RxBinding 사용 전

NonRxBinding.kt

class MainActivity : AppCompatActivity() {

    private var isButtonClickProcessing = false

    @SuppressLint("CheckResult")
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val nicknameInputField = findViewById<EditText>(R.id.nicknameInputField)
        val passwordInputField = findViewById<EditText>(R.id.passwordInputField)
        val okButton = findViewById<Button>(R.id.okButton)

        nicknameInputField.addTextChangedListener(object : TextWatcher {
            override fun afterTextChanged(p0: Editable?) {
            }

            override fun beforeTextChanged(p0: CharSequence?, p1: Int, p2: Int, p3: Int) {
            }

            override fun onTextChanged(text: CharSequence?, p1: Int, p2: Int, p3: Int) {
                text?.let { // 입력 내용에 따라 버튼색 변하게 하기
                    if (text.length >= 4 && passwordInputField.length() >= 4) {
                        okButton.setBackgroundColor(Color.BLUE)
                    } else {
                        okButton.setBackgroundColor(Color.GRAY)
                    }
                }
            }
        })

        passwordInputField.addTextChangedListener(object : TextWatcher {
            override fun afterTextChanged(p0: Editable?) {
            }

            override fun beforeTextChanged(p0: CharSequence?, p1: Int, p2: Int, p3: Int) {
            }

            override fun onTextChanged(text: CharSequence?, p1: Int, p2: Int, p3: Int) {
                text?.let { // 입력 내용에 따라 버튼색 변하게 하기
                    if (text.length >= 4 && nicknameInputField.length() >= 4) {
                        okButton.setBackgroundColor(Color.BLUE)
                    } else {
                        okButton.setBackgroundColor(Color.GRAY)
                    }
                }
            }
        })

        okButton.setOnClickListener {
            // 버튼 클릭에 쿨타임 걸기
            if(isButtonClickProcessing) return@setOnClickListener
            isButtonClickProcessing = true
            Observable.timer(1, TimeUnit.SECONDS).subscribe { isButtonClickProcessing = false }

            when {
                nicknameInputField.length() < 4 -> Toast.makeText(this, "닉네임 4글자 이상!", Toast.LENGTH_SHORT).show()
                passwordInputField.length() < 4 -> Toast.makeText(this, "패스워드 4글자 이상!", Toast.LENGTH_SHORT).show()
                else -> {
                    nicknameInputField.setText("")
                    passwordInputField.setText("")
                    Toast.makeText(this, "OK!", Toast.LENGTH_SHORT).show()
                }
            }
        }
    }
}