So I'm trying to update an overlay with a timer however it always crashes. I read something about UI thread but I'm kinda lost on what that even means.
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
WindowManager windowManager = (WindowManager) getSystemService(WINDOW_SERVICE);
overlayView.getBackground().setAlpha(50);
windowManager.addView(overlayView, params);
new Thread(new Runnable() {
public void run() {
while (true) {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
//crashing here//
overlayView.getBackground().setAlpha(150);
//testing if updating
counter = counter + 1;
notification.setContentText("number" + counter);
startForeground(1, notification.build());
}
}
}).start();
return START_NOT_STICKY;
}
It always returns this error:
android.view.ViewRootImpl$CalledFromWrongThreadException: Only the
original thread that created a view hierarchy can touch its views.
Android do not allow updating UI from any thread except UI/Main thread. I see you have created a new Thread so your updating UI stuff is on a worker thread which is not allowed in Android.
A simple solution is to create a handler of main thread and post a runnable to it.
new Handler(Looper.getMainLooper()).post(new Runnable() {
public void run() {
// modify UI here
// overlayView.getBackground().setAlpha(150);
}
});
Related
I have a activity that call startService(intent) and this one in his method onStatCommand() create a thread that checks the running app every second.
The problem is that the thread freze the creation of the activity and the screen show only a white screen. If i delete the for(;;) statment in the thread it works. why?
here there is the onStartCommand() code:
#Override
public int onStartCommand(Intent intent,int flags,int startid)
{
super.onStartCommand(intent,flags,startid);
final Thread thread= new Thread(){
#Override
public void run()
{
Context context = getApplicationContext();
for(;;) {
long current = System.currentTimeMillis();
UsageStatsManager usageStatsManager = ((UsageStatsManager) context.getSystemService(Context.USAGE_STATS_SERVICE));
for (UsageStats usageStats : usageStatsManager.queryAndAggregateUsageStats( current - 1000*2, current).values()) {
Log.i("Path changed name",usageStats.getPackageName());
if(usageStats.getPackageName()=="com.android.chrome")
{
Log.i("Path name",usageStats.getPackageName());
stopSelf();
break;
}
}
try {
currentThread().sleep(1000);
}catch (InterruptedException e)
{
e.printStackTrace();
}
}
}
};
thread.run();;
return 0;
}
There is problem with Thread code, You should call Start method to start a new Thread not run.
Problem code:
thread.run();
Fixed code:
thread.start();
I'm currently trying to do an app that keeps track of the phone through the GPS by using a service. in order to get the GPS to update the coordinates, I need to use a handler within the service. Right now the proble I have is that when the I do the Handler.post, it gets stuck in an loop, and after that, it completely ignores the rest of the service code.
When I was debugging, I found out that the handler was alternating messages between methods but nothing useful came out of it, it was just a loop between the same methods over and over again.
Here's my Service code that includes the handler:
public int onStartCommand(Intent intent, int flags, int startId)
{
ctx = ServicioDeFondo.this;
mHandler = new Handler();
reportarGPS = new Thread(new Runnable() { public void run()
{
try
{
while(true)
{
mHandler.post(new Runnable() {
#Override
public void run() {
gps = new GPSTrack(ctx);
latitude = String.valueOf(gps.getLatitude());
longitude = String.valueOf(gps.getLongitude());
}
});
Thread.sleep(10000);
try {
new APISendClass().execute();
Thread.sleep(10000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
catch (Exception e)
{
//TODO Auto-generated catch block
e.printStackTrace();
}
} });
reportarGPS.start();
return START_STICKY;
}
I"ve been stuck here all day, any help would be greatly appreciated!
With your brief description of the problem, it's hard to understand what the expected behavior is. You don't explain what GPSTrack and APISendClass do and what type of objects that are. You state "it gets stuck in a loop". It's not clear what "it" is. With the while (true) statement, the thread will loop until cancelled.
Note that Service methods, such as onStartCommand() run on the main thread. That means that your Handler() constructor associates the handler with the main thread. The runnables you post to that handler run on the main thread. Is that what you wanted?
Also note that stopping the service by stopSelf() or Context.stopService() does not kill the thread. You need to have code to cancel the thread when it is no longer needed. This is often done in onDestroy().
I took the code you posted, replaced the calls to unknown objects with Log statements and ran it. The logcat output alternated between "Get lat/long" and "APISendClass()".
