I'm implementing Service that establishes TCP connection with server and then allows clients to pass messages through this connection. Clients connect to service with bindService call. As a result onServiceConnected called in clients ServiceConnection object. The problem is that onServiceConnected called right after return from bindService, but my Service was not established connection with server at this moment. Can I somehow delay onServiceConnected call while connection was not established? If it is not possible please suggest some good pattern for my case. Thank you.
You should do it as follows:
Service code:
class MyService implements Service {
private boolean mIsConnectionEstablished = false;
// Binder given to clients
private final IBinder mBinder = new LocalBinder();
public class LocalBinder extends Binder {
public MyService getService() {
// Return this instance of LocalService so clients can call public
// methods
return MyService.this;
}
}
public interface OnConnectionEstablishedListener {
public void onConnectionEstablished();
}
private OnConnectionEstablishedListener mListener;
#Override
public void onCreate() {
super.onCreate();
new Thread( new Runnable() {
#Override
void run() {
//Connect to the server here
notifyConnectionEstablished();
}
}).start();
}
#Override
public IBinder onBind(Intent intent) {
return mBinder;
}
private void notifyConnectionEstablished() {
mIsConnectionEstablished = true;
if(mListener != null) {
mListener.onConnectionEstablished();
}
}
public void setOnConnectionEstablishedListener(
OnConnectionEstablishedListener listener) {
mListener = listener
// Already connected to server. Notify immediately.
if(mIsConnectionEstablished) {
mListener.onConnectionEstablished();
}
}
}
Activity code:
class MyActivity extends Activity implements ServiceConnection,
OnConnectionEstablishedListener {
private MyService mService;
private boolean mBound;
#Override
public void onCreate() {
super.onCreate();
//bind the service here
Intent intent = new Intent(this, MyService.class);
bindService(intent, this, BIND_AUTO_CREATE);
}
#Override
public void onServiceConnected(ComponentName className, IBinder service) {
LocalBinder binder = (LocalBinder) service;
mService = binder.getService();
mBound = true;
mService.setOnConnectionEstablishedListener(this);
}
#Override
public void onServiceDisconnected(ComponentName arg0) {
mBound = false;
}
#Override
public void onConnectionEstablished() {
// At this point the service has been bound and connected to the server
// Do stuff here
// Note: This method is called from a non-UI thread.
}
}
Related
In this, the service is been create repeated times but I need to get the instance of running service so that I can start the timer task. The object of this service can get from any activity. The basic aim is to start the timer task after the particular button click.
public class MainActivity extends Activity {
MyService mService;
boolean mBound = false;
int b=0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
findViewById(R.id.btn_start_timer).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (mBound) {
mService.runTimerTask(++b);
}
}
});
}
#Override
protected void onStart() {
super.onStart();
// Bind to LocalService
Intent intent = new Intent(this, MyService.class);
bindService(intent, mConnection, Context.BIND_AUTO_CREATE);
}
#Override
protected void onStop() {
super.onStop();
unbindService(mConnection);
mBound = false;
}
/** Defines callbacks for service binding, passed to bindService() */
private ServiceConnection mConnection = new ServiceConnection() {
#Override
public void onServiceConnected(ComponentName className,
IBinder service) {
// We've bound to LocalService, cast the IBinder and get LocalService instance
MyService.LocalBinder binder = (MyService.LocalBinder) service;
mService = binder.getService();
mBound = true;
}
#Override
public void onServiceDisconnected(ComponentName arg0) {
mBound = false;
}
};
}
You could create a ServiceManager class and route all methods through that and store it in the application:
public class YourApplication extends Application {
...
private ServiceManager serviceManager = ...;
public ServiceManager getServiceManager() {
return serviceManager;
}
}
In MainActivity:
ServiceManager serviceManager = ((YourApplication)getApplication()).getServiceManager();
MyService runningService = serviceManager.getRunningService();
The ServiceManager would handle unbinding etc and all methods that involve the state of the service. So you just ask the ServiceManager for the running service. Where you have ServiceConnection::onServiceConnected doing the work, delegate that work to the ServiceManager so it can keep state and share it with the rest of the application:
public void onServiceConnected(ComponentName className,
IBinder service) {
((YourApplication)getApplication()).getServiceManager().bind(service);
}
It's a general technique for sharing object state across an application but you'd need to tailor it to fit.
