Java Android TextView 计时器
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Android TextView Timer
提问by Isaac Waller
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.
对于我的 Android 应用程序，有一个计时器可以测量已经过去了多少时间。每 100 毫秒，我都会用一些文本更新我的 TextView，比如“分数：10 时间：100.10 秒”。但是，我发现 TextView 只更新前几次。该应用程序仍然非常敏感，但标签不会更新。我试图调用 .invalidate()，但它仍然不起作用。我不知道是否有办法解决这个问题，或者有更好的小部件可以使用。
Here is a example of my code:
这是我的代码示例：
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);
}
采纳答案by Ben Bederson
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:
一般的解决方案是使用 android.os.Handler 而不是在 UI 线程中运行。它只执行一次性回调，因此每次调用回调时都必须再次触发它。但它很容易使用。几年前写了一篇关于这个主题的博客文章：
http://android-developers.blogspot.com/2007/11/stitch-in-time.html
http://android-developers.blogspot.com/2007/11/stitch-in-time.html
回答by haseman
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.
我认为正在发生的事情是您正在脱离 UI 线程。有一个处理所有屏幕更新的“looper”线程。如果您尝试调用“invalidate()”并且您不在此线程上，则不会发生任何事情。
Try using "postInvalidate()" on your view instead. It'll let you update a view when you're not in the current UI thread.
尝试在您的视图上使用“postInvalidate()”。当您不在当前 UI 线程中时，它会让您更新视图。
More info here
更多信息在这里
回答by Jotiram Chavan
Use Below code to set time on TextView
使用下面的代码在 TextView 上设置时间
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);
}
}
回答by Volodymyr
There is one more way to change text each second; this is ValueAnimator. Here is my solution:
还有一种每秒更改文本的方法；这是ValueAnimator。这是我的解决方案：
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();
