I'm trying to start a service on android in order to performe some network-related tasks in background. I have written a basic network-manager for my app, which is a service. I basically used the tutorial from the android documentation. The basic structure goes as following:
public class MyNetworkManager extends Service {
// some code
private final IBinder mBinder = (IBinder) new MyBinder();
#Override
public IBinder onBind(Intent arg0) {
return mBinder;
}
public class MyBinder extends Binder {
MyNetworkManager getService() {
return MyNetworkManager.this;
}
}
public void onCreate() {
// some network related stuff like setting up sockets etc.
}
public void onStart(Intent intent, int startid) {
while(true) {
// receive new connections etc
}
}
The calling app/activity is then:
public class AndroidNetworkManagerClient extends Activity {
private Button buttonSend;
private EditText inputText;
private TextView outputText;
private MyNetworkManager networkManager;
private ServiceConnection mConnection = new ServiceConnection() {
public void onServiceConnected(ComponentName className, IBinder binder) {
networkManager = ((MyNetworkManager.MyBinder) binder).getService();
}
public void onServiceDisconnected(ComponentName className) {
networkManager = null;
}
};
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
inputText = (EditText) findViewById(R.id.textInput);
outputText = (TextView) findViewById(R.id.textOutput);
buttonSend = (Button)this.findViewById(R.id.buttonSend);
buttonSend.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
if (inputText.getText().length() != 0) {
outputText.append("Out: " + inputText.getText() + "\n");
networkManager.sendData("localhost", inputText.getText().toString());
}
}
});
bindService(new Intent(this, MyNetworkManager.class), mConnection, Context.BIND_AUTO_CREATE);
doSomeAppRelatedStuff();
}
bindService() seems to be called without any problems, but the variable "networkManager" is always null! I already tried to debug into the onCreate() method or onServiceConnected() but it seems, that these parts are not reached at all (at least no breakpoint was triggered).
The service is already registered in the AndroidManifest.xml:
package="some.random.name"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="8" />
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<application
android:icon="#drawable/ic_launcher"
android:label="#string/app_name" >
<activity
android:name=".AndroidNetworkManagerClient"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service android:name=".MyNetworkManager"></service>
</application>
Anyone an idea?
Chances are, your Activity is getting into doSomeAppRelatedStuff() and trying to use networkManager before the binding is complete.
If doSomeAppRelatedStuff() absolutely must have the network manager to function, move your call to doSomeAppRelatedStuff() into onServiceConnected() so it won't actually start until the binding is complete. Note that if you do that, your onStart() and onResume() calls will probably (but not guaranteed!) happen before the binding is complete, so program accordingly.
Related
Hi I am new to android and exploring the services part.I could not bind the service using bind method.I could not figure out whether it is problem with bind method or on service connected.Someone please help me with it.Thanks in advance
Activity code:
public class MainActivity extends AppCompatActivity {
MyService pavan ;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
Intent i = new Intent(this,MyService.class);
this.startService(i);
System.err.println("before binding**************************");
this.bindService(i, con, Context.BIND_AUTO_CREATE);
this.unbindService(con);this.stopService(i);
}
public ServiceConnection con = new ServiceConnection() {
#Override
public void onServiceConnected(ComponentName name, IBinder service) {
pavan = ((MyService.localbinder)service).getservice();
System.err.println("here service gets binded");
Toast.makeText(getBaseContext(),"Service connected",Toast.LENGTH_LONG);
}
#Override
public void onServiceDisconnected(ComponentName name) {
Toast.makeText(getBaseContext(),"oops this is moment of Service disconnected",Toast.LENGTH_LONG);
}
};
}
Service code:
public class MyService extends Service {
public MyService() {
}
public class localbinder extends Binder{
public MyService getservice(){
return MyService.this;
}
}
IBinder ibinder = new localbinder();;
#Override
public IBinder onBind(Intent intent) {
return ibinder;
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
return Service.START_STICKY;
}
#Override
public void onCreate() {
super.onCreate();
}
}
manifest code:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.coolguy.pract">
<uses-permission android:name="android.permission.BIND_ACCESSIBILITY_SERVICE"/>
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity
android:name=".MainActivity"
android:label="#string/app_name"
android:theme="#style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service
android:name=".MyService"
android:enabled="true"
android:exported="true"></service>
</application>
</manifest>
Finally I got the problem in my code.Context.BIND_AUTO_CREATE automatically invokes startService().So here when I invoked bind method since service is already running it goes to on onStartCommand.So just do not use startservice with Context.BIND_AUTO_CREATE flag.
