Android-Listveiw的checkbox,Button焦点问题

    
CheckBox抢占Item焦点，导致Item点击无效!
方法一：CheckBox设置android:clickable="false" 
方法二：在Item根布局或ListView布局设置android:descendantFocusability="blocksDescendants"

在ListView的Item中的Button,CheckBox等子控件会抢占焦点,使得点击item本身没有响应！
常用android:descendantFocusability=”blocksDescendants”覆盖子类控件焦点
    descendantFocusability属性定义viewGroup和其子控件之间关系：
    beforeDescendants：viewgroup会优先其子类控件而获取到焦点
    afterDescendants：viewgroup只有当其子类控件不需要获取焦点时才获取焦点
    blocksDescendants：viewgroup会覆盖子类控件而直接获得焦点

<LinearLayout
    android:descendantFocusability="blocksDescendants">
        
    <CheckBox
        android:clickable="false"/> 
</LinearLayout>

<ListView
    android:descendantFocusability="blocksDescendants"/>
        

适配器在getview()中重复使用[被移除屏幕的item,即不可见的项]
会造成被选中的checkbox重新出现，显示异常，故需要记录checkbox的状态！

public class MyAdapter extends BaseAdapter implements OnItemClickListener { 
    private HashMap<Integer, Boolean> isSelected; // 记录checkbox状态

    public MyAdapter() {        
        // 初始化所有checkbox为未选择  
        isSelected = new HashMap<Integer, Boolean>();  
        for (int i = 0; i < list.size(); i++)
            isSelected.put(i, false);
    }
    
    @Override  
    public View getView(int position, View convertView, ViewGroup arg2) {              
        ViewHolder holder;
        ...
        holder.cb.setChecked(isSelected.get(position)); // 更新checkbox状态
        return view;
    }  

    @Override  
    public void onItemClick(AdapterView<?> arg0, View view,  
            int position, long arg3) {
        // 切换checkbox状态
        isSelected.put(position, !isSelected.get(position));
        notifyDataSetChanged();
    }  

}  

public class MainActivity extends Activity {
    ...
    MyAdapter adp = new MyAdapter();
    listview.setAdapter(adp);
    listview.setOnItemClickListener(adp);
    ...
}

简书：http://www.jianshu.com/p/b2aa0485f7b8
CSDN博客: http://blog.csdn.net/qq_32115439/article/details/53710915
GitHub博客: http://lioil.win/2016/04/20/ListView-CheckBox.html
Coding博客: http://c.lioil.win/2016/04/20/ListView-CheckBox.html