I have my mp3 files in a folder and saved it in a particular path, I am not able to play the file from my code. How to play it?

```
String filePath = (File.separator+"storage"+File.separator+"emulated"+File.separator+"0"+File.separator + "sdcard" + File.separator + "Android" + File.separator + "obb" + File.separator + "convertMp3ToDb" + File.separator + "ldoce6_hwd_gb" + File.separator + fileName).toString();
                final File file = new File(filePath);
                Uri uri_path = Uri.fromFile(file);
                if (uri_path!=null) {
                    try {
                        mediaPlayer.setDataSource(uri_path.getPath());
                        mediaPlayer.prepare();                           
                        mediaPlayer.start();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }

```

My Log cat Error is:

```
 System.err: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.media.MediaPlayer.setDataSource(java.lang.String)' on a null object reference
W/System.err:     at com.mobifusion.android.ldoce5.Fragment.DetailPageFragment.playSound(DetailPageFragment.java:523)
07-14 13:03:27.896 28522-30026/com.mobifusion.android.ldoce5 W/System.err:     at com.mobifusion.android.ldoce5.Util.JavaScriptInterface.checkUsUkExampleSoundButton(JavaScriptInterface.java:292)
07-14 13:03:27.896 28522-30026/com.mobifusion.android.ldoce5 W/System.err:     at org.chromium.base.SystemMessageHandler.nativeDoRunLoopOnce(Native Method)
07-14 13:03:27.896 28522-30026/com.mobifusion.android.ldoce5 W/System.err:     at org.chromium.base.SystemMessageHandler.handleMessage(SystemMessageHandler.java:39)
07-14 13:03:27.896 28522-30026/com.mobifusion.android.ldoce5 W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:102)
07-14 13:03:27.896 28522-30026/com.mobifusion.android.ldoce5 W/System.err:     at android.os.Looper.loop(Looper.java:145)
07-14 13:03:27.896 28522-30026/com.mobifusion.android.ldoce5 W/System.err:     at android.os.HandlerThread.run(HandlerThread.java:61)

```