使用ViewPager作为一个页面进行切换，里面可以存放很多View，但有时在操作View时不小心滑动一下就有可能跳到下一页，这并不是我们想要的，这里就需要重写ViewPager修改它的滑动条件
效果图
程序目录结构
BTViewPager.java
package com.example.viewpagerdemo;
import android.content.Context;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.widget.Scroller;
/**
* 解决ViewPager滑动过于灵敏，只有滑动距离大于100才滑到另一页
*
* @author Administrator
*
*/
public class BTViewPager extends ViewPager {
private static final String TAG = "dzt_pager";
private static final int MOVE_LIMITATION = 100;// 触发移动的像素距离
private float mLastMotionX; // 手指触碰屏幕的最后一次x坐标
private int mCurScreen;
private Scroller mScroller; // 滑动控件
public BTViewPager(Context context) {
super(context);
// TODO Auto-generated constructor stub
init(context);
}
public BTViewPager(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO Auto-generated constructor stub
init(context);
}
private void init(Context context) {
mScroller = new Scroller(context);
mCurScreen = 0;// 默认设置显示第一个VIEW
}
@Override
public boolean onTouchEvent(MotionEvent event) {
// TODO Auto-generated method stub
final int action = event.getAction();
final float x = event.getX();
switch (action) {
case MotionEvent.ACTION_DOWN:
Log.d(TAG, "[BTViewPager->]onTouchEvent ACTION_DOWN");
mLastMotionX = x;
break;
case MotionEvent.ACTION_MOVE:
Log.d(TAG, "[BTViewPager->]onTouchEvent ACTION_MOVE");
break;
case MotionEvent.ACTION_UP:
Log.d(TAG, "Item = " + getCurrentItem() + " count = "
+ getChildCount());
if (Math.abs(x - mLastMotionX) ]onTouchEvent--end");
return super.onTouchEvent(event);
}
@Override
public void computeScroll() {
// TODO Auto-generated method stub
Log.d(TAG, "[BTViewPager->]computeScroll");
super.computeScroll();
if (mScroller.computeScrollOffset()) {
Log.d(TAG,
"[BTViewPager->]computeScroll x = " + mScroller.getCurrX());
scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
invalidate();
}
}
/**
* 根据滑动的距离判断移动到第几个视图
*/
public void snapToDestination() {
final int screenWidth = getWidth();
final int destScreen = (getScrollX() + screenWidth / 2) / screenWidth;
Log.d(TAG, "[BTViewPager->]snapToDestination screenWidth = "
+ screenWidth + " destScreen = " + destScreen);
snapToScreen(destScreen);
}
/**
* 滚动到制定的视图
*
* @param whichScreen
*视图下标
*/
public void snapToScreen(int whichScreen) {
// whichScreen = Math.max(0, Math.min(whichScreen, getChildCount() -
// 1));
if (getScrollX() != (whichScreen * getWidth())) {
final int delta = whichScreen * getWidth() - getScrollX();
Log.d(TAG, "[BTViewPager->]snapToScreen-whichScreen = "
+ whichScreen + " delta = " + delta + " scrollX = "
+ getScrollX());
mScroller.startScroll(getScrollX(), 0, delta, 0,
Math.abs(delta) * 2);
mCurScreen = whichScreen;
invalidate();
}
}
/**
* 用于拦截手势事件的，每个手势事件都会先调用这个方法。Layout里的onInterceptTouchEvent默认返回值是false,
* 这样touch事件会传递到childview控件 ，如果返回false子控件可以响应，否则了控件不响应，这里主要是拦截子控件的响应，
* 对ViewGroup不管返回值是什么都会执行onTouchEvent
*/
@Override
public boolean onInterceptTouchEvent(MotionEvent arg0) {
// TODO Auto-generated method stub
Log.d(TAG, "[BTViewPager->]onInterceptTouchEvent");
final int action = arg0.getAction();
final float x = arg0.getX();
switch (action) {
case MotionEvent.ACTION_DOWN:
Log.d(TAG, "onInterceptTouchEvent---ACTION_DOWN ");
mLastMotionX = x;
break;
case MotionEvent.ACTION_MOVE:
Log.d(TAG, "onInterceptTouchEvent---ACTION_MOVE ");
break;
case MotionEvent.ACTION_UP:
Log.d(TAG, "onInterceptTouchEvent---ACTION_UP ");
break;
default:
break;
}
return super.onInterceptTouchEvent(arg0);
}
}
只要是在onTouchEvent的UP中处理滑动的条件
if (Math.abs(x - mLastMotionX) 只有滑动的距离大于100才进行上下页处理，否则就停在当前页，当前页使用getCurrentItem()获取，有一点要注意在ViewPager中getChildCount()获取的值是错误的，不清楚是什么原因，在ViewGroup中是有效的，这个可能要查看ViewPager源码才能弄清楚是什么原因，有知道的朋友可以告知我！
完整Demo：http://download.csdn.net/detail/deng0zhaotai/7384637