I'm developing an application, which plays music in the background by using service.
Music stops when we hit back app will be paused and but, music is not resuming when I get back to the application.
public class backService extends Service implements ComponentCallbacks2 {
private MediaPlayer mp;
SharedPreferences sharedpreferences;
public Boolean musicSwitch;
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
return START_STICKY;
}
#Override
public void onDestroy() {
super.onDestroy();
if (mp != null){
mp.stop();
mp.release();
}
}
#Override
public void onCreate() {
super.onCreate();
sharedpreferences = getSharedPreferences(mypreference,
Context.MODE_PRIVATE);
musicSwitch = sharedpreferences.getBoolean("music", true);
if(musicSwitch){
mp = MediaPlayer.create(this, R.raw.all);
mp.setLooping(true);
mp.start();
}
}
#Override
public void onTrimMemory(final int level) {
if (level == ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN) {
if(mp != null){
mp.pause();
}
}
}
#Nullable
#Override
public IBinder onBind(Intent intent) {
return null;
}
}
I want the application to resume music when we get back to the application, I have tried using onResume method, but there is no onResume method in services.
TIA
1) You need to create foreground service to prevent it from killing by OS
How can we prevent a Service from being killed by OS?
2) You can bind service (bindService(serviceIntent)) and use Binder interface
https://developer.android.com/guide/components/bound-services.html#Binder
public class LocalService extends Service {
// Binder given to clients
private final IBinder mBinder = new LocalBinder();
// Random number generator
private final Random mGenerator = new Random();
/**
* Class used for the client Binder. Because we know this service always
* runs in the same process as its clients, we don't need to deal with IPC.
*/
public class LocalBinder extends Binder {
LocalService getService() {
// Return this instance of LocalService so clients can call public methods
return LocalService.this;
}
}
#Override
public IBinder onBind(Intent intent) {
return mBinder;
}
/** method for clients */
public int getRandomNumber() {
return mGenerator.nextInt(100);
}
}
Activity:
public class BindingActivity extends Activity {
LocalService mService;
boolean mBound = false;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
#Override
protected void onStart() {
super.onStart();
// Bind to LocalService
Intent intent = new Intent(this, LocalService.class);
bindService(intent, mConnection, Context.BIND_AUTO_CREATE);
}
#Override
protected void onStop() {
super.onStop();
unbindService(mConnection);
mBound = false;
}
/** Called when a button is clicked (the button in the layout file attaches to
* this method with the android:onClick attribute) */
public void onButtonClick(View v) {
if (mBound) {
// Call a method from the LocalService.
// However, if this call were something that might hang, then this request should
// occur in a separate thread to avoid slowing down the activity performance.
int num = mService.getRandomNumber();
Toast.makeText(this, "number: " + num, Toast.LENGTH_SHORT).show();
}
}
/** Defines callbacks for service binding, passed to bindService() */
private ServiceConnection mConnection = new ServiceConnection() {
#Override
public void onServiceConnected(ComponentName className,
IBinder service) {
// We've bound to LocalService, cast the IBinder and get LocalService instance
LocalBinder binder = (LocalBinder) service;
mService = binder.getService();
mBound = true;
}
#Override
public void onServiceDisconnected(ComponentName arg0) {
mBound = false;
}
}
}
3) Then, in your activity onResume you can call method from your Binder to control music
I have background service which started on device boot . I want to get some data from that service in my activity .
I want the data, only when my activity start. so the basic requirement is that when my activity start it make a connection with the background service and get the data from this service and when activity stop then disconnect from the service.
You need to use bindService() to bind with running service and communicate with it.
