Question

我正在我的音乐播放器上制作一个Android应用程序，其中我使用listview填充了我的设备中的所有歌曲，但是在Android 6.0中我的应用程序崩溃了，因为我打开它。当我没有时它不会崩溃在应用信息中手动提供存储权限，然后显示我的歌曲。我已经使用了android 6.0请求权限，它导致要求用户询问对存储的访问权限，但是它不再显示该列表。我坚持这个......！

MainActivity.java

public class MainActivity extends AppCompatActivity implements MediaPlayerControl  {
    private ArrayList<Song> songList;
    private ListView songView;
    private MusicController controller;
    private MusicService musicSrv;
    private Intent playIntent;
    private boolean musicBound=false;
    private boolean paused=false, playbackPaused=false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        songView = (ListView) findViewById(R.id.song_list);
        songList = new ArrayList<Song>();

    //Android 6.0
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE)
            != PackageManager.PERMISSION_GRANTED) {
        if (ActivityCompat.shouldShowRequestPermissionRationale(this,
                Manifest.permission.READ_EXTERNAL_STORAGE)) {


        } else {

        }
    } else {
        ActivityCompat.requestPermissions(this,
                new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},1002);
    }
}
//Android 6.0
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
    switch (requestCode){
        case 1002:
            if(grantResults.length>0 && grantResults[0]==PackageManager.PERMISSION_GRANTED){
                getSongList();
                // List songs in Alphabetical Order
                Collections.sort(songList, new Comparator<Song>() {
                    public int compare(Song a, Song b) {
                        return a.getTitle().compareTo(b.getTitle());
                    }
                });

                SongAdapter songAdt = new SongAdapter(this, songList);
                songView.setAdapter(songAdt);
                setController();
            }else{

            }
            return;
    }
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case R.id.action_shuffle:
            musicSrv.setShuffle();
            break;
        case R.id.action_end:
            stopService(playIntent);
            musicSrv = null;
            System.exit(0);
            break;
    }
    return super.onOptionsItemSelected(item);
}
@Override
protected void onStart() {
    super.onStart();
    if(playIntent==null) {
        playIntent = new Intent(this, MusicService.class);
        bindService(playIntent, musicConnection, Context.BIND_AUTO_CREATE);
        startService(playIntent);
    }
}

@Override
protected void onPause() {
    super.onPause();
    paused=true;
}

@Override
protected void onResume() {
    super.onResume();
    if(paused){
        setController();
        paused=false;
    }
}
@Override
protected void onStop() {
    controller.hide();
    super.onStop();
}
@Override
protected void onDestroy() {
    stopService(playIntent);
    musicSrv=null;
    super.onDestroy();
}
public void songPicked(View view){
    musicSrv.setSong(Integer.parseInt(view.getTag().toString()));
    musicSrv.playSong();
    if(playbackPaused){
        setController();
        playbackPaused=false;
    }controller.show(0);
}

//connect to the service
private ServiceConnection musicConnection = new ServiceConnection(){

    @Override
    public void onServiceConnected(ComponentName name, IBinder service) {
        MusicService.MusicBinder binder = (MusicService.MusicBinder)service;
        //get service
        musicSrv = binder.getService();
        //pass list
        musicSrv.setList(songList);
        musicBound = true;
    }

    @Override
    public void onServiceDisconnected(ComponentName name) {
        musicBound = false;
    }
};

public void getSongList() {
    //retrieve song info
    ContentResolver musicResolver = getContentResolver();
    Uri musicUri = android.provider.MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
    Cursor musicCursor = musicResolver.query(musicUri, null, null, null, null);

    if(musicCursor!=null && musicCursor.moveToFirst()){
        //get columns
        int titleColumn = musicCursor.getColumnIndex
                (android.provider.MediaStore.Audio.Media.TITLE);
        int idColumn = musicCursor.getColumnIndex
                (android.provider.MediaStore.Audio.Media._ID);
        int artistColumn = musicCursor.getColumnIndex
                (android.provider.MediaStore.Audio.Media.ARTIST);
        //add songs to list
        do {
            long thisId = musicCursor.getLong(idColumn);
            String thisTitle = musicCursor.getString(titleColumn);
            String thisArtist = musicCursor.getString(artistColumn);
            songList.add(new Song(thisId, thisTitle, thisArtist));
        }
        while (musicCursor.moveToNext());
    }
}

Answer 1

您可以使用此android library来更轻松地处理运行时权限。

如果您的Activity是PermisoActivity的子类，请求权限就像：

一样简单

    Permiso.getInstance().requestPermissions(new Permiso.IOnPermissionResult() {
    @Override
    public void onPermissionResult(Permiso.ResultSet resultSet) {
        if (resultSet.areAllPermissionsGranted()) {
            // Permission granted!
        } else {
            // Permission denied.
        }
    }

    @Override
    public void onRationaleRequested(Permiso.IOnRationaleProvided callback, String... permissions) {
        Permiso.getInstance().showRationaleInDialog("Title", "Message", null, callback);
    }
}, Manifest.permission.READ_EXTERNAL_STORAGE);

摇篮

 dependencies {
    compile 'com.greysonparrelli.permiso:permiso:0.2.0'
}

您也可以添加多个权限，请访问link分享。您可以详细了解所有信息。

Answer 2

此代码允许您通过检查是否已授予权限来在运行时请求权限，如果没有，请让用户启用权限。

if(ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_COARSE_LOCATION}, MY_PERMISSION_RESPONSE);
        }

在这种情况下检查的权限与位置服务有关。只需用你想要的任何许可来替换ACCESS_COARSE_LOCATION。

我想在app运行时android Marshmallow请求权限..！

2 个答案: