如何在android中将dialogbox设置为动态定时器

import android.app.AlertDialog;
import android.app.Dialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v4.app.DialogFragment;
import android.widget.TextView;

public class TimerDialog extends DialogFragment {
    private static final int TIMER_DELAY = 1000; // 定时器延迟时间，单位为毫秒
    private static final int TIMER_MSG = 1; // 定时器消息标识

    private int timerCount = 10; // 定时器初始值，单位为秒
    private TextView timerTextView;
    private Handler timerHandler;

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder.setTitle("定时器弹窗");
        builder.setMessage("剩余时间：");
        builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                // 点击确定按钮的操作
            }
        });

        timerTextView = new TextView(getActivity());
        builder.setView(timerTextView);

        return builder.create();
    }

    @Override
    public void onStart() {
        super.onStart();
        startTimer();
    }

    @Override
    public void onStop() {
        super.onStop();
        stopTimer();
    }

    private void startTimer() {
        timerHandler = new Handler(new Handler.Callback() {
            @Override
            public boolean handleMessage(Message msg) {
                if (msg.what == TIMER_MSG) {
                    timerCount--;
                    timerTextView.setText(String.valueOf(timerCount));
                    if (timerCount > 0) {
                        timerHandler.sendEmptyMessageDelayed(TIMER_MSG, TIMER_DELAY);
                    } else {
                        // 定时器结束的操作
                    }
                }
                return true;
            }
        });

        timerHandler.sendEmptyMessageDelayed(TIMER_MSG, TIMER_DELAY);
    }

    private void stopTimer() {
        if (timerHandler != null) {
            timerHandler.removeCallbacksAndMessages(null);
        }
    }
}

TimerDialog timerDialog = new TimerDialog();
timerDialog.show(getSupportFragmentManager(), "timer_dialog");