CODEWITHSUNDEEP
android
herpderp
herpderp

Reputation: 16167

How to change a TextView every second in Android

I've made a simple Android music player. I want to have a TextView that shows the current time in the song in minutes:seconds format. So the first thing I tried was to make the activity Runnable and put this in run():

int position = 0;
while (MPService.getMP() != null && position<MPService.duration) {
try {
    Thread.sleep(1000);
    position = MPService.getSongPosition();
} catch (InterruptedException e) {
    return;
}

// ... convert position to formatted minutes:seconds string ...

currentTime.setText(time); // currentTime = (TextView) findViewById(R.id.current_time);

But that fails because I can only touch a TextView in the thread where it was created. So then I tried using runOnUiThread(), but that doesn't work because then Thread.sleep(1000) is called repeatedly on the main thread, so the activity just hangs at a blank screen. So any ideas how I can solve this?

new code:

private int startTime = 0;
private Handler timeHandler = new Handler();
private Runnable updateTime = new Runnable() {
    public void run() {
        final int start = startTime;
        int millis = appService.getSongPosition() - start;
        int seconds = (int) ((millis / 1000) % 60);
        int minutes = (int) ((millis / 1000) / 60);
        Log.d("seconds",Integer.toString(seconds)); // no problem here
        if (seconds < 10) {
            // this is hit, yet the text never changes from the original value of 0:00
            currentTime.setText(String.format("%d:0%d",minutes,seconds));
        } else {
            currentTime.setText(String.format("%d:%d",minutes,seconds));
        }
        timeHandler.postAtTime(this,(((minutes*60)+seconds+1)*1000));
    }

};

private ServiceConnection onService = new ServiceConnection() {
public void onServiceConnected(ComponentName className,
        IBinder rawBinder) {
      appService = ((MPService.LocalBinder)rawBinder).getService();

    // start playing the song, etc. 

    if (startTime == 0) {
        startTime = appService.getSongPosition();
        timeHandler.removeCallbacks(updateTime);
        timeHandler.postDelayed(updateTime,1000);
    }
}

Upvotes: 17

Views: 37792

Answers (5)

MusiGenesis
MusiGenesis

Reputation: 75296

Use a Timer for this (instead of a while loop with a Thread.Sleep in it). See this article for an example of how to use a timer to update a UI element periodically:

Updating the UI from a timer

Edit: updated way-back link, thanks to Arialdo: http://web.archive.org/web/20100126090836/http://developer.android.com/intl/zh-TW/resources/articles/timed-ui-updates.html

Edit 2: non way-back link, thanks to gatoatigrado: http://android-developers.blogspot.com/2007/11/stitch-in-time.html

Upvotes: 10

Jim C
Jim C

Reputation: 1845

I think the below blog article clearly gives a very nice solution. Especially, if you are a background service and want to regularly update your UI from this service using a timer-like functionality. It really helped me, much more than the 2007 blog link posted by MusiGenesis above.

https://www.websmithing.com/2011/02/01/how-to-update-the-ui-in-an-android-activity-using-data-from-a-background-service/

Upvotes: 0

NamPham
NamPham

Reputation: 243

This is one more Timer example and I'm using this code in my project. https://stackoverflow.com/a/18028882/1265456

Upvotes: 0

JanOlMajti
JanOlMajti

Reputation: 1397

what about this:

    int delay = 5000; // delay for 5 sec.
    int period = 1000; // repeat every sec.

    Timer timer = new Timer();
    timer.scheduleAtFixedRate(new TimerTask()
        {
            public void run()
            {
                //your code
            }
        }, delay, period);

Upvotes: 13

jtt
jtt

Reputation: 13541

You have to use a handler to handle the interaction with the GUI. Specifically a thread cannot touch ANYTHING on the main thread. You do something in a thread and if you NEED something to be changed in your main thread, then you call a handler and do it there.

Specifically it would look something like this:

Thread t = new Thread(new Runnable(){ ... do stuff here

Handler.postMessage(); }

Then somewhere else in your code, you do

Handler h = new Handler(){

something something... modify ui element here }

Idea its like this, thread does something, notifies the handler, the handler then takes this message and does something like update a textview on the UI thread.

Upvotes: 4

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