Develop Reference

How to send data back from Activity to AccessibilityService?

I have a class that extends AccessibilityService and when there is a certain event starts an activity.
The problem is that when the activity ends, it should send data back to 'AccessibilityService'. Does anyone have an idea on how to do that?
Example:
public class MyAccessibilityService extends AccessibilityService {
#Override
public void onAccessibilityEvent(AccessibilityEvent event) {
if (event.getEventType()==AccessibilityEvent.TYPE_VIEW_TEXT_CHANGED){
Intent intent=new Intent(getApplicationContext(),DialogActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
// String resul=set result When Activity is closed
}
}
Thanks in advance!

AccesibilityService is an inherited class from Service class. So we can refer that question to this:
How to have Android Service communicate with Activity
The easiest way for your question:
1) Call startService() in your Activity's onDestroy() method:
#Override
protected void onDestroy() {
super.onDestroy();
Intent intent = new Intent(getApplicationContext(), MyAccessibilityService.class);
intent.putExtra("data","yourData");
startService(intent);
}
2) Override your MyAccessibilityService's onStartCommand() method:
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
super.onStartCommand(intent, flags, startId);
String data="";
if(intent.getExtras().containsKey("data"))
data = intent.getStringExtra("data");
return START_STICKY;
}

1)Call startActivity(intent) from your accessibility service on any event.
String msg = "your message";
Intent intent = new Intent(serviceContext, activityClassName.class);
intent.putExtra("message",msg);
startActivity(intent);
2)Now in your activities onCreate(Bundle bundle) method you can get intent.
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent intent = getIntent();
String msg = intent.getStringExtra("message");
Log.e(LOG_TAG,"Message From Service - "+msg); //Message From Service - your message
}
Using Intent you can pass data from Service to Activity.

Get intent in Service return NullPointerException

I create Service and call it from MainActivity.class with put string extra to intent but when I call getStringExtra in onStartCommand, it returns NullPointerException
Here is my code:
MainService.class :
public class MainService extends Service {
private WindowManager wm;
private WindowManager.LayoutParams params;
#Override
public IBinder onBind(Intent i) {
return null;
}
#Override
public void onCreate() {
super.onCreate();
}
#Override
public void onDestroy() {
super.onDestroy();
if (mView != null) {
WindowManager wm = (WindowManager) getSystemService(WINDOW_SERVICE);
wm.removeView(mView);
}
}
#Override
public void onStart(Intent intent, int startId) {
super.onStart(intent, startId);
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
final String quote = intent.getStringExtra("quote");
Log.d("datastring",quote);
return super.onStartCommand(intent, flags, startId);
}
}
In MainActivity.class I called :
Intent i=new Intent(MainActivity.this, MainService.class);
i.putExtra("quote", "dataquote");
stopService(i);
How I can get string from MainActivity in MainService?

If you want to provide more data to your Service you need to use something like:
Intent intent = new Intent(MainActivity.this, MainService.class);
intent.putExtra("quote", "dataquote");
startService(intent);
This will start the service and you should be able to get the data intent in the onStartCommand(). If the Service is already running, onStartCommand() will still be called with the new intent. This is because Service components are inherently singleton, so only one instance of a particular service run at a time.
In your case, you are providing the data via stopService(intent). Not only its not possible to get this intent, your Service will also stop after this statement so, you cannot really do much with the data even if you could have read it.
If you still need to stop your Service and pass data at the same time, you should check this post.

Android: how to have a localbroadcast reciever inside service

I have service in which I want to have a localbroadcast receiver. I want to recieve a value from the activity to my services onCreate.
Note: I can get a value from an activity to my service in onStartCommand() using intent. But here I want a value from activity in onCreate of the service.
The following is my service file:
public class MediaServiceSimha extends Service {
private MediaPlayer player;
String musicpath;
private ResponseReceiver receiver;
public MediaServiceSimha() {}
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public void onDestroy() {
LocalBroadcastManager localBroadcastManager = LocalBroadcastManager.getInstance(this);
localBroadcastManager.unregisterReceiver(receiver);
super.onDestroy();
}
#Override
public boolean onUnbind(Intent intent) {
return super.onUnbind(intent);
}
#
Override
public int onStartCommand(Intent intent, int flags, int startId) {
player.start();
return super.onStartCommand(intent, flags, startId);
}
#Override
public void onCreate() {
super.onCreate();
IntentFilter broadcastFilter = new IntentFilter("com.example.myintentserviceapp.intent_service.ALL_DONE");
receiver = new ResponseReceiver();
LocalBroadcastManager localBroadcastManager = LocalBroadcastManager.getInstance(this);
localBroadcastManager.registerReceiver(receiver, broadcastFilter);
}
public class ResponseReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
musicpath = intent.getStringExtra("musicpath");
}
}
}
The following is my activity file where I want to pass a value called musicpath
public class ServiceTest extends AppCompatActivity {
Intent intent;
public static final String TEXT_INPUT = "inText";
//MediaServiceSimha mediaServiceSimha;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
L.m("activity_oncreate_starting");
setContentView(R.layout.activity_service_test);
intent= new Intent(this,MediaServiceSimha.class);
startService(intent);
Intent broadcastIntent = new Intent();
broadcastIntent.setAction("com.example.myintentserviceapp.intent_service.ALL_DONE");
broadcastIntent.putExtra("musicpath", "/storage/emulated/0/Download/1.mp3");
LocalBroadcastManager localBroadcastManager = LocalBroadcastManager.getInstance(this);
localBroadcastManager.sendBroadcast(broadcastIntent)
}
}
After running, it says musicpath value is null.
How to do it?

