Question

如果事实证明这是一个愚蠢的问题我很抱歉，它可能会成为一个快速解决方案，但我无法弄明白。我在android studio中构建一个音乐播放器，并且没有sdcard上的歌曲都没有出现在列表视图中，只有内存中的那些，即使我确实实现了getExternalStorageDirectory（）并在清单中添加了权限文件。关于这种或建设性批评的任何意见都是非常苛刻的。这是主要的java类。

public class MainActivity extends AppCompatActivity {

    ListView lv;
    String[] items;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        lv = (ListView) findViewById(R.id.lvPlayList);

        //---------------------------------------------> V HERE V <-------------------------

        final ArrayList<File> mySongs = findSongs(Environment.getExternalStorageDirectory());
        //----------------------------------------------------------------------------------
        items = new String[ mySongs.size() ];

        for(int i = 0; i<mySongs.size(); i++) {
            toast(mySongs.get(i).getName().toString());
            items[i] = mySongs.get(i).getName().toString().replace(".mp3", "").replace(".wav", "");
        }

        ArrayAdapter<String> adp = new ArrayAdapter<>(getApplicationContext(), R.layout.song_layout, R.id.textView, items);
        lv.setAdapter(adp);
        lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                startActivity(new Intent(getApplicationContext(), Player.class).putExtra("pos",position).putExtra("songlist",mySongs));
            }
        });
    }

    public ArrayList<File> findSongs(File root) {
        ArrayList<File> al = new ArrayList<>();
        File[] files = root.listFiles();
        for(File singleFile : files) {
            if(singleFile.isDirectory() && !singleFile.isHidden()) {
                al.addAll(findSongs(singleFile));
            } else {
                if(singleFile.getName().endsWith(".mp3") || singleFile.getName().endsWith(".wav")) {
                    al.add(singleFile);
                }
            }
        }
        return al;
    }

    public void toast(String text) {
        Toast.makeText(getApplicationContext(), text, Toast.LENGTH_SHORT).show();
    }
}

Answer 1

使用此方法从您的设备获取filePath列表

 ArrayList<String> findSongs(String rootPath) {
    ArrayList<String> fileList = new ArrayList<>();
    try{
       File rootFolder = new File(rootPath);
       File[] files = rootFolder.listFiles(); //here you will get NPE if directory doesn't contains  any file,handle it like this.
       for (File file : files) {
         if (file.isDirectory()) {
               if (findSongs(file.getAbsolutePath()) != null) {
                    fileList.addAll(findSongs(file.getAbsolutePath()));
                } else {
                    break;
                }
         } else if (file.getName().endsWith(".mp3")) {
             fileList.add(file.getAbsolutePath());
         }
    }
    return fileList;
    }catch(Exception e){
       return null;
    }
}

但你需要从sdCard获取文件，为那个传递＆＃34; / storage / sdcard1 /＆＃34;作为findSongs（String path）方法的参数，如下所示：

onCreate(Bundle svaeInstance){
 ........
 ........
  if(findSongs("/storage/sdcard1/")!=null){
    ArrayList<String> listOfFilePath=findSongs("/storage/sdcard1/"); // here you will get all the files path which contains .mp3 at the end.
 //do the remaining stuff
  }else { Toast.makeText(this, "sdCard not available", Toast.LENGTH_SHORT).show();
  }
 ......
}

注意：使用＆＃34; / storage / sdcard1 /＆＃34;用于从sdCard读取文件并使用Environment.getExternalStorageDirectory（）。getAbsolutePath（）从手机内存中读取文件。

希望这会对你有所帮助。

Android Studio音乐播放器无法从SD卡读取，只能读取内存

1 个答案: