找不到媒体播放器文件异常

Question

I'm writing a basic android mp3 player app that uses the MediaPlayer app to play an mp3 file stored locally on an Android phone.

However, whenever I try calling MediaPlayer.create() i get a java.io.FileNotFoundException .

I've checked to make sure that the mp3 is in the correct path and I've tried running this on both an emulated Android and my own phone but I keep getting the same error.

Here's my onCreate function where I'm having the problem:

@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Uri uri = Uri.parse(Environment.getExternalStorageDirectory().getPath() + 
       "/Download/sam_stone.mp3");

    med = MediaPlayer.create(getApplicationContext(), uri);
}

Here's the error I'm getting:

java.io.FileNotFoundException: /storage/emulated/0/Download/sam_stone.mp3 (Permission denied) at java.io.FileInputStream.open(Native Method) at java.io.FileInputStream.(FileInputStream.java:146) at android.media.MediaPlayer.setDataSource(MediaPlayer.java:1088) at android.media.MediaPlayer.setDataSource(MediaPlayer.java:1067) at android.media.MediaPlayer.setDataSource(MediaPlayer.java:1009) at android.media.MediaPlayer.setDataSource(MediaPlayer.java:967) at android.media.MediaPlayer.create(MediaPlayer.java:874) at android.media.MediaPlayer.create(MediaPlayer.java:851) at android.media.MediaPlayer.create(MediaPlayer.java:830) at hn.mediaplayer.MainActivity.onCreate(MainActivity.java:48) at android.app.Activity.performCreate(Activity.java:6662) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2599) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707) at android.app .ActivityThread.-wrap12(ActivityThread.java) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:154) at android.app.ActivityThread.main(ActivityThread.java:6077) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)

Answer 1

Add permission in AndroidManifest.xml

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

and also add run time permission above android version 5.0

Answer 2

First thing is you need to add the permission to AndiodManifest.xml file

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

Then in your activity

public  boolean isStoragePermissionGranted() {
if (Build.VERSION.SDK_INT >= 23) {
    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 { 
    Log.v(TAG,"Permission is granted");
    return true;
}}

Then the permission result call back where you can resume the task :

@Override
 public void onRequestPermissionsResult(int requestCode, String[] permissions, 
 int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if(grantResults[0]== PackageManager.PERMISSION_GRANTED){
    Log.v(TAG,"Permission: "+permissions[0]+ " "+grantResults[0]);
}}

Answer 3

You have to add READ_EXTERNAL_STORAGE permission in manifest.

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

and from marshmallow and above you have to request from the users for Dangerous permission .

read doc for requesting runtime permission