When using a wait in an AsyncTask, I get ERROR/AndroidRuntime(24230): Caused by: java.lang.IllegalMonitorStateException: object not locked by thread before wait()
Is it possible to use an Asynctask just for waiting? How?
Thanks
class WaitSplash extends AsyncTask<Void, Void, Void> {
protected Void doInBackground(Void... params) {
try {
wait(MIN_SPLASH_DURATION);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
protected void onPostExecute() {
waitSplashFinished = true;
finished();
}
}
Use Thread.sleep() instead of wait().
You can use Thread.sleep method
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
#Override
protected String doInBackground(String... params) {
// TODO Auto-generated method stub
try {
Thread.currentThread();
Thread.sleep(5000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
If you're looking to just postpone execution of a method for a set amount of time, a good option is Handler.postDelayed()
define the handler and runnable...
private Handler handler = new Handler();
private Runnable runnable = new Runnable() {
finished();
};
and execute with delay...
handler.postDelayed(runnable, MIN_SPLASH_DURATION);
Use threads for this
public class SplashActivity extends Activity{
int splashTime = 5000;
private Thread splashThread;
private Context mContext;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.mContext = this;
setContentView(R.layout.splash_layout);
splashThread = new Thread(){
public void run() {
try{
synchronized (this) {
wait(splashTime);
}
}catch(InterruptedException ex){
ex.printStackTrace();
}finally{
Intent i = new Intent(mContext,LocationDemo.class);
startActivity(i);
stop();
}
}
};
splashThread.start();
}
public boolean onTouchEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
synchronized (splashThread) {
splashThread.notifyAll();
}
}
return true;
}
on touch event, thread get notified.. can change according to your need.
You have this way to work with asyntask and wait();
public class yourAsynctask extends AsyncTask<Void, Void, Void> {
public boolean inWait;
public boolean stopWork;
#Override
protected void onPreExecute() {
inWait = false;
stopWork = false;
}
#Override
protected Void doInBackground(Void... params) {
synchronized (this) {
while(true) {
if(stopWork) return null;
if(youHaveWork) {
//make some
} else {
try {
wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
return null;
}
public void mynotify() {
synchronized (this) {
if(inWait) {
notify();
inWait = false;
}
}
}
public void setStopWork() {
synchronized (this) {
stopWork = false;
if(inWait) {
notify();
inWait = false;
}
}
}
}
Related
I have IntentService that need to wait in method a() for results of onReceive() of BroadcastReceiver().
For now i use lmao wait(5000)... so it's not too elegant
IntentService:
private boolean methodA() {
try {
synchronized (mLocalBroadcastReceiver) {
mLocalBroadcastReceiver.wait(3000);
}
} catch (InterruptedException e) {
Log.e(TAG,"error, thread interrupted");
e.printStackTrace();
}
if(CONSTANT == true){
return true;
else
return false;
}
BroadCastRecievier:
#Override
public void onReceive(Context context, Intent intent) {
CONSTANT = true //changes somehow between true/false
}
In other words: return value of methodA depends on results of onReceive(). How to synchronize two threads?
Finally i used thread like that:
private void waitForResponse() {
//wait for response
thread = new WaitForStatus();
thread.run();
try {
synchronized (thread) {
thread.wait();
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
private class WaitForAppStatus implements Runnable {
#Override
public void run() {
while (true) {
if (CONSTANT != -1) {
break;
} else {
try {
wait(400);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
}
I have tried updating my user interface using the text view what i have done is a run a while loop indefinitely and left the thread for sleep for one second..
int i;
while(true)
{
Thread.Sleep(1000);
textView.setText(updateTime);
}
Use runOnUiThread and surround with try catch for Thread.sleep(1000)
int i;
while(true)
{
try {
Thread.sleep(1000);
runOnUiThread(new Runnable() {
#Override
public void run() {
// TODO Auto-generated method stub
textView.setText(updateTime);
}
});
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
Try this one arnab...
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final TextView textView = (TextView) findViewById(R.id.displayid);
handler = new Handler() {
#Override
public void handleMessage(Message msg) {
bundle = msg.getData();
textView.setText(bundle.getString("mKey"));
}
};
}
public void press(View v) {
new Thread(new Runnable() {
#Override
public void run() {
while (true) {
synchronized (this) {
try {
wait(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
bundle = new Bundle();
message = handler.obtainMessage();
simpleDateFormat = new SimpleDateFormat("hh:mm:ss YYYY/mm/dd", Locale.US);
date = simpleDateFormat.format(new Date());
bundle.putString("mKey", date);
message.setData(bundle);
handler.sendMessage(message);
}
}
}
}).start();
}
Try runOnUiThread:
runOnUiThread(new Runnable() {
#Override
public void run() {
textView.setText(updateTime);
}
});
After recieving a pictures from user, putting them in an array, animate() method is called from main, this method contains Asynktask. How can I finish this AsyncTask?
This is my code:
private void animate() {
new AsyncTask<Void, Void, Void>() {
#Override
protected Void doInBackground(Void... params) {
try {
Thread.sleep(1000);
runOnUiThread(new Runnable() {
#Override
public void run() {
iv.setImageResource(pics[0]);
}
});
} catch (Exception ex) {
ex.printStackTrace();
}
while (true) {
try {
Thread.sleep(500);
runOnUiThread(new Runnable() {
#Override
public void run() {
iv.setImageResource(pics[pos]);
pos = (pos + 1);
}
});
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
}.execute();
}
From your code, I guess what you want is to change the image you show in an ImageView periodically. I'd suggest to change your code to use a Timer:
private Timer mTimer;
private void startCarousel(){
mTimer = new Timer();
TimerTask timerTask = new TimerTask() {
public void run() {
// Your periodic task...
