To know the difference between IntentService and Service in Android, I created the below posted small test of a Service class. The MainActivity has a Button, when pressed, the
service will be started using startService() as shown below in the code, which will result in a call to onStartCommand(). In onStartCommand(), i run a loop for 10 seconds, and I
expected that, that loop will block the UI "the butoon". Actually that what happened exactly when I first time start the Service, but when I press the button after the 10 seconds
elapsed, it will result in a call to onStartCommand() but the log message inside the onStartCommand() never get displayed plus the UI is never blocked.
can anyone please explain what the body of the onStartCommand() is executed and blocks the UI only when the Service first started and never afterwards?
MainActivity
public class MainActivity extends AppCompatActivity {
private Button mbtnSend = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.mbtnSend = (Button) findViewById(R.id.btn_send);
this.mbtnSend.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(getApplicationContext(), MyService.class);
startService(intent);
}
});
}
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
registerReceiver(this.mBCR_VALUE_SENT, new IntentFilter(MyIntentService.INTENT_ACTION));
this.mbtnSend = (Button) findViewById(R.id.btn_send);
this.mbtnSend.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(getApplicationContext(), MyIntentService.class);
intent.putExtra("intent_key", ++i);
startService(intent);
}
});
}
}
MyIntentService:
public class MyService extends Service{
private final String TAG = this.getClass().getSimpleName();
private long mStartTime;
#Override
public void onCreate() {
super.onCreate();
Log.w(TAG, SubTag.msg("onCreate"));
this.mStartTime = TimeUtils.getTSSec();
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.w(TAG, SubTag.msg("onStartCommand"));
while ( (TimeUtils.getTSSec() - this.mStartTime) <=10) {
Log.w(TAG, SubTag.msg("time: " + (TimeUtils.getTSSec() - this.mStartTime)));
SystemClock.sleep(1000);
}
return Service.START_STICKY;
}
#Nullable
#Override
public IBinder onBind(Intent intent) {
Log.w(TAG, SubTag.msg("onBind"));
return null;
}
#Override
public void onDestroy() {
super.onDestroy();
Log.w(TAG, SubTag.msg("onDestroy"));
}
}
You are setting mStartTime to TimeUtils.getTSSec() in onCreate(), which means that it will get intialized only once.
Afterwards, onStartCommand() is called, but the mStartTime timestamp is not being updated, so the while loop never runs.
I believe that moving the line where you initialize mStartTime to onStartCommand() before the while loop will make your thread hang again.
Related
I know that is a well known subject, but I have tried lot of things. I have an simple application, dedicated to a specific user, application has an mainActivity which is displaying some status on screen and it's starting two services, one is making request from a server (at every 5 minutes) and one which is sending sms and replay to server (at every ten minutes).
The application is running on a Samsung pocket 2 with Android 4.4.2, this device is used only for this application. While the device is connected to ADB the services are working just fine, but if I disconnect the phone and let it running normally, the services are killed repeatable and restarted after a while. The messaged are send with very much delay. I would be thankful for any suggestions.
Here is my code:
Main activity:
public class MainActivity extends Activity {
private TextView _internet;
private TextView _signal;
private TextView _server;
private BroadcastReceiver receiver;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
init();
IntentFilter intentFilter = new IntentFilter(Constants.SS);
receiverWorker();
registerReceiver(receiver, intentFilter);
startService(new Intent(this, RefreshDBService.class));
startService(new Intent(this, SmsService.class));
}
private void receiverWorker() {
receiver = new BroadcastReceiver() {
public void onReceive(Context arg0, Intent arg1) {
checkState();
}};
}
public void refreshButonClicked(View v) {
checkState();
}`
Here is my first service:
public class RefreshDBService extends Service {
private Thread _backgroundWork;
private ScheduledExecutorService scheduleTaskExecutor = Executors.newScheduledThreadPool(1);
private DataBaseOperations _dataSource;
#Override
public void onCreate() {
super.onCreate();
_dataSource = new DataBaseOperations(this);
_backgroundWork = new Thread(new Runnable() {
#Override
public void run() {
if(Checks.checkInternetConnection(getApplicationContext())){
if(ServerOperations.isServerAvailable(getApplicationContext())){
String inputData = ServerOperations.makeRequest(Constants.GET_DATA_ROUTE, ServerOperations.getMessagesFromServer(getApplicationContext()));
ArrayList<DataSmsObj> dataFromServer=null;
if(inputData!=null && !inputData.isEmpty()){
