labs-mobile-applications/app/src/main/java/com/example/myapplication/MainActivity.kt

package com.example.myapplication

import android.os.Bundle
import android.widget.Button
import android.widget.EditText
import android.widget.TextView
import androidx.activity.ComponentActivity

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        setContentView(R.layout.activity_main)

        val etInput = findViewById<EditText>(R.id.etInput)
        val btnApply = findViewById<Button>(R.id.btnApply)
        val tvResult = findViewById<TextView>(R.id.tvResult)

        btnApply.setOnClickListener {
            val text = etInput.text.toString().trim()
            if (text.isEmpty()) {
                tvResult.text = "Введите текст!"
            } else {
                tvResult.text = "РЕЗУЛЬТАТ: ${text.uppercase()}"
            }
        }
    }
}