Mediaplayer出现问题并在ListView中播放歌曲

Question

I have a problem with playing songs, which are in listview.

Songs are correctly save, but I can not to play them.

I have a path of songs, so everything should work...

Here is a code in oncreate and outside:

  listView = (ListView) findViewById(R.id.filesList); ArrayList<String> FilesInFolder = GetFiles("/sdcard/Kandydaci"); listView.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, FilesInFolder)); listView.setOnItemClickListener(new AdapterView.OnItemClickListener() { public void onItemClick(AdapterView<?> parent, View v, int position, long id) { MediaPlayer mediaPlayer = new MediaPlayer(); try { File audioFile = getApplicationContext().getCacheDir(); String name = (String) parent.getItemAtPosition(position); String OUTPUT_FILE ="sdcard/Kandydaci/"+name; mediaPlayer.setDataSource(OUTPUT_FILE); mediaPlayer.prepare(); mediaPlayer.start(); } catch (IOException e) { e.printStackTrace(); } } }); public ArrayList<String> GetFiles(String DirectoryPath) { ArrayList<String> MyFiles = new ArrayList<String>(); File f = new File(DirectoryPath); f.mkdirs(); File[] files = f.listFiles(); if (files.length == 0) return null; else { for (int i=0; i<files.length; i++) MyFiles.add(files[i].getName()); } return MyFiles; } 

And here is bug, which I get after click on item in listview:

 E/ExtMediaPlayer-JNI: env->IsInstanceOf fails E/MediaPlayer-JNI: JNIMediaPlayerFactory: bIsQCMediaPlayerPresent 0 E/ExtMediaPlayer-JNI: env->IsInstanceOf fails E/MediaPlayer-JNI: JNIMediaPlayerFactory: bIsQCMediaPlayerPresent 0 E/FileSource: Failed to open file 'sdcard/Kandydaci/Thu Nov 30 17:36:34 GMT+01:00 2017.mp3'. (Permission denied) E/GenericSource: Failed to create data source! E/MediaPlayer: error (1, -2147483648) 

Answer 1

your code is absolutely correct but problem is you missed defining permission to access EXTERNAL STORAGE.

So go like that.

Declare in manifest:

   <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

Now add this code before list setting:

If(ContextCompat.checkSelfPermission(MainActivity.this, permission) != PackageManager.PERMISSION_GRANTED) 
 { 
      // Should we show an explanation?
      if (ActivityCompat.shouldShowRequestPermissionRationale(MainActivity.this, permission)) 
      {
            //This is called if user has denied the permission before
            //In this case I am just asking the permission again 
           ActivityCompat.requestPermissions(MainActivity.this, new String[]{permission}, requestCode); 
     }
     else 
     { 
           ActivityCompat.requestPermissions(MainActivity.this, new String[]{permission}, requestCode);
     } 
 }
 else {
       Toast.makeText(this, "" + permission + " is already granted.", Toast.LENGTH_SHORT).show(); 

  }

By this code you will get the storage access permissions, here permission is:

   String ="Manifest.permission.WRITE_EXTERNAL_STORAGE";

Happy coding!!