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App crash in Android Studio 4 emulator while testing recording and play

I've met with problems while testing a recording app on the emulator(Pixel 3a API 30)
Below is the Java code that I searched for in the tutorial on Youtube.
In the video it can be tested normally.
When it comes to me, it kept crashing when I hit on the stop recording button.
//Request Runtime Permission
if (!checkPermissionFromDevice())
requestPermission();
//Init view
pl_btn = (Button)findViewById(R.id.play_btn);
rcrd_btn = (Button)findViewById(R.id.record_button);
stp_rcrd_btn = (Button)findViewById(R.id.stop_record_btn);
ps_btn = (Button)findViewById(R.id.pause_btn);
//From Android M, need request Run-time permission
rcrd_btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (checkPermissionFromDevice()) {
pathSave = Environment.getExternalStorageDirectory()
.getAbsolutePath() + "/"
+ UUID.randomUUID().toString() + "audio_record.3gp";
setupMediaRecorder();
try {
mediaRecorder.prepare();
mediaRecorder.start();
} catch (IOException e) {
e.printStackTrace();
}
pl_btn.setEnabled(false);
ps_btn.setEnabled(false);
rcrd_btn.setEnabled(false);
stp_rcrd_btn.setEnabled(true);
Toast.makeText(recording_and_play_test.this, "Recording...", Toast.LENGTH_SHORT).show();
} else {
requestPermission();
}
}
});
stp_rcrd_btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
mediaRecorder.stop();
stp_rcrd_btn.setEnabled(false);
pl_btn.setEnabled(true);
rcrd_btn.setEnabled(true);
ps_btn.setEnabled(false);
}
});
pl_btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
ps_btn.setEnabled(true);
stp_rcrd_btn.setEnabled(false);
rcrd_btn.setEnabled(false);
mediaPlayer = new MediaPlayer();
try {
mediaPlayer.setDataSource(pathSave);
mediaPlayer.prepare();
}catch (IOException e){
e.printStackTrace();
}
mediaPlayer.start();
Toast.makeText(recording_and_play_test.this, "Playing...", Toast.LENGTH_SHORT).show();
}
});
ps_btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
stp_rcrd_btn.setEnabled(false);
rcrd_btn.setEnabled(true);
pl_btn.setEnabled(true);
ps_btn.setEnabled(false);
if (mediaPlayer != null){
mediaPlayer.stop();
mediaPlayer.release();
setupMediaRecorder();
}
}
});
}
private void setupMediaRecorder() {
mediaRecorder = new MediaRecorder();
mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
mediaRecorder.setAudioEncoder(MediaRecorder.OutputFormat.AMR_NB);
mediaRecorder.setOutputFile(pathSave);
}
private void requestPermission() {
ActivityCompat.requestPermissions(this, new String[]{
Manifest.permission.WRITE_EXTERNAL_STORAGE,
Manifest.permission.RECORD_AUDIO
},REQUEST_PERMISSION_CODE);
}
And here's what the activity looks like
While I hit the stop recording button while executing the recording function, the app then just crashed and restarts again.
Here's what the build log says
E/MediaRecorder: stop called in an invalid state: 4
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.adrsingingscope, PID: 7309
java.lang.IllegalStateException
at android.media.MediaRecorder.stop(Native Method)
at com.example.adrsingingscope.recording_and_play_test$2.onClick(recording_and_play_test.java:88)
at android.view.View.performClick(View.java:7448)
at android.view.View.performClickInternal(View.java:7425)
at android.view.View.access$3600(View.java:810)
at android.view.View$PerformClick.run(View.java:28305)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)

This could be a problem with the path you created to save a file. These things can be easy to mess up. The media recorder has its own state and STATE 4 in which your app crashed in the state of recording. So it didn't stop and something happened in between that process so I assume it is related to saving your file to external storage.
You can find MEDIA_RECORDER_STATES here: https://android.googlesource.com/platform/frameworks/av/+/android-4.2.2_r1.2/include/media/mediarecorder.h#96
There are three things you can try.
Change your save file path
Try changing your path to a different directory. Sometimes you are trying to reach the directory you are not allowed to or it doesn't exist. More you can read in this answer: https://stackoverflow.com/a/33107120/14759470
Check your AndroidManifest.xml for permissions
Check if you wrote your permissions in AndroidManifest.xml as you should. You need WRITE_EXTERNAL_STORAGE and RECORD_AUDIO for this. In your code, it even says that from Android M (6.0) you need RUN_TIME permission. So just add them on top of your manifest file if you didn't.
Make your code better
Don't stop the recorder if it's already stopped. This will throw an exception. Don't release if already released, also an exception, and so on. So test your code for bugs, make breakpoints, and find your weak spots. It will be easier for you to find your errors. Also, check the log for more error messages since this one doesn't give us much.