My goal was to pass a variable value directly to oncreate in the service class.
I tried LocalBroadcast's reciver and also onbindservices - onServiceConnected
Both of them i found that they will only get executed untill oncreate -> onbind/onstartcommand get executed in the services.
So only option left is onstartcommand()
So when we pass values using intent then they can be used immediately inside onstartcommand.

when you are calling start service it doesn't mean it will call immediately,so wait for oncreate of service,whenever your service getstarted you can send a callback to your activity then you can broadcast values to your service
public service callback() // callback from service started
{
Intent broadcastIntent = new Intent();
broadcastIntent.setAction("com.example.myintentserviceapp.intent_service.ALL_DONE");
broadcastIntent.putExtra("musicpath", "/storage/emulated/0/Download/1.mp3");
LocalBroadcastManager localBroadcastManager = LocalBroadcastManager.getInstance(this);
localBroadcastManager.sendBroadcast(broadcastIntent)
}
public class MediaServiceSimha extends Service {
#Override
public void onCreate() {
super.onCreate();
IntentFilter broadcastFilter = new IntentFilter("com.example.myintentserviceapp.intent_service.ALL_DONE");
receiver = new ResponseReceiver();
LocalBroadcastManager localBroadcastManager = LocalBroadcastManager.getInstance(this);
localBroadcastManager.registerReceiver(receiver, broadcastFilter);
sendCallback(); // using interface or broadcast receiver to send callback to activity
}
}

Communication between Activity and Service

I am trying to make my own MusicPlayer for android. Where i came to a problem is running some things in background. Main activity manages GUI and up to now all the songs are playing. I wanted to separate GUI and music playing classes. I want to put music managing part in Service and leave other things as they are now.
My problem is that i can't organize communication between Activity and Service as lot of communication is happening between them including moving objects in both directions. I tried many techniques that I searched here on Stack Overflow but every time I had problems. I need Service to be able to send objects to Activity and vice versa. When I add widget i also want it to be able to communicate with Service.
Any tips are appreciated, if you need source code place comment bellow but now in this transition it became chaotic.
Is there any more advanced tutorial on this than calling one method that returns random number from service? :P
EDIT: Possible solution is to use RoboGuice library and move objects with injection

