Develop Reference

How to load new values of JSON after every 10 seconds

Hi people I am getting problem in getting my latest JSON value after every 10 seconds. I have developed this code and now I am stucked in this. When I run this code it shows the value after second and did not get updated the second time. I have implemented the handler but it is also not working here.
public class MainActivity extends AppCompatActivity {
TextView a,b,c,d,e,f,g,h;
String result = "";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
a=(TextView) findViewById(R.id.a);
b=(TextView) findViewById(R.id.b);
c=(TextView) findViewById(R.id.c);
DownloadTask task = new DownloadTask();
task.execute("https://api.thingspeak.com/channels/12345/feeds.json?results=1");
}
public class DownloadTask extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... urls) {
URL url;
HttpURLConnection urlConnection = null;
try {
url = new URL(urls[0]);
urlConnection = (HttpURLConnection) url.openConnection();
InputStream in = urlConnection.getInputStream();
InputStreamReader reader = new InputStreamReader(in);
int data = reader.read();
while (data != -1) {
char current = (char) data;
result += current;
data = reader.read();
}
return result;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(final String result) {
super.onPostExecute(result);
new Handler().postDelayed(new Runnable() {
public void run() {
search(result);
}
}, 10000);
}
public void search(String result){
try {
JSONObject jsonObject = new JSONObject(result);
JSONArray weatherInfo = jsonObject.getJSONArray("feeds");
JSONObject legsobject = weatherInfo.getJSONObject(0);
a.setText(legsobject.getString("field1"));
b.setText(legsobject.getString("field2"));
c.setText(legsobject.getString("field3"));
}catch (JSONException e) {
e.printStackTrace();
}
}
}
}
I want to get my value refreshed after every 10 seconds and it is not doing it.
Can any one guide me that how can I make it possible.

Try this code ..
private final int INTERVAL_MILLI = 60000; // define your time..
Handler mHandler;
#Override
protected void onDestroy() {
super.onDestroy();
mHandler.removeCallbacks(SyncData);
}
Runnable SyncData = new Runnable() {
#Override
public void run() {
// call your code here..
Log.e(TAG, "SyncData1: " + new java.sql.Date(System.currentTimeMillis()).toString());
final String Token = AppSetting.getStringSharedPref(mContext, Constants.USER_KEY_TOKEN, "");
if (!TextUtils.isEmpty(Token) && !CommonUtils.isServiceRunning(mContext)) {
Log.e(TAG, "SyncData2: " + new java.sql.Date(System.currentTimeMillis()).toString());
startService(new Intent(mContext, SyncService.class));
}
callSyncData();
}
};
public void callSyncData()
{
mHandler.postDelayed(SyncData, INTERVAL_MILLI);
}
and callSyncData() method called in activity onCreate method and run method.

To begin with, I don't like the idea of hammering the server with a request every 10s even nothing changes really. If you can move to a solution with notification from the server it will be better.
If you still need to do that you can use three common solutions to fire a repeating task with a period:
1- Use Timer & TimerTask
For this solution you need to declare your timer task to run:
final TimerTask repeatedTask = new TimerTask() {
#Override
public void run() {
//you stuff here
}
};
Then you need to schedule your task using a timer like below:
final Timer timer = new Timer();
timer.scheduleAtFixedRate(repeatedTask,0, 10 * 1000);
==> Don't forget to call timer.cancel(); when your are done (or activity pause, stop, ...)
2- Use ScheduledThreadPoolExecutor
This is basically a replacing for Timer task starting android 5.0. The setup is more easy and straightforward like below:
ScheduledExecutorService executor = Executors.newScheduledThreadPool(1);
executor.scheduleAtFixedRate(new Runnable() {
#Override
public void run() {
//you stuff here
}
}, 0, 10, TimeUnit.SECONDS);
==> don't forget to shutdown your executor when you are done by calling : executor.shutdown();
3- Use Handler
The tip here is to repost the runnable after downloading your json like mentionned in the previous answer.

