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