dataFromServer = ServerOperations.fromJsonToObjects(inputData);
if(dataFromServer.size()>0){
_dataSource.open();
_dataSource.insertDataFromServer(dataFromServer);
_dataSource.close();
}
}
System.out.println("check server for messages in pending status, received -> "+ dataFromServer.size());
}else{
System.out.println("no server");
sentErrorToUI(Constants.NO_SERVER);
}
}else{
System.out.println("no internet");
sentErrorToUI(Constants.NO_INTERNET);
}
}
});
}
public int onStartCommand(Intent intent, int flags, int startId) {
scheduleTaskExecutor.scheduleWithFixedDelay(_backgroundWork, 0, Constants.NEXT_CYCLE/2, TimeUnit.MINUTES);
return START_REDELIVER_INTENT;
}
#Override
public void onDestroy() {
super.onDestroy();
scheduleTaskExecutor.shutdownNow();
}
public IBinder onBind(Intent intent) {
return null;
}
private void sentErrorToUI(String message){
Intent intent = new Intent(Constants.SS);
intent.putExtra(Constants.SS, message);
System.out.println("trimit" +message);
sendBroadcast(intent);
}
}
And this is the second one:
public class SmsService extends Service {
private Thread _backgroundWork;
private ScheduledExecutorService scheduleTaskExecutor = Executors.newScheduledThreadPool(1);
private DataBaseOperations _dataSource;
#Override
public void onCreate() {
super.onCreate();
_dataSource = new DataBaseOperations(this);
_backgroundWork = new Thread(new Runnable() {
#Override
public void run() {
sendFeedbackToServer();
List<DataSmsObj> dataToSent = new ArrayList<DataSmsObj>();
_dataSource.open();
dataToSent = _dataSource.getDataToSent();
_dataSource.close();
System.out.println("messages to sent: "+ dataToSent.size());
for (int i = 0; i < dataToSent.size(); i++) {
//here the messages are send, the code is to long to put it here, but if is need i can do it afterwards
}
}
});
}
public int onStartCommand(Intent intent, int flags, int startId) {
scheduleTaskExecutor.scheduleWithFixedDelay(_backgroundWork, 0, Constants.NEXT_CYCLE, TimeUnit.MINUTES);
return START_REDELIVER_INTENT;
}
#Override
public void onDestroy() {
super.onDestroy();
scheduleTaskExecutor.shutdownNow();
public IBinder onBind(Intent intent) {
return null;
}
If you are using a background Service with a scheduled task, it could be killed by the system. The only way to prevent the killing is a foreground Service. Quoting the documentation:
A foreground service is a service that the user is actively aware of and is not a candidate for the system to kill when low on memory.
You have to call the method startForeground() inside your Service using a Notification to show it. For further information you can check: https://developer.android.com/guide/components/services.html#Foreground
By the way, I recommend you to use the new JobScheduler api above api 21.
https://developer.android.com/reference/android/app/job/JobScheduler.html
Android kills service based on priority stack.
Android: keeping a background service alive (preventing process death)
What is START_STICKY,START_NOT_STICKY and START_REDELIVER_INTENT Service
Above links might help you.
Your devices will sleeps if it is unplugged from computer . So, the solutions :
Use startForeground method to prevent service to be killed and/or use AlarmManager in order to charge event.
It is possible to use start_stiky flag but it just restarts the process if it killed by system.
For a demo I print a Toast after Evert 10 sec. using Service class.
It works fine, I'm getting the Toast after every 10 sec if I am on the Activity when I leave the app, Service is not giving the o/p.
But I want to that toast either I'll kill the App or back press Here is code snippet :
ServiceDemo.java
public class ServiceDemo extends Activity {
private Handler myHandler = new Handler();
private Runnable drawRunnable = new Runnable() {
#Override
public void run() {
as();
myHandler.postDelayed(this, 10000);
}
};
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_service_demo);
myHandler.postDelayed(drawRunnable, 10000);
startService(new Intent(this, MyService.class));
}
public void as(){
startService(new Intent(this, MyService.class));
}
#Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
}
}
Service.java
public class MyService extends Service {
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public void onCreate() {
Toast.makeText(this, "HOHO Service Created...", Toast.LENGTH_LONG).show();
}
#Override
public void onDestroy() {
}
#Override
public void onStart(Intent intent, int startid) {
Toast.makeText(this, "Service Started...", Toast.LENGTH_LONG).show();
}
}
Edit 1
moveTaskToBack(true);
I put this into the onBackPressed method I Service give the o/p if I am not on the screen but When I kill the App, Service not responding
I think you need to override onStartCommand instead of onStart()
like:
public int onStartCommand(Intent intent, int flags, int startid)
{
Toast.makeText(this, "Service Started...", Toast.LENGTH_LONG).show();
return Service.START_STICKY;
}
i think AlarmManager is what you want.