Reference : http://developer.android.com/guide/components/bound-services.html
For example (from Android Docs),
public class BindingActivity extends Activity {
YourService mService;
boolean mBound = false;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
#Override
protected void onStart() {
super.onStart();
// Bind to Your Service
Intent intent = new Intent(this, YourService.class);
bindService(intent, mConnection, Context.BIND_AUTO_CREATE);
}
#Override
protected void onStop() {
super.onStop();
// Unbind from the service
if (mBound) {
unbindService(mConnection);
mBound = false;
}
}
/** Called when a button is clicked (the button in the layout file attaches to
* this method with the android:onClick attribute) */
public void onButtonClick(View v) {
if (mBound) {
// Call a method from your Service.
// However, if this call were something that might hang, then this request should
// occur in a separate thread to avoid slowing down the activity performance.
int num = mService.getRandomNumber();
Toast.makeText(this, "number: " + num, Toast.LENGTH_SHORT).show();
}
}
/** Defines callbacks for service binding, passed to bindService() */
private ServiceConnection mConnection = new ServiceConnection() {
#Override
public void onServiceConnected(ComponentName className,
IBinder service) {
// We've bound to the running Service, cast the IBinder and get instance
LocalBinder binder = (LocalBinder) service;
mService = binder.getService();
mBound = true;
}
#Override
public void onServiceDisconnected(ComponentName arg0) {
mBound = false;
}
};
}
In your service,
public class LocalService extends Service {
// Binder given to clients
private final IBinder mBinder = new LocalBinder();
// Random number generator
private final Random mGenerator = new Random();
/**
* Class used for the client Binder. Because we know this service always
* runs in the same process as its clients, we don't need to deal with IPC.
*/
public class LocalBinder extends Binder {
LocalService getService() {
// Return this instance of LocalService so clients can call public methods
return LocalService.this;
}
}
#Override
public IBinder onBind(Intent intent) {
return mBinder;
}
/** method for clients */
public int getRandomNumber() {
return mGenerator.nextInt(100);
}
}
Basically, you should use bindService() in your activity onStart() and unbindService() in onStop()
MainActivity starts my TestService in onCreate and bind in onStart method. AsyncThread is started in TestService onStartCommand. bind and unbind methods are called in correct sequences. All things work perfectly, absolutely no issue :).
Issue starts from here: If MainActivity is terminated then running Async thread is also stopped w/o any interrupt exception but TestService is still running which I can check at Running Application Setting.
Please help me to find out why thread stops working.
PS: I cross checked with Thread/Handler but same result.
MainActivity and Service code are here:
public class MainActivity extends Activity implements IServiceInterface {
boolean mBound = false;
TestService mTestService = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
Intent serviceIntent = new Intent(this, TestService.class);
startService(serviceIntent);
}
#Override
protected void onStart() {
super.onStart();
// Bind to LocalService
NSLogger.i("service binding....");
Intent intent = new Intent(this, TestService.class);
bindService(intent, mBindConnection, Context.BIND_AUTO_CREATE);
}
#Override
protected void onStop() {
super.onStop();
if (mBound) {
NSLogger.i("service unbinding....");
unbindService(mBindConnection);
mBound = false;
}
}
/** Defines callbacks for service binding, passed to bindService() */
private ServiceConnection mBindConnection = new ServiceConnection() {
#Override
public void onServiceConnected(ComponentName className,
IBinder service) {
// We've bound to LocalService, cast the IBinder and get LocalService instance
NSLogger.i("UI is connected to service");
LocalBinder binder = (LocalBinder) service;
mTestService = binder.getTestService();
mBound = true;
}
#Override
public void onServiceDisconnected(ComponentName arg0) {
NSLogger.i("UI is disconnected from service");
mBound = false;
mTestService = null;
}
};
}
public class TestService extends Service implements Runnable, Handler.Callback{
// Binder given to inproc clients
private final IBinder mBinder = new LocalBinder();
#Override
public IBinder onBind(Intent intent) {
mUIIsBound = true;
return mBinder;
}
public boolean onUnbind (Intent intent) {
mUIIsBound = false;
NSLogger.i("unbind service");
return true;
}
public class LocalBinder extends Binder {
TestService getTestService() {
return TestService.this;
}
}
public void onDestroy() {
//NEVER CALLED.
