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.
Related
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 an Android Activity called Main that calls a Service called MainService as follows:
Intent intent = new Intent(this, MainService.class);
if(MainService.getInstance() == null){
Log.d(TAG, "Calling MainService");
startService(intent);
}
MainService maintains a variable during its lifetime that I wish to access in Main later on. How do I do this?
Thanks.
You can bind the service and can have the service instance forever. Below sample code will help you:-
Service Class
public class MusicService extends Service {
MyBinder binder=new MyBinder();
MusicService services;
static Context context;
#Override
public IBinder onBind(Intent arg0) {
// TODO Auto-generated method stub
return binder;
}
#Override
public void onCreate() {
super.onCreate();
context=getApplicationContext();
MediaPlayer mPlayer = MediaPlayer.create(getApplicationContext(), R.raw.yaar);
mPlayer.start();
}
public class MyBinder extends Binder
{
public MusicService getServiceSystem()
{
return MusicService.this;
}
}
#Override
public void onDestroy() {
super.onDestroy();
}
}
Activity
public class MainActivity extends AppCompatActivity {
MusicService services;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ServiceConnection connection=new ServiceConnection() {
#Override
public void onServiceConnected(ComponentName name, IBinder service) {
MusicService.MyBinder binderr=(MusicService.MyBinder)service;
services=binderr.getServiceSystem();
}
#Override
public void onServiceDisconnected(ComponentName name) {
}
};
Intent intent= new Intent(this, MusicService.class);
startService(intent);
}
}
You can then use service anywhere you need in activity. Hope it helps.
Yes, you can access variables inside service, but for that you have to bind to this service first. After that, use accessors for getting or setting variables or call any other method of the service.
See https://developer.android.com/guide/components/bound-services.html
To communicate with Service, what is the different between bindService() and create a instance of service? Why should need to use bindService() to communicate with service? I was confused by it.
(1)
public class BLEService extends Service {
private static BLEService sService;
#Override
public void onCreate() {
super.onCreate();
sService = this;
}
public static BLEService getInstance() {
return sService;
}
}
public class HeartRateActivity extends Activity {
private BLEService mBLEService;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mBLEService = BLEService.getInstance();
}
}
(2)
public class BLEService extends Service {
private final IBinder mBinder = new LocalBinder();
private BLEService mBLEService;
public class LocalBinder extends Binder {
public MyleService getServerInstance() {
return MyleService.this;
}
}
}
public class HeartRateActivity extends Activity {
private BLEService mBLEService;
private boolean mBounded;
#Override
protected void onStart() {
super.onStart();
Intent mIntent = new Intent(this, BLEService.class);
bindService(mIntent, mConnection, BIND_AUTO_CREATE);
}
ServiceConnection mConnection = new ServiceConnection() {
public void onServiceDisconnected(ComponentName name) {
mBounded = false;
mBLEService = null;
}
public void onServiceConnected(ComponentName name, IBinder service) {
mBounded = true;
LocalBinder mLocalBinder = (LocalBinder)service;
mBLEService = mLocalBinder.getServerInstance();
}
};
}
Thanks
Edit: Remove new operator in onCreate() of service
You would not instantiate a Service object via its constructor using the new keyword. A service is intended to be a long-running process that is not necessarily tied to the lifetime of the Activity that wants access to it. As such, services are something that you use an Intent to signal to Android that you wish to run them in the same way that you use Intent objects to signal that you wish to start a new Activity.
Using .bindService() you can signal to Android that you want to attach to a running service (and to implicitly start that service if it isn't running already). Once bound, you can communicate with the service via whichever interfaces it has available.
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()
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.
}
}