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Keep UI responsive while fetch data from internet alternative of Handler postDelayed

I have a ArrayList that I fetch from internet. Now I am performing the list retrieval using Handler postdelayed. Like below in the onCreate of the activity.
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
lis_dat.remove(lis_dat.size() - 1);
if (gri_not_lis) {
rv_3r_ada.notifyItemRemoved(lis_dat.size());
} else {
rv_3r_2c_ada.notifyItemRemoved(lis_dat.size());
}
List<String> lis_of_dat;
int cou = 0, pos = lis_dat.size();
String gen_sta, gen_end, gen_mon;
if (yea) {
String[] mon_sym = new DateFormatSymbols().getMonths();
lis_of_dat = Arrays.asList(mon_sym);
} else {
int how_man;
if (lis_is_new) {
how_man = 500;
} else {
how_man = 15;
}
if (day_in_bet(sta, end) <= how_man) {
gen_sta = sta;
gen_end = end;
} else {
gen_sta = sta;
Calendar cal = Calendar.getInstance();
cal.setTime(db_han.con_dat(sta));
cal.add(Calendar.DATE, how_man);
gen_end = USE_DAT.format(cal.getTime());
}
lis_of_dat = gen_dat_in_bet(gen_sta, gen_end);
}
for (String dat : lis_of_dat) {
if (yea) {
Date date = get_mon_dat(dat, YEA.format(db_han.con_dat(sta)));
gen_sta = get_mon_fir_or_las_dat(date, true);
gen_end = get_mon_fir_or_las_dat(date, false);
gen_mon = dat;
} else {
gen_sta = dat;
gen_end = null;
gen_mon = mon;
}
add_to_lis(gen_sta, gen_end, gen_mon, pos, gri_not_lis);
pos++;
}
pos_f[0] = pos;
cou_f[0] = cou;
is_loa = false;
}
}, 1000);
Now my question is this 1000 milliseconds here may vary in different devices. On whom the UI will stay frozen. So what's the alternative of this. Instead of waiting for 1 sec how can I wait till the UI loading is complete and then I do the retrieval?
I could use AsyncTask but then the task will stay running till the task is complete even if I go to another activity. but i don't need the task running after onPause is called. So how do I do it?

You can use AsyncTask which running in separate thread, your keeps UI responsive . You can cancel it in onPause of Activity by calling **asyncTaskRunner.cancel(true) **
private class AsyncTaskRunner extends AsyncTask<String, String, String> {
private String resp;
ProgressDialog progressDialog;
#Override
protected String doInBackground(String... params) {
return resp;
}
#Override
protected void onPostExecute(String result) {
}
#Override
protected void onPreExecute() {
}
#Override
protected void onProgressUpdate(String... text) {
}
}

You can save instance of handler and then remove all call backs in
onPause of the activity.
private Handler handler = new Handler();
handler.postDelayed(() -> {
// do you task here
},1000);
#Override
public void onPause() {
super.onPause();
handler.removeCallbacksAndMessages(null); // this is important
}
And if you want something which do not freeze UI without any delay,
there you go
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Executors.newSingleThreadExecutor().submit(() -> {
// Do you task here without any delay it will not freeze the UI
});
}
You can also try this,
class MyThread implements Runnable{
#Override
public void run() {
// Your Task Here, put your all calculations Here
}
}
and then in onCrate()
ExecutorService executor = Executors.newSingleThreadExecutor();
executor.submit(new MyThread());
and then in onPause() or onDestory()
executor.shutdownNow();// this will stop the thread instantly

