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Why variable gets reset on button click(s) in Android?

Can someone help me to understand what is happening here? Have been trying to debug, but feel like stuck!
I am trying to animate some online images in my Android app using the following method.
private void animateImages() {
// URL loading
// int i = 1; (initialized earlier)
// ArrayList<String> myImages = new ArrayList<>(); (initialized earlier)
myImages.clear();
While (i < 11) {
// Adds ten images using web link
myImages.add("My_web_url");
i++;
}
AccelerateInterpolator adi = new AccelerateInterpolator();
try {
Field mScroller = ViewPager.class.getDeclaredField("mScroller");
mScroller.setAccessible(true);
mScroller.set(viewPager, new MyScroller(getApplicationContext(), adi, 1));
}
catch (NoSuchFieldException e) {
e.printStackTrace();
}
catch (IllegalAccessException e) {
e.printStackTrace();
}
if (viewPager != null) {
viewPager.setAdapter(new MyPageAdapter(getApplicationContext(), myImages));
}
final Handler handler = new Handler();
final Runnable Update = new Runnable() {
// Printing variables for debugging
System.out.println("The page number is=" + currentPage);
System.out.println("The myImages size is=" + myImages.size());
public void run() {
if (currentPage == myImages.size() - 1) {
currentPage = 0;
}
viewPager.setCurrentItem(currentPage++, true);
}
};
timer = new Timer();
timer.schedule(new TimerTask() {
#Override
public void run() {
handler.post(Update);
}
// delay and period can be initialized as desired
}, delay, period);
}
}
When I call this method in OnCreate, animation works fine. However, when I call this method in OnClickButton Listener, variable myImages size (before public void run()) become zero and due to this animation doesn't work.
In the above, MySCroller and MyPageAdapeter are java classes. But, most likely, the issue is related to button click, and I don't understand why it resets the myImages size which halts the animation!
This is how button click listener is called. What am I doing wrong?
MyButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
animateImages();
}
});
Edit 1:
Thanks to all the comments, I made a little progress.
I moved all these variables from MainActivity to animateImages() method. The animation runs with button click as well but there is a bump in animation, where too images moves too fast then bump and so on..
// Added just before while loop
DELAY_MS = 1000;
PERIOD_MS = 1000;
i = 1;
currentPage = 0;
I notice the same animation bump if I move the URL loading while loop to OnCreate().

The second time you call animateImages it clears myImages but then doesn't loop because i is not reset so it remains empty. Move creation of that list to onCreate instead to avoid that issue.

Media Player loading media again and again

I am making a chat application and I have implemented the feature for sending audio messages.But here I find one thing which I don't want it to happen.It is that whenever my adapter gets updated,The media player starts loading again. In this way there will be an issue for if someone is listening to an audio and the user at other end sends a message ,the media player stops and it loads again.Here is the code of my adapter.
final MediaPlayer mediaPlayer;
mediaPlayer = new MediaPlayer();
mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
handler = new Handler();
try {
mediaPlayer.setOnCompletionListener(mediaPlayer1 -> {
mediaPlayer1.stop();
binding.audioSeekbar.setProgress(0);
});
if (mediaPlayer.isPlaying()){
mediaPlayer.stop();
mediaPlayer.release();
}
mediaPlayer.setDataSource(finalUrlToLoad[1]);
mediaPlayer.setVolume(1f, 1f);
mediaPlayer.prepareAsync();
mediaPlayer.setOnPreparedListener(mediaPlayer1 -> {
int totalDuration = mediaPlayer1.getDuration();
binding.totalDurationAudio.setText(createTimeLabel(totalDuration));
binding.loadingAudio.setVisibility(GONE);
binding.playPauseAudio.setVisibility(VISIBLE);
});
} catch (IOException e) {e.printStackTrace();}
binding.playPauseAudio.setOnClickListener(view -> {
if (mediaPlayer.isPlaying()){
handler.removeCallbacks(runnable);
mediaPlayer.pause();
binding.playPauseAudio.setImageResource(R.drawable.pause_to_play);
Drawable drawable = binding.playPauseAudio.getDrawable();
if( drawable instanceof AnimatedVectorDrawable) {
AnimatedVectorDrawable animation = (AnimatedVectorDrawable) drawable;
animation.start();
}
}else {
mediaPlayer.seekTo(binding.audioSeekbar.getProgress());
mediaPlayer.start();
handler.post(runnable);
binding.playPauseAudio.setImageResource(R.drawable.play_to_pause);
Drawable drawable = binding.playPauseAudio.getDrawable();
if( drawable instanceof AnimatedVectorDrawable) {
AnimatedVectorDrawable animation = (AnimatedVectorDrawable) drawable;
animation.start();
}
}
});
runnable = () -> {
int totalTime = mediaPlayer.getDuration();
binding.audioSeekbar.setMax(totalTime);
int currentPosition = mediaPlayer.getCurrentPosition();
binding.audioSeekbar.setProgress(currentPosition);
binding.totalDurationAudio.setText(createTimeLabel(totalTime));
Log.d("time", String.valueOf(currentPosition));
handler.postDelayed(runnable,1000);
};
binding.audioSeekbar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
#Override
public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
if (b){
mediaPlayer.seekTo(i);
seekBar.setProgress(i);
}
}
#Override
public void onStartTrackingTouch(SeekBar seekBar) {
}
#Override
public void onStopTrackingTouch(SeekBar seekBar) {
}
});
mediaPlayer.setOnBufferingUpdateListener((mediaPlayer1, i) -> binding.audioSeekbar.setSecondaryProgress(i));
Here finalurltoload[1] is the url for the audio.
Now what do I need to do in order to prevent loading it again and again.
I will be really grateful to who answer this question.
Thanks😊.