I'm having some problems with services.
Service:
public class MyService extends Service {
public MyService() {
}
private static final String TAG = "AutoService";
private Timer timer;
private TimerTask task;
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public void onCreate() {
Toast.makeText(this, "Auto Service Created", Toast.LENGTH_LONG).show();
Log.d(TAG, "onCreate");
int delay = 5000; // delay for 5 sec.
int period = 5000; // repeat every sec.
timer = new Timer();
timer.scheduleAtFixedRate(task = new TimerTask(){
public void run()
{
System.out.println("done");
}
}, delay, period);
}
#Override
public boolean stopService(Intent name) {
timer.cancel();
task.cancel();
return super.stopService(name);
}
#Override
public void onDestroy(){
Toast.makeText(this, "Service Destroyed", Toast.LENGTH_SHORT).show();
super.onDestroy();
}
MainActivity:
public class ClientSocket extends ActionBarActivity {
CheckBox enablecheck;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_client_socket);
enablecheck = (CheckBox)findViewById(R.id.enablecheck);
enablecheck.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener()
{
#Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
// TODO Auto-generated method stub
if(enablecheck.isChecked()){
startService(new Intent(ClientSocket.this, MyService.class));
}else
{
stopService(new Intent(ClientSocket.this, MyService.class));
}
}
});
}
Manifest file:
<?xml version="1.0" encoding="utf-8"?>
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:theme="#style/Theme.AppCompat.Light" >
<activity
android:name=".ClientSocket"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service
android:name=".MyService"
android:enabled="true"
android:exported="true" >
</service>
</application>
I'm just testing, when I try to stop the service, the fuction onDestroy() is called but don't stop the service. The service/android:exported and android:enable both are true.
Any help?
The Timer instance create a background thread. If you want to stop the service completely you also need to stop the thread. Timer has a cancel() method you can call in the onDestroy() method to terminate the Timer.
Also, exporting the service means other applications (processes) can access it. You most likely don't need that.
The issue in the code is a misunderstanding of what
#Override
public boolean stopService(Intent name) {
timer.cancel();
task.cancel();
return super.stopService(name);
}
really does.
It is not a callback that is called when the service is stopped. Instead it is overriding the stopService method on Context, which you call to stop a service (as you do in the Activity in your example).
In fact the override of stopServicein your code has no effect at all.
timer.cancel();
task.cancel();
should be placed in the onDestroy method of your service.
My service extends IntentService and when it is started with startService, onHandleIntent gets called. However, when the service is started with bindService (I do need binding), onHandleIntent does not get called.
Should onHandleIntent be called when IntentService is started with bindService? Is startService the only way IntentService should be started?
The documentation for IntentService says the following:
Clients send requests through startService(Intent) calls; the service is started as needed, handles each Intent in turn using a worker thread, and stops itself when it runs out of work.
Currently I solve my problem by calling startService right after bindService but I find it ugly. I would like to know is there a way to make it work with just one call.
Code snippets follow, it might be that I am missing something obvious.