pause program between adding and removing a TextView

I'm working on a tank-game and I have a TextView which represents the shot. Now I want to display the TextView at the specific point and remove it after a second that it looks like the shot goes further step by step. But when I add a countdown or a Thread.sleep the program stops for a second but the TextView doesn't disappear. i want to move the TextView over the screen and after every iteration of my for loop i want to wait a second and then rearrange it again?
Here is the code :
public void shot(float power, float winkel, Button button) {
if(winkel>90) {
winkel = winkel - 10;
}else if(winkel<90){
winkel = winkel +10;
}
for (double i = 0; i<100;i = i+ 1) {
final TextView textView = new TextView(context);
textView.setText(".");
double x = tanks.get(currentTank).getxPos()+(i*power*Math.cos(winkel *(Math.PI/180)));
double y = tanks.get(currentTank).getyPos()+(-1*(i*power*Math.sin(winkel *(Math.PI/180))));
double gravity = (-1*((9.81/2)*Math.pow(i,2)));
y = (y-gravity);
textView.setX((float) x);
textView.setY((float) y);
layout.addView(textView);
for (int j = 0;j<tanks.size();j++){
if(textView.getX()>tanks.get(j).getxPos()&&textView.getX()<tanks.get(j).getxPos()+100){
if(textView.getY()>tanks.get(j).getyPos()&&textView.getY()<tanks.get(j).getyPos()+100){
float k = tanks.get(j).getxPos()-textView.getX();
if(k<0){
k = k*-1;
}
makeDamage(k,tanks.get(j));
}
}
}
new CountDownTimer(2000,1000){
#Override
public void onTick(long millisUntilFinished) {
}
#Override
public void onFinish() {
layout.removeView(textView);
}
}.start();
}
newTurn();
}
I want to pause the program after adding the TextView for one second and the remove it. The program stops but the TextView doesn't disappear till the for-loop finished. Then all TextViews disappear.
Problem solved:
i've added all positions in a array and then this
public void drawShot(final Button firework, final ArrayList<TextView> toDraw){
final int[] i = {0};
final Handler mHandler = new Handler();
firework.setOnClickListener(new View.OnClickListener() {
#RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
#Override
public void onClick(View v) {
firework(firework,toDraw.get(i[0]).getX(),toDraw.get(i[0]).getY());
}
});
Runnable runnable = new Runnable() {
#Override
public void run() {
layout.addView(toDraw.get(i[0]));
if(!check(toDraw.get(i[0]))) {
mHandler.postDelayed(this, (long) 1);
}
i[0]++;
}
};
// start it with:
mHandler.post(runnable);
}

probably need to run the remove command on main thread
Handler mainHandler = new Handler(context.getMainLooper());
Runnable myRunnable = new Runnable() {
#Override
public void run() {
layout.removeView(textView);
}
};
mainHandler.post(myRunnable);

Display values in ArrayList one by one in textView

I am trying to display values inside ArrayList on single line textView one by one after some interval. How to achieve this without blocking the main thread?
I have written code which is able to do this with Thread.sleep but, after a few seconds of running, activity is getting crashed. I have used For Loop & Thread.sleep to iterate every ArrayList value after some interval.
When activity crashes, I am getting IndexOutOfBondException after a few seconds of running.
public void errorRepeater() {
Thread t = new Thread() {
#Override
public void run() {
// !isInterrupted()
while (!isInterrupted()) {
for (xz = 0; xz < errorList.size(); xz++) {
try {
Thread.sleep(2000); //1000ms = 1 sec
runOnUiThread(new Runnable() {
#Override
public void run() {
String sErrorList = errorList.get(xz);
String sErrorListOkBox = errorListOkBox.get(xz);
Log.i("MQTT sErrorList", sErrorList);
TextView tvC1HPLP = findViewById(R.id.errormsg);
tvC1HPLP.setText(sErrorList);
TextView tvok = findViewById(R.id.ok);
tvok.setText(sErrorListOkBox);
rl.setBackgroundResource(R.drawable.errorred);
tvC1HPLP.setTextColor(Color.RED);
}
});
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
};
t.start();
}
textView should display values inside ArrayList one by one without crashing activity.

Just for reference, you can try something like this.
// You can define those both textview globally.
TextView tvC1HPLP = findViewById(R.id.errormsg);
TextView tvok = findViewById(R.id.ok);
Handler mHandler = new Handler();
final Runnable runnable = new Runnable() {
int count = 0;
#Override
public void run() {
String sErrorList = errorList.get(count%errorList.size);
String sErrorListOkBox = errorListOkBox.get(count%errorListOkBox.size);
tvC1HPLP.setText(sErrorList);
tvok.setText(sErrorListOkBox);
rl.setBackgroundResource(R.drawable.errorred);
tvC1HPLP.setTextColor(Color.RED);
count++;
mHandler.postDelayed(this, 4000); // four second in ms
}
};
mHandler.postDelayed(runnable, 1000);

