解决ListView中的Item点击事件和子控件的冲突或者item点击没有反应

fragment中添加了button和checkbox这些控件，此时这些子控件会将焦点获取到，所以常常当点击item时变化的是子控件，item本身的点击没有响应。

这时候就可以使用descendantFocusability来解决啦，API描述如下：
android:descendantFocusability

该属性是当一个为view获取焦点时，定义viewGroup和其子控件两者之间的关系。

属性的值有三种：

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

通常我们用到的是第三种，即在Item布局的根布局加上android:descendantFocusability=”blocksDescendants”的属性。

写这个demo顺便复习一下BaseAdapter

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class Audition1 extends Activity {

    private ListView listView;
a
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_audition1);
        initComponents();

    }

    private void initComponents() {
        listView = (ListView) findViewById(R.id.listView);
        listView.setAdapter(new MyAdapter(this));
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView arg0, View arg1, int arg2,
                    long arg3) {
                Toast.makeText(getApplicationContext(), "item", 300).show();

            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_audition1, menu);
        return true;
    }

    public final class ViewHolder {
        public TextView textView;
        public Button button;
        public ImageView imageView;
    }

    class MyAdapter extends BaseAdapter {

        private LayoutInflater mInflater;

        public MyAdapter(Context context) {
            this.mInflater = LayoutInflater.from(context);
        }

        @Override
        public int getCount() {
            return 3;
        }

        @Override
        public Object getItem(int position) {
            return null;
        }

        @Override
        public long getItemId(int position) {
            return position;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            ViewHolder holder = null;
            if (convertView == null) {
                holder = new ViewHolder();

                convertView = mInflater.inflate(R.layout.item, null);
                holder.imageView = (ImageView) convertView
                        .findViewById(R.id.imageView);
                holder.textView = (TextView) convertView
                        .findViewById(R.id.textViewId);
                holder.button = (Button) convertView.findViewById(R.id.button);
                holder.textView.setText("shit");
                holder.button.setOnClickListener(new View.OnClickListener() {

                    @Override
                    public void onClick(View v) {
                        AlertDialog.Builder builder = new AlertDialog.Builder(
                                Audition1.this);
                        builder.setMessage("dialog");
                        builder.setTitle("title");
                        builder.create();
                        builder.show();
                    }
                });
                convertView.setTag(holder);
            } else {
                convertView.getTag();
            }

            return convertView;
        }

    }

}

    xmlns:tools="http://schemas.android.com/tools"
    android:layout_
    android:layout_ >

            android:id="@+id/listView"
        android:layout_
        android:layout_
        android:padding="@dimen/padding_medium"
        tools:context=".Audition1"
        android:divider/>

?

    xmlns:tools="http://schemas.android.com/tools"
    android:layout_
    android:layout_
    android:orientation="horizontal">
 
            android:id="@+id/textViewId"
        android:layout_
        android:layout_
        android:text="@string/hello_world"
        />
            android:id="@+id/imageView"
        android:layout_
        android:layout_
        android:src="@drawable/ic_launcher"
        android:contentDescription="@string/app_name"
        />
 
            android:id="@+id/button"
        android:layout_
        android:layout_
        android:text="press"
        android:focusable="false"
        />
 

原因是button强制获取了item的焦点，只要设置button的focusable为false即可。