怎么得到listview长按事件中按的是哪个条目？用这个方法不行啊

just4rmb 2012-08-04 09:33:32

在处理android中listview的长按事件中，我需要知道长按的是哪个条目，用了网上的一个方法，理应成功，却没有成功，贴出来请教一下各位高手,从setOnCreateContextMenuListener开始往下看就行



package com.example.myktvlist;



import java.util.ArrayList;

import java.util.HashMap;

import android.app.Activity;

import android.content.ContentValues;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

import android.os.Bundle;

import android.text.TextUtils;

import android.view.ContextMenu;

import android.view.ContextMenu.ContextMenuInfo;

import android.view.MenuItem;

import android.view.View;

import android.view.View.OnCreateContextMenuListener;

import android.widget.AdapterView;

import android.widget.AdapterView.AdapterContextMenuInfo;

import android.widget.AdapterView.OnItemLongClickListener;

import android.widget.AdapterView.OnItemClickListener;

import android.widget.ListView;

import android.widget.SimpleAdapter;

import android.widget.TextView;

import android.widget.Toast;



public class ListActivity extends Activity{

	//private String songName;

	//private String singerName;



	protected static final int COMFIRM = 0;



	public void onCreate(Bundle savedInstanceState) {

		final int CONFIRM = 1; 

		System.out.println("step into listActivity");

		super.onCreate(savedInstanceState);

		setContentView(R.layout.my_list_view);

		final ListView list = (ListView)findViewById(R.id.MyListView); 

		ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();

		DatabaseHelper dbHelper = new DatabaseHelper(ListActivity.this,"songList");

		SQLiteDatabase db = dbHelper.getReadableDatabase();

		Cursor cursor = db.query("user", new String[]{"songName","singerName"}, "id=?",new String[]{"1"},null,null, null);

		System.out.println("query complete");

		cursor.moveToFirst();

		if(cursor.isFirst())

			System.out.println("moveToFirst complete");

		do{

			System.out.println("step into while");

			String songName = cursor.getString(cursor.getColumnIndex("songName"));

			String singerName = cursor.getString(cursor.getColumnIndex("singerName"));

			//如果是多项数据怎么办呢？

			System.out.println("getData complete");

	       	HashMap<String, String> map = new HashMap<String, String>();

        	map.put("songName",songName);

        	map.put("singerName",singerName);

        	System.out.println("putData complete");

        	mylist.add(map);

        	System.out.println("addData complete");

			//System.out.println("query--->" + name);

			System.out.println(singerName);

		}while(cursor.moveToNext());

		SimpleAdapter mSchedule = new SimpleAdapter(this, //没什么解释

				mylist,//数据来源 

                R.layout.my_list_item,//ListItem的XML实现

                //动态数组与ListItem对应的子项        

                new String[] {"songName", "singerName"}, 

                //ListItem的XML文件里面的两个TextView ID

                new int[] {R.id.songName,R.id.singerName});

				//添加并且显示

		list.setAdapter(mSchedule);

		

		list.setOnCreateContextMenuListener(new OnCreateContextMenuListener(){

			public void onCreateContextMenu(ContextMenu menu, View arg1,ContextMenuInfo arg2) {

				menu.setHeaderTitle(R.string.contentMenu);

				menu.add(0, COMFIRM, 6,R.string.confirm);

				menu.add(1,1,5,"hah");

			}

		});

		list.setOnItemLongClickListener(new OnItemLongClickListener() {



			public boolean onItemLongClick(AdapterView<?> ada, View view,

					int index, long longIndex) {

				list.showContextMenu();

				return true;

			}

		});

		list.setOnItemClickListener(new OnItemClickListener(){

			//Toast t=Toast.makeText(this, "长按删除该曲目", Toast.LENGTH_LONG);

			//t.show();

			public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,

					long arg3) {

				// TODO Auto-generated method stub			

			}

		});

		db.close();

	}	



	//怎么在这个函数知道选择的是哪个条目？

	public boolean onContextItemSelected(MenuItem item) {

		AdapterContextMenuInfo info = (AdapterContextMenuInfo) item

				.getMenuInfo();

		// info.targetView得到list.xml中的LinearLayout对象.

		System.out.println("item = " + item);

		System.out.println("info = " + info);

		String songName = ((TextView) info.targetView.findViewById(R.id.songName)) //R.id.confirm

				.getText().toString();

		System.out.println("songName is");

		System.out.println(songName);

		if (!TextUtils.isEmpty(songName)) {

			if(item.getItemId() == COMFIRM) {

				DatabaseHelper dbHelper = new DatabaseHelper(ListActivity.this,"songList");

				SQLiteDatabase db = dbHelper.getWritableDatabase();

				ContentValues values = new ContentValues();

				db.delete("user","songName",new String[]{"chen"});

			}

		}

		return false;

	}

}

功能是长按listview中的条目，显示“确实删除吗？”的菜单，在点击“确认”之后会删除所选的条目。
但是我用onContextItemSelected这个函数中的item中用AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();得到的info用System.out.print得到的却是null，这导致运行错误，怎么解决呢？

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AMinfo 2012-08-04

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[Quote=引用 3 楼的回复:]
好像找到错误之处了，是setOnItemLongClickListener要return false,这个函数returne false和true的区别在于啥？
[/Quote]

return false的意思是将长按事件传递给其他视图
return true的意思中止传递。

just4rmb 2012-08-04