Pro Android with Kotlin

134
CHAPTER 8: APIs
To use the Firebase JobDispatcher, it first must be installed. To do so, add the following to 
your module’s build.gradle file, in the dependencies section:
implementation 'com.firebase:firebase-jobdispatcher:0.8.5'
As a first step, implement a job class as follows:
import com.firebase.jobdispatcher.*
class MyJobService : JobService() {
var jobThread:Thread? = null
override fun onStopJob(job: JobParameters?): Boolean {
Log.e("LOG", "onStopJob()")
jobThread?.interrupt()
jobThread = null
return false // this job should not be retried
}
override fun onStartJob(job: JobParameters): Boolean {
Log.e("LOG", "onStartJob()")
jobThread?.interrupt()
jobThread = Thread {
Log.i("LOG", "started job thread")
// do job work...
jobFinished(job, false)
// instead use true to signal a retry
jobThread = null
Log.i("LOG", "finished job thread")
}
jobThread?.start()
return true // work is going on in the background
}
}
Then register the job in the manifest file AndroidManifest.xml as follows:
android:exported="false"
android:name=".MyJobService">

"com.firebase.jobdispatcher.ACTION_EXECUTE"
/>

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135
CHAPTER 8: APIs
To include a check for availability, you have to perform the following steps:
1. Google Play Services needs to be added to the SDK installation. 
Inside Android Studio, go to Tools ➤ Android ➤ SDK Manager. In the 
menu choose Appearance & Behavior ➤ System Settings ➤ Android 
SDK. On the SDK Tools tab, select Google Play Services and then 
click the OK button.
2. Right-click the project, choose Open Module Settings, and in the 
menu select your app module. Go to the Dependencies tab, and add 
the library com.google.android.gms:play-services by clicking the + 
button.
To actually schedule a job from in your app, you can acquire the service, create a job, and 
then register this job by using this:
val gps = GoogleApiAvailability.getInstance().
isGooglePlayServicesAvailable(this)
if(gps == ConnectionResult.SUCCESS) {
// Create a new dispatcher using the Google Play
// driver.
val dispatcher = FirebaseJobDispatcher(
GooglePlayDriver(this))
val myJob = dispatcher.newJobBuilder()
.setService(MyJobService::class.java)
// the JobService that will be called
.setTag("my-unique-tag")
// uniquely identifies the job
.build()
dispatcher.mustSchedule(myJob)
} else {
Log.e("LOG", "GooglePlayServices not available: " +
GoogleApiAvailability.getInstance().
getErrorString(gps))
}
This example scheduled a job with basic job scheduling characteristics. For more complex 
needs, the job builder allows for more options, as shown in Table 
8-3
. Just chain them 
before the .build() method.

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