Java Question Getting an answer from b4a in a Event which is raised

DonManfred · Nov 2, 2017

https://www.b4x.com/android/forum/threads/firebase-jobdispatcher.85613/

The wish here is about the firebase Jobdispatcher.

For this one need to write a service which then extends their JobService. Inside this service the developer need to answer (give a true/false result).

Is it possible to raise an event in B4A (probably used inside starter) from this java-service AND to get back an Answer from the B4A Event which is raised?

This is a basic service for this...

B4X:

import com.firebase.jobdispatcher.JobParameters;
import com.firebase.jobdispatcher.JobService;

public class MyJobService extends JobService {
    @Override
    public boolean onStartJob(JobParameters job) {
        // Do some work here

        return false; // Answers the question: "Is there still work going on?"
    }

    @Override
    public boolean onStopJob(JobParameters job) {
        return false; // Answers the question: "Should this job be retried?"
    }

[..]
}

In onStartJob for example i would like to raise an event to b4a.
But it must be somehow synchronours or so. I need to get the answer to return true/false to the base service...

Can someone help me with an example on how this would work?

Erel · Nov 2, 2017

Check this example: https://www.b4x.com/android/forum/threads/example-of-extends-in-service.74880/#content

ba.raiseEvent returns a value so you can use it to get the required result.

DonManfred · Nov 2, 2017

I think in the past my knowledge was to low... It seems that i now understand this sample.
Thank you again for pointing me into!

I´m just on the way trying it out ;-)

DonManfred · Nov 2, 2017

Erel said:
Check this example

In this case (i´ve written a similar Service) i get the error

B4A Version: 7.30
Parse den Code. (0.00s)
Kompiliere den Code. (0.02s)
Kompiliere Layoutcode. (0.00s)
Organisiere Libraries. (0.00s)
Generiere R Datei. (0.04s)
Kompiliere generierten Java Code. Error
javac 1.8.0_141
src\b4a\example\dispatch.java:63: error: onStart(Intent,int) in dispatch cannot override onStart(Intent,int) in JobService
public void onStart(android.content.Intent intent, int startId) {
^
overridden method is final
Note: src\b4a\example\starter.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
1 error

Based on their docu a minimal Service can look like this:

The simplest possible JobService:

B4X:

import com.firebase.jobdispatcher.JobParameters;
import com.firebase.jobdispatcher.JobService;

public class MyJobService extends JobService {
    @Override
    public boolean onStartJob(JobParameters job) {
        // Do some work here

        return false; // Answers the question: "Is there still work going on?"
    }

    @Override
    public boolean onStopJob(JobParameters job) {
        return false; // Answers the question: "Should this job be retried?"
    }
}

So i can not override the onstart method here....

tigrot · Nov 2, 2017

I have read the Firebase jobdispatcher three times and I was not able to understand what it is for.
Also the issue that Don found in example is a little strange...
Can somebody try to explain to this poor old IT man the functions of this scheduler?
Thank you!
Mauro

tigrot · Nov 2, 2017

I understood the GitHub page on the fourth read!
Never mind.
Now I'm aware!

Mauro

Erel · Nov 2, 2017

DonManfred said:
In this case (i´ve written a similar Service) i get the error

I see. You will not be able to use #Extends in this case as they made the onStart method a final method.

While there are other options available to communicate with external services, I wouldn't recommend wrapping this specific library unless you are very familiar with Android services internal life cycle. It will be "easy" to create a wrapper that works in most cases and fail in less common cases.

Java Question Getting an answer from b4a in a Event which is raised

DonManfred

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Erel

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DonManfred

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tigrot

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Java Question Getting an answer from b4a in a Event which is raised

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