It's hard to tell from this code but I assume this is all set in your onBind event? If so, then this means every time RecyclerView creates a new holder and binds it, the associated media will be prepped and loaded, and whichever is the 'last holder to have been called with onBind, "wins" (and is what MediaPlayer will be loaded with). Since by default RecyclerView typically creates multiple holders up front, you are seeing your MediaPlayer being "loaded" multiple times.
You probably just don't want to do the initialization of each audio message in the onBind. Instead, just use the onBind event to initialize state variables (duration, progress, etc.) to some default value, hide them and bind the specific audio Uri. Then when the user takes some action like tapping on the holder, you unhide an indeterminate progress bar while the initialization takes place, and in the onPrepared() event unhide the state information (duration, progress, seekbar, etc.), and finally hide the indeterminate progress bar and start the audio.
I assume you are also sending over the sound file as part of your messaging app (i.e. not storing it on the web somewhere in a central location?), and this file gets stored in an app-specific storage location? If so, you don't need to worry about persisting the permission to that URI, but if that isn't the case you will.

First extract the media player code into singleton class like AudioManager.
Add few method like setMediaUpdateListener that set a callback for seek duration. and togglePlayPause to play or pause the audio.
Passed the message id or any unique identifier to the audio manager while playing the video.
In Adapter class onBind Method.
First Compare the id and playing Id is same like AudioManager.getInstance().isPlaying(messageId);
If yes then set the seekUpdatelistner to the audio manager class.
also update the play/pause icon based on AudioManager.isPlaying() method.
3.if user play other message by clicking play button. call AudioManager.play(message) method.In which we release the previous message and play the new one.
If current message is not playing then reset the view on non-playing state.
If Auto play is enabled then you need to check if audioManager is free then only you can play the last message otherwise ignored.
Like a class who are managing the audio for you and store all the state.
class AudioManager {
public static AudioManager instance;
final MediaPlayer mediaPlayer;
private AudioListener audioListener;
private Uri currentPlaying;
public AudioManager getInstance() {
if (instance == null) {
instance = new AudioManager();
}
}
public void play(Uri dataUri) {
if (mediaPlayer != null && currentPlaying == null || currentPlaying.equals(dataUri)) {
if (!mediaPlayer.isPlaying) {
mediaPlayer.play();
}
return;
} else if (mediaPlayer != null) {
mediaPlayer.stop();
mediaPlayer.release();
}
mediaPlayer = new MediaPlayer();
mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
handler = new Handler();
try {
mediaPlayer.setOnCompletionListener(mediaPlayer1 -> {
mediaPlayer1.stop();
sendProgress(0);
});
if (mediaPlayer.isPlaying()) {
mediaPlayer.stop();
mediaPlayer.release();
}
mediaPlayer.setDataSource(dataUri;
mediaPlayer.setVolume(1f, 1f);
mediaPlayer.prepareAsync();
mediaPlayer.setOnPreparedListener(mediaPlayer1 -> {
int totalDuration = mediaPlayer1.getDuration();
sendTotalDuration(totalDuration);
});
} catch (IOException e) {
e.printStackTrace();
}
}
public void pause() {
// update the pause code.
}
public void sendProgress(int progress) {
if (audioListener != null) {
audioListener.onProgress(progress);
}
}
public void sendTotalDuration(int duration) {
if (audioListener != null) {
audioListener.onTotalDuraration(duration);
}
}
public void AudioListener(AudioListener audioListener) {
this.audioListener = audioListener;
}
public interface AudioListener {
void onProgress(int progress);
void onTotalDuraration(int duration);
void onAudioPlayed();
void onAudioPaused():
}
}

