[Kotlin] ViewModel

ViewModel  +  DataBinding  +  LiveData  +  BindingAdapter

---

build.gradle (Module: app)

apply plugin: 'kotlin-kapt'


android {
    dataBinding {
    	enabled = true
    }
}

 

 

 

 

 

 

 

MainViewModel.kt

package com.jwsoft.kotlinproject

import androidx.lifecycle.MutableLiveData
import androidx.lifecycle.ViewModel

class MainViewModel : ViewModel() {
    var liveColor: MutableLiveData<Int> = MutableLiveData()
}

 

 

 

 

 

 

 

BindingAdapters.kt

package com.jwsoft.kotlinproject

import android.view.View
import androidx.annotation.ColorInt
import androidx.databinding.BindingAdapter

object BindingAdapters {

    @JvmStatic
    @BindingAdapter("android:colorJW")
    fun setColor(view: View, @ColorInt color: Int) {
        view.setBackgroundColor(color)
    }

}

@BindingAdapter 어노테이션 사용 시

build.gradle (Module: app) 안에

apply plugin: 'kotlin-kapt' 추가해야 함.

 

 

 

 

 

 

activity_main.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">
    <data>
        <variable
            name="mainActivity"
            type="com.jwsoft.kotlinproject.MainActivity" />
    </data>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:orientation="vertical"
        android:colorJW="@{mainActivity.viewModel.liveColor}"
        tools:context=".MainActivity">

        <Button
            android:id="@+id/btnRed"
            android:layout_width="200dp"
            android:layout_height="100dp"
            android:textAllCaps="false"
            android:text="Red"
            android:textSize="30dp"
            android:textStyle="bold|italic" />

        <Button
            android:id="@+id/btnGreen"
            android:layout_width="200dp"
            android:layout_height="100dp"
            android:textAllCaps="false"
            android:text="Green"
            android:textSize="30dp"
            android:textStyle="bold|italic" />

        <Button
            android:id="@+id/btnBlue"
            android:layout_width="200dp"
            android:layout_height="100dp"
            android:textAllCaps="false"
            android:text="Blue"
            android:textSize="30dp"
            android:textStyle="bold|italic" />

    </LinearLayout>
</layout>

activity_main.xml

 

 

 

 

 

 

MainActivity.kt

package com.jwsoft.kotlinproject

import android.graphics.Color
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.databinding.DataBindingUtil
import androidx.lifecycle.ViewModelProvider
import com.jwsoft.kotlinproject.databinding.ActivityMainBinding

class MainActivity : AppCompatActivity() {

    private lateinit var binding: ActivityMainBinding
    lateinit var viewModel: MainViewModel

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

        viewModel = ViewModelProvider(this, ViewModelProvider.NewInstanceFactory()).get(MainViewModel::class.java)

        binding.apply {
            mainActivity = this@MainActivity
            lifecycleOwner = this@MainActivity

            btnRed.setOnClickListener {
                viewModel.liveColor.value = Color.rgb(255,121,121)
            }
            btnGreen.setOnClickListener {
                viewModel.liveColor.value = Color.rgb(121,255,121)
            }
            btnBlue.setOnClickListener {
                viewModel.liveColor.value = Color.rgb(121,121,255)
            }
        }
    }
    
}

실행 결과