ExampleService.java
public class ExampleService extends IntentService {
private class IncomingHandler extends Handler {
#Override
public void handleMessage(Message message) {
if (message.replyTo != null) {
outMessenger = message.replyTo;
}
}
}
private Messenger messenger = new Messenger(new IncomingHandler());
private Messenger outMessenger = null;
public ExampleService() {
super("ExampleService");
}
#Override
public IBinder onBind(Intent intent) {
return messenger.getBinder();
}
#Override
protected void onHandleIntent(Intent arg0) {
System.out.println("Service started");
for (int i = 0; i < 5; i++) {
SystemClock.sleep(5000);
if (outMessenger != null) {
try {
outMessenger.send(Message.obtain());
} catch (RemoteException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
Service Manifest.xml
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.service"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="3"
android:targetSdkVersion="15" />
<application
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="#string/title_activity_main" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service android:name=".ExampleService">
<intent-filter>
<action android:name="com.example.service.ExampleService" />
</intent-filter>
</service>
</application>
</manifest>
MainActivity.java (caller)
public class MainActivity extends Activity implements ServiceConnection {
private class IncomingHandler extends Handler {
#Override
public void handleMessage(Message msg) {
Toast.makeText(getApplicationContext(), "Message received", Toast.LENGTH_SHORT).show();
System.out.println("Message received!");
super.handleMessage(msg);
}
}
private Messenger messenger = new Messenger(new IncomingHandler());
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button = (Button) findViewById(R.id.button1);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent("com.example.service.ExampleService");
bindService(intent, MainActivity.this, Context.BIND_AUTO_CREATE);
//startService(intent);
}
});
}
#Override
public void onServiceConnected(ComponentName name, IBinder binder) {
Message message = Message.obtain();
message.replyTo = messenger;
try {
new Messenger(binder).send(message);
} catch (RemoteException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
#Override
public void onServiceDisconnected(ComponentName name) {
// TODO Auto-generated method stub
}
}
Should onHandleIntent be called when IntentService is started with bindService?
No.
Is startService the only way IntentService should be started?
IMHO, yes. IMHO, IntentService is not designed for the binding pattern.
In your case, you can:
Pass a Messenger from the activity in an Intent extra in the command sent by startService(), or
Use LocalBroadcastManager, or
Use Otto, or
Use an ordered broadcast, if the IntentService might continue past the activity's life and you want to, say, display a Notification when the work gets done in that case,
Etc.
You must call both startService and bindService.
This was worked for me.
I have this Service class:
public class BluetoothService extends Service {
private static Activity mActivity;
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public void onCreate() {
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(BluetoothAdapter.ACTION_STATE_CHANGED);
this.registerReceiver(bluetoothReceiver, intentFilter);
}
#Override
public void onDestroy() {
if (bluetoothReceiver != null) {
this.unregisterReceiver(bluetoothReceiver);
}
}
#Override
public void onStart(Intent intent, int startid) {
//
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
return START_STICKY;
}
public static BroadcastReceiver bluetoothReceiver = new BroadcastReceiver(){
#Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals(BluetoothAdapter.ACTION_STATE_CHANGED)) {
final int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, BluetoothAdapter.ERROR);
TextView tvStatus = (TextView) mActivity.findViewById(R.id.tvtatus);
Messaging.appendMessage(tvStatus, Bluetooth.getDeviceState(state));
if (Bluetooth.isBluetoothEnabled()) {
Messaging.appendMessage(tvStatus, Bluetooth.showMessage());
}
}
}
};
}
And in my Activity class, I have this:
public class MainActivity extends Activity {
private TextView tvStatus;
private Intent intentBluetooth;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tvStatus = (TextView)findViewById(R.id.tvtatus);
intentBluetooth = new Intent(this, BluetoothService.class);
startService(intentBluetooth);
}
}
The BroadcastReceiver method (bluetoothReceiver) in the Service class is never called. I don't know why. If I have the IntentFilter and the BroadcastReceiver codes above all in an Activity, then it works - but not in a [separate] Service. I'm stumped.
My AndroidManifest.xml is:
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.onegoal.androidexample"
android:versionCode="1"
android:versionName="1.0.0"
android:installLocation="auto"
android:hardwareAccelerated="true">
<uses-sdk android:minSdkVersion="7" android:targetSdkVersion="15" />
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-feature android:name="android.hardware.bluetooth" android:required="false" />
<application
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme"
android:debuggable="true" >
<activity
android:name=".MainActivity"
android:label="#string/app_name"
android:theme="#android:style/Theme.NoTitleBar" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service android:name=".BluetoothService">
</service>
</application>
</manifest>
I'm new to Android so what I'm doing may not be the best. Hope someone can help me.
maybe the fact that your receiver is static causing the problem.