My program stop responding after I press a play button

So I created a small app with a play and a stop button. When I press the play button it should loop until I press the stop button. The problem is, once I press the play button, I can't do anything else and the stop button is not responsive. If I try to press the stop button my app says app doesn't respond and quit. I don't know why this is happening and I'm super new to Android and Java so this is a bit complicated for me to know why it doesn't work. Here is my actual code :
Play and stop method :
public void play() {
playing = true;
while (playing) {
for (int i = 0; i < 4; i++) {
if (buttonArray[i].isChecked()) {
sp.play(snareId, 1, 1, 1, 0, 1);
}
if (!playing) {
break;
}
try {
Thread.sleep(1000);
if(i == 3) i = -1;
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
public void stop(){
playing = false;//
}
Main activity
playButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v)
{
mySample.play();
}
});
stopButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v)
{
mySample.stop();
}
});

According Android document, there are some common patterns to look for when diagnosing ANRs:
The app is doing slow operations involving I/O on the main thread.
The app is doing a long calculation on the main thread.
The main thread is doing a synchronous binder call to another
process, and that other process is taking a long time to return.
And others.
You are in situation number 2 because you create an infinite loop while(playing) in main thread (it's UI thread in this case). Just listen to changes from check boxes and do your task respectively.
public void play(){
//call startService to play sound
//for each toggle button
buttonArray[i].setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (isChecked) {
//do your tasks
} else {
//do your tasks
}
}
});
}
public void stop(){
//call stopService to play sound
//for each toogle button:
buttonArray[i].setOnCheckedChangeListener(null);
}

Unexpected behavior: immediate completion of media player

I am trying to restore audio to the position it was and the file it was when the user left the fragment. To do this I save the location of the audio file, and the seek position using personal prefs, along with a boolean for whether or not the audio was playing when the user left. I save this info first thing in onPause().
When I resume, I initialize the views etc. and the very last thing I do in onResume is read from personal prefs and play the audio stored there is appropriate.
However when I try to play from onResume, the media completion listener gets called immediately and the file gets skipped.
I have been running tests and I know that the media player is handed the right data, is prepared correctly and set to play.
The way I am trying to play the audio is the same way I do it if a user clicks manually to play audio, and that works flawlessly.
Only when trying to 'restore' the audio to where it was when a user left does the completion listener get called immediately.
Has anyone seen this before?
public void setAudioURLAndPLay(Context context, String url)
{
Log.d(TAG, "setAudioURLAndPLay");
CacheQueue.getInstance().addImmediateTaskToQueue(CacheQueue.AUDIO_TASK, context, url, 0, handler);
}
private void playCahcedFile(String location)
{
Log.d(TAG, "playCahcedFile");
try
{
this.reset();
this.setAudioStreamType(AudioManager.STREAM_MUSIC);
this.setDataSource(location);
this.setOnPreparedListener(new OnPreparedListener()
{
#Override
public void onPrepared(MediaPlayer mp)
{
setPlay();
}
});
this.prepareAsync();
}
catch (Exception e)
{
Log.d(TAG, "Exception", e);
}
}
public void setPlay()
{
Log.d(TAG, "setPlay");
this.start();
this.setProgressHandler(this.listener);
}
and where the calls are being made
public void initializeFromResume()
{
PersonalPrefs prefs = new PersonalPrefs(getActivity());
if (!prefs.isPLaying())
{
return;
}
else
{
playNewAudio(prefs.getURL());
// ((ActivityMain) getActivity()).getMediaManager().setSeek(prefs.getSeek());
}
}
private void playNewAudio(String url)
{
getMediaManager().setAudioURLAndPLay(getActivity(), url)
mediaState = MediaState.playing;
initializeSeekBar();
getMediaManager().setOnCompletionListener(this);
mediaController.togglePlayButton(mediaState);
}

