[JETPACK_Android View] DataBinding

1 ViewBinding과의 차이?

- 데이터를 연결해주는 역할로 사용할 수 있음

- ViewBinding을 데이터와 같이 결합해서 사용

- LiveData와 함께 활용 가능

 

2 Activity

- layout에 감싸야 Binding에 오류가 나지 않는 점에 유의 !

// activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<layout
        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">

        <androidx.constraintlayout.widget.ConstraintLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            tools:context=".MainActivity">

                <TextView
                    android:id="@+id/dataBindingEx"
                    android:textSize="50sp"
                    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_toTopOf="parent" />

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

// MainActivity.kt

class MainActivity : AppCompatActivity() {

    private lateinit var binding : ActivityMainBinding

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = DataBindingUtil.setContentView(this, R.layout.activity_main)

        // dataBindingEx에 접근해서 text를 Hello World! > 바뀐 텍스트로 바꿀겁니다!

        binding.dataBindingEx.text = "바뀐 텍스트"
        binding.dataBindingEx.setOnClickListener {
            val intent = Intent(this, SecondActivity::class.java)
            startActivity(intent)
        }
    }
}

 

3 Fragment

// activity_second.xml

<?xml version="1.0" encoding="utf-8"?>
<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=".SecondActivity">

    <FrameLayout
        android:id="@+id/frameArea"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</androidx.constraintlayout.widget.ConstraintLayout>

// SecondActivity.kt

class SecondActivity : AppCompatActivity() {

    val manager = supportFragmentManager

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_second)

        // 프레그먼트 사용을 위한 FragmentManager 설정
        val transaction = manager.beginTransaction()
        val fragment = TestFragment()
        transaction.replace(R.id.frameArea, fragment)
        transaction.addToBackStack(null)
        transaction.commit()
    }
}

// fragment_test.xml

<?xml version="1.0" encoding="utf-8"?>
<layout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">
    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".TestFragment">

        <TextView
            android:id="@+id/fragmentText"
            android:textSize="50sp"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:text="@string/hello_blank_fragment" />

    </FrameLayout>
</layout>

// TestFragment.kt

class TestFragment : Fragment() {

    lateinit var binding : FragmentTestBinding
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
    }

    override fun onCreateView( inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?
    ): View? {

        // 데이터 바인딩을 이용해 텍스트를 바꿀게요 !
        binding = DataBindingUtil.inflate(inflater, R.layout.fragment_test, container, false)
        binding.fragmentText.text = "변경된 텍스트"
        return binding.root
    }
}