You have to user AlarmManager, here's an example : Alarm Manager Example
Your task will be executed even if the application is terminated.
But if the application is killed by the user, the Alarm will be canceled. See this discussion How to create a persistent AlarmManager
I have a service and an activity that communicate.
When I click the button(I have galaxy s3 there is only one button) then my activity of course disapear and my service is keep running but if I click the back (touch) button then my service is destroyed.
How can I change that?I want the service to keep running untill the activity destroys it.
EDIT
Here is the code:
Service:
public class MyService extends Service
{
private static final String TAG = "BroadcastService";
public static final String BROADCAST_ACTION = "com.websmithing.broadcasttest.displayevent";
private final Handler handler = new Handler();
private Intent intent;
int counter = 0;
#Override
public void onCreate()
{
super.onCreate();
intent = new Intent(BROADCAST_ACTION);
}
#Override
public void onStart(Intent intent, int startId)
{
// handler.removeCallbacks(sendUpdatesToUI);
handler.postDelayed(sendUpdatesToUI, 1000); // 1 second
}
private Runnable sendUpdatesToUI = new Runnable() {
public void run() {
DisplayLoggingInfo();
handler.postDelayed(this, 1000); // 10 seconds
}
};
private void DisplayLoggingInfo() {
intent.putExtra("counter", String.valueOf(++counter));
sendBroadcast(intent);
}
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public void onDestroy() {
handler.removeCallbacks(sendUpdatesToUI);
super.onDestroy();
}
}
Activity:
public class MainActivity extends Activity {
private static final String TAG = "BroadcastTest";
private Intent intent;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
intent = new Intent(this, MyService.class);
startService(intent);
registerReceiver(broadcastReceiver, new IntentFilter(MyService.BROADCAST_ACTION));
}
private BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
updateUI(intent);
}
};
#Override
public void onDestroy() {
super.onPause();
unregisterReceiver(broadcastReceiver);
stopService(intent);
}
private void updateUI(Intent intent)
{
String counter = intent.getStringExtra("counter");
Log.d(TAG, counter);
TextView txtCounter = (TextView) findViewById(R.id.textView1);
txtCounter.setText(counter);
}
}
you can put your app in the background instead off finishing it.
#Override
public void onBackPressed() {
moveTaskToBack(true);
// super.onBackPressed();
}
Ofcourse your service stops, when you press the back button. The back button most calls finish() on the activity, and it is destroyed. When you press the other button (the home button), it just minimizes your app, and it will be only destroyed later, when the OS wants to free up space.
If you want to keep your service running, make it a foreground service, and dont stop it on activity destroy.
Hi friends i have a one problem to solve...I want to destroy the service completely, once i call onDestroy() method from Activity. But my problem is that i am unable to destroy it completely.. in background its keep on running, i am sharing the sample code what i tried..
//Activity Class
public class ServiceToAct extends Activity {
private static final String TAG = "BroadcastEvent";
private Intent intent;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
intent = new Intent(this, BroadcastService.class);
startService(intent);
registerReceiver(broadcastReceiver, new IntentFilter(myService.BROADCAST_ACTION));
}
/*#Override
protected void onResume() {
super.onResume();
}*/
#Override
protected void onPause() {
super.onPause();
unregisterReceiver(broadcastReceiver);
}
#Override
protected void onDestroy() {
stopService(intent);
Toast.makeText(this, "Destroy Completely", Toast.LENGTH_LONG).show();
}
private BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
}
};
}
// service class
public class myService extends Service {
private static final String TAG = "BroadcastEvent";
public static final String BROADCAST_ACTION = "com.service.activity.myService";
private final Handler handler = new Handler();
Intent intent;
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public void onCreate() {
super.onCreate();
Toast.makeText(this, "created", Toast.LENGTH_LONG).show();
intent = new Intent(BROADCAST_ACTION);
}
#Override
public void onStart(Intent intent, int startId) {
super.onStart(intent, startId);
Toast.makeText(this, "start", Toast.LENGTH_LONG).show();
handler.removeCallbacks(sendToUI);
handler.postDelayed(sendToUI, 1000);
}
#Override
public void onDestroy() {
super.onDestroy();
stopSelf();
//stopService(intent);
Toast.makeText(this, "Destroy", Toast.LENGTH_LONG).show();
}
private Runnable sendToUI = new Runnable() {
#Override
public void run() {
myData();
handler.postDelayed(this, 10000);
}
};
private void myData() {
Log.d(TAG, "keep on entering");
Toast.makeText(this, "Keep on despling in UI", Toast.LENGTH_LONG).show();
sendBroadcast(intent);
}
}
Here Actually i want to update my UI from service, Mine everything is working, but if i destroy the service its keep on calling myData() method, and i am getting the Toast msg if i close the application also.