}
public int onStartCommand(Intent intent2, int flags, int startId) {
NSLogger.i("TestService start!");
new DownloadConfiguration().execute();
return START_STICKY;
}
private class DownloadConfiguration extends AsyncTask<Void, Integer, Boolean> {
#Override
protected Boolean doInBackground(Void... params) {
try {
NSLogger.i("before sleep");
Thread.sleep(5000);
NSLogger.i("After sleep");
} catch (InterruptedException e) {
e.printStackTrace();
}
return true;
}
}
I've created a service (BackupBoundService). In here I've methods to request data to a server using Retrofit.
I've a fragment in a tab view that has a list view. This list view has to be populated with the data returned from the request made to the server in the service. I've implemented the code but I'm getting a NPE (NullPointerException). I know that the binding is an asynchronous event and I strongly believe this is the reason I'm getting the NPE.
Here's my service class:
private final IBinder binder = new LocalBinder();
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
return Service.START_STICKY;
}
#Override
public IBinder onBind(Intent intent) {
return binder;
}
/**
* Class passed back to the client activity.
*/
public class LocalBinder extends Binder {
public BackupBoundService getService() {
return BackupBoundService.this;
}
}
/************************************************
* *
* Service Methods *
* *
***********************************************/
And here is my Fragment class where I bind and call the public methods in the service class:
private BackupBoundService backupBoundService;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
(...)
Utils.isMyServiceRunning(BackupBoundService.class); // Here I get the service is running
backupBoundService.listAllBackupsInTheCloudAsync(); // Here I get the NPE, saying backupBoundService is null
return view;
}
// Backup Service
private ServiceConnection backupServiceConnection = new ServiceConnection() {
#Override
public void onServiceConnected(ComponentName className, IBinder service) {
// We've bound to LocalService, cast the IBinder and get LocalService instance
LocalBinder binder = (LocalBinder) service;
backupBoundService = binder.getService();
isBound = true;
Log.d(TAG, "On Service Connected -> Yup!");
}
#Override
public void onServiceDisconnected(ComponentName arg0) {
isBound = false;
}
};
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
Intent intent = new Intent(ApplicationContextProvider.getContext(), BackupBoundService.class);
ApplicationContextProvider.getContext().bindService(intent, backupServiceConnection, Context.BIND_AUTO_CREATE);
Utils.setContext(getActivity());
Utils.isMyServiceRunning(BackupBoundService.class); // Here I get that service is running
}
So, how can I avoid the NPE and still populate the listview on onCreate()?
Check the code comments to understand where the NPE occurs
Here is my isServiceRunning method, in case someone is wondering:
public static boolean isMyServiceRunning(Class<?> serviceClass) {
MainActivity myActivity = (MainActivity) getContext();
ActivityManager manager = (ActivityManager) myActivity.getSystemService(Context.ACTIVITY_SERVICE);
for (RunningServiceInfo service : manager.getRunningServices(Integer.MAX_VALUE)) {
if (serviceClass.getName().equals(service.service.getClassName())) {
Log.d(TAG, "YES SERVICE IS RUNNING!");
return true;
}
}
Log.d(TAG, "NO, SERVICE NOT RUNNING");
return false;
}
I solved my problem by calling the method from my service inside onServiceConnected
// Backup Service
private ServiceConnection backupServiceConnection = new ServiceConnection() {
#Override
public void onServiceConnected(ComponentName className, IBinder service) {
// We've bound to LocalService, cast the IBinder and get LocalService instance
LocalBinder binder = (LocalBinder) service;
backupBoundService = binder.getService();
isBound = true;
// Call here my method
Log.d(TAG, "On Service Connected -> Yup!");
}
#Override
public void onServiceDisconnected(ComponentName arg0) {
isBound = false;
}
};
It's not the most clean and pretty way to do it IMO but it works. Nevertheless, I'll keep this question open in case someone comes with a better and cleaner solution.