I have implemented communication between Activity and Service using Bind and Callbacks interface.
For sending data to the service I used Binder which retruns the Service instace to the Activity, and then the Activity can access public methods in the Service.
To send data back to the Activity from the Service, I used Callbacks interface like you are using when you want to communicate between Fragment and Activity.
Here is some code samples for each:
The following example shows Activity and Service bidirectional relationship:
The Activity has 2 buttons:
The first button will start and stop the service.
The second button will start a timer which runs in the service.
The service will update the Activity through callback with the timer progress.
My Activity:
//Activity implements the Callbacks interface which defined in the Service
public class MainActivity extends ActionBarActivity implements MyService.Callbacks{
ToggleButton toggleButton;
ToggleButton tbStartTask;
TextView tvServiceState;
TextView tvServiceOutput;
Intent serviceIntent;
MyService myService;
int seconds;
int minutes;
int hours;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
serviceIntent = new Intent(MainActivity.this, MyService.class);
setViewsWidgets();
}
private void setViewsWidgets() {
toggleButton = (ToggleButton)findViewById(R.id.toggleButton);
toggleButton.setOnClickListener(btListener);
tbStartTask = (ToggleButton)findViewById(R.id.tbStartServiceTask);
tbStartTask.setOnClickListener(btListener);
tvServiceState = (TextView)findViewById(R.id.tvServiceState);
tvServiceOutput = (TextView)findViewById(R.id.tvServiceOutput);
}
private ServiceConnection mConnection = new ServiceConnection() {
#Override
public void onServiceConnected(ComponentName className,
IBinder service) {
Toast.makeText(MainActivity.this, "onServiceConnected called", Toast.LENGTH_SHORT).show();
// We've binded to LocalService, cast the IBinder and get LocalService instance
MyService.LocalBinder binder = (MyService.LocalBinder) service;
myService = binder.getServiceInstance(); //Get instance of your service!
myService.registerClient(MainActivity.this); //Activity register in the service as client for callabcks!
tvServiceState.setText("Connected to service...");
tbStartTask.setEnabled(true);
}
#Override
public void onServiceDisconnected(ComponentName arg0) {
Toast.makeText(MainActivity.this, "onServiceDisconnected called", Toast.LENGTH_SHORT).show();
tvServiceState.setText("Service disconnected");
tbStartTask.setEnabled(false);
}
};
View.OnClickListener btListener = new View.OnClickListener() {
#Override
public void onClick(View v) {
if(v == toggleButton){
if(toggleButton.isChecked()){
startService(serviceIntent); //Starting the service
bindService(serviceIntent, mConnection, Context.BIND_AUTO_CREATE); //Binding to the service!
Toast.makeText(MainActivity.this, "Button checked", Toast.LENGTH_SHORT).show();
}else{
unbindService(mConnection);
stopService(serviceIntent);
Toast.makeText(MainActivity.this, "Button unchecked", Toast.LENGTH_SHORT).show();
tvServiceState.setText("Service disconnected");
tbStartTask.setEnabled(false);
}
}
if(v == tbStartTask){
if(tbStartTask.isChecked()){
myService.startCounter();
}else{
myService.stopCounter();
}
}
}
};
#Override
public void updateClient(long millis) {
seconds = (int) (millis / 1000) % 60 ;
minutes = (int) ((millis / (1000*60)) % 60);
hours = (int) ((millis / (1000*60*60)) % 24);
tvServiceOutput.setText((hours>0 ? String.format("%d:", hours) : "") + ((this.minutes<10 && this.hours > 0)? "0" + String.format("%d:", minutes) : String.format("%d:", minutes)) + (this.seconds<10 ? "0" + this.seconds: this.seconds));
}
}
And here is the service:
public class MyService extends Service {
NotificationManager notificationManager;
NotificationCompat.Builder mBuilder;
Callbacks activity;
private long startTime = 0;
private long millis = 0;
private final IBinder mBinder = new LocalBinder();
Handler handler = new Handler();
Runnable serviceRunnable = new Runnable() {
#Override
public void run() {
millis = System.currentTimeMillis() - startTime;
activity.updateClient(millis); //Update Activity (client) by the implementd callback
handler.postDelayed(this, 1000);
}
};
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
//Do what you need in onStartCommand when service has been started
return START_NOT_STICKY;
}
#Override
public IBinder onBind(Intent intent) {
return mBinder;
}
//returns the instance of the service
public class LocalBinder extends Binder{
public MyService getServiceInstance(){
return MyService.this;
}
}
//Here Activity register to the service as Callbacks client
public void registerClient(Activity activity){
this.activity = (Callbacks)activity;
}
public void startCounter(){
startTime = System.currentTimeMillis();
handler.postDelayed(serviceRunnable, 0);
Toast.makeText(getApplicationContext(), "Counter started", Toast.LENGTH_SHORT).show();
}
public void stopCounter(){
handler.removeCallbacks(serviceRunnable);
}
//callbacks interface for communication with service clients!
public interface Callbacks{
public void updateClient(long data);
}
}

Update: July 10 2016
IMO I think using BroadcastReceiver for custom events is better way
as the Messengers mentioned don't handle activity recreation on device
rotation as well as possible memory leaks.
You may create custom BroadCast Receiver for events in the activity, Then you may also use Messengers.
In your Activity
create a MessageHandler class as
public static class MessageHandler extends Handler {
#Override
public void handleMessage(Message message) {
int state = message.arg1;
switch (state) {
case HIDE:
progressBar.setVisibility(View.GONE);
break;
case SHOW:
progressBar.setVisibility(View.VISIBLE);
break;
}
}
}
Now you can have it's instance as
public static Handler messageHandler = new MessageHandler();
Start your Service with this Handler object as an extra data as
Intent startService = new Intent(context, SERVICE.class)
startService.putExtra("MESSENGER", new Messenger(messageHandler));
context.startService(startService);
In your Service you receive this object from the intent and initialize the Messenger variable in Service as
private Messenger messageHandler;
Bundle extras = intent.getExtras();
messageHandler = (Messenger) extras.get("MESSENGER");
sendMessage(ProgressBarState.SHOW);
And then write a method sendMessage to send messages to activity.
public void sendMessage(ProgressBarState state) {
Message message = Message.obtain();
switch (state) {
case SHOW :
message.arg1 = Home.SHOW;
break;
case HIDE :
message.arg1 = Home.HIDE;
break;
}
try {
messageHandler.send(message);
} catch (RemoteException e) {
e.printStackTrace();
}
}
The sample code above shows and hides a ProgressBar in Activity as messages are received from Service.

