사용자 입력 처리

UI와 코드 연결하기

ViewBinding 활성화하기

// app/build.gradle (inside android { })
android {
    ...
    buildFeatures {
        viewBinding = true
    }
}

ViewBinding 사용하기

import androidx.appcompat.app.AppCompatActivity
import com.example.myapp.databinding.ActivityMainBinding

class MainActivity : AppCompatActivity() {

    private lateinit var binding: ActivityMainBinding

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        // Access views directly — no casting!
        binding.tvTitle.text = "Hello!"
    }
}

버튼 클릭 처리하기

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    binding = ActivityMainBinding.inflate(layoutInflater)
    setContentView(binding.root)

    var count = 0
    binding.btnIncrement.setOnClickListener {
        count++
        binding.tvCount.text = "Count: $count"
    }

    binding.btnReset.setOnClickListener {
        count = 0
        binding.tvCount.text = "Count: 0"
    }
}

EditText 입력 읽기

EditText + 버튼 예제

binding.btnGreet.setOnClickListener {
    val name = binding.etName.text.toString().trim()

    if (name.isBlank()) {
        binding.tvResult.text = "Please enter your name"
        return@setOnClickListener
    }

    binding.tvResult.text = "Hello, $name!"
}

Toast 메시지

Toast 예제

import android.widget.Toast

binding.btnSave.setOnClickListener {
    val input = binding.etEmail.text.toString().trim()

    if (input.contains("@")) {
        Toast.makeText(
            this,
            "Saved: $input",
            Toast.LENGTH_SHORT
        ).show()
    } else {
        Toast.makeText(
            this,
            "Invalid email address",
            Toast.LENGTH_LONG
        ).show()
    }
}

입력 유형과 키보드

빠른 확인

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