自动回滚的listview

package com.isoftstone.listviewdemo;

import android.content.Context;

import android.graphics.Rect;

import android.util.AttributeSet;

import android.util.Log;

import android.view.GestureDetector;

import android.view.MotionEvent;

import android.view.View;

import android.view.GestureDetector.OnGestureListener;

import android.view.animation.TranslateAnimation;

import android.widget.ListView;

public class MyListViewDemoActivity extends ListView {

private boolean outBound = false;

private int distance;

private int firstOut;

private static final String TAG = "wljie";

public MyListViewDemoActivity(Context context, AttributeSet attrs) {

super(context, attrs);

Log.d(TAG, "IN 1");

}

public MyListViewDemoActivity(Context context, AttributeSet attrs,

int defStyle) {

super(context, attrs, defStyle);

Log.d(TAG, "IN 2");

}

public MyListViewDemoActivity(Context context) {

super(context);

Log.d(TAG, "IN 3");

}

GestureDetector gestureDetector = new GestureDetector(

new OnGestureListener() {

@Override

public boolean onSingleTapUp(MotionEvent e) {

// TODO Auto-generated method stub

return false;

}

@Override

public void onShowPress(MotionEvent e) {

// TODO Auto-generated method stub

}

/**

* 手势滑动的时候触发

*/

@Override

public boolean onScroll(MotionEvent e1, MotionEvent e2,

float distanceX, float distanceY) {

Log.d(TAG, "ENTER onscroll");

int firstPos = getFirstVisiblePosition();

int lastPos = getLastVisiblePosition();

int itemCount = getCount();

// outbound Top

if (outBound && firstPos != 0 && lastPos != (itemCount - 1)) {

scrollTo(0, 0);

return false;

}

View firstView = getChildAt(firstPos);

View lastView = getChildAt(lastPos - 1);

if (!outBound)

firstOut = (int) e2.getRawY();

if (firstView != null

&& (outBound || (firstPos == 0

&& firstView.getTop() == 0 && distanceY < 0))) {

// Record the length of each slide

distance = firstOut - (int) e2.getRawY();

scrollTo(0, distance / 2);

return true;

}

if (lastView == null

&& (outBound || (lastPos == itemCount - 1 && distanceY > 0))) {

Log.d("bottom", "bottom");

distance = (int) (firstOut - e2.getRawY());// 此处应为正直，因为view向上<span

// style="background-color: rgb(160, 255, 255);">滑动</span>

scrollBy(0, distance / 2);

return true;

}

// outbound Bottom

return false;

}

@Override

public void onLongPress(MotionEvent e) {

// TODO Auto-generated method stub

}

@Override

public boolean onFling(MotionEvent e1, MotionEvent e2,

float velocityX, float velocityY) {

// TODO Auto-generated method stub

return false;

}

@Override

public boolean onDown(MotionEvent e) {

// TODO Auto-generated method stub

return false;

}

});

@Override

public boolean dispatchTouchEvent(MotionEvent event) {

Log.d(TAG, "dispatchTouchEvent");

int act = event.getAction();

if ((act == MotionEvent.ACTION_UP || act == MotionEvent.ACTION_CANCEL)

&& outBound) {

outBound = false;

// scroll back

}

if (!gestureDetector.onTouchEvent(event)) {

outBound = false;

} else {

outBound = true;

}

Rect rect = new Rect();

getLocalVisibleRect(rect);

TranslateAnimation am = new TranslateAnimation(0, 0, -rect.top, 0);

am.setDuration(300);

startAnimation(am);

scrollTo(0, 0);

return super.dispatchTouchEvent(event);

}

}