Intents are good solution for communication between Activitiy and Service.
A fast solution for receive intents in your service is subclassing IntentService class. It handles asynchronous requests expressed as Intents using a queue and worker thread.
For communication from service to Activity you can broadcast the intent but instead of using normal sendBroadcast() from Context, a more efficent way is to use LocalBroadcastManager from support library.
Example service.
public class MyIntentService extends IntentService {
private static final String ACTION_FOO = "com.myapp.action.FOO";
private static final String EXTRA_PARAM_A = "com.myapp.extra.PARAM_A";
public static final String BROADCAST_ACTION_BAZ = "com.myapp.broadcast_action.FOO";
public static final String EXTRA_PARAM_B = "com.myapp.extra.PARAM_B";
// called by activity to communicate to service
public static void startActionFoo(Context context, String param1) {
Intent intent = new Intent(context, MyIntentService.class);
intent.setAction(ACTION_FOO);
intent.putExtra(EXTRA_PARAM1, param1);
context.startService(intent);
}
public MyIntentService() {
super("MyIntentService");
}
#Override
protected void onHandleIntent(Intent intent) {
if (intent != null) {
final String action = intent.getAction();
if (ACTION_FOO.equals(action)) {
final String param1 = intent.getStringExtra(EXTRA_PARAM_A);
// do something
}
}
}
// called to send data to Activity
public static void broadcastActionBaz(String param) {
Intent intent = new Intent(BROADCAST_ACTION_BAZ);
intent.putExtra(EXTRA_PARAM_B, param);
LocalBroadcastManager bm = LocalBroadcastManager.getInstance(this);
bm.sendBroadcast(intent);
}
}
Example Activity
public class MainActivity extends ActionBarActivity {
// handler for received data from service
private final BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals(MyIntentService.BROADCAST_ACTION_BAZ)) {
final String param = intent.getStringExtra(EXTRA_PARAM_B);
// do something
}
}
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
IntentFilter filter = new IntentFilter();
filter.addAction(MyIntentService.BROADCAST_ACTION_BAZ);
LocalBroadcastManager bm = LocalBroadcastManager.getInstance(this);
bm.registerReceiver(mBroadcastReceiver, filter);
}
#Override
protected void onDestroy() {
LocalBroadcastManager bm = LocalBroadcastManager.getInstance(this);
bm.unregisterReceiver(mBroadcastReceiver);
super.onDestroy();
}
// send data to MyService
protected void communicateToService(String parameter) {
MyIntentService.startActionFoo(this, parameter);
}
}

I think there is a problem with the correct answer. I have not enough reputation to comment on it.
Right in the answer:
Activity call bindService() to get pointer to Service is ok. Because service context is maintained when connection is maintained.
wrong in the answer:
service pointer to Activity class to call back is bad way. Activity instance maybe not null during Activity context is being Release => exception here.
solution for the wrong in the answer:
service send intent to Activity. and Activity receiver intent via BroadcastReceiver.
Note:
in this case, Service and Activity in the same Process, you should use LocalBroadcastManager to send intent. It make performance and security better