BroadcastReceiver should never be static. it can cause lots of problems.
other really bad design problem with your code - holding reference to activity inside service, and using it to modify views is really wrong thing to do. it can cause easily to memory leek.
the right why to communicate between Service and Activity is by implement android's Messanger, or sending broadcasts between them via BroadcastReceiver.
if you'll listen to my advice - you won't be have to make your receiver static (I guess you've made it static only because you are using the mActivity static instance inside)
and I'm pretty sure it will solve your problem
you can read about Messanger here: http://developer.android.com/reference/android/os/Messenger.html
sure you'll find lots of usage examples in the net.
example of broadcasting updates to the activity from service:
public class MyService extends Service {
#Override
public IBinder onBind(Intent arg0) {
// TODO Auto-generated method stub
return null;
}
#Override
public void onCreate() {
super.onCreate();
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(BluetoothAdapter.ACTION_STATE_CHANGED);
this.registerReceiver(bluetoothReceiver, intentFilter);
}
#Override
public void onDestroy() {
if (bluetoothReceiver != null) {
this.unregisterReceiver(bluetoothReceiver);
}
super.onDestroy();
}
public BroadcastReceiver bluetoothReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals(BluetoothAdapter.ACTION_STATE_CHANGED)) {
final int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, BluetoothAdapter.ERROR);
updateUIWithNewState(state);
}
}
};
protected void updateUIWithNewState(int state) {
Intent intent = new Intent("serviceUpdateReceivedAction");
intent.putExtra("state", state);
sendBroadcast(intent);
}
}
and that's the activity:
public class MyActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent intent = new Intent(this, MyService.class);
startService(intent);
}
#Override
protected void onResume() {
super.onResume();
registerReceiver(mServiceUpdatesReceiver, new IntentFilter("serviceUpdateReceivedAction"));
}
#Override
protected void onPause() {
unregisterReceiver(mServiceUpdatesReceiver);
super.onPause();
}
private BroadcastReceiver mServiceUpdatesReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
int state = intent.getIntExtra("state", -1);
// do what ever you want in the UI according to the state
}
};
}
I am trying to bind to a service, but the bind service method always returns false. I believe the problem is in my connection. When I import the location of the LocalBinder class (in the service) I dont get any compile errors but the bindService call is still false.
Service information:
//binder for client
private final IBinder mBinder = new LocalBinder();
//client class binder
public class LocalBinder extends Binder {
ServiceA getService() {
// Return this instance of LocalService so clients can call public methods
return ServiceA.this;
}
}
#Override
public IBinder onBind(Intent arg0) {
return mBinder;
}
//called when service is created
public void onCreate(){
super.onCreate();
Toast.makeText(this,"ServiceA is started",Toast.LENGTH_SHORT).show();
}
Connection:
private ServiceConnection connect2A = new ServiceConnection() {
#Override
public void onServiceConnected(ComponentName className,
IBinder service) {
// We've bound to LocalService, cast the IBinder and get LocalService instance
LocalBinder newBinder = (LocalBinder) service;
mainService = newBinder.getService();
bound = true;
}
#Override
public void onServiceDisconnected(ComponentName arg0) {
bound = false;
}
};
Initial calls:
#Override
protected void onStart(){
super.onStart();
Intent intent = new Intent(this, ServiceA.class);
startService(intent);
boolean check = bindService(intent,connect2A,0);
Toast.makeText(this, "Return from check is: " + check, Toast.LENGTH_LONG).show();
//program does get to this point, but binding fails
}
the AndroidManifest.XML file:
<application android:icon="#drawable/icon" android:label="#string/app_name">
<activity android:name=".ServiceTest2Activity"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service android:enabled="true" android:name=".serviceA" />
</application>
Some ideas:
-What class is the onStart() method in? I bind to my services in onCreate().
-Do you perhaps need to pass Context.BIND_AUTO_CREATE to the bindService call? e.g.
boolean check = bindService(intent, connect2A, Context.BIND_AUTO_CREATE);
-As the other commenter suggests, you should post the relevant snippets from your AndroidManifest.xml.
-You should put some trace/toast in the onServiceConnected method so you know if it is getting called.