android - Android activityView 中倒计时/计时器的后台任务

Question

我在 mm:ss 中创建了一个具有良好锁定输出的倒数计时器

因此，如果我之前切换到 activityView 并返回到带有计时器的 Activity ，一切看起来都不错，但是;-):

• 计时器仍在后台运行 - 但它看起来很糟糕，没有计数......
• 这样我就可以启动第二个、第三个……计时器，因为按钮已经激活

所以我知道我必须设置所有这些设置，这是很正常的。我必须设置

• 禁用 startButon - 当计数器运行时...
• 如果用户返回并且计数器仍然有效，则刷新 activityView

也许你可以告诉我如何为 ANDROID 做到这一点？这是我的工作代码:

some imports....
public class BasicActivity extends Activity {


 ImageButton start, stop;
 TextView timer;




 /** Called when the activity is first created. */
 //Ist dei Verbindung zur XML
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.basic_activity);

//TIMER
    start = (ImageButton)findViewById(R.id.startButton);
    stop  = (ImageButton)findViewById(R.id.stopButton);
    timer = (TextView)findViewById(R.id.basicCountDown);
    timer.setText(getString(R.string.basic01)); // Platzhalter im Textfeld.

    final MyCounter timer = new MyCounter(10000,1000);
    start.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            timer.start();
        }
    });
    stop.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            timer.cancel();
        }
    });

}
public class MyCounter extends CountDownTimer{

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

    @Override
    public void onFinish() {
        System.out.println("Timer Completed.");
        timer.setText(getString(R.string.basic02));

        //Spielt den TON ab, wenn die ZEit um ist. Siehe Methode playSound!
        playSound();



        //Notification
        new AlertDialog.Builder(BasicActivity.this).setTitle(getString(R.string.app_name)).setMessage(getString(R.string.basicNotificationMessage)).setIcon(R.drawable.ic_launcher).setNeutralButton(getString(R.string.ButtonOK), null).show();
    }

    @Override
    public void onTick(long millisUntilFinished) {


        SimpleDateFormat dateFormat = new SimpleDateFormat("mm:ss");
       // dateFormat.setTimeZone(TimeZone.getTimeZone("GMT"));
        Date date = new Date(millisUntilFinished);
        timer.setText(dateFormat.format(date));

       // System.out.println("Timer  : " + (millisUntilFinished/1000));
        System.out.println("Timer   : " + dateFormat.format(date));
    }
}


    //Sound nach Ablauf der Zeit
    public void playSound() {
        final MediaPlayer mp = MediaPlayer.create(getApplicationContext(), R.raw.ton_timer);
        mp.start();

    }




}

Answer 1

1.

start.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            v.setEnabled(false);
            timer.start();
        }
    });

 stop.setOnClickListener(new OnClickListener() {
    @Override
    public void onClick(View v) {
        timer.cancel();
        start.setEnabled(true)
    }
});

@Override
public void onFinish() {
    System.out.println("Timer Completed.");
    timer.setText(getString(R.string.basic02));
    start.setEnabled(true);
    //Spielt den TON ab, wenn die ZEit um ist. Siehe Methode playSound!
    playSound();



//Notification
new  AlertDialog.Builder(BasicActivity.this).setTitle(getString(R.string.app_name)).setMessage(getString(R.string.basicNotificationMessage)).setIcon(R.drawable.ic_launcher).setNeutralButton(getString(R.string.ButtonOK), null).show();
}

refresh the activityView if the user come back and the counter is still sctive

这有点棘手。当然，如果您离开 Activity，您应该取消 CountDownTimer，否则您的 Activity 可能会泄漏。