My issue is i don't want that toast msg once the service is desroyed
I used stopService(intent) method, which destroy the service, but background method myData() is keep on calling
for stop service completely use this ..
myActivity.java
#Override
public void onDestroy() {
stopService(intent);
super.onDestroy();
Toast.makeText(this, "Destroy", Toast.LENGTH_LONG).show();
}
service.java
#Override
public void onDestroy()
{
stopSelf();
super.onDestroy();
}
You'd better never call onXxx() derectly.
Use stopService(Intent i) in your activity and stopSelf() in you service to stop instead.
use stopService() method after updating UI
or
Instead of using startService use bindService in the activity. When activity destroys, service also destroys
I am continuing to study from the book "Pro Android 2," working through the Service example that consists of two classes: BackgroundService.java and MainActivity.java. The MainActivity class is shown below and has a couple buttons. The unbind button, unbindBtn, stops the Service but doesn't appear to do much else like kill the thread the Service started.
public class MainActivity extends Activity {
private static final String TAG = "MainActivity";
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Log.d(TAG, "starting service");
Button bindBtn = (Button)findViewById(R.id.bindBtn);
bindBtn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
Intent backgroundService = new Intent(MainActivity.this, com.marie.mainactivity.BackgroundService.class);
startService(backgroundService);
}
});
Button unbindBtn = (Button)findViewById(R.id.unbindBtn);
unbindBtn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
stopService(new Intent(MainActivity.this, BackgroundService.class));
}
});
}
}
The documentation says "if your service is going to do any CPU intensive work or blocking operations..., you should create a new thread within the service to do that work." And that's exactly what the BackgroundService class does below. As you can see below I've added a while(true) loop in the thread's run() method to see what happens to the thread when I stop the Service.
public class BackgroundService extends Service {
private NotificationManager notificationMgr;
#Override
public void onCreate() {
super.onCreate();
notificationMgr = NotificationManager)getSystemService(NOTIFICATION_SERVICE);
displayNotificationMessage("starting Background Service");
Thread thr = new Thread(null, new ServiceWorker(), "BackgroundService");
thr.start();
}
class ServiceWorker implements Runnable
{
public void run() {
// do background processing here...
long count = 0;
while (true) {
if (count++ > 1000000)
{
count = 0;
Log.d("ServiceWorker", "count reached");
}
}
//stop the service when done...
//BackgroundService.this.stopSelf();
}
}
#Override
public void onDestroy()
{
displayNotificationMessage("stopping Background Service");
super.onDestroy();
}
#Override
public void onStart(Intent intent, int startId) {
super.onStart(intent, startId);
}
#Override
public IBinder onBind(Intent intent) {
return null;
}
private void displayNotificationMessage(String message)
{
Notification notification = new Notification(R.drawable.note, message, System.currentTimeMillis());
PendingIntent contentIntent = PendingIntent.getActivity(this, 0, new Intent(this, MainActivity.class), 0);
notification.setLatestEventInfo(this, "Background Service", message, contentIntent);
notificationMgr.notify(R.id.app_notification_id, notification);
}
}
When I press the unbind button, unbindBtn, in the MainActivity class I trust the Service in this example will be stopped. But from what I can see in logcat the thread that was started by the Service continues to run. It's like the thread is now some kind of orphan with no apparent way to stop it. I've seen other source code use a while(true) loop in a thread's run() method. This seems bad unless a way to break out of the loop is provided. Is that typically how it's done? Or are there other ways to kill a thread after the Service that started it has stopped?
You should provide a 'running' boolean.
while(running) {
//do your stuff
}
You want to make it something that you can update. Perhaps your Service's onDestroy() method should call a stopProcessing() method on your Runnable, which will set the 'running' boolean to false.