为ListView创建ContextMenu

ContextMenu称为上下文菜单，一般在控件上长按时弹出。今天我们学习ContextMenu的用法，这里与listview相结合，先在ListView显示几个Item,然后在Item上长按，弹出一个菜单（就是ContextMenu）,点击菜单上的项目，提示刚才长按的Item的Position。

main.xml文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent" android:layout_height="fill_parent"
    android:orientation="vertical">

	<TextView android:id="@+id/text" android:text="zzz"
		android:textSize="18sp" android:textColor="#FFFFFF"
		android:layout_width="fill_parent" android:layout_height="wrap_content"/>
	
	<ListView android:id="@+id/list"
		android:layout_width="fill_parent" android:layout_height="fill_parent">
	</ListView>
</LinearLayout>

菜单有3个条目，在/res/menu/test_menu.xml中定义，和OptionMenu差不多，只是没有Icon

package com.hello.menu;

import android.app.Activity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ContextMenu.ContextMenuInfo;
import android.widget.AdapterView.AdapterContextMenuInfo;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;

public class ApiDemos extends Activity {
    /** Called when the activity is first created. */
	
	private TextView mTextView;
	private ListView mListView;
	private String [] values;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        mTextView = (TextView) findViewById(R.id.text);

        //下面的代码用于初始化一些数据
        values = new String[30];
        StringBuilder sb = new StringBuilder("z");
        for (int i = 0; i < values.length; i++) {
        	sb.append(i);
        	values[i] = sb.toString();
        }

        mListView = (ListView) findViewById(R.id.list);
        mListView.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, values));
        mTextView.setText(String.valueOf(mListView.getAdapter().getCount()));
        
        //为ListView注册ContextMenu
        registerForContextMenu(mListView);
    }

    //创建ContextMenu
    @Override
    public void onCreateContextMenu(ContextMenu menu, View v,
    		ContextMenuInfo menuInfo) {
    	// TODO Auto-generated method stub
    	if (v.getId() == R.id.list) {
	    	MenuInflater inflater = getMenuInflater();
	        menu.setHeaderTitle("contextView sample").setHeaderIcon(R.drawable.icon);
	        inflater.inflate(R.menu.test_menu, menu);
    	}
    	super.onCreateContextMenu(menu, v, menuInfo);
    }
    
    @Override
    public boolean onContextItemSelected(MenuItem item) {
    	// TODO Auto-generated method stub
    	if (item.getMenuInfo() instanceof AdapterContextMenuInfo) {
    		AdapterContextMenuInfo menuInfo = (AdapterContextMenuInfo) item.getMenuInfo();
                //处理菜单的点击事件
    		switch (item.getItemId()) {
    		case R.id.call:
    			mTextView.setText(item.getTitle().toString() + menuInfo.position);
    			break;
    		case R.id.cc:
                        mTextView.setText(item.getTitle().toString() + menuInfo.position);
    			break;
    		case R.id.poweroff :
                        mTextView.setText(item.getTitle().toString() + menuInfo.position);
    			break;
    		}
    		
    	}
    	return super.onContextItemSelected(item);
    }
}