Cannot get next song to play after onCompleteListener

I have read numerous different responses on this matter but I just wanted to clarify one thing about the onCompletionListener method for MediaPlayer. I have a configuration that is currently working and playing a song after it completes the first one, but after the second one ends it will not play another song from the array. It will also not display the metadata for the new track either. My guess is that the onCompletionListener only runs once and doesn't transfer to the newly created MediaPlayer instance. More Specifically the answer I'm looking for is can the onCompleteListener run more than once? Or is it a non looping function?
Video demonstrating the issue: https://youtu.be/WXDtCktTh3M
Here is what I have for my listener block:
mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
public void onCompletion(MediaPlayer arg0) {
if (chosenPath == null) {
seekBar.setProgress(0);
mediaPlayer.seekTo(0);
} else {
songOrderCounter += 1;
System.out.println("SONG_ITERATOR_COUNT: " + songOrderCounter);
try {
/*handler.removeCallbacks(moveSeekBarThread);
songUpdateTimeHandler.removeCallbacks(updateSongTime);*/
Log.d("PATH_WORKING", allMusicFiles[songOrderCounter].toString());
mediaPlayer.stop();
mediaPlayer.reset();
mediaPlayer.release();
mediaPlayer = new MediaPlayer();
mediaPlayer.setDataSource(allMusicFiles[songOrderCounter].toString());
mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
#Override
public void onPrepared(MediaPlayer mp) {
mediaPlayer.start();
metaRetriever();
seekBar.setProgress(0);
seekBar.setMax(mediaPlayer.getDuration());
trackTime();
}
});
mediaPlayer.prepareAsync();
metaRetriever(); /* Moved inside onPrepared*/
} catch (Exception e) {
System.out.println("NEXT_SONG_FAILED: " + e);
}
}
}
});
UPDATE
The reason this is not working is because I have created a new MediaPlayer Instance in the onCompletion() function so the listener will not associate with the newly created MediaPlayer instance. Therefore it will not listen for the completion of the newly created MediaPlayer. I removed the new MediaPlayer section of code from the setOnCompleteListener() function and now there are issues with the runnable threads that are keeping track of seekbar and time progress causing it to crash when it reaches the end of the file
D/PATH_WORKING: /storage/emulated/0/Music/01 Control.mp3
I/System.out: NEXT_SONG_FAILED: java.lang.IllegalStateException
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.macyg.androidmediaplayer, PID: 12784
java.lang.IllegalStateException
at android.media.MediaPlayer.getCurrentPosition(Native Method)
at com.example.macyg.androidmediaplayer.MainActivity$12.run(MainActivity.java:596)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)
And the Runnable causing the crash:
private Runnable moveSeekBarThread = new Runnable() {
public void run() {
if(mediaPlayer.getCurrentPosition() <= mediaPlayer.getDuration()) {
int mediaPos_new = mediaPlayer.getCurrentPosition();
int mediaMax_new = mediaPlayer.getDuration();
seekBar.setMax(mediaMax_new);
seekBar.setProgress(mediaPos_new);
handler.postDelayed(this, 100); //Looping the thread after 0.3 second
// seconds
}else{}
}
};

java.lang.IllegalStateException in MediaPlayer

This is my code:
final MediaPlayer[] threeSound = new MediaPlayer[1];
threeSound[0] = new MediaPlayer();
final CountDownTimer playThreeSound = new CountDownTimer(1000, 1) {
boolean timerStarted = false;
#Override
public void onTick(long millisUntilFinished) {
torgText.setText("3...");
if (!timerStarted) {
timerStarted = true;
threeSound[0] = MediaPlayer.create(PlayActivity.this, R.raw.three);
try {
threeSound[0].prepare();
threeSound[0].start();
} catch (IOException e) {
e.printStackTrace();
Log.e("IOE", "Something went wrong");
}
}
}
#Override
public void onFinish() {
if (threeSound[0].isPlaying()) {
threeSound[0].stop();
}
playTwoSound.start();
}
};
It throws IllegalStateException. These are logs:
FATAL EXCEPTION: main
Process: testapplication.android.com.guesstune_v2, PID: 3641
java.lang.IllegalStateException
at android.media.MediaPlayer._prepare(Native Method)
at android.media.MediaPlayer.prepare(MediaPlayer.java:1351)
at testapplication.android.com.guesstune_v2.PlayActivity$6.onTick(PlayActivity.java:316)
at android.os.CountDownTimer$1.handleMessage(CountDownTimer.java:133)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:7007)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
What is wrong with preparing MediaPlayer? What should I add to the code? I'm a newbie, sorry for a probably stupid question and for bad English.

The documentation for MediaPlayer states:
MediaPlayer create (Context context, int resid)
Convenience method to create a MediaPlayer for a given resource id. On success, prepare() will already have been called and must not be called again.
https://developer.android.com/reference/android/media/MediaPlayer.html#create(android.content.Context, int)
So your IllegalStateException occurs because prepare() requires the MediaPlayer to be in either a Initialized or Stopped state, but when create(Context context, int resid) is invoked, it calls prepare() resulting in the MediaPlayer being in the Prepared state which it must not be when prepare() is invoked.
In short: remove the prepare() call and the IllegalStateException should no longer occur.
A full State Diagram and list of valid states is presented in the documentation.