You can use TimerTask and Timer. If you need to update UI components you should run it on UI thread.
final TimerTask yourRepeatedTask = new TimerTask() {
#Override
public void run() {
runOnUiThread(new Runnable() {
#Override
public void run() {
//your code here
}
});
}
};
And the Timer which schedules your task in a given interval. In your case, it is 10s. Make sure to give the interval in milliseconds.
final Timer timer = new Timer();
timer.scheduleAtFixedRate(yourRepeatedTask ,0, 10 * 1000);
At last call timer.cancel() to stop the timer.
#Override
protected void onPause() {
if (timer != null) {
timer.cancel();
}
super.onPause();
}

How to set time out for AsyncTask execution?

I have been trying to create time out while AsyncTask execution more than 1 minute. If the time up, then should exit with Notification.
This is my code:
private class GetLongLat extends AsyncTask<Void, Void, Void> {
#Override
protected void onPreExecute() {
super.onPreExecute();
longlatDialog = new ProgressDialog(MainActivity.this);
longlatDialog.setMessage("Fetching Data. Please wait..");
longlatDialog.setCancelable(false);
longlatDialog.show();
}
#Override
protected Void doInBackground(Void... arg0) {
GPSTracker gpsTracker;
//This is the timer to set time out
Timer timer = new Timer();
timer.schedule(new TaskKiller(this), 3000);
timer.cancel();
do{
gpsTracker = new GPSTracker(MainActivity.this);
gpsTracker.getLocation();
}while(!String.valueOf(gpsTracker.latitude).equals("0.0"));
return null;
}
protected void onCancelled() {
// do something, inform user etc.
Toast.makeText(getApplicationContext(), "Failed getting long lat. Please check your internet connection", Toast.LENGTH_LONG).show();
System.exit(1);
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
if (longlatDialog.isShowing())
longlatDialog.dismiss();
}
}
And this is a class called in doInBackground to set the time up.
class TaskKiller extends TimerTask {
private AsyncTask<?, ?, ?> mTask;
public TaskKiller(AsyncTask<?, ?, ?> task) {
this.mTask = task;
}
public void run() {
mTask.cancel(true);
}
}
But when i run the code, nothing happen. I mean the progress dialog always run very long time.
EDIT
I have edit my code to call GetLongLat something like this:
GetLongLat n = new GetLongLat();
n.execute();
try {
n.get(3000, TimeUnit.MILLISECONDS);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (TimeoutException e) {
// TODO Auto-generated catch block
Toast.makeText(getApplicationContext(), "Failed getting long lat. Please check your internet connection", Toast.LENGTH_LONG).show();
System.exit(1);
}
But also, doesn't work.

I think you can use AsyncTask.get()
GetLongLat n = new GetLongLat();
n.get(30000, TimeUnit.MILLISECONDS);
you will have to use the n.get in a separate Thread..
Edited: one more different method but not efficient.,
GetLongLat n = new GetLongLat();
n.execute();
Handler handler = new Handler();
handler.postDelayed(new Runnable()
{
#Override
public void run() {
if ( n.getStatus() == AsyncTask.Status.RUNNING )
n.cancel(true);
}
}, 30000 );

why are you canceling the timer? just after calling schedule()?
Cancels the Timer and all scheduled tasks
timer.cancel(); should be removed. check docs for cancel()

You can achieve this behaviour in many ways.
Here's an example using CountDownTimer
// Start your AsyncTask
private YourAsyncTask mTask = new YourAsyncTask().execute();
// Run a timer after you started the AsyncTask
new CountDownTimer(60000, 1000) {
public void onTick(long millisUntilFinished) {
// Do nothing
}
public void onFinish() {
mTask.cancel(true);
}
}.start();
You are cancelling the timer just after initiating it. You can do it like this too. But this type of busy waiting is not recommended at all.
#Override
protected Void doInBackground(Void... arg0) {
GPSTracker gpsTracker;
//This is the timer to set time out
new CountDownTimer(60000, 1000) {
public void onTick(long millisUntilFinished) {
// Do nothing
}
public void onFinish() {
// Set latitude to zero to finish the while loop outside.
// gpsTracker.latitude = "0.0"; // Something like this
}
}.start();
do{
gpsTracker = new GPSTracker(MainActivity.this);
gpsTracker.getLocation();
}while(!String.valueOf(gpsTracker.latitude).equals("0.0"));
return null;
}

