android:ListActivity 无法打开 sdcard mp3 既不能播放 mp3

Posted 2023-04-19

【中文标题】android:ListActivity 无法打开 sdcard mp3 既不能播放 mp3

【英文标题】：android:ListActivity unable to open sdcard mp3 neither play mp3

【发布时间】：2015-09-29 11:36:46

【问题描述】：

ListActivity 在录制活动和新活动中尝试从 SD 卡打开保存的录制文件时关闭，显示 ListView 已启动但未从 externalsdcard 打开 sdcard 内容 mp3 以在其中播放文件！ 谢谢

这是我的代码

public class Droid extends ListActivity 

    private static final String MEDIA_PATH = new String(Environment
            .getExternalStorageDirectory().getPath());
    private List<String> songs = new ArrayList<String>();
    private MediaPlayer mp = new MediaPlayer();
    private int currentPosition = 0;

    @Override
    public void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);
        setContentView(R.layout.songlist);
        updateSongList();
    

    public void updateSongList() 
        File home = new File(MEDIA_PATH);
        if (home.listFiles(new Filter()).length > 0) 
            for (File file : home.listFiles(new Filter())) 
                songs.add(file.getName());
            

            ArrayAdapter<String> songList = new ArrayAdapter<String>(this,
                    R.layout.song_item, songs);
            setListAdapter(songList);
        
    

    class Filter implements FilenameFilter 
        public boolean accept(File dir, String name) 
            return (name.endsWith(".3gp"));
        
    

    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) 
        currentPosition = position;
        playSong(MEDIA_PATH + songs.get(position));
    

    private void playSong(String songPath) 
        try 

            mp.reset();
            mp.setDataSource(songPath);
            mp.prepare();
            mp.start();

            // Setup listener so next song starts automatically
            mp.setOnCompletionListener(new OnCompletionListener() 

                public void onCompletion(MediaPlayer arg0) 
                    nextSong();
                

            );

         catch (IOException e) 
            Log.v(getString(R.string.app_name), e.getMessage());
        
    

    private void nextSong() 
        if (++currentPosition >= songs.size()) 
            // Last song, just reset currentPosition
            currentPosition = 0;
         else 
            // Play next song
            playSong(MEDIA_PATH + songs.get(currentPosition));
        
    

songlist.xml

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

    <ListView android:id="@android:id/list"
              android:layout_
              android:layout_
              android:layout_weight="1"
              android:drawSelectorOnTop="false"/>

    <TextView android:id="@id/android:empty"
              android:layout_
              android:layout_
              android:text="@string/media"/>
</LinearLayout>

song_item.xml

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

    <TextView android:id="@android:id/text1"
        android:layout_
        android:layout_/>
</LinearLayout>

强制关闭选项菜单上的新类 Droid

    case R.id.droid:
      Intent dr = new Intent(MainActivity.this, Droid.class);
      startActivity(dr);
      return true;  

【问题讨论】：

需要查看堆栈跟踪

检查答案并给出答复

没有获取外部 sdcard mp3 来播放

可能是您的歌曲列表为空或为空

sdcard 里还有，但是无法获取文件和播放

【参考方案1】：

你没有在你的 Manifest 中声明你的 Drod Activity。

如果所有其他工作正常，则您应该发布堆栈跟踪。

【参考方案2】：

改变这个

 public class Droid extends ListActivity

到

  public class Droid extends Activity

  // U already define listview in xml so no need to extends activity as ListActivity


// implements this method,
   listview.setOnItemClickListener(new OnItemClickListener() 

        @Override
        public void onItemClick(AdapterView<?> arg0, View view,
                int position, long id) 
            currentPosition = position;
            playSong(MEDIA_PATH + songs.get(position));
        
    );

【讨论】：

onListItemClick err 也想玩