CODEWITHSUNDEEP
androidmultithreadingrunnable
D.Madu
D.Madu

Reputation: 507

Is it right to put intent inside a Runnable thread?

In my app I use Room library for read/write values. In one activity I am reading a value from my SQLite db and I need to pass that value to next activity. Just because we cannot read values in main thread I am using a different thread. When I tried to put those values to intent.putExtra outside the thread it gives me Nullpointerexception. But if I put my intent within the thread everything seem to be ok. I wanna know whether is it ok to put my intent within the thread? Is this the correct method? Do I need to use AsyncTask?

    Runnable r = new Runnable(){
        @Override
        public void run() {
            List<Vehicle> list = dDb.vehicleDao().getAll();
            for (Vehicle s : list) {
                vehicleNumber = s.getVehicleNo();
                vehicleDescrp = s.getDescription();
            }

            // Session manager
            session = new SessionManager(getApplicationContext());

            // Check if user is already logged in or not
            if (session.isLoggedIn()) {

                // Launch main activity
                Intent intent = new Intent(LoginActivity.this, MainActivity.class);
                intent.putExtra("VEHICLEID", vehicleNumber);
                intent.putExtra("VEHICLEDS", vehicleDescrp);
                startActivity(intent);
                finish();

            }
        }
    };

    Thread newThread= new Thread(r);
    newThread.start();

Upvotes: 0

Views: 881

Answers (1)

Andrey Danilov
Andrey Danilov

Reputation: 6602

That will not work because you cannot do things like opening Actvity outside of the Main Thread.

If you really need it you have to wrap it with

runOnUiThread(new Runnable() {
     void run() {
         // Do stuff…
     }
});

So in ur case it will look like 

Runnable r = new Runnable(){
    @Override
    public void run() {
        List<Vehicle> list = dDb.vehicleDao().getAll();
        for (Vehicle s : list) {
            vehicleNumber = s.getVehicleNo();
            vehicleDescrp = s.getDescription();
        }

        // Session manager
        session = new SessionManager(getApplicationContext());

        // Check if user is already logged in or not
        if (session.isLoggedIn()) {
           LoginActivity.this.runOnUiThread(new Runnable() {
           void run() {
                // Launch main activity
                Intent intent = new Intent(LoginActivity.this, MainActivity.class);
                intent.putExtra("VEHICLEID", vehicleNumber);
                intent.putExtra("VEHICLEDS", vehicleDescrp);
                startActivity(intent);
                finish();
        }
    };

Thread newThread= new Thread(r);
newThread.start();

Upvotes: 2

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