android - android中的全局定时器

Question

我想制作一个计时器，它会在我的应用程序的每个 Activity 中显示。

我知道如何为下面的 Activity 设置计时器是我的代码

public class Timer extends Activity implements OnClickListener {
    public TextView mTextField;
    private Button btnstart;

    public String formatTime(long millis) { 
        String output = "00:00"; 
        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; 
    } 
    public CountDownTimer Counter1;

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

        //Declare Start/Stop button 
        btnstart = (Button)findViewById(R.id.btnThread1); 
        btnstart.setOnClickListener(this);
        //Button btnstop = (Button)findViewById(R.id.button02); 
        //Button btnpass = (Button)findViewById(R.id.button03);

        //Declare Text fields to show time left 
        final TextView mCounter1TextField=(TextView)findViewById(R.id.txtThread1); 
        final TextView mCounter2TextField = (TextView)findViewById(R.id.txtThread2); 
        //final TextView mCounter3TextField=(TextView)findViewById(R.id.textView03); 



        //Counter 1 
        Counter1 = new CountDownTimer(120000 , 1000) { 
            public void onTick(long millisUntilFinished) { 
                mCounter1TextField.setText("Seconds left: " + formatTime(millisUntilFinished)); 
            } 

            public void onFinish() { 
                mCounter1TextField.setText("Finished!"); 
                // Counter1.start();
            } 
        }; 
    }

    @Override
    public void onClick(View v) {
        if(v == btnstart)
        {
            Counter1.start();
        }

    }
}

我想知道如何让它全局化？？

Answer 1

你可以有一个单例类来保存你的 CountDownTimer

// This is not a real singleton, Google to get a proper Java implementation
public class TimerSingleton {

  // Should not be public, you should of course encapsulate access to that timer.
  // static keyword says that one timer object is shared by all instance of TimerSingleton 
  public static CountDownTimer timer = new CountDownTimer();
}

// Access to the timer from an activity:
TimerSingleton.timer.start();

第二个选项是让您的计时器成为自定义应用程序类的成员:Use Application class for global variables

第三种选择:制作一个本地服务，在启动时启动计时器。

请记住，在选项 1 和 2 的情况下，如果操作系统决定终止您的应用程序，计时器将消失(即，当 Activity 重新创建时，CountDownTimer 对象将被重置)。