android自定义时分计时器

有人需要倒计时的秒表吗，纯代码实现，自定义的时分计时器
step1:

package com.unayshah.myapplication;

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import java.lang.reflect.Type;
import java.util.List;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;

public class HomeActivity extends AppCompatActivity {
    private EditText et_hour, et_minute;
    private Button btn_start;
    private TextView tv_home;
    private String etHourString, etMinuteString;
    private int etHourInt = 0;
    private int etMinuteInt = 0;
    private long timeMillis = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        et_hour = findViewById(R.id.et_hour);
        et_minute = findViewById(R.id.et_minute);
        btn_start = findViewById(R.id.btn_start);
        tv_home = findViewById(R.id.tv_home);

        btn_start.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                etHourString = et_hour.getText().toString();
                etMinuteString = et_minute.getText().toString();
                etHourInt = Integer.parseInt(etHourString);
                etMinuteInt = Integer.parseInt(etMinuteString);
                timeMillis = etMinuteInt * 60 * 1000 + etHourInt * 60 * 60 * 1000;
                mScheduledExecutorService.scheduleAtFixedRate(new Runnable() {
                    @Override
                    public void run() {
                        timeMillis = timeMillis - 1000;
                        try {
                            Message msg = new Message();
                            msg.what = 402;
                            msg.obj = timeMillis;
                            mHandler.sendMessage(msg);
                            Thread.sleep(1000);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                }, 1, 1, TimeUnit.SECONDS);
            }
        });
    }

    private ScheduledExecutorService mScheduledExecutorService = Executors.newScheduledThreadPool(0, new ThreadFactory() {
        @Override
        public Thread newThread(@NonNull Runnable r) {

            return new Thread(r) {
                @Override
                public void run() {
                    Log.e("lzp", "newThread");
                    super.run();
                    Log.e("lzp", "newThread over");
                }
            };
        }
    });

    private Handler mHandler = new Handler(new Handler.Callback() {
        @Override
        public boolean handleMessage(@NonNull Message message) {
            if (message.what == 402) {
                long post = (long) message.obj;
                Log.e("lzp", "newThread" + post + "\t" + formatTime(post));
                if (post < 1) {
                    tv_home.setVisibility(View.INVISIBLE);
                } else {
                    tv_home.setVisibility(View.VISIBLE);
                }
                tv_home.setText(formatTime(post));
            }
            return false;
        }
    });

    public static String formatTime(Long ms) {
        Integer ss = 1000;
        Integer mi = ss * 60;
        Integer hh = mi * 60;
        Integer dd = hh * 24;
        Long day = ms / dd;
        Long hour = (ms - day * dd) / hh;
        Long minute = (ms - day * dd - hour * hh) / mi;
        Long second = (ms - day * dd - hour * hh - minute * mi) / ss;
        Long milliSecond = ms - day * dd - hour * hh - minute * mi - second * ss;
        StringBuffer sb = new StringBuffer();
        if (day > 0) {
            sb.append(String.format("%02d", day) + "天");
        }
        if (hour >= 0) {
            sb.append(String.format("%02d", hour) + ":");
        }
        if (minute >= 0) {
            sb.append(String.format("%02d", minute) + ":");
        }
        if (second >= 0) {
            sb.append(String.format("%02d", second));
        }
        if (milliSecond > 0) {
            sb.append(milliSecond + "毫秒");
        }
        return sb.toString();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.e("lzp", "onDestroy注销:");
        //mScheduledExecutorService.shutdown();
    }
}