CODEWITHSUNDEEP
androidmultithreading
Anoir Nechi
Anoir Nechi

Reputation: 81

setText wont work in the thread

Hi i have this code to modify a text view but it keeps telling me : Only the original thread that created a view hierarchy can touch its views. here is my code : 

public void Simulation()
{
    ambientTemp = 20;
    engTemp = 20;
    mileage = 123456;
    fuel = 100;

    thread = new Thread()
    {
        menu1_Fragment f1 = new menu1_Fragment();
        menu2_Fragment f2 = new menu2_Fragment();
        menu3_Fragment f3 = new menu3_Fragment();

        public void run()
        {
            for (int i=0; i<l; i++)
            {
                try {
                    Thread.sleep(99);
                }
                catch (InterruptedException e)
                {
                    e.printStackTrace();
                }



                speed = SPEED[i];
                revs = ENGSPEED[i];
                System.out.println(speed);
                System.out.println(revs);
                    fuel -= 1;
                    System.out.println(fuel);
                    engTemp += 0.5;
                    System.out.println(engTemp);
                    mileage += 1;
                    System.out.println(mileage);

                    ...
                    View item2 = findViewById(R.id.milage);
                   // f1.setMileage(item2,mileage);
                    View item3 = findViewById(R.id.ambienttemp);
                    f1.setAmbientTemp(item3,ambientTemp);
                    View item4 = findViewById(R.id.gear);
                    f1.setGear(item4,gear);
                    transaction.replace(R.id.container, f1);
                    transaction.commit();
                }

f1.setMileage(item2,mileage); this one is causing the probleme ... how can i fix it please

Upvotes: 0

Views: 56

Answers (1)

Genevieve
Genevieve

Reputation: 450

put all your codes related to a view inside a ui thread

     runOnUiThread(new Runnable() {
        @Override
        public void run() {
                      View item2 = findViewById(R.id.milage);
               // f1.setMileage(item2,mileage);
                View item3 = findViewById(R.id.ambienttemp);
                f1.setAmbientTemp(item3,ambientTemp);
                View item4 = findViewById(R.id.gear);
                f1.setGear(item4,gear);
                transaction.replace(R.id.container, f1);
                transaction.commit();

        }
    });

Your application must create other threads and put long running work on non-UI threads. There are options on how to accomplish the creation of alternate threads. You can create and start your own java.lang.Thread. You can create and start an AsyncTask - Android’s own thread simplification mechanism. The non-UI thread then handles long running processing – like downloading a file – while the UI thread sticks to displaying the UI and reacting to user events. Life seems good again.

However, there is a problem in paradise. Unfortunately, the user interface (UI) cannot be updated by non-UI threads. For example, after successfully downloading a file, a separate (non-UI) thread can’t show an AlertDialog, update a TextView widget, otherwise make a UI change to indicate the file has been successfully downloaded. If you attempt to update the UI from a non-UI thread, the application will compile, but you get a CalledFromWrongThreadException thrown from the point your non-UI thread attempts to make the UI change. As the exception message will inform you, “Only the original thread that created a view hierarchy can touch its views.”

for reference, click this link http://www.intertech.com/Blog/android-non-ui-to-ui-thread-communications-part-1-of-5/

Upvotes: 2

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