I figured it out and will post the answer to anyone who has similar troubles in the future.
Just need to run a post delayed. Not exactly amazing, but it works.
h.postDelayed(new Runnable()
{
#Override
public void run()
{
PersonalPrefs prefs = new PersonalPrefs(getActivity());
playNewAudio(prefs.getURL());
}
}, 1000);

Game Over and Pause/Resume taking care of the thread

I have a few issues I am having a hard time find good information on how to fix. First off I have a Game Over screen that shows up when it should. I have tried to use setting the Threads running to false so it stop running and then when the screen is touched to set it back to true, but it does not take the screen back to it running. Also I'm going to need to be able to actually clear all the times so that it resets it (what is a good way to do that). This similarly I will need I am assuming for the Pause and Resume. If running isnt set to false it appears to continue running even with sleep() just in slower increments. Here is my thread to see if you notice what I can do.
public class GameLoopThread extends Thread {
private GameView view;
public static boolean running = false;
static final long FPS = 10;
public GameLoopThread(GameView view) {
this.view = view;
}
public void setRunning(boolean run) {
running = run;
}
#Override
public void run() {
long ticksPS = 1000 / FPS;
long startTime;
long sleepTime;
while (running) {
Canvas c = null;
startTime = System.currentTimeMillis();
try {
c = view.getHolder().lockCanvas();
synchronized (view.getHolder()) {
view.onDraw(c);
}
} finally {
if (c != null) {
view.getHolder().unlockCanvasAndPost(c);
}
}
sleepTime = ticksPS-(System.currentTimeMillis() - startTime);
try {
if (sleepTime > 0)
sleep(sleepTime);
else
sleep(10);
} catch (Exception e) {}
}
}
}
Now this part is causing a large issue for the Pause/Resume. I have a handler.postDelayed handling the spawning of my sprites. Basically when the screen appears paused (cause it looks like it is if i use the sleep) the problem is that the handler (which is in the GameView) is seeming like the time is still running for it. Is there a way to reset it back to zero... preferably on both the classes for the Game Over and to pause the handler as well during the Pause? Thanks
EDIT: As of right now I'm trying to use an options menu to make a new game by making it reopen the activity that runs the game. It appears to reset it but it freezes it in the process. Anyone know how I can fix this?
#Override
public boolean onCreateOptionsMenu(Menu menu){
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()){
case R.id.newgame:
GameView.gameState=0;
GameLoopThread.running=true;
Intent game = new Intent(PlayGame.this, PlayGame.class);
startActivity(game);
break;
case R.id.pause: Toast.makeText(this, "You pressed Pause", Toast.LENGTH_LONG).show();
break;
case R.id.quit: Toast.makeText(this, "You pressed Quit", Toast.LENGTH_LONG).show();
break;
}
return true;
}
Thats my options menu.

This may not seem like the anwser you are looking for, but if you want to create code that's easily extendable (and learn a new desgin pattern!) then this is the way to go.
Most games use a State Machine for these kind of things.
For example
interface GameState{
public void render(long elapsedTime);
}
Now you can create different states, like a MenuState, GameState, PauseState, OptionState, GameOverState, etc.
Some pseudo code to get the idea across:
State currentState = null;
public void run(){
while(true){
// Do your loop here
currentState.render(time);
}
}
public void setState(State state){
currentState = state;
}
States Example:
public class MenuState implements GameState{
public void render(long elapsedTime){
//Render menu here
}
}
Or
public class GameState implements GameState{
public void render(long elapsedTime){
//Render gameplay here
}
}
currentState points to the current state and decides which one gets rendered/updated. Just change it's reference and your pause menu gets drawn.
This is a very common design pattern in games, search around!
Good luck!