Handler mHandler;
Context ctx;
Thread reportGPS;
public int onStartCommand(Intent intent, int flags, int startId){
Log.i("TEST", "onStartCommand()");
ctx = this;
// Service methods run on main thread.
// Handler constructor with no args associates Handler
// with current thread, which here is the main thread.
mHandler = new Handler();
reportGPS = new Thread(new Runnable() {
#Override
public void run() {
try {
while (true) {
mHandler.post(new Runnable() {
#Override
public void run() {
// This runnable is posted to the main thread.
// Is that what you intended?
//gps = new GPSTrack(ctx);
//latitude = String.valueOf(gps.getLatitude());
//longitude = String.valueOf(gps.getLongitude());
Log.i("TEST", "Get lat/long");
}
});
Thread.sleep(2000);
try {
//new APISendClass().execute();
Log.i("TEST", "APISendClass().execute()");
Thread.sleep(5000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
reportGPS.start();
return START_STICKY;
}
i want to start Asynchoronous task after some sleep time. For that i am using thread and i start my asynchronous task in that thread finally block. But it gives cant create a handler inside a thread exception.
i am using the following logic.
thread= new Thread()
{
public void run()
{
try
{
int waited = 0;
while (waited < 300)
{
sleep(100);
waited += 100;
}
}
catch (InterruptedException e)
{
// do nothing
}
finally
{
Load ld=new Load();
ld.execute();
}
}
};
thread.start();
Well, first of all, if the final goal is to run AsyncTask after some delay, I would use Handler.postDelayed instead of creating separate Thread and sleeping there:
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
new Load().execute();
}
}, 300); //300ms timeout
But, if you really wanna make fun of Android, you can create HandlerThread - special thread which has looper in it, so your AsyncTask will not be complaining anymore:
thread= new HandlerThread("my_thread")
{
public void run()
{
try
{
int waited = 0;
while (waited < 300)
{
sleep(100);
waited += 100;
}
}
catch (InterruptedException e)
{
// do nothing
}
finally
{
Load ld=new Load();
ld.execute();
}
}
};
thread.start();
Please note that you are responsible for calling quit() on this thread. Also I'm not sure what happens if you quit this thread before AsyncTask is done. I don't remember where AsyncTask posts its results - to the main thread, or to the thread it was called from...
In any case, second option is just a mess, so don't do it:) Use the first one
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
// Do whatever you want.
}
}, SPLASH_TIME_OUT);
}
You can use like above. there SPLASH_TIME_OUT is the millisecond value that u want to make a delay.
Use Handler class, and define Runnable YourAsyncTask that will contain code executed after sleepTime
mHandler.postDelayed(YourAsyncTask, sleepTime);
You must run AsyncTask in UI thread, so you can use something like this:
class YourThread extends Thread{
private Activity _activity;
public YourThread(Activity _activity){
this activity = _activity;}
public void run()
{
try
{
int waited = 0;
while (waited < 300)
{
sleep(100);
waited += 100;
}
}
catch (InterruptedException e)
{
// do nothing
}
finally
{
activity.runOnUiThread(new Runnable() {
#Override
public void run() {
Load ld=new Load();
ld.execute();
}
});
}
}
}
and in your activity call thread like this:
YourThread thread = new YourThread(this);
thread.start();
also note: use soft reference to activity or do not forget kill thred when activity will be destroyed.
just do your like below code:
define a thread globally.
public static Thread thread;
thread= new Thread() {
public void run() {
sleep(time);
Message msg = setTextHandler.obtainMessage(2);
setTextHandler.sendMessage(msg);
}
};
thread.start();
and your handler look like
private final Handler setTextHandler = new Handler() {
#Override
public void handleMessage(Message msg) {
if (thread!= null) {
thread.interrupt();
thread= null;
}
switch (msg.what) {
case 2: //do your work here
Load ld=new Load();
ld.execute();
break;
}
}
};
I'm trying to send a toast notification of an error in a thread. The thread is started in a service that is called from the main thread. I've tried several things with View.post and some weird handler stuff, but nothing seems to work. An excerpt of the thread is as follows:
public int onStartCommand(Intent intent, int flags, int startId)
{
new Thread(new Runnable(){
public void run() {
boolean bol = true;
while (bol)
{
try
{
//Some socket code...
}
catch (Exception e)
{
//Where I want the toast code.
