如何从JobScheduler的JobService将MediaPlayer对象传递给AsyncTask

Question

I am using JobScheduler which uses AsyncTask for its JobService. In the class MJobExecutor which extends AsyncTask uses MediaPlayer.I want to pass the Media Player Object but how. Following is my code for the AsyncTask class called MJobExecutor.java I have made a constructor to pass the MediaPlayer object.But the code seems not working.

public class MJobExecutor extends AsyncTask<Void,Void,String> {

ValueExchange value;
private MediaPlayer player;
//Constructor to pass MediaPlayer object.
public MJobExecutor(MediaPlayer player){
    this.player = player;
}
@Override
protected String doInBackground(Void... params) {

    value = new ValueExchange();
    Calendar cal = Calendar.getInstance();
    Date date=cal.getTime();
    DateFormat dateFormat = new SimpleDateFormat("hh:mm a");
    String formattedDate=dateFormat.format(date);
    if(formattedDate.equals(value.getString())){

    }
    play();
    return "Long running task finishes." + value.getString();
}



private void play(){
    if(player == null){
        //Below the getApplicationContext() not working even after the constructor-
        //being declared.
        player = MediaPlayer.create(getApplicatioContext(),R.raw.bensoundfunkyelement);
        player.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
            @Override
            public void onCompletion(MediaPlayer mp) {
                stopPlayer();
            }
        });
    }
    player.start();
}
private void stop(){
    stopPlayer();
}
private void stopPlayer(){
    if(player != null){
        player.release();
        player = null;
    }
}

}

And again in class MJobScheduler.java which extends JobService, MediaPlayer object is passed.But yet it is not working.

public class MJobScheduler extends JobService {

MJobExecutor mJobExecutor;
String alarmTime;
ValueExchange value;
MediaPlayer player;
@Override
public boolean onStartJob(final JobParameters params) {
    alarmTime = params.getExtras().getString("alarmTime");
    value = new ValueExchange();
    value.setString(alarmTime);
    //MediaPlayer object is Passed into the constructor-
    //but the app crashes
    mJobExecutor = new MJobExecutor(player){

        @Override
        protected void onPostExecute(String s) {
            Toast.makeText(getApplicationContext(),alarmTime+" "+s,Toast.LENGTH_LONG).show();
            jobFinished(params,false);
        }
    };
    mJobExecutor.execute();
    return true;
}

@Override
public boolean onStopJob(JobParameters params) {
    mJobExecutor.cancel(false);
    return false;
}
}

The Main Activity class is as follows...

public class MainActivity extends AppCompatActivity {

private static final int JOB_ID = 101;
JobScheduler jobScheduler;
JobInfo jobInfo;



TextView textTime;
ImageButton ibLeft,ibRight,ibTop,ibBottom;
TextClock textClock;



String alarmTime = "12:00 AM";

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);



    textTime = (TextView)findViewById(R.id.textView);
    ibLeft = (ImageButton)findViewById(R.id.left);
    ibRight = (ImageButton)findViewById(R.id.right);
    ibTop = (ImageButton)findViewById(R.id.top);
    ibBottom = (ImageButton)findViewById(R.id.bottom);

    textClock.setPadding(0,250,0,0);


    ComponentName componentName = new ComponentName(this,MJobScheduler.class);
    PersistableBundle bundle = new PersistableBundle();
    bundle.putString("alarmTime",alarmTime);

    JobInfo.Builder builder = new JobInfo.Builder(JOB_ID,componentName);

    builder.setExtras(bundle);
    builder.setPeriodic(5000);
    builder.setRequiredNetworkType(JobInfo.NETWORK_TYPE_ANY);
    builder.setPersisted(true);
    jobInfo = builder.build();
    jobScheduler = (JobScheduler) getSystemService(JOB_SCHEDULER_SERVICE);



}


public void Start(View view) {

    jobScheduler.schedule(jobInfo);
    Toast.makeText(this,"Job Started...",Toast.LENGTH_LONG).show();
}

public void Stop(View view) {
    jobScheduler.cancel(JOB_ID);
    Toast.makeText(this,"Job Cancelled...",Toast.LENGTH_LONG).show();
}


}

Answer 1

Instantiate your MediaPlayer object inside class MJobScheduler so that you won't need context inside your AsyncTask .

player = MediaPlayer.create(getApplicatioContext(),R.raw.bensoundfunkyelement);

Move the above line from your method play in class MJobExecutor to the method onStartJob of class MJobScheduler before the line mJobExecutor = new MJobExecutor(player)...

Then in your method play , remove the condition check if(player == null) because it will always be false preventing the code inside it from being executed.

So body of your method onStartJob will be as follows:

alarmTime = params.getExtras().getString("alarmTime");
value = new ValueExchange();
value.setString(alarmTime);

player = MediaPlayer.create(getApplicatioContext(), R.raw.bensoundfunkyelement);
mJobExecutor = new MJobExecutor(player){

    @Override
    protected void onPostExecute(String s) {
        Toast.makeText(getApplicationContext(),alarmTime+" "+s,Toast.LENGTH_LONG).show();
        jobFinished(params,false);
    }
};
mJobExecutor.execute();
return true;

And your play method will be as follows:

private void play() {
    player.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
        @Override
        public void onCompletion(MediaPlayer mp) {
            stopPlayer();
        }
    });
    player.start();
}