}
};
mTimer.schedule(timerTask, 1000, 500);
}
private void stopCarousel(){
if(mTimer != null){
mTimer.cancel();
mTimer.purge();
}
}
Is it possible to do splash screen that will execute HTTP request and if this request is executing too long, i.e. 7-10 seconds, then abort the request and jump to the main activity?
The below code is what I did, but it doesn't work - the timeout isn't working, the HTTP request and jumping are working. As I understand, it's possible to use the AsyncTask's get() method or handler with delay. Get() method should be in separate thread but it doesn't work. How to do this task?
EDIT:
public class SplashActivity extends Activity {
private static final String TAG = "SplashActivity";
private Handler handler = new Handler();
private Runnable r;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.splash_layout);
if (Helpers.isNetworkConnected(getApplicationContext())) {
Log.d(TAG, "Has Internet");
final DownloadFAQ downloadFAQ = new DownloadFAQ();
new Thread(new Runnable() {
public void run() {
try {
Log.d(TAG, "Timing...");
downloadFAQ.execute().get(1000, TimeUnit.MILLISECONDS);
SplashActivity.this.runOnUiThread(new Runnable() {
public void run() {
Log.d(TAG, "redirect");
redirect();
}
});
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
} catch (TimeoutException e) {
downloadFAQ.cancel(true);
Log.d(TAG, "Task has benn canceled");
if (downloadFAQ.isCancelled())
redirect();
}
}
}).start();
} else {
r = new Runnable() {
public void run() {
redirect();
}
};
handler.postDelayed(r, 2500);
}
}
private class DownloadFAQ extends AsyncTask<Void, Void, Void> {
#Override
protected Void doInBackground(Void... params) {
Log.d(TAG, "Execute task");
ServerAPI server = new ServerAPI(getApplicationContext());
server.serverRequest(ServerAPI.GET_FAQ, null);
return null;
}
}
private void redirect() {
Intent i = new Intent(SplashActivity.this, TabsActivity.class);
startActivity(i);
finish();
}
#Override
protected void onDestroy() {
super.onDestroy();
handler.removeCallbacks(r);
}
}
because you are trying to start AsyncTask again inside doInBackground when it's still running . change your code as to get it work :
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.splash_layout);
downloadFAQ = new DownloadFAQ();
new Thread(new Runnable() {
public void run() {
try {
downloadFAQ.execute().get(2000, TimeUnit.MILLISECONDS);
SplashActivity.thisrunOnUiThread(new Runnable() {
public void run() {
// start Activity here
Intent i = new Intent(SplashActivity.this,
TabsActivity.class);
SplashActivity.this.startActivity(i);
SplashActivity.this.finish();
}
});
} 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
e.printStackTrace();
}
}
}).start();
}
and you will need to remove downloadFAQ.get(2000, TimeUnit.MILLISECONDS); from doInBackground method change your AsyncTask as
private class DownloadFAQ extends AsyncTask<Void, Void, Void> {
#Override
protected Void doInBackground(Void... params) {
ServerAPI server = new ServerAPI(getApplicationContext());
server.serverRequest(ServerAPI.GET_FAQ, null);
return null;
}
protected void onPostExecute(Void result) {
}
}
consider using asyncTask status:
AsyncTask.Status
How do I call the SensorManager from inside -
protected String doInBackground(String... params) {
.....
}
I have to log the acclerometer data on to a file. This application runs in the background. Hence I am using AsyncTask to implement it. I need to start and stop the logging by pressing the button (onClick). Any pointers would be helpful!!
This is the update... The file written is empty...How do I start the logging?
public class AsyncTaskActivity extends Activity implements SensorEventListener{
Button btn;
File root = Environment.getExternalStorageDirectory();
StringBuilder builder = new StringBuilder();
File gpxfile = new File(root, "TestFile.txt");
String fileText = "Data";
FileWriter gpxwriter;
BufferedWriter out;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
btn = (Button) findViewById(R.id.button1);
btn.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
new LongOperation(new AsyncTaskActivity()).execute("");
}
});
}
private class LongOperation extends AsyncTask<String, Void, String> {
private AsyncTaskActivity mActivity;
public LongOperation (AsyncTaskActivity activity) {
mActivity = activity;
}
#Override
protected String doInBackground(String... params) {
try {
gpxwriter = new FileWriter(gpxfile);
out = new BufferedWriter(gpxwriter);
if (root.canWrite()){
SensorManager manager = (SensorManager) mActivity.getSystemService(Context.SENSOR_SERVICE);
Sensor accelerometer = manager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
if(!manager.registerListener((SensorEventListener) this, accelerometer, SensorManager.SENSOR_DELAY_GAME)){
System.out.println("Could not start!!!!!!!!!");
}
out.write("Start");
out.newLine();
out.close();
}
} catch (IOException e) {
Log.e("doIn","Could not write file " + e.getMessage());
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(String result) {
TextView txt = (TextView) findViewById(R.id.output);
txt.setText("File written successfully!!!");
}
#Override
protected void onPreExecute() {
}
#Override
protected void onProgressUpdate(Void... values) {
}
}
#Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
// TODO Auto-generated method stub
}
#Override
public void onSensorChanged(SensorEvent event) {
// TODO Auto-generated method stub
builder.setLength(0);
builder.append(event.values[0]+","+event.values[1]+","+event.values[2]);
try {
out.append(builder.toString());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
Pass the Activity Instance to the constructor of the AsyncTask and then access the Sensor Manager
class MyTask extends AsyncTask<URL, Integer, List> {
private MainActivity mActivity;
public MyTask(MainActivity activity) {
mActivity = activity;
}
protected List doInBackground(URL... url) {
SensorManager mSensorManager = (SensorManager)
mActivity.getSystemService(SENSOR_SERVICE)
....
return ..;
}
}