VideoView setVideoUri No Content Provider

I am developing an Android app that needs to play an .mp4 video from my local server.
I have this code:
mPreview = (VideoView) findViewById(R.id.video_preview);
mPreview.setVisibility(View.VISIBLE);
mPreview.setVideoURI(Uri.parse("http://192.168.1.100:7676/getVideoByFileName.php?name=C%3A%2FSpinShot%2FResults%2FSpinShot-201701311359177714.mp4"));
mPreview.setOnPreparedListener(createOnPreparedListener());
private MediaPlayer.OnPreparedListener createOnPreparedListener() {
return new MediaPlayer.OnPreparedListener() {
#Override
public void onPrepared(MediaPlayer mp) {
mp.start();
}
};
}
And every time it gets executed, I get this error:
D/MediaPlayer: setDataSource IOException | SecurityException happend :
java.io.FileNotFoundException: No content provider: http://192.168.1.100:7676/getVideoByFileName.php?name=C%3A%2FSpinShot%2FResults%2FSpinShot-201701311359177714.mp4
at android.content.ContentResolver.openTypedAssetFileDescriptor(ContentResolver.java:1141)
at android.content.ContentResolver.openAssetFileDescriptor(ContentResolver.java:991)
at android.content.ContentResolver.openAssetFileDescriptor(ContentResolver.java:914)
at android.media.MediaPlayer.setDataSource(MediaPlayer.java:1121)
at android.widget.VideoView.openVideo(VideoView.java:371)
at android.widget.VideoView.access$2100(VideoView.java:71)
at android.widget.VideoView$7.surfaceCreated(VideoView.java:652)
at android.view.SurfaceView.updateWindow(SurfaceView.java:712)
at android.view.SurfaceView$3.onPreDraw(SurfaceView.java:209)
at android.view.ViewTreeObserver.dispatchOnPreDraw(ViewTreeObserver.java:1014)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2510)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1437)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7403)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:920)
at android.view.Choreographer.doCallbacks(Choreographer.java:695)
at android.view.Choreographer.doFrame(Choreographer.java:631)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:906)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:7229)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
No video plays in the VideoView. Any help would be appreciated.

Turns out my Firewall affects their connection. Turned it off and it works just fine.

java.lang.NullPointerException in Admob while showing Rewarded Video

In Android,When I tried to load the Ad in Admob and there is no internet connection the code reaches onRewardedVideoAdFailedToLoad() and after sometime say 30 sec the app force closes with the below mentioned error.
I hope this is not the null pointer exception that I can handle. It is happening in the SDK I guess. Please let me know how to resolve this.
Code
private void setRewardedVideo() {
rewardedVideoAd = MobileAds.getRewardedVideoAdInstance(this);
rewardedVideoAd.setUserId(REWARD);
AdRequest adRequest = new AdRequest.Builder().build();
rewardedVideoAd.loadAd(AD_UNIT_ID_REWARDED_VIDEO_AD, adRequest);
rewardedVideoAd.setRewardedVideoAdListener(new RewardedVideoAdListener() {
#Override
public void onRewardedVideoAdLoaded() {
System.out.println("onRewardedVideoAdLoaded()");
if (rewardedVideoAd.isLoaded()) {
rewardedVideoAd.show();
}
}
#Override
public void onRewardedVideoAdOpened() {
System.out.println("onRewardedVideoAdOpened()");
}
#Override
public void onRewardedVideoStarted() {
System.out.println("onRewardedVideoStarted()");
}
#Override
public void onRewardedVideoAdClosed() {
System.out.println("onRewardedVideoAdClosed()");
}
#Override
public void onRewarded(RewardItem rewardItem) {
System.out.println("onRewarded()");
}
#Override
public void onRewardedVideoAdLeftApplication() {
System.out.println("onRewardedVideoAdLeftApplication()");
}
#Override
public void onRewardedVideoAdFailedToLoad(int i) {
System.out.println("onRewardedVideoAdFailedToLoad()");
}
});
}
Logcat
java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.ViewParent com.google.android.gms.ads.internal.au.getParent()' on a null object reference
at com.google.android.gms.ads.internal.a.b(SourceFile:513)
at com.google.android.gms.ads.internal.b.b(SourceFile:318)
at com.google.android.gms.ads.internal.a.c(SourceFile:520)
at com.google.android.gms.ads.internal.aq.run(SourceFile:64)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5296)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

Ensure the user has connectivity before even trying to load the ads, there may be some deeper issue with AdMob that forces this NPE despite no internet.
private void setRewardedVideo() {
if (!isNetworkAvailable()) {
// Log no internet
return;
}
rewardedVideoAd = MobileAds.getRewardedVideoAdInstance(this);
rewardedVideoAd.setUserId(REWARD);
....
}
It may even make sense to ensure user has internet before trying to use adMob incase it is something with their library that is causing the issue. See this answer for that.