为什么Postdelayed不在if语句中工作 [英] Why Postdelayed is not working in the if statement

问题描述

当我在if语句中放置 postDelayed（this，1000）; 时，为什么计时器停止工作，就在秒++; ？
布局中有3个按钮（开始，停止，重置）。按Start-> running = true，按stop-> running = stop，按reset-> running = false seconds = 0

Why does the timer stop working when i put the postDelayed(this,1000); inside the if statement, just under seconds++;? There are 3 buttons (start,stop,reset) in the layout. Press Start->running=true,press stop->running=stop,press reset->running=false seconds=0

private void runTimer() {

    final TextView timeView = (TextView) findViewById(R.id.time_view);
    final Handler handler = new Handler();

    handler.post(new Runnable() {

        @Override
        public void run() {
            int hours = seconds / 3600;
            int minutes = (seconds % 3600) / 60;
            int secs = seconds % 60;

            String time = String.format("%d:%2d:%02d", hours, minutes, secs);
            timeView.setText(time);
            if (running) {
                seconds++;
            //handler.postDelayed(this, 1000);
            //doesnt work if i put it here
            }
            handler.postDelayed(this, 1000);
        }
    });

}

推荐答案

你调用的时间 runTimer（）变量运行设置为false。很可能你必须将 runTimer（）的调用移到 onClickStart（）方法中（在设置为run之后） ）。$
当声明布尔值时，默认值为false。

At the time you call runTimer() the variable running is set to false. Most likely you have to move the call to runTimer() into the onClickStart() method (after setting running to true).
When declaring booleans their default value is assumed with false.

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