[Kotlin] DataBinding + LiveData + BindingAdapter

DataBinding  +  LiveData  +  BindingAdapter

---

build.gradle (Module: app)

apply plugin: 'kotlin-kapt'


android {
    dataBinding {
    	enabled = true
    }
}

 

 

 

 

 

 

 

BindingAdapters.kt

package com.jwsoft.kotlinproject

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

object BindingAdapters {

    @JvmStatic
    @BindingAdapter("android:visibleJW")
    fun setVisible(view: View, bool: Boolean) {
        if (bool) view.visibility = View.VISIBLE
        else view.visibility = View.INVISIBLE
    }

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

}

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

    <LinearLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:orientation="vertical"
        android:colorJW="@{mainActivity.liveColor}"
        tools:context=".MainActivity">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:hint="혀가 길지 않은 개발자\nJames Kim"
            android:textSize="30dp"
            android:textStyle="bold"
            android:textAlignment="center"
            android:visibleJW="@{mainActivity.liveVisible}"
            />

        <Button
            android:id="@+id/btnVisible"
            android:layout_width="200dp"
            android:layout_height="wrap_content"
            android:textAllCaps="false"
            android:text="Visible"
            android:textSize="40dp"
            android:textStyle="italic|bold"
            android:layout_marginTop="30dp" />

        <Button
            android:id="@+id/btnInvisible"
            android:layout_width="200dp"
            android:layout_height="wrap_content"
            android:textAllCaps="false"
            android:text="Invisible"
            android:textSize="40dp"
            android:textStyle="italic|bold" />

        <Button
            android:id="@+id/btnChange"
            android:layout_width="300dp"
            android:layout_height="wrap_content"
            android:textAllCaps="false"
            android:text="Change Background Color"
            android:textSize="20dp"
            android:textStyle="italic|bold"
            android:layout_marginTop="100dp"/>

    </LinearLayout>

</layout>

activity_main.xml

 

 

 

 

 

 

 

MainActivity.kt

package com.jwsoft.kotlinproject

import android.graphics.Color
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.databinding.DataBindingUtil
import androidx.lifecycle.MutableLiveData
import com.jwsoft