blocks|key|1416899|text|我认为正在发生的事情是你正在脱离UI线程。只有一个"looper“线程来处理所有的屏幕更新。如果你试图调用"invalidate()“，而你不在这个线程上，那么什么都不会发生。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1416900|尝试在视图上使用"postInvalidate()“。它可以让你在不在当前UI线程中的时候更新视图。|1416901|更多信息here|offset|length|1416902|entityMap|0|LINK|mutability|MUTABLE|url|http://code.google.com/android/reference/android/view/View.html#postInvalidate()^0|0|0|4|4|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Q|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@$F|S|G|T|1|U]]|A|$]]|$1|H|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|I|$J|$5|K|L|M|A|$N|O]]]]

What I think is happening is you're falling off the UI thread. There is a single "looper" thread which handles all screen updates. If you attempt to call "invalidate()" and you're not on this thread nothing will happen.

Try using "postInvalidate()" on your view instead. It'll let you update a view when you're not in the current UI thread.

More info <a href="http://code.google.com/android/reference/android/view/View.html#postInvalidate()" rel="nofollow noreferrer">here</a>

blocks|key|1631811|text|一般的解决方案是使用在UI线程中运行的android.os.Handler。它只做一次回调，所以每次调用你的回调时，你都必须再次触发它。但是它很容易使用。几年前写过一篇关于这个话题的博客文章：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1631812|http://android-developers.blogspot.com/2007/11/stitch-in-time.html|offset|length|1631813|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|1U|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@$D|O|E|P|1|Q]]|A|$]]|$1|F|3|-4|5|6|7|R|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|C]]]]

The general solution is to use android.os.Handler instead which runs in the UI thread. It only does one-shot callbacks, so you have to trigger it again every time your callback is called. But it is easy enough to use. A blog post on this topic was written a couple of years ago: 

<a href="http://android-developers.blogspot.com/2007/11/stitch-in-time.html" rel="noreferrer">http://android-developers.blogspot.com/2007/11/stitch-in-time.html</a>

blocks|key|1417115|text|使用以下代码在TextView上设置时间|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1417116|public+class+MyCountDownTimer+extends+CountDownTimer+{
++++++++public+MyCountDownTimer(long+startTime,+long+interval)+{
++++++++++++super(startTime,+interval);
++++++++}

++++++++@Override
++++++++public+void+onFinish()+{

++++++++++++ExamActivity.this.submitresult();
++++++++}

++++++++@Override
++++++++public+void+onTick(long+millisUntilFinished)+{

++++++++++++long+millis+=+millisUntilFinished;

++++++++++++int+seconds+=+(int)+(millis+/+1000)+%25+60;
++++++++++++int+minutes+=+(int)+((millis+/+(1000+*+60))+%25+60);
++++++++++++int+hours+=+(int)+((millis+/+(1000+*+60`enter+code+here`+*+60))+%25+24);

++++++++++++String+ms+=+String
++++++++++++++++++++.format("%2502d:%2502d:%2502d",+hours,+minutes,+seconds);
++++++++++++txtimedisplay.setText(ms);
++++++++}
++++}|code-block|syntax|javascript|1417117|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Use Below code to set time on TextView 

<pre><code>public class MyCountDownTimer extends CountDownTimer {
 public MyCountDownTimer(long startTime, long interval) {
 super(startTime, interval);
 }

 @Override
 public void onFinish() {

 ExamActivity.this.submitresult();
 }

 @Override
 public void onTick(long millisUntilFinished) {

 long millis = millisUntilFinished;

 int seconds = (int) (millis / 1000) % 60;
 int minutes = (int) ((millis / (1000 * 60)) % 60);
 int hours = (int) ((millis / (1000 * 60`enter code here` * 60)) % 24);

 String ms = String
 .format("%02d:%02d:%02d", hours, minutes, seconds);
 txtimedisplay.setText(ms);
 }
 }
</code></pre>

blocks|key|1417187|text|每秒更改文本的方法还有一种，那就是ValueAnimator。以下是我的解决方案：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1417188|++long+startTime+=+System.currentTimeMillis();
++ValueAnimator+animator+=+new+ValueAnimator();
++++++++++++animator.setObjectValues(0,+1000);
++++++++++++animator.setDuration(1000);
++++++++++++animator.setRepeatCount(ValueAnimator.INFINITE);
++++++++++++animator.addListener(new+AnimatorListenerAdapter()+{

++++++++++++++++@Override
++++++++++++++++public+void+onAnimationStart(Animator+animation)+{
++++++++++++++++++++long+currentTime+=+System.currentTimeMillis();
++++++++++++++++++++String+text+=+TimeFormatUtils.formatTime(startTime+-+currentTime);
+++++++++++++++++++yourTextView.setText(text);
++++++++++++++++}

++++++++++++++++@Override
++++++++++++++++public+void+onAnimationRepeat(Animator+animation)+{
++++++++++++++++++++long+currentTime+=+System.currentTimeMillis();
++++++++++++++++++++String+text+=+TimeFormatUtils.formatTime(startTime+-+currentTime);
++++++++++++++++++++yourTextView.setText(text);
++++++++++++++++}
++++++++++++});
++++++++++++animator.start();|code-block|syntax|javascript|1417189|entityMap^0|H|D|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

There is one more way to change text each second; this is <code>ValueAnimator</code>. Here is my solution:

<pre><code> long startTime = System.currentTimeMillis();
 ValueAnimator animator = new ValueAnimator();
 animator.setObjectValues(0, 1000);
 animator.setDuration(1000);
 animator.setRepeatCount(ValueAnimator.INFINITE);
 animator.addListener(new AnimatorListenerAdapter() {

 @Override
 public void onAnimationStart(Animator animation) {
 long currentTime = System.currentTimeMillis();
 String text = TimeFormatUtils.formatTime(startTime - currentTime);
 yourTextView.setText(text);
 }

 @Override
 public void onAnimationRepeat(Animator animation) {
 long currentTime = System.currentTimeMillis();
 String text = TimeFormatUtils.formatTime(startTime - currentTime);
 yourTextView.setText(text);
 }
 });
 animator.start();
</code></pre>

For my Android application there is a timer that measures how much time has passed. Ever 100 milliseconds I update my TextView with some text like "Score: 10 Time: 100.10 seconds". But, I find the TextView only updates the first few times. The application is still very responsive, but the label will not update. I tried to call .invalidate(), but it still does not work. I don't know if there is some way to fix this, or a better widget to use.

Here is a example of my code:

<pre><code>float seconds;
java.util.Timer gametimer;
void updatecount() { TextView t = (TextView)findViewById(R.id.topscore);
t.setText("Score: 10 - Time: "+seconds+" seconds");
t.postInvalidate();
}
public void onCreate(Bundle sis) {
... Load the UI, etc...
 gametimer.schedule(new TimerTask() { public void run() {
 seconds+=0.1; updatecount();
} }, 100, 100);
}
</code></pre>

Android TextView Timer

Android

对于我的Android应用程序，有一个计时器来测量已经过去了多少时间。每隔100毫秒，我就会用一些文本更新我的TextView，比如“得分: 10分: 100.10秒”。但是，我发现TextView只更新了前几次。应用程序的响应仍然很快，但标签不会更新。我尝试调用.invalidate()，但它仍然不起作用。我不知道是...

问安卓TextView计时器
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