[Kotlin] 코틀린 바인딩(binding)하는 법

1. viewBinding

 

1.1 gradle 추가(module)

android studio 버전 4.0 이상

android {
    ...
    buildFeatures {
        viewBinding true
    }
}

android studio 버전 3.6 ~ 4.0

android {
    ...
    viewBinding {
        enabled = true
    }
}

 

1.2 테스트용 TextView 추가 및 Activity 작성

activity_main.xml

<TextView
    android:id="@+id/exText"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Hello World!"
    android:textSize="50dp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toTopOf="parent" />

<Button
    android:id="@+id/exBtn"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="버튼"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/exText" />

MainActivity.kt

private lateinit var binding: ActivityMainBinding
private lateinit var tv: TextView
private lateinit var btn: Button

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

    //xml에 만든 view를 가져오기
    binding = ActivityMainBinding.inflate(layoutInflater)
    setContentView(binding.root)

    //view에 담긴 TextView, Button 호출
    tv = binding.exText
    btn = binding.exBtn

    //버튼 클릭 이벤트
    btn.setOnClickListener {
        tv.text = "kotlin"
    }

}

1.3 결과

실행화면

 

 

 

2. dataBinding

 

2.1 gradle 추가(Module)

android studio 버전 4.0 이상

android {
    ...
    buildFeatures {
        dataBinding true
    }
}

android studio 버전 3.6 ~ 4.0

android {
    ...
    viewBinding {
        enabled = true
    }
}

 

2.2 <layout></layout> 추가

activity_main.xml

<layout>

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

    </androidx.constraintlayout.widget.ConstraintLayout>
    
</layout>

<layout>태그 안에 xml 작성

 

2.3 xml에 <data> 작성 및 

 

activity_main.xml

<layout>
    <data>
    
        <variable
            name="Test"
            type="com.example.studyProject.MainActivity" />
    </data>
    
    <androidx.constraintlayout.widget.ConstraintLayout>
        <TextView
            android:id="@+id/exText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@{test.text}"
            android:textSize="50dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="parent" />
        ...
    </androidx.constraintlayout.widget.ConstraintLayout>
    
</layout>

2.4 Activity 작성

MainActivity.kt

private lateinit var binding: ActivityMainBinding
private lateinit var tv: TextView
private lateinit var btn: Button

var text = "123"

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

    //binding
    binding = DataBindingUtil.setContentView(this, R.layout.activity_main)
    binding.test = this

    tv = binding.exText
    btn = binding.exBtn

    btn.setOnClickListener {
        text = "456"
        binding.invalidateAll()
    }

}

2.5 결과

실행화면

 

참고 사이트

https://developer.android.com/topic/libraries/view-binding

뷰 결합  |  Android 개발자  |  Android Developers

https://developer.android.com/topic/libraries/data-binding

데이터 결합 라이브러리  |  Android 개발자  |  Android Developers