我想播放用户以前选择的音乐文件。选择文件似乎是可行的（我得到了一个看起来合理的路径），获得权限也是可行的，但是媒体播放器抛出filenotfound。因为我提前10秒选择了这个文件，所以它必须存在。
错误出现在“播放音乐”功能中
我的代码是：

public class Settings extends Fragment {

    View mView;
    final int MY_STORAGE_PERMISSION_CODE = 101;

    public Settings() {}

   public static Settings newInstance(String param1, String param2) {
        Settings fragment = new Settings();
        Bundle args = new Bundle();
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_settings, container, false);
        mView = view;
        String musicFileFromDatabase = DatabaseInteractor.getDatabaseInteractor(view.getContext()).
                getSetting(DatabaseInteractor.SETTING_MUSIC_FILE);  //gets saved path to music file from database

        view.findViewById(R.id.musicFileLabel).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent;
                intent = new Intent();
                intent.setAction(Intent.ACTION_GET_CONTENT);
                intent.setType("audio/mpeg");
                startActivityForResult(Intent.createChooser(intent, getString(R.string.select_audio_file_title)), 1);
            }
        });

        view.findViewById(R.id.button_play_music).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(DatabaseInteractor.getDatabaseInteractor(getContext()).getSetting(DatabaseInteractor.SETTING_MUSIC_FILE).equals("")) {
                    Toast.makeText(getContext(), R.string.select_a_file_first, Toast.LENGTH_LONG).show();
                    return;
                }
                if(ContextCompat.checkSelfPermission(getActivity().getApplicationContext(),
                        Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
                    requestPermissions(new String[] {Manifest.permission.READ_EXTERNAL_STORAGE },MY_STORAGE_PERMISSION_CODE);
                } else {
                    playMusic();
                }
            }
        });
        return view;
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == 1 && resultCode == Activity.RESULT_OK) {
            if ((data != null) && (data.getData() != null)) {
                Uri audioFileUri = data.getData();
                String path = audioFileUri.getPath();
                //put the path as String into database
                DatabaseInteractor.getDatabaseInteractor(this.getContext()).
                        updateSetting(DatabaseInteractor.SETTING_MUSIC_FILE, path);
                Navigation.findNavController(mView).navigate(SettingsDirections.actionSettingsSelf());
            }
        }
    }
    @Override
    public void onRequestPermissionsResult(int requestCode,@NonNull String[] permissions,@NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode,permissions,grantResults);
        if (requestCode == MY_STORAGE_PERMISSION_CODE) {
            if (grantResults.length > 0
                    && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                playMusic();
            }
            else {
                Toast.makeText(getContext(),
                        R.string.app_needs_permission,
                        Toast.LENGTH_LONG)
                        .show();
            }
        }
    }
    private void playMusic() {
        String filePath = "file:///" + DatabaseInteractor.getDatabaseInteractor(getContext()).
                getSetting(DatabaseInteractor.SETTING_MUSIC_FILE);
        Uri uri= Uri.parse(filePath);

        MediaPlayer mediaPlayer = new MediaPlayer();
        mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
        try {
            mediaPlayer.setDataSource(getActivity().getApplicationContext(), uri);
            mediaPlayer.prepare();
            mediaPlayer.start();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

我的目标是：

W/System.err: java.io.FileNotFoundException: /external/audio/media/167714: open failed: ENOENT (No such file or directory)
W/System.err:     at libcore.io.IoBridge.open(IoBridge.java:496)
W/System.err:     at java.io.FileInputStream.<init>(FileInputStream.java:159)
        at android.media.MediaPlayer.setDataSource(MediaPlayer.java:1264)
        at android.media.MediaPlayer.setDataSource(MediaPlayer.java:1208)
        at android.media.MediaPlayer.setDataSource(MediaPlayer.java:1173)
        at android.media.MediaPlayer.setDataSource(MediaPlayer.java:1103)
W/System.err:     at android.media.MediaPlayer.setDataSource(MediaPlayer.java:1049)
        at de.annikaknepper.archery.Settings.playMusic(Settings.java:130)
        at de.annikaknepper.archery.Settings.access$000(Settings.java:34)
        at de.annikaknepper.archery.Settings$2.onClick(Settings.java:85)
        at android.view.View.performClick(View.java:7192)
        at android.view.View.performClickInternal(View.java:7166)
W/System.err:     at android.view.View.access$3500(View.java:824)
        at android.view.View$PerformClick.run(View.java:27592)
        at android.os.Handler.handleCallback(Handler.java:888)
        at android.os.Handler.dispatchMessage(Handler.java:100)
W/System.err:     at android.os.Looper.loop(Looper.java:213)
        at android.app.ActivityThread.main(ActivityThread.java:8178)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:513)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1101)
W/System.err: Caused by: android.system.ErrnoException: open failed: ENOENT (No such file or directory)
W/System.err:     at libcore.io.Linux.open(Native Method)
        at libcore.io.ForwardingOs.open(ForwardingOs.java:167)
        at libcore.io.BlockGuardOs.open(BlockGuardOs.java:252)
        at libcore.io.ForwardingOs.open(ForwardingOs.java:167)
        at android.app.ActivityThread$AndroidOs.open(ActivityThread.java:8046)
        at libcore.io.IoBridge.open(IoBridge.java:482)
W/System.err:   ... 20 more