I created an app that reads books to the user.
The user needs to be able to continue reading
from the same position as he was in a previous app session.
How do i do something like that, if a process kill can occur anytime?
you can create here a service class in your app like this and create an api with your backend too :-
Service Class OnClearFromRecentService.class:-
public class OnClearFromRecentService extends Service {
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
return START_NOT_STICKY;
}
#Override
public void onDestroy() {
super.onDestroy();
}
#Override
public void onTaskRemoved(Intent rootIntent) {
callApi();
stopSelf();
}
public void callApi(){
//set your api here
}
}
and set this service class in your manifeast :-
<service
android:name=".halper.OnClearFromRecentService"
android:stopWithTask="false" />
and start this service when your video is play :-
OnClearFromRecentService onClearFromRecentService = new OnClearFromRecentService();
or stop your service where your you need to stop service like this:-
onClearFromRecentService.onTaskRemoved(new Intent(LandingScreen.this, OnClearFromRecentService.class));
So here is what I am trying to understand.
I have a service like this
public MyService extends Service {
public List<MyListener> listenersList = new ArrayList<>();
public void addListeners(MyListeners mylistener) {
listenersList.add(myListener);
}
public void eventAOccured(){
for ( MyListner mylistener : listeners ) {
mylistener.eventAOccured();
}
}
public void eventBOccured(){
for ( MyListner mylistener : listeners ) {
mylistener.eventBOccured();
}
}
}
And here is my MyListener Interface which activities
public Interface MyListener {
public eventAOccured();
public eventBOccured();
}
Now we have three activites
public Activity1 extends AppCompatActivity implements MyListener{
public static int myVariable = 1;
//starts service. For sake of brevity I am skipping this part.
MyService.add(this);
//on click of a button
startActivity( new Intent (Activity1.this, Activity2.class);
//Now I know this will put Activity1 in paused state
#Override
public void eventAOccured() {
//Call activity 3
}
#Override
public void eventBOccured() {
myVariable = 3;
}
}
This is the second activity which is called by clicking a button in activity 1. After Activity2 is launched, lets say eventB occurs. Now If I access myVariable from Activity1, will it be 1 or 3.
After some time let us say, eventA has occured. Now will Activity3 will be launched?
I know an activity being paused means it is no longer visible to the user, but will the communication with service continue?
yes, paused activity still will receive the event as it is in the back stack of system and is not destroyed.
Override the onStartCommand(Intent intent, int flags, int startId) and returen STRAT_STICKY. this will restart the service.
You can check following Example.
public class Test extends Service {
#Nullable
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.e("Test Service ", "onStartCommand");
return START_STICKY; //It will restart Service in onPause/onDestroy
}
#Override
public void onCreate() {
super.onCreate();
//Do your operation
}
}
I have an application which allows to read and write (notify) in BLE. Following the sample example, I created my own read and write functions in the class BluetoothLeService as follows:
public void readCharacteristic()
{
//My function
}
public void writeCustomCharacteristic(int value)
{
//My function
}
I want to keep read and write data when the application is in background. Hence, I must to make a service to do it. A simple structure of a service will be
public class backgroundservice extends Service
{
private static final String TAG = "MyService";
#Override
public void onCreate() {
super.onCreate();
Log.d(TAG, "onCreate");
}
#Override
public IBinder onBind(Intent intent) {
return null;
}
public void onDestroy() {
Log.d(TAG, "onDestroy");
}
#Override
public int onStartCommand(Intent intent, int flags, int startId)
{
return START_NOT_STICKY;
}
}
My question is how can I read/write data when my application is in background? If I use above service, which function do I need to use to call readCharacteristic() and writeCustomCharacteristic(int value)? For example, the writeCustomCharacteristic(int value) is called every 10 seconds. Thank all
I am stuck with the problem of Activity + Service in that I have following number of Activities and Services.
Activities:
LoginActivity => OrderListActivity => AddOrderActivity => ConfirmOrderActivity
Services:
ReceivingOrderService - Receiving New Data From Server
SendingOrderService - Sending new Data to Server
Above both Service Calling from another Separate Service on duration of some interval.
