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关于音乐播放器空指针异常的问题 本人学习安卓不久,照着书上写了个音乐播放器,敲完代码是没有错误的,运行后发现出错了,一调试时显示音乐列表的activity出错了,现把MusicList代码贴上,希望各位大神看到帮忙解决,多谢! package com.example.musicplayer; import java.util.ArrayList; import java.util.HashMap; import java.util.Iterator; import java.util.List; import com.example.musicplayer.R.layout; import android.app.ListActivity; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.widget.ListView; import android.widget.SimpleAdapter; public class MusicList extends ListActivity{ private List<Mp3Info> mp3Infos=null; @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); setContentView(R.layout.local_mp3_list); } @Override protected void onResume() { // TODO Auto-generated method stub //获取目录下文件名称 FileUtils fileUtil=new FileUtils(); mp3Infos=fileUtil.getMp3Files("/mp3"); List<HashMap<String,String>> list=new ArrayList<HashMap<String,String>>(); //向list集合中添加信息对象 for(Iterator iterator=mp3Infos.iterator();iterator.hasNext();){ Mp3Info mp3Info=(Mp3Info)iterator.next(); HashMap<String, String> map=new HashMap<String, String>(); map.put("mp3_name", mp3Info.getMp3Name()); map.put("mp3_size", mp3Info.getMp3Size()); list.add(map); } //定义列表适配器 SimpleAdapter adapter=new SimpleAdapter(this,list,R.layout.mp3info_item, new String[]{"mp3_name","mp3_size"},new int[]{R.id.mp3_name,R.id.mp3_size}); setListAdapter(adapter); super.onResume(); } //选择跳转列表中的一个选项时,跳转到播放界面 @Override protected void onListItemClick(ListView l, View v, int position, long id) { // TODO Auto-generated method stub if(mp3Infos!=null){ Mp3Info mp3Info=mp3Infos.get(position); Intent intent=new Intent(); intent.putExtra("mp3Info", mp3Info); intent.setClass(this, MusicPlay.class); startActivity(intent); } } }
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