Progress bar.setProgress(variable) in a background thread

Question

this is my first question on stack (great community, thanks!)

So, I have this problem:

I'm developing an android application with a tab layout. Whenever I navigate to the "Status" tab, I'd like to show a circular ProgressBar that is updated according to the value of a variable. Let's call this variable prog. Moreover, I'd like to display in the center of the ProgressBar a TextView that displays the same value of prog.

I have came up with this part of code:

public class StatusFragment extends Fragment
{

    private ProgressBar torqueRefProgressBar;
    private TextView torqueRefTextView;


    RunningThreadExample r;
    private Thread t1;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
    {
        //Inflate the layout for this fragment
        return ...;

    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState)
    {
        // Initializations and other parts not relevant for the question...

        this.torqueRefProgressBar   =   getView().findViewById(R.id.torqueRefProgressBar);

        this.torqueRefTextView      =   getView().findViewById(R.id.torqueRefTextView);


        t1 = new Thread( this.torqueRefProgressBar, this.torqueRefTextView)); // passing arguments by value but values are references to the objects, therefore I'm passing by ref

        t1.start();


    }

}

In this Fragment I create the ProgressBar and the TextView and then pass them to the Runnable as you can see below

public class RunningThreadExample implements Runnable
{

    ProgressBar torqueRefProgBar_thread;
    TextView torqueRefTextView_thread;

    public RunningThreadExample(ProgressBar progressBar, TextView textView)
    {
        this.torqueRefProgBar_thread = progressBar;
        this.torqueRefTextView_thread = textView;
        this.endScale = this.torqueRefProgBar_thread.getMax();
    }

    @Override
    public void run()
    {
        android.os.Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);

       float i = 0;

       double temp = 0;


        while(Running)
        {
            try
            {
                Thread.sleep(1000/60); // update freq 60Hz
            }
            catch (InterruptedException e)
            {
                e.printStackTrace();
            }

            temp = getCurrentVariableValue(); // Not shown here (returns a double)

            this.torqueRefProgBar_thread.setProgress((int) temp);
            this.torqueRefTextView_thread.setText(String.valueOf(temp));

        }

        Log.i(INFO_TAG,"Finishing thread!!!!!");

    }


}

I'd like this update to run all the time the app is working (for this reason I've neglected AsyncTask). After a while, it happens that the ProgressBar stops updating, while the TextView continues to work without any problem.

I've been reading that a possible cause could be that the calling setProgress(temp) might stuck the UI. However I can't understand while the TextView is still working.

Can you suggest a better way to make the progressBar update?

Thank you!

score 0 · Answer 1 · edited Mar 25 '20 at 16:04

0

See this thread:

Android basics: running code in the UI thread

So to summarize, Android requires certain types and sections of code to run in a specific context. Many tools such as Handlers are available to help with these tasks but it was difficult to learn to begin with.

edited Mar 25 '20 at 16:04

Abra

19,142
7
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answered Mar 25 '20 at 16:03

Patrick Sturm

393
1
13

Thank you, Handlers did work for me. I didn't realize it was sufficient to pass the UI components as arguments of the constructor of the runnable being called and to delegate the update to the main Looper. Your suggestion was really great – tip Mar 26 '20 at 14:37

score 0 · Answer 2 · answered Mar 25 '20 at 16:05

0

You cannot affect View from any Thread other than Main Thread. Do the following in run() method

runOnUiThread(new Runnable() { 
// 
run(){

 this.torqueRefProgBar_thread.setProgress((int) temp);
      }      this.torqueRefTextView_thread.setText(String.valueOf(temp));
);

answered Mar 25 '20 at 16:05

abhi

961
9
13

Sorry, I did not get where to call `runOnUiMethod() `. I've tried calling inside my `run() ` but it is not defined – tip Mar 25 '20 at 16:17

Progress bar.setProgress(variable) in a background thread

2 Answers2