I have an error in a thread making time "run" (update every second)

Question

Here is my code:

public void run() {
        try {
            while (!isInterrupted()) {
                Thread.sleep(1000);
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {

                    }
                });
            }
        } catch (InterruptedException e) {
        }
    }
};
thread.start();

The Thread is called Thread and I want to display the time in a TextView called TextView. There is some error in the Threadbecause even though the time displays in the TextView, it does not update every second. Thanks

Have you tried debugging? The question, as it is, is very hard to answer. — f1sh, Aug 10 '17 at 11:21
@NejsemNikdo Check this answer about the use of Handler: https://stackoverflow.com/a/32640896/3965050 — Matias Olocco, Aug 10 '17 at 11:27
@f1sh, I think that the problem is with "updating textview" in line 8 (`public void run() { //here }`. But I am not sure with this and besides I don't know how to "update the textview" — Nejsem Nikdo, Aug 10 '17 at 11:28

Matias Olocco · Answer 1 · 2017-08-10T20:24:34.993

2

As stated, you should use Handler with Runnable, here is an example with your code:

final Handler handler = new Handler();
final Runnable task = new Runnable() {
    @Override
    public void run() {
        //Your code
        handler.postDelayed(this, 1000);
    }
};
handler.postDelayed(task, 1000);

More info about Handlers, in the doc.

edited Aug 10 '17 at 20:24

answered Aug 10 '17 at 11:33

Matias Olocco

509
4
9

It shows an error "Variable 'task' might not have been initialized" on `task` in the first `handler.postDelayed(task, 1000)` (under my code) – Nejsem Nikdo Aug 10 '17 at 14:51
Thanks, now it does not show the error, but the clock in my app is still not running :( – Nejsem Nikdo Aug 12 '17 at 09:16
@NejsemNikdo Can you please update your full code in the question? please, make it full, because that should work. – Matias Olocco Aug 14 '17 at 08:57

score 2 · Answer 2 · answered Aug 10 '17 at 11:36

2

use Runnable And Handler

Runnable runnable = new Runnable() {
    @Override
    public void run() {

        Date time = Calendar.getInstance().getTime();
        textView.setText(DateFormat.format("hh:mm", time));

        handler.postDelayed(this, 1000);
    }
};

Handler handler = new Handler();
handler.post(runnable);

answered Aug 10 '17 at 11:36

Ali Faris

17,754
10
45
70

Check that he starts sleeping the thread, so the first post should be delayed as well. – Matias Olocco Aug 10 '17 at 11:38
I think he do that to make the task execute every second , not that he want to make it delay – Ali Faris Aug 10 '17 at 11:40
1

Yes, of course, but he could put the sleep after the execution of his code, putting it at the begining is just to delay the first execution as well (maybe he is putting some data in the TextView already?, who knows...). But then again, maybe it is just a mistake. Just an observation. – Matias Olocco Aug 10 '17 at 11:42

I have an error in a thread making time "run" (update every second)

2 Answers2