访问内部存储中的音乐文件。 安卓

Question

我有以下方法：

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_list_of_songs);
        ListView songsListView = findViewById(R.id.songList);
        songsList = new ArrayList<Song>();
        if (isStoragePermissionGranted()) {
            getSongsList();
        }
        Collections.sort(songsList, new Comparator<Song>() {
            @Override
            public int compare(Song o1, Song o2) {
                return o1.getTitle().compareTo(o2.getTitle());
            }
        });
        SongAdapter adapter = new SongAdapter(this, songsList);
        songsListView.setAdapter(adapter);
    }

    public void getSongsList(){
        ContentResolver musicResolver = getContentResolver();
        Uri musicUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
        @SuppressLint("Recycle")
        Cursor musicCursor = musicResolver.query(musicUri,null,null,null,null);
        if (musicCursor!=null && musicCursor.moveToFirst()){
            int titleColumn = musicCursor.getColumnIndex(MediaStore.Audio.Media.TITLE);
            int idColumn = musicCursor.getColumnIndex(MediaStore.Audio.Media._ID);
            int artistColumn = musicCursor.getColumnIndex(MediaStore.Audio.Media.ARTIST);
            do{
                long thisId = musicCursor.getLong(idColumn);
                String thisTitle = musicCursor.getString(titleColumn);
                String thisArtist = musicCursor.getString(artistColumn);
                songsList.add(new Song(thisId, thisTitle, thisArtist));
            }while (musicCursor.moveToNext());
        }
    }

    public  boolean isStoragePermissionGranted() {
        String TAG = this.getClass().getSimpleName();
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (checkSelfPermission(android.Manifest.permission.WRITE_EXTERNAL_STORAGE)
                    == PackageManager.PERMISSION_GRANTED) {
                Log.v(TAG,"Permission is granted");
                return true;
            } else {

                Log.v(TAG,"Permission is revoked");
                ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
                return false;
            }
        }
        else { //permission is automatically granted on sdk<23 upon installation
            Log.v(TAG,"Permission is granted");
            return true;
        }
    }

具有此方法的活动应按字母顺序显示内部存储中的歌曲列表。 但是当我运行程序时，我在这个活动中看不到任何东西。 当我在日志中观看时，我没有看到任何带有此活动标签的内容，但是当我在调试器中观看时，我看到该方法boolean isStoragePermissionGranted()返回false

所以，在这种情况下，我有一个问题：如何获得从内部存储中获取音乐的许可？

Answer 1

您还应该检查 READ_EXTERNAL_STORAGE

public  boolean isReadStoragePermissionGranted() {
    if (Build.VERSION.SDK_INT >= 23) {
        if (checkSelfPermission(Manifest.permission.READ_EXTERNAL_STORAGE)
                == PackageManager.PERMISSION_GRANTED) {
            Log.v(TAG,"Permission is granted1");
            return true;
        } else {

            Log.v(TAG,"Permission is revoked1");
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, 3);
            return false;
        }
    }
    else { //permission is automatically granted on sdk<23 upon installation
        Log.v(TAG,"Permission is granted1");
        return true;
    }
}