CheckAutoSyncReceivingOrder - To call ReceivingOrderService (Interval 15Mins)
CheckAutoSyncSendingOrder - To call SendingOrderService (Interval 3Mins)
CheckAutoSyncReceivingOrder:
public class CheckAutoSyncReceivingOrder extends Service {
Timer timer;
#Override
public IBinder onBind(Intent arg0) {
// TODO Auto-generated method stub
return null;
}
#Override
public void onStart(Intent intent, int startId) {
// TODO Auto-generated method stub
if(timer != null) {
timer.cancel();
Log.i(TAG, "RECEIVING OLD TIMER CANCELLED>>>");
}
timer = new Timer();
timer.schedule(new TimerTask() {
#Override
public void run() {
if(InternetConnection.checkConnection(getApplicationContext())) {
if(getDatabasePath(DatabaseHelper.DATABASE_NAME).exists())
startService(new Intent(CheckAutoSyncReceivingOrder.this, ReceivingOrderService.class));
} else {
Log.d(TAG, "Connection not available");
}
}
}, 0, 60000); // 1000*60*15 = 9,00,000 = 15 minutes
}
#Override
public void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
if(timer != null)
timer.cancel();
Log.d(TAG, "Stopping Receiving...");
}
}
CheckAutoSyncSendingOrder:
public class CheckAutoSyncSendingOrder extends Service {
Timer timer;
#Override
public IBinder onBind(Intent arg0) {
// TODO Auto-generated method stub
return null;
}
#Override
public void onStart(Intent intent, int startId) {
// TODO Auto-generated method stub
if(timer != null) {
timer.cancel();
Log.i(TAG, "OLD TIMER CANCELLED>>>");
}
timer = new Timer();
timer.schedule(new TimerTask() {
#Override
public void run() {
Log.i(TAG, ">>>>>>>> SENDING AUTO SYNC SERVICE >>>>>>>>");
if(InternetConnection.checkConnection(getApplicationContext())) {
if(getDatabasePath(DatabaseHelper.DATABASE_NAME).exists())
startService(new Intent(CheckAutoSyncSendingOrder.this, SendingOrderService.class));
} else {
Log.d(TAG, "connection not available");
}
}
}, 0, 120000); // 1000*120*15 = 1,800,000 = 15 minutes
}
#Override
public void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
if(timer != null)
timer.cancel();
Log.d(TAG, "Stopping Sending...");
}
}
ConfirmOrderActivity#Final Task which i have called for Insert Data:
new AsyncTask<Void, Void, Integer>() {
ProgressDialog progressDialog;
#Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
progressDialog = new ProgressDialog(
ConfirmOrderProductActivity.this);
progressDialog.setMessage("Inserting "
+ (isInquiry ? "Inquiry" : "Order") + "...");
progressDialog.setCancelable(false);
progressDialog
.setProgressStyle(ProgressDialog.STYLE_SPINNER);
progressDialog.show();
}
#Override
protected Integer doInBackground(Void... params) {
// TODO Auto-generated method stub
int account_id = context.getSharedPreferences(PREF_DATA,
MODE_APPEND).getInt(DATA_ACCOUNT_ID, 0);
/**
* Check Whether isInquiry or not...