CallBack from MediaPlayer

I have a MediaPlayer and an audio file, which I need to play, also I have an ArrayList with the certain seconds of this audio file, on this seconds while audio is playing, I need to switch pages in the ViewPager. How to get a CallBack from the MediaPlayer in these certain moments of the time? or maybe you will recommend some other way how is possible to do it.
What I have right now is the method, where I use CountDownTimer, which change pages in ViewPager, but it works wrong and it doesn't take into the account fact that an audio track can be stop and then resume.
public void startPlayingLabels() {
mPlayer = new MediaPlayer();
try {
String mFileName = CameraFragment.mAudioFolder + "/" + ViewActivity.parentName + ".3gp";
mPlayer.setDataSource(mFileName);
mPlayer.prepare();
mPlayer.start();
for (int i=0; i<zeroLabelPosition.size()-1; i++) {
final int finalI = i;
new CountDownTimer(Integer.parseInt(String.valueOf(Integer.parseInt((String) zeroTime.get(finalI + 1)) - Integer.parseInt((String) zeroTime.get(finalI)))), 1000) {
public void onTick(long millisUntilFinished) {
}
public void onFinish() {
mPager.setCurrentItem(Integer.parseInt(String.valueOf(zeroLabelPosition.get(finalI))));
}
}.start();
}
} catch (IOException e1) {
e1.printStackTrace();
}
}

Android madiaplayer does not have any timeline update, thats why you can write your own, or you can use something like this.
CountDownTimer timer;
int timeStampIterator;
int[] timeStamp = new int[5]; // your own time stamps when view must be switched
void play() {
mPlayer.start();
timer = new CountDownTimer(mPlayer.getDuration() - mPlayer.getCurrentPosition(), 1000) {
#Override
public void onTick(long millisUntilFinished) {
int timeSpends = mPlayer.getDuration() - mPlayer.getCurrentPosition();
if (timeSpends == timeStamp[timeStampIterator]) {
//switchToNExtSlide();
timeStampIterator++;
}
}
#Override
public void onFinish() {
}
}.start();
}
void pause() {
mPlayer.pause();
timer.cancel();
timer = null;
}
void stop() {
mPlayer.stop();
timer.cancel();
timer = null;
timeStampIterator = 0;
}

you can also use handler for it like following
Handler handler = new Handler();
Runnable notification = new Runnable() {
public void run() {
startPlayProgressUpdater();// change hear page for view pager, because it call after every 1 second
}
};
handler.postDelayed(notification, 1000);

java android , delay inside onclick button includes gui changes

I am trying to simulate an sending msg progress .
The main idea is to colour the members who message sent to them, promote the status bar etc.. (gui changes ) all this with delay for each loop iteration.
The main problem is that everything is going inside the onClick listener and runing thread inside it wont help ): cause gui is changing only after delay is completed.
Any one may advice me how to do this simulation ?
send.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
for(int i=0; i<phoneNumbers.size(); i++){
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
}
members.get(i).setBackgroundColor(Color.GREEN);
members.get(i).invalidate();
mProgressDialog.setProgress(i+1);
sentCount.setText(getString(R.string.msgSentCount) + (i+1));
if(i==12){
scroolView.animate().translationYBy(-50);}
}
}
});
Thanks you very much !

If I unserstood you right - fake progress + waiting time. First of all handlers a perferct to delay an output:
//Fake Progress
progress = new ProgressDialog(this);
open(this);
// Delay output
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
setData();
}
}, 6000);
in the function setData(), do the task you wanna run after
and progress bar for fake:
public void open(Activity activity) {
progress.setMessage("Fakeprogress, Data Mining...");
progress.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
progress.setIndeterminate(false);
progress.setCancelable(false);
progress.setMax(100);
progress.setProgress(10);
progress.show();
final int totalProgressTime = 100;
final Thread t = new Thread() {
#Override
public void run() {
int jumpTime = 0;
while (jumpTime < totalProgressTime) {
try {
sleep(60);
//System.out.println("********" + jumpTime);
jumpTime += 1;
progress.setProgress(0);
progress.setProgress(jumpTime);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
progress.dismiss();
}
};
t.start();
}

Finaly got it works with recursion !!!!
public static int counter=0;
public void runMother(final Handler handler)
{
if(counter==3)return;
handler.postDelayed(new Runnable() {
#Override
public void run() {
members.get(counter).setBackgroundColor(Color.GREEN);
counter++;
runMother(handler);
}
}, 1000*counter);