}
}
}
}).start();
return START_STICKY;
}
Try following inside the thread in the service:
Handler h = new Handler(context.getMainLooper());
// Although you need to pass an appropriate context
h.post(new Runnable() {
#Override
public void run() {
Toast.makeText(context,message,Toast.LENGTH_LONG).show();
}
});
Taken from answer given by #Alex Gitelman here on Android: How can i show a toast from a thread running in a remote service? . This might help somebody as it helped me.
Toast can be shown only from UI Thread (Main Thread). To show Toast from some other threads you have to use Handler.
Threads, Handlers and AsyncTask
Yes you should use a Handler, and bind you Activity to your Service
Once the Handler is set, here is what you should do,
Message msg = Message.obtain(null, MyActivity.TOAST);
Bundle bundle = new Bundle();
bundle.putString(MyActivity.TOAST_MSG, "Toast message");
msg.setData(bundle);
try {
myActivityMessenger.send(msg);
} catch (RemoteException e) {
if (D) Log.w(TAG, "Unable to send() the toast message back to the UI.");
e.printStackTrace();
}
myActivityMessenger is set with the Handler of your MyActivity and sent to the Service when you bind MyActivity to it.
However displaying a Toast with a Service as context should work (but it's not the best way), so maybe it's because you try to make it from a new Thread. What is your code for making the Toast ?
new Thread(){
#Override
public void run() {
runOnUiThread(new Runnable() {
#Override
public void run() {
_dialog.dismiss();
Toast.makeText(LatestNewsActivity.this, "NO Internet Connection Available", Toast.LENGTH_LONG).show();
}
});
}
}.start();
I am developing an Android app and I am doing some heavy work (bringing data from an online web page and parsing it to store in database) in a service. Currently, it is taking about 20+ mins and for this time my UI is stuck. I was thinking of using a thread in service so my UI doesn't get stuck but it is giving error. I am using the following code:
Thread thread = new Thread()
{
#Override
public void run() {
try {
while(true) {
sleep(1000);
Toast.makeText(getBaseContext(), "Running Thread...", Toast.LENGTH_LONG).show();
}
} catch (InterruptedException e) {
Toast.makeText(getBaseContext(), e.toString(), Toast.LENGTH_LONG).show();
}
}
};
thread.start();
This simple code is giving run time error. Even If I take out the while loop, it is still not working.
Please, can any one tell me what mistake I am doing. Apparently, I copied this code directly from an e-book. It is suppose to work but its not.
Android commandment: thou shall not interact with UI objects from your own threads
Wrap your Toast Display into runOnUIThread(new Runnable() { });
Example of new thread creation taken from Android samples (android-8\SampleSyncAdapter\src\com\example\android\samplesync\client\NetworkUtilities.java):
public static Thread performOnBackgroundThread(final Runnable runnable) {
final Thread t = new Thread() {
#Override
public void run() {
try {
runnable.run();
} finally {
}
}
};
t.start();
return t;
}
runnable is the Runnable that contains your Network operations.
You can use HandlerThread and post to it, here is an example to service that has one.
public class NetworkService extends Service {
private HandlerThread mHandlerThread;
private Handler mHandler;
private final IBinder mBinder = new MyLocalBinder();
#Override
public void onCreate() {
super.onCreate();
mHandlerThread = new HandlerThread("LocalServiceThread");
mHandlerThread.start();
mHandler = new Handler(mHandlerThread.getLooper());
}
public void postRunnable(Runnable runnable) {
mHandler.post(runnable);
}
public class MyLocalBinder extends Binder {
public NetworkService getService() {
return NetworkService.this;
}
}
#Override
public IBinder onBind(Intent intent) {
return mBinder;
}
}
You may define your jobs in a runnable object, use a thread object for running it and start this thread in your service's onStartCommand() function. Here is my notes:
In your service class:
define your main loop in an Runnable object
create Thread object with the runnable object as parameter
In your service class's onStartCommand method():
call thread object's start function()
my code :
private Runnable busyLoop = new Runnable() {
public void run() {
int count = 1;
while(true) {
count ++;
try {
Thread.sleep(100);
} catch (Exception ex) {
;
}
ConvertService.running.sendNotification("busyLoop" + count);
}
}
};
public int onStartCommand(Intent intent, int flags, int startId) {
sendNotification("onStartCommand");
if (! t.isAlive()) {
t.start();
}
return START_STICKY;
}