main activity

package com.example.myapplication;

import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

import androidx.appcompat.app.AppCompatActivity;

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Locale;

public class MainActivity extends AppCompatActivity {
    private EditText edtTime, edtDate, edtName;
    private Button btnExit;

    private void startClock() {
        final Handler handler = new Handler();
        handler.post(new Runnable() {
            @Override
            public void run() {
                // Lấy giờ hệ thống
                Calendar calendar = Calendar.getInstance();
                SimpleDateFormat timeFormat = new SimpleDateFormat("HH:mm:ss", Locale.getDefault());
                String currentTime = timeFormat.format(calendar.getTime());

                // Hiển thị lên EditText
                edtTime.setText(currentTime);

                // Tự gọi lại chính nó sau 1 giây (1000ms)
                handler.postDelayed(this, 1000);
            }
        });
    }


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        startClock();

        edtName = findViewById(R.id.mainEditNameText);
        edtDate = findViewById(R.id.mainEditTextDate);
        edtTime = findViewById(R.id.mainEditTextTime);

        Intent intent = getIntent();
        String username = intent.getStringExtra("user_key");
        edtName.setText(username);

        Calendar calendar = Calendar.getInstance();
        SimpleDateFormat dateFormat = new SimpleDateFormat("dd/MM/yy", Locale.getDefault());
        String currentDate = dateFormat.format(calendar.getTime());

        SimpleDateFormat timeFormat = new SimpleDateFormat("HH:mm:ss", Locale.getDefault());
        String currentTime = timeFormat.format(calendar.getTime());

        edtDate.setText(currentDate);
        edtTime.setText(currentTime);

        btnExit = findViewById(R.id.mainExitButton);
        btnExit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this, LoginActivity.class);
                startActivity(intent);
            }
        });
    }
}