每秒更新TextView中的数字

Question

我正在编写我的第一个应用程序,我需要每秒在文本视图中更新数字,直到按下按钮.使用处理程序似乎是不可能的,因为数字是在处理程序之外创建和存储的,但它不能被声明为final,因为它需要更改.Thread.sleep在执行上面写的一些代码之前,似乎还会使应用程序无限期挂起.

final TextView countView = (TextView) findViewById(R.id.counter);
        countView.setText("100,000,000,000");

    //set a Calendar object to be 00:00:00:00 on Jan 1, 2015
    final Calendar startTime = Calendar.getInstance();
    startTime.set(2015, 0, 0, 12, 0, 0);
    startTime.set(Calendar.MILLISECOND, 0);

final Button startButton = (Button) findViewById(R.id.startButton);
        startButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                //set a Calendar to be the time that the button is clicked and find the difference in ms between it and startTime
                Calendar nowTime = Calendar.getInstance();
                double milStart = startTime.getTimeInMillis();
                double milNow = nowTime.getTimeInMillis();
                double diff = (milNow-milStart)/1000;     //difference in seconds between "start" date and current date

                double total = 100000000000L;   //# that needs to be updated
                for(long i = 0L; i < diff; i++) {
                    total += 1.8;
                }
                countView.setText(NumberFormat.getInstance().format(total));

我需要total每秒继续增加1.8或每556毫秒增加1.

while(true) {
   countView.setText(NumberFormat.getInstance().format(total));
   total += 1.8;
   try {
      Thread.sleep(1000);
       } catch (InterruptedException e) {}
 } 

单击按钮后,应用程序将无限期挂起,这样即使第一个按钮countView.setText(NumberFormat.getInstance().format(total));也不会执行.

使用处理程序对我来说似乎不可行,因为total如果声明为final则无法工作,但在处理程序内创建变量并循环它会导致值永远不会改变.

我错过了明显的解决方案吗？这是我对Java的第一次真正努力,所以这对我来说都是新手

Answer 1

你可以使用Handler

Handler h = new Handler();
final Runnable r = new Runnable() {
        int count = 0;
        @Override
        public void run() {
            count++;
            textView.setText(""+count*1.8);
            h.postDelayed(this, 1000); //ms
        }
    };
h.postDelayed(r, 1000); // one second in ms

停止你可以使用h.removeCallbacksAndMessages(null);