Here's another approach. In your doInBackground method, you can use System.currentTimeMillis to check whether 1 minute has elapsed or not.
protected Void doInBackground(Void... arg0) {
GPSTracker gpsTracker;
long startTime = System.currentTimeMillis();
do{
gpsTracker = new GPSTracker(MainActivity.this);
gpsTracker.getLocation();
}while(!String.valueOf(gpsTracker.latitude).equals("0.0")
&& ((System.currentTimeMillis() - startTime) <= 60000);//60000 millisecond = 1 minute
return null;
}
`

Just alter your code like this and check whether your async task is getting cancelled or not.
GetLongLat getLongLatAsync = new GetLongLat();
getLongLatAsync.execute();
try {
Handler handler = new Handler();
/** 1st method **/
handler.postDelayed(new Runnable()
{
#Override
public void run() {
if (getLongLatAsync.getStatus() == AsyncTask.Status.RUNNING )
getLongLatAsync.cancel(true);
}
}, 3000 ); //3 Seconds
/** 1st method ends **/
/** second method */
handler.post(new Runnable()
{
#Override
public void run() {
getLongLatAsync.get(3000, TimeUnit.MILLISECONDS);//You should run it in seperated thread or else it will block ui thread.
}
});
/** Second method ends**/
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (TimeoutException e) {
// TODO Auto-generated catch block
Toast.makeText(getApplicationContext(), "Failed getting long lat. Please check your internet connection", Toast.LENGTH_LONG).show();
}
and in the onCancelld method write your logic
#Override
protected void onCancelled() {
Log.d(TAG,"Asynctask has been cancelled.");
}

Wait for thread to finish and then move to next position

i am trying to display a Toast on the screen and when Toast fades off then move to the next question. I have tried with Thread but cannot seem to manage.
My code:
next.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (getUserSelection()){
position = position + 3;
if (position < questionsArray.size()) {
curName = questionsArray.get(position).getName();
curArray = questionsArray.get(position).getAnswers();
curIscorrect = questionsArray.get(position).getIscorrect();
setupQuestionView(curName, curArray, curIscorrect);
} else {
StringGenerator.showToast(QuestionsActivity.this, "Your score : " + score + "/" + (questionsArray.size() / 3));
}
}else {
StringGenerator.showToast(QuestionsActivity.this, getString(R.string.noanswerselected));
}
}
});
and the getUserSelectionMethod:
private boolean getUserSelection() {
correct = (RadioButton)findViewById(group.getCheckedRadioButtonId());
if (correct == null){
return false;
}else {
correctAnswerText = correct.getText().toString();
if (map.get(correctAnswerText).equals(Constants.CORRECTANSWER)) {
score++;
setCorrectMessage();
return true;
} else {
setWrongMessage();
return true;
}
}
}
private void setCorrectMessage() {
correctToast = new Toast(QuestionsActivity.this);
correctToastView = getLayoutInflater().inflate(R.layout.correct, (ViewGroup) findViewById(R.id.correctRootLayout));
correctText = (TextView)correctToastView.findViewById(R.id.correctTextView);
correctText.setText(getString(R.string.correctAnswer));
correctToast.setDuration(Toast.LENGTH_SHORT);
correctToast.setView(correctToastView);
correctToast.show();
correctThread = new Thread(new Runnable() {
#Override
public void run() {
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
correctToast.cancel();
}
});
correctThread.start();
}
private void setWrongMessage() {
wrongToast = new Toast(QuestionsActivity.this);
wrongToastView = getLayoutInflater().inflate(R.layout.wrong, (ViewGroup) findViewById(R.id.wrongRootLayout));
wrongText = (TextView)wrongToastView.findViewById(R.id.wrongTextView);
wrongText.setText(getString(R.string.wrongAnswer));
wrongToast.setDuration(Toast.LENGTH_SHORT);
wrongToast.setView(wrongToastView);
wrongToast.show();
wrongThread = new Thread(new Runnable() {
#Override
public void run() {
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
wrongToast.cancel();
}
});
wrongThread.start();
}
Any suggestion on how to do this?

