itemView.getScrollX(), 0, -delta, 0, Math.abs(delta));
postInvalidate(); // 刷新itemView
}
/**
* 向左滑动，根据上面我们知道向左滑动为正值
*/
private void scrollLeft()
{
removeDirection = RemoveDirection.LEFT;
final int delta = (screenWidth - itemView.getScrollX());
// 调用startScroll方法来设置一些滚动的参数，我们在computeScroll()方法中调用scrollTo来滚动item
scroller.startScroll(itemView.getScrollX(), 0, delta, 0, Math.abs(delta));
postInvalidate(); // 刷新itemView
}
/**
* 根据手指滚动itemView的距离来判断是滚动到开始位置还是向左或者向右滚动
*/
private void scrollByDistanceX()
{
// 如果向左滚动的距离大于屏幕的三分之一，就让其删除
if (itemView.getScrollX() >= screenWidth / 3)
{
scrollLeft();
}
else if (itemView.getScrollX() <= -screenWidth / 3)
{
scrollRight();
}
else
{
// 滚回到原始位置,为了偷下懒这里是直接调用scrollTo滚动
itemView.scrollTo(0, 0);
}
}
/**
* 处理我们拖动ListView item的逻辑
*/
@Override
public boolean onTouchEvent(MotionEvent ev)
{
if (isSlide && slidePosition != AdapterView.INVALID_POSITION)
{
addVelocityTracker(ev);
final int action = ev.getAction();
int x = (int) ev.getX();
switch (action)
{
case MotionEvent.ACTION_MOVE:
int deltaX = downX - x;
downX = x;
// 手指拖动itemView滚动, deltaX大于0向左滚动，小于0向右滚
itemView.scrollBy(deltaX, 0);
break;
case MotionEvent.ACTION_UP:
int velocityX = getScrollVelocity();
if (velocityX > SNAP_VELOCITY)
{
scrollRight();
}
else if (velocityX < -SNAP_VELOCITY)
{
scrollLeft();
}
else
{
scrollByDistanceX();
}
recycleVelocityTracker();
// 手指离开的时候就不响应左右滚动
isSlide = false;
break;
}
return true; // 拖动的时候ListView不滚动
}
// 否则直接交给ListView来处理onTouchEvent事件
return super.onTouchEvent(ev);
}
@Override
public void computeScroll()
{
// 调用startScroll的时候scroller.computeScrollOffset()返回true，
if (scroller.computeScrollOffset())
{
// 让ListView item根据当前的滚动偏移量进行滚动
itemView.scrollTo(scroller.getCurrX(), scroller.getCurrY());
postInvalidate();
// 滚动动画结束的时候调用回调接口
if (scroller.isFinished())
{
if (mRemoveListener == null)
{
// mRemoveListener = new SimpleRemoveListenerImpl();
throw new NullPointerException("RemoveListener is null, we should called setRemoveListener()");
}
itemView.scrollTo(0, 0);
mRemoveListener.removeItem(removeDirection, slidePosition);
}
}
}
/**
* 添加用户的速度跟踪器
*
* @param event
*/
private void addVelocityTracker(MotionEvent event)
{
if (velocityTracker == null)
{
velocityTracker = VelocityTracker.obtain();
}
velocityTracker.addMovement(event);
}
/**
* 移除用户速度跟踪器
*/
private void recycleVelocityTracker()
{
if (velocityTracker != null)
{
velocityTracker.recycle();
velocityTracker = null;
}
}
/**
* 获取X方向的滑动速度,大于0向右滑动，反之向左
*
* @return
*/
private int getScrollVelocity()
{
velocityTracker.computeCurrentVelocity(1000);
int velocity = (int) velocityTracker.getXVelocity();
return velocity;
}
/**
*
* 当ListView item滑出屏幕，回调这个接口 我们需要在回调方法removeItem()中移除该Item,然后刷新ListView
*
* @author xiaanming
*
*/
public interface RemoveListener
{
public void removeItem(RemoveDirection direction, int position);
}
@Override
protected void onDraw(Canvas canvas)
{
canvas.drawBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.image2), 0, 0, null);
super.onDraw(canvas);
}
}