코틀린 / 버튼 눌러서 더하기 결과 확인

1. build.gradle설정

뷰바인딩을 쓰기위해서...

    buildFeatures{
        viewBinding true
   }

2. MainActivity 설정

맴버함수 추가

 private val binding by lazy{
        ActivityMainBinding.inflate(layoutInflater)
    }

setContentView수정

setContentView(binding.root)

MainActivity코드

class MainActivity : AppCompatActivity() {
    private val binding by lazy{
        ActivityMainBinding.inflate(layoutInflater)
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(binding.root)

        binding.plusResultBtn.setOnClickListener{


            if(binding.plusNum1.text.isNotBlank()&&
                    binding.plusNum2.text.isNotBlank()){
	
    //ResultActivity에 값 전달
                var intent = Intent(this,
                    ResultActivity::class.java).apply {

                        putExtra("num1",
                            parseInt(binding.plusNum1.text.toString())
                        )
                        putExtra("num2",
                            parseInt(binding.plusNum2.text.toString())
                        )
                }
                startActivity(intent)
            }
        }
    }
}

ResultActivity코드

class ResultActivity : AppCompatActivity() {
    private val binding by lazy{
        ActivityResultBinding.inflate(layoutInflater)
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(binding.root)

//값 받아옴
        val num1 = intent.getIntExtra("num1", 0)
        val num2= intent.getIntExtra("num2", 0)

        val plusResult = num1+num2
		binding.plusResult.setText("$plusResult")

        Toast.makeText(this, "$plusResult",Toast.LENGTH_SHORT).show()
        

    }
}