倒计时器具有可由用户设置的递增/递减选项

Question

我是 Java 语言新手，但以前使用过 C 语言。我尝试了很多方法来解决以下问题，但无法解决，所以我需要帮助。 我正在尝试执行以下操作：

• 将 5 分钟计时器（计数器）设置为默认值，以便在按下 Start_button 时启动。

•如果没有按下Start_button，并且用户按下Up_button /Down_button，则在屏幕上显示计时器选项； 5、10 和 15 分钟，如果用户按下 Starts_button，它将开始对所选计时器进行倒计时。

•定时器运行时；

  •If Up_button /Down_button is pressed once then reset timer and show previous time setting i.e. 5, 10 or 15minutes.
  •If Up_button /Down_button is pressed again then display timer options on screen and if the user presses Starts_button it starts the timer chosen.  

眼下;一旦按下“开始”按钮，计时器就会开始倒计时 5 分钟。但我不知道显示计时器选项并启动所选计时器的最佳方式。

感谢您的帮助，提前非常感谢您。

如上所述；我正在学习 Java 编程，所以别着急 ;-) 请向我展示您认为最适合这个问题的代码

这就是我到目前为止所做的：

public class Test extends Activity {

// Display Counter Variables
public static Button Up, Down, Green;

TextView timeDisplay;
MyCount counter, counter1, counter2;
int state = 0;
int length = 300000; //5minutes
int length1 = 600000; //10minutes
int length2 = 900000; //15minutes
long startTime = 0;
long currentTime = 0;
long timeElapsed = 0;
long timeRemaining = 0;
long prevTimeRemaining = 0;
boolean up_pressed = false;
boolean down_pressed = false;
private boolean timerStarted=false;

Button start;

  public String formatTime(long millis) {
        String output = "";
        long seconds = millis / 1000;
        long minutes = seconds / 60;

        seconds = seconds % 60;
        minutes = minutes % 60;

        String secondsD = String.valueOf(seconds);
        String minutesD = String.valueOf(minutes);

        if (seconds < 10)
          secondsD = "0" + seconds;
        if (minutes < 10)
          minutesD = "0" + minutes;

        output = minutesD + " : " + secondsD;
        return output;
      }


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.test);


    timeDisplay = (TextView) findViewById(R.id.timer);
    counter = new MyCount (length, 1000);
    counter1 = new MyCount (length1, 1000);
    counter2 = new MyCount (length2, 1000);

    start = (Button) findViewById(R.id.Button);
    Up = (Button)findViewById(R.id.Yellow);
    Down = (Button)findViewById(R.id.Blue);



start.setOnClickListener(new OnClickListener() {
    public void onClick(View v) {
        switch (state) {
        case 0:
          startTime = System.currentTimeMillis();
            counter.start();
            timerStarted=true;
            start.setText(R.string.pause);
              state=1;

          break;

       case 1:
          // pause
          currentTime = System.currentTimeMillis();
          timeElapsed = currentTime - startTime;
          if (prevTimeRemaining == 0)
            timeRemaining = length - timeElapsed;
          else
            timeRemaining = prevTimeRemaining - timeElapsed;
          counter.cancel();
          timeDisplay.setText("" + formatTime(timeRemaining));
          start.setText(R.string.resume);
          prevTimeRemaining = timeRemaining;

          // resume
          counter = new MyCount(timeRemaining, 1000);
          state = 0;
          break;

        case 2:
          prevTimeRemaining = 0;
          timerStarted=false;
          counter = new MyCount(length, 1000);
          start.setText(R.string.start);
          timeDisplay.setText(R.string.timer);
          state = 0;
        }
    }
});


    Up.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            down_pressed=true;

            if(up_pressed=true && timerStarted==true 
                || timerStarted==false){
                //Display timer (increment i.e. show 5min --> 10min ..> 15min)

                //start timer chosen by user
            }

        }
    });


    Down.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            down_pressed=true;
            if(down_pressed=true && timerStarted==true 
                || timerStarted==false){
                //Display timer (decrement i.e. show 15min --> 10min ..> 5min)

                //start timer chosen by user
            }
        }
    });
}


  public class MyCount extends CountDownTimer {

      public MyCount(long millisInFuture, long countDownInterval) {
        super(millisInFuture, countDownInterval);
      }

      public void onFinish() {
        timeDisplay.setText("done!");
        state = 2;
       start.setText(R.string.restart);
      }

      public void onTick (long millisUntilFinished) {
        timeDisplay.setText ("Left: "  + formatTime(millisUntilFinished));

      }

    }

}

Answer 1

我认为你不需要为此创建一个新课程。

我会简单地创建一个全局变量，例如。

private CountDownTimer myCount;

我建议将其放入类似的方法中，

private void setTimer(long countdownMs, long tickMs) {
  CountDownTimer myCount = new CountDownTimer(countdownMs,tickMs) {
  /// TODO
  }.start();
}

如果您需要重新启动计时器，

myCount.cancel()
setTimer(...);

如果您需要更多详细信息，可以调用 Comment :)