如何改变一个TextView每一秒在Android中 [英] How to change a TextView every second in Android

问题描述

我做了一个简单的Andr​​oid音乐播放器。我想有一个TextView，显示当前时间在歌曲分：秒格式。所以，我想的第一件事是，使活动的Runnable，并把这个在run（）：

  INT位置= 0;
而（MPService.getMP（）= NULL和放大器;！＆安培;位置＆LT; MPService.duration）{
尝试 {
    视频下载（1000）;
    位置= MPService.getSongPosition（）;
}赶上（InterruptedException异常E）{
    返回;
}

// ...转换位置格式化分：秒串...

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

但是，失败，因为我只能摸一个TextView在其中创建线程。于是我试着用runOnUiThread（），但是，这并不工作，因为那时视频下载（1000）是在主线程中反复调用，因此该活动只是挂在空白屏幕。因此，任何想法如何，我可以解决这个问题？

---

新的code：

 私人诠释的startTime = 0;
私人处理程序timeHandler =新的处理程序（）;
私人Runnable接口录入=新的Runnable（）{
    公共无效的run（）{
        最终诠释开始= startTime时;
        INT米利斯= appService.getSongPosition（） - 启动;
        INT秒=（int）的（（米利斯/ 1000）％60）;
        INT分钟=（int）的（（米利斯/ 1000）/ 60）;
        Log.d（秒，Integer.toString（秒））; //这里没有问题
        如果（秒-1，10）{
            //这个被击中，但文从来没有从0:00原值改变
            currentTime.setText（的String.Format（％D：0％D，分，秒））;
        } 其他 {
            currentTime.setText（的String.Format（％D：％D，分，秒））;
        }
        timeHandler.postAtTime（此，（（（分钟* 60）+秒+ 1）* 1000））;
    }

};

私人ServiceConnection onService =新ServiceConnection（）{
公共无效onServiceConnected（组件名类名，
        的IBinder rawBinder）{
      AppService服务=（（MPService.LocalBinder）rawBinder）.getService（）;

    //开始播放歌曲等。

    如果（startTime时== 0）{
        的startTime = appService.getSongPosition（）;
        timeHandler.removeCallbacks（录入）;
        timeHandler.postDelayed（录入，1000）;
    }
}
 

解决方案

使用定时器本（而不是，而在里面循环使用 Thread.sleep代码）。请参阅本文的如何使用定时器来定期更新UI元素的例子：

从计时器更新UI

修改：路回更新的链接，这要归功于 Arialdo ：<一href="http://web.archive.org/web/20100126090836/http://developer.android.com/intl/zh-TW/resources/articles/timed-ui-updates.html" rel="nofollow">http://web.archive.org/web/20100126090836/http://developer.android.com/intl/zh-TW/resources/articles/timed-ui-updates.html

编辑2 ：路回非链接，感谢 gatoatigrado ： http://android-developers.blogspot.com/2007/11/stitch-in-time.html

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);
    }
}

解决方案

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

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