You can determine the toast visibility:
toast.getView().getWindowToken()
If the result is null, than your toast isn't visible anymore, and than you can run any code you want.

as stated in this answer you can start a thread that waits the duration of the Toast:
Thread thread = new Thread(){
#Override
public void run() {
try {
Thread.sleep(3500); // 3.5seconds!
// Do the stuff you want to be done after the Toast disappeared
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
Toast.LENGTH_SHORT and Toast.LENGTH_LONG are only flags so you have to either hard code the duration or keep them in a constant. The durations are 3.5s (long) and 2s (short).
If you want to manipulate some of your views, you cannot do this in another thread than the "main" UI thread. So you have to implement a kind of callback/polling mechanism to get notified when the SleepThread has finished.
Check this answer to read about a couple of ways to do this. Probably the easiest of them to understand and implement is this:
After you started your Thread you can check if it is still alive and running by calling thread.isAlive(). In this way you can do a while loop that runs while the thread is running:
// start your thread
while(thread.isAlive()){}
// continue the work. The other thread has finished.
Please note that this is NOT the most elegant way to do this! Check the other possibilities in the answer I've mentioned above for more elegant solutions (especially the last one with the listeners is very interesting and worth reading!)

That's because the Thread class is purely executed in the background and you need to manipulate the view in the Main thread. To solve your issue just replace the Thread with AsynTask.
AsyncTask<Void,Void,Void> a = new AsyncTask<Void, Void, Void>() {
#Override
protected Void doInBackground(Void... params) {
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
correctToast.cancel();
}
};
a.execute();
If you look at my code you can see my onPostExecute, this method is called in the Main Thread.

My Error was because i was trying to acess UI Elements through another Thread so modifying the code like this:
Thread thread = new Thread(new Runnable() {
#Override
public void run() {
try {
Thread.sleep(500);
QuestionsActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
moveToNextQuestion();
}
});
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
thread.start();
did the trick. I hope my answer helps someone!!!

Android - Moveing an Activity inside of background thread

Every time I`m trying to finish an activity inside of a timer method, the activity comes back alive over and over again.
I running this activity:
public class PlayerNoAdmin extends ActionBarActivity {
Timer myTimer; boolean isAdmin;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_player_no_admin);
Intent oldIntent = getIntent();
if (oldIntent != null && oldIntent.hasExtra("THE_LIST")){
songs = oldIntent.getParcelableArrayListExtra("THE_LIST");
id = oldIntent.getIntExtra("ID",0);
listId = oldIntent.getIntExtra("LIST_ID",0);
isAdmin = oldIntent.getBooleanExtra("IS_ADMIN",false);
}
//update the list every k seconds
myTimer = new Timer();
myTimer.schedule(new TimerTask() {
#Override
public void run() {
TimerMethod();
}
}, 0, k_time2Update);
}
private void TimerMethod() {
//This method is called directly by the timer
//and runs in the same thread as the timer.
//We call the method that will work with the UI
//through the runOnUiThread method.
this.runOnUiThread(Timer_Tick);
}
private Runnable Timer_Tick = new Runnable() {
public void run() {
//Here check for update in the list every 30 seconds and send the new location
String url = getRunUrl();
new TaskMusicPlay().execute(url);
}
};
private class TaskMusicPlay extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... params) {
String jsonResult = null;
try {
String url = params[0];
TestMain client = new TestMain();
jsonResult = client.doGetRequest(url);
} catch (IOException e) {
e.printStackTrace();
}
return jsonResult;
}
#Override
protected void onPostExecute(String aVoid) {
super.onPostExecute(aVoid);
checkIfNew(aVoid);
}
private void checkIfNew(String result) {
try {
JSONObject object = new JSONObject(result);
String temp = object.getJSONObject("info").getString("isAdmin");
isAdmin = (temp.equals("true"));
if (isAdmin) {
Intent intent = new Intent(getApplication(),YouTubePlayer.class);
intent.putExtra("THE_LIST", songs);
intent.putExtra("ID", id);
intent.putExtra("LIST_ID",listId);
intent.putExtra("IS_ADMIN",isAdmin);
startActivity(intent);
finish();
}
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}
At the end, I succeeded to move to the YouTubePlayer activity, but every few seconds the app returns to the code of this activity (and then executes again the startActivity call and goes back to YouTubePlayer) and that's going on and on.