*/
product_type = isWeight ? 1 : 0;
if (isInquiry) {
/*
* INSERTING DATA IN INQUIRY TABLE
*/
return m_inquiry_id;
} else {
/*
* INSERTING DATA IN ORDER TABLE
*/
return m_order_id;
}
}
#Override
protected void onPostExecute(Integer m_order_id) {
// TODO Auto-generated method stub
super.onPostExecute(m_order_id);
progressDialog.dismiss();
if (dbHelper.db.isOpen())
dbHelper.close();
String title = "Retry";
String message = "There is some problem, Go Back and Try Again";
AlertDialog.Builder alert = new AlertDialog.Builder(
ConfirmOrderProductActivity.this);
if (m_order_id != -1) {
title = isInquiry ? "New Inquiry" : "New Order";
message = isInquiry ? "Your Inquiry Send Successfully." : "Your Order Saved Successfully.";
alert.setIcon(R.drawable.success).setCancelable(false);
} else {
alert.setIcon(R.drawable.fail).setCancelable(false);
}
alert.setTitle(title).setMessage(message)
.setPositiveButton("OK", new OnClickListener() {
#Override
public void onClick(DialogInterface dialog,
int which) {
// TODO Auto-generated method stub
dialog.dismiss();
startActivity(new Intent(
ConfirmOrderProductActivity.this,
FragmentChangeActivity.class)
.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP));
/* Opening Left to Right Animation */
overridePendingTransition(R.anim.right_out,
R.anim.right_in);
}
});
AlertDialog alertDialog = alert.create();
alertDialog.show();
}
}.execute();
Everything is working fine as per flow of inserting records in database.
After Adding Inquiry:
Destroying Activity and Getting following Logcat:
Main Problem:
When I placed order successfully from ConfirmOrderActivity, It is displaying AlertDialog of Success Message which is cancellable false. When I Stop application from this Activity, Its calling both CheckAutoSyncReceivingOrder and CheckAutoSyncSendingOrder automatically.
Edited:
I am calling both Service from LoginActivity only, after that it
will called automatically after given intervals But Problem occurs
when I destroy ConfirmOrderActivity when dialog is shown.
I didn't know why it happens that Why its running automatically when I stop Activity Directly.
I have tried onStartCommand() with START_NON_STICKY in Service but not working. (as START_STICKY is default.)
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
return START_NOT_STICKY;
}
Is there any solution?
You need to either run your service in the foreground so when the activity is destroyed so will the service or use a bound service and manage the binding with the activity lifecycle, so it is not continually restarted when the activity is destroyed.
From this android docs tutorial Bound Services
You need to do this for each service.
public class CheckAutoSyncReceivingOrder extends Service {
// Binder given to clients
private final IBinder mBinder = new LocalBinder();
public class LocalBinder extends Binder {
CheckAutoSyncReceivingOrder getService() {
return CheckAutoSyncReceivingOrder.this;
}
}
#Override
public IBinder onBind(Intent intent) {
return mBinder;
}
From your activity that creates and calls the service, that when it is destroyed you want your service destroyed.
public class BindingActivity extends Activity {
CheckAutoSyncReceivingOr mService;
boolean mBound = false;
#Override
protected void onStart() {
super.onStart();
// Bind to CheckAutoSyncReceivingOr
Intent intent = new Intent(this, CheckAutoSyncReceivingOr.class);
bindService(intent, mConnection, Context.BIND_AUTO_CREATE);
}
#Override
protected void onStop() {
super.onStop();
// Unbind from the service
if (mBound) {
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 CheckAutoSyncReceivingOr, cast the IBinder and get CheckAutoSyncReceivingOr instance
LocalBinder binder = (LocalBinder) service;
mService = binder.getService();
mBound = true;
}
#Override
public void onServiceDisconnected(ComponentName arg0) {
mBound = false;
}
};
}
And manage the service lifecycle. Restart the same service with your timer, do not create a new service.
public class ExampleService extends Service {
int mStartMode; // indicates how to behave if the service is killed
IBinder mBinder; // interface for clients that bind
boolean mAllowRebind; // indicates whether onRebind should be used
#Override
public void onCreate() {
// The service is being created
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
// The service is starting, due to a call to startService()
return mStartMode;
}
#Override
public IBinder onBind(Intent intent) {
// A client is binding to the service with bindService()
return mBinder;
}
#Override
public boolean onUnbind(Intent intent) {
// All clients have unbound with unbindService()
return mAllowRebind;
}
#Override
public void onRebind(Intent intent) {
// A client is binding to the service with bindService(),
// after onUnbind() has already been called
}
#Override
public void onDestroy() {
// The service is no longer used and is being destroyed
}
}
Note START_NOT_STICKY will only prevent the service from restarting if the device is low on memory.
Be mindful that you where you are starting services, just start it once and allow the service to maintain it's own lifecycle until you destroy it with your activity.
