单击后，如何制作一个可重启CountdownTimer的按钮？

Question

I have a function that has a timer that I want to "restart" every time you click the button. I tried doing this but when the button is clicked several times it appears that there are several timers still going on when I only want the one. How do I fix this?

So, onClick => Cancel last timer => Start new timer

public void startService(android.view.View view) {
    final SharedPreferences sP = getSharedPreferences("com.example.safetyNet", MODE_PRIVATE);
    final Button button = findViewById(R.id.button3);
    final Intent transIntent = new Intent(this, CheckPinActivity.class);

    CountDownTimer cdt = new CountDownTimer(sP.getInt("TiT", 10) * 1000, 1000) {
        @Override
        public void onTick(long millisUntilFinished) {
            button.setText(String.valueOf(millisUntilFinished).substring(0,2));
        }

        @Override
        public void onFinish() {
            if(sP.getBoolean("lockedDown", false) == true){
                startActivity(transIntent);
            }
        }
    };

    cdt.cancel();
    cdt.start();

}

Answer 1

The problem is that, everytime you call the method "startService(android.view.View view) {}", a new CountDownTimer is created, so the previous CountDownTimer that you created is not the same reference as this one.

To solve that, you are going to have to create the CountDownTimer as a class member for your class:

public YourClass {

  private CountDownTimer cdt;

  .... (do whatever)....

  public void startService(android.view.View view) {
final SharedPreferences sP = getSharedPreferences("com.example.safetyNet", MODE_PRIVATE);
final Button button = findViewById(R.id.button3);
final Intent transIntent = new Intent(this, CheckPinActivity.class);

if (cdt == null) {
 cdt = new CountDownTimer(sP.getInt("TiT", 10) * 1000, 1000) {
    @Override
    public void onTick(long millisUntilFinished) {
        button.setText(String.valueOf(millisUntilFinished).substring(0,2));
    }

    @Override
    public void onFinish() {
        if(sP.getBoolean("lockedDown", false) == true){
            startActivity(transIntent);
        }
    }
};
} else {
  cdt.cancel();
  }
   cdt.start();
}

Hope that helps you