Your Timer is periodically calling the player to start over and over again.
You must make a cancel() call to the Timer if it is no longer needed so you prevent it from holding a reference for your activity and thus preventing from being removed from the backstack and GC.
http://developer.android.com/reference/java/util/Timer.html
And your Timer is not running on the same thread as it's code because the timer thread iis another Thread and the Code in the Timer is running on UI. You can check it out by adding some logs in the Timer's run method outside of the runOnUIThread() and inside of it.

Stop a service and timer after fixed interval of time, android?

In my app, I have a service implementing timer task through which i am getting user's location after every 10 seconds.
The thing I am stuck with is I would like to stop this service as well as timer after say 1 or 2 minutes.
I am not able to put behind the logic for it.
Please help me out.
public class TimeService extends Service {
// constant
public static final long NOTIFY_INTERVAL = 20 * 1000; // 10 seconds
// run on another Thread to avoid crash
private Handler mHandler = new Handler();
// timer handling
private Timer mTimer = null;
int i=0;
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public void onCreate() {
// cancel if already existed
if(mTimer != null) {
mTimer.cancel();
} else {
// recreate new
mTimer = new Timer();
}
// schedule task
mTimer.scheduleAtFixedRate(new TimeDisplayTimerTask(), 0, NOTIFY_INTERVAL);
}
class TimeDisplayTimerTask extends TimerTask {
#Override
public void run() {
// run on another thread
mHandler.post(new Runnable() {
#Override
public void run() {
// display toast
Toast.makeText(getApplicationContext(), getDateTime(),
Toast.LENGTH_SHORT).show();
new LongOperation().execute("");
}
});
}
private String getDateTime() {
// get date time in custom format
SimpleDateFormat sdf = new SimpleDateFormat("[yyyy/MM/dd - HH:mm:ss]");
return sdf.format(new Date());
}
}
private class LongOperation extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... params) {
System.out.println("bgnotification Long operation doinbackground called----> ");
return "";
}
#Override
protected void onPostExecute(String result) {
System.out.println("bgnotification Long operation post execute called----> ");
if(i<3){
GPSTracker mGPS = new GPSTracker(getApplicationContext());
onLocationChanged(mGPS);i++;
Toast.makeText(getApplicationContext(), "HEllo Post execute called",
}
#Override
protected void onPreExecute() {
System.out.println("bgnotification Long operation pre execute called----> ");
}
#Override
protected void onProgressUpdate(Void... values) {
}
}
public void onLocationChanged(GPSTracker track) {
// Getting latitude
double latitude = track.getLatitude();
// Getting longitude
double longitude = track.getLongitude();
System.out.println( latitude);
System.out.println( longitude);
Geocoder geocoder = new Geocoder(this, Locale.getDefault());
try
{
List<Address> addresses = geocoder.getFromLocation(latitude, longitude, 1);
Log.e("Addresses","-->"+addresses);
}
catch (IOException e)
{
e.printStackTrace();
}
}
}

#Wishy to stop service and timer task at certain time you need to make an other timer task which going to execute one time and execution time duration will be whatever you specify. In run method u need to write mTimer.purge(); mTimer.cancel() and stopService(newIntent(class.this,yourservice.class));

An easier solution is making timer public static.
public class TimeService extends Service {
//...
private Timer mTimer = null;
//...
}
another Activity:
//...
if(TimeService.mTimer!=null) TimeService.mTimer.cancel();
//...

Override onDestroy() method in service class like thus:
#Override
public void onDestroy() {
super.onDestroy();
if (mTimer != null) {
mTimer.cancel();
}
}
Call stopService() there where you want to stop your service, like thus:
stopService(serviceIntent);
That's all.