This is in reply to your original unedited question, when the app was mysteriously crashing:
You need to destroy the dialog before the context window the dialog is attached to. That will cause a problem. So this is where program flow and the order of closing and cleaning up resources is important. They, frequently have to be destroyed in the reverse order they were created if they are dependent upon parent windows (which is often in the form of a particular activity).
It's difficult to trace your code, so this is a generic answer.
Make use of onPause and onDestroy in your activities.
In all your activities, manage any resources you have created within that activity and with a null check, close them down. Like you have in your service class. If you want to override the parent onDestroy, place your custom code before super.onDestroy.
protected void onDestroy() {
if(timer != null)
timer.cancel();
Log.d(TAG, "Stopping Sending...");
super.onDestroy();
}
(1)For Your Dialog:
The solution is to call dismiss() on the Dialog you created before exiting the Activity, e.g. in onDestroy(). All Windows & Dialog should be closed before leaving an Activity.
(2)For Your service autostart:
you have to look at the value the service returns from its onStartCommand method. The default value is START_STICKY which will restart the service after it is destroyed. Take a look at the onStartCommand documentation for more details:
If the process that runs your service gets killed, the Android system will restart it automatically it is default behavior.
This behavior is defined by the return value of onStartCommand() in your Service implementation. The constant START_NOT_STICKY tells Android not to restart the service if it s running while the process is "killed".
You need to Override method onStartCommand() in your service class and move all your code from onStart() method to onStartCommand() method.
According to the Android Documentation:
For started services, there are two additional major modes of
operation they can decide to run in, depending on the value they
return from onStartCommand(): START_STICKY is used for services that
are explicitly started and stopped as needed, while START_NOT_STICKY
or START_REDELIVER_INTENT are used for services that should only
remain running while processing any commands sent to them
onStart() method calls each time when service is restarted but onStartCommand() method will not called if you return START_NON_STICKY.
Don't use onStart() anymore, it's deprecated.
I hope it helps you.
Services got killed when application got killed (add logs in service onStartCommand() and onDestroy() function and try clearing app from recent list and you will see onDestroy() is called. Android will re-start service if you have returned START_STICKY intent in onStartCommand()).
There are two approaches to fix your problem.
Either make your two services as foreground service.
Instead of using CheckAutoSyncReceivingOrder and CheckAutoSyncSendingOrder to schedule start of another services, you should use AlarmManager to schedule your task.
This is my code for service class here previous_network_type is global static variable it is not initialized in oncreate() or onstartcommand() function also not from activity on create function why is that any help?? whenever i used it, it gives me 0 value it should give me 10 after starting of this service but returns 0. To be more clear
First MyService has previous_network_type variable i want to assign it a value in oncreate or oncommand function
which i'l use in another class which is broadcast receiver
and you know that broadcast receiver runs only when an event is occur so what m trying to do whenever a particular event occur i want to access this value
public class MyService extends Service {
static int previous_network_type=0;
public void onCreate() {
previous_network_type=10;
};
public int onStartCommand(Intent intent, int flags, int startId) {
previous_network_type=10;
return Service.START_STICKY;
}
}
and the code of other class(Broadcast receiver is given below)
public void onReceive(Context context, Intent intent)
{
MyService.current_network_type=MyService.previous_network_type;
}
public class MainActivity extends Activity {
Intent i;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
i=new Intent(this,MyService.class);
startService(i);
}
#Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();;
stopService(i);
}
}
public class MyService extends Service {
static int previous_network_type=0;
public void onCreate() {
previous_network_type=10;
};
public int onStartCommand(Intent intent, int flags, int startId) {
previous_network_type=10;
Log.e("check","Value"+previous_network_type);
return Service.START_STICKY;
}
#Override
public IBinder onBind(Intent intent) {
// TODO Auto-generated method stub
return null;
}
}
check once if you have defined the Service in Android.manifest.xml
<service android:name="com.example.kuchbhi.MyService"
></service>
Just make sure that you are accessing the value after the service has been created/started.
Try to debug.