BaseAdapter导致notifyDataSetChanged()无效的四个原因及处理方法

原地址： http://blog.csdn.net/dawanganban/article/details/21376979?utm_source=tuicool&utm_medium=referral
前一段时间在做一个项目的时候遇到了一个关于BaseAdapter的notifyDataSetChanged()方法无效问题，当时在网上搜了一个解决方法，今天又遇到了一个类似的问题，我在这里做个记录，防止以后再次发生，或者其他朋友再次遇到。

一、ScrollView中嵌套ListView或GridView

原因：两个的滚动监听冲突

解决方法：重写ListView或GridView

package com.meritit.lottery.view;

import android.content.Context;
import android.util.AttributeSet;
import android.widget.ListView;

public class SerialListView extends ListView {

public SerialListView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
// TODO Auto-generated constructor stub
}

public SerialListView(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO Auto-generated constructor stub
}

public SerialListView(Context context) {
super(context);
// TODO Auto-generated constructor stub
}

/**
* 为了取消滚动效果，可以放入滚动组建中重写了此方法
*/
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2,
MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec, expandSpec);
}

}

二、ListView或GridView的外部容器重写onTouchEvent(MotionEvent event)方法

详细请看：http://blog.csdn.net/xxxzhi/article/details/12314775

这类问题解决方法很简单，只需要onTouchEvent返回false即可

例如：

public boolean onTouchEvent(MotionEvent event) {
// TODO Auto-generated method stub
final int action = event.getAction();
final float x = event.getX();
final float y = event.getY();

switch (action) {
case MotionEvent.ACTION_DOWN:
System.out.println("父类点击onTouchEvent");
Log.i("", "onTouchEvent ACTION_DOWN");
if (mVelocityTracker == null) {
mVelocityTracker = VelocityTracker.obtain();
mVelocityTracker.addMovement(event);
}
if (!mScroller.isFinished()){
mScroller.abortAnimation();
}
mLastMotionX = x;
mLastMotionY = y;
break;

case MotionEvent.ACTION_MOVE:
System.out.println("父类滑动onTouchEvent");
int deltaX = (int)(mLastMotionX - x);
if (IsCanMove(deltaX))
{
if (mVelocityTracker != null)
{
mVelocityTracker.addMovement(event);
}
mLastMotionX = x;
scrollBy(deltaX, 0);
}

break;
case MotionEvent.ACTION_UP:
System.out.println("父类放开onTouchEvent");
int velocityX = 0;
if (mVelocityTracker != null)
{
mVelocityTracker.addMovement(event);
mVelocityTracker.computeCurrentVelocity(1000);
velocityX = (int) mVelocityTracker.getXVelocity();
}
if (velocityX > SNAP_VELOCITY && mCurScreen > 0) {
// Fling enough to move left
Log.e(TAG, "snap left");
snapToScreen(mCurScreen - 1);
} else if (velocityX < -SNAP_VELOCITY
&& mCurScreen < getChildCount() - 1) {
// Fling enough to move right
Log.e(TAG, "snap right");
snapToScreen(mCurScreen + 1);
} else {
snapToDestination();
}

if (mVelocityTracker != null) {
mVelocityTracker.recycle();
mVelocityTracker = null;
}
// mTouchState = TOUCH_STATE_REST;
break;
}
return false;
}
三、数据传值问题

注意改变Adapter内的数据，如下：list_contents和toparr是改变后的数据

mycqbaseAdapter.contents=list_contents;
mycqtitleAdapter.toparr = toparr;
mycqbaseAdapter.notifyDataSetChanged();
mycqtitleAdapter.notifyDataSetChanged();

有一种错误的写法就是直接调用notifyData方法

mycqbaseAdapter.notifyDataSetChanged();  
mycqtitleAdapter.notifyDataSetChanged(); 

四、ViewGroup中notifyDataSetChanged()无效

@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
// if (changed) {
menu_view = getChildAt(0);
content_view = getChildAt(1);

content_view.measure(0, 0);
content_view.layout(0, 0, getWidth(), getHeight());
// }
}

注释掉onLayout中的if(changed)即可。