체크박스

 

체크박스의 체크 여부를 텍스트뷰에 보여주도록 하자

 

1. activity_main.xml

체크박스와 텍스트 뷰를 만들어준다

<androidx.constraintlayout.widget.ConstraintLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">

    <CheckBox
            android:text="CheckBox"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/checkBox"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.498"
            app:layout_constraintBottom_toBottomOf="parent"/>

    <TextView
            android:id="@+id/textView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Hello World!"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/checkBox"
            app:layout_constraintVertical_bias="0.201"/>

</androidx.constraintlayout.widget.ConstraintLayout>

 

 

2. build.gradle설정 추가

buildFeatures{
    viewBinding true
}

 

3. MainActivity.kt

첫번째 방법

class MainActivity : AppCompatActivity() {

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

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(binding.root)
        binding.checkBox.setOnCheckedChangeListener(checklistener)
    }
    
    // 체크박스가 여러개일때는 이 방법이 효율적임
    val checklistener by lazy {
        CompoundButton.OnCheckedChangeListener { buttonView, isChecked ->
            val checkBox = findViewById<CheckBox>(R.id.checkBox)
            val textView = findViewById<TextView>(R.id.textView)

            if (isChecked){
                when(buttonView.id){
                    R.id.checkBox ->{
                        textView.text = "첵크됨"
                    }
                }
            }else{
                when(buttonView.id){
                    R.id.checkBox ->{
                        textView.text = "첵크 해제됨"
                    }
                }
            }
        }
    }
}

 

두번째 방법

class MainActivity : AppCompatActivity() {

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

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

        setContentView(R.layout.activity_main)

        val checkBox = findViewById<CheckBox>(R.id.checkBox)
        val textView = findViewById<TextView>(R.id.textView)

        checkBox.setOnCheckedChangeListener { _, isChecked ->
            if (isChecked) {
                textView.text = "첵크됨"
            } else {
                textView.text = "첵크 해제됨"
            }
        }
    }
}

 

 

결과물