This is a simple example of communication between activity and service
Activity
MyReceiver myReceiver; //my global var receiver
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layourAwesomexD);
registerReceiver();
}
//When the activity resume, the receiver is going to register...
#Override
protected void onResume() {
super.onResume();
checkStatusService(); // verficarStatusServicio(); <- name change
registerReceiver();
}
//when the activity stop, the receiver is going to unregister...
#Override
protected void onStop() {
unregisterReceiver(myReceiver); //unregister my receiver...
super.onStop();
}
//function to register receiver :3
private void registerReceiver(){
//Register BroadcastReceiver
//to receive event from our service
myReceiver = new MyReceiver();
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(MyService.SENDMESAGGE);
registerReceiver(myReceiver, intentFilter);
}
// class of receiver, the magic is here...
private class MyReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context arg0, Intent arg1) {
//verify if the extra var exist
System.out.println(arg1.hasExtra("message")); // true or false
//another example...
System.out.println(arg1.getExtras().containsKey("message")); // true or false
//if var exist only print or do some stuff
if (arg1.hasExtra("message")) {
//do what you want to
System.out.println(arg1.getStringExtra("message"));
}
}
}
public void checkStatusService(){
if(MyService.serviceStatus!=null){
if(MyService.serviceStatus == true){
//do something
//textview.text("Service is running");
}else{
//do something
//textview.text("Service is not running");
}
}
}
Service
public class MyService extends Service {
final static String SENDMESAGGE = "passMessage";
public static Boolean serviceStatus = false;
#Override
public void onCreate() {
super.onCreate();
serviceStatus=true;
}
#Nullable
#Override
public IBinder onBind(Intent intent) {return null;}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
//you service etc...
passMessageToActivity("hello my friend this an example of send a string...");
return START_STICKY;
}
#Override
public void onDestroy() {
super.onDestroy();
passMessageToActivity("The service is finished, This is going to be more cooler than the heart of your ex...");
System.out.println("onDestroy");
serviceStatus=false;
}
private void passMessageToActivity(String message){
Intent intent = new Intent();
intent.setAction(SENDMESAGGE);
intent.putExtra("message",message);
sendBroadcast(intent);
}
}
if we don't unregister BroadcastReceiver we will have an error, you need to unregister when the activity go onPause, onStop, onDestroy...
if you don't register BroadcastReceiver when you back to activity, it will not listen anything from the service... the service will send information to BroadcastReceiver but it will not receive anything because it isn't registered.
When you create more than one service, the following services are going to begin in onStartCommand.
You can pass information to service with intent and you get it in onStartCommand
Difference about return in onStartCommand: Difference between START_STICKY and START_REDELIVER_INTENT? and check the official website of google: Services

The best way in this case is to communicate by doing broadcasting from your service for different actions and receiving it in your activity. You can create a custom broadcast and send some codes defining specific events like complete, change, prepare etc...

Most easy and efficient way will be using EventBus from GreenRobot.
Use simple 3 steps:
1 Define events
public static class MessageEvent { /* Additional fields if needed */ }
2 Prepare subscribers: Declare and annotate your subscribing method, optionally specify a thread mode:
#Subscribe(threadMode = ThreadMode.MAIN)
public void onMessageEvent(MessageEvent event) {/* Do something */};
Register and unregister your subscriber. For example on Android, activities and fragments should usually register according to their life cycle:
#Override
public void onStart() {
super.onStart();
EventBus.getDefault().register(this);
}
#Override
public void onStop() {
super.onStop();
EventBus.getDefault().unregister(this);
}
3 Post events:
EventBus.getDefault().post(new MessageEvent());

Very easy yet powerful way is to use EventBus you can add it to your gradle build and enjoy the easy publisher/subscriber pattern .

Do intents change when they are sent through IPC?

I'm using a ResultReceiver to allow a service to pass data through to an activity. I'm experiencing some difficulties with comparing intents that have been sent through IPC, it looks like the objects are changing, and thus can't be compared using a standard hashcode(.equals) comparison. I've created some sample code that will reproduce the scenario:
MyActivity.java:
public class MyActivity extends Activity {
private final Handler mHandler = new Handler();
private Intent serviceIntent;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
MyReceiver receiver = new MyReceiver(mHandler);
serviceIntent = new Intent(this, MyService.class);
serviceIntent.putExtra("receiver", receiver);
startService(serviceIntent);
}
public class MyReceiver extends ResultReceiver {
public MyReceiver(Handler handler) {
super(handler);
}
#Override
protected void onReceiveResult(int resultCode, Bundle resultData) {
Intent intent = resultData.getParcelable("intent");
if(intent.equals(serviceIntent)) {
Log.d("TEST", "Same intent!");
} else {
Log.d("TEST", "Different intents!");
}
}
}
}
MyService.java
public class MyService extends Service {
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
ResultReceiver receiver = intent.getExtras().getParcelable("receiver");
Bundle b = new Bundle();
b.putParcelable("intent", intent);
receiver.send(100, b);
stopSelf();
return Service.START_NOT_STICKY;
}
}
Don't forget to register the service in the manifest if you want to run this.
So the intent is sent back and forth, no change is made in the process and yet my activity insists that the two references differ. What's going on here?

The intent created by Intent intent = resultData.getParcelable("intent") and private Intent serviceIntent are not the same object, even if they are created to contain the exact same data. The current .equals() function simply checks if the intents are the same object; you will have to write your own .equals() function to determine if the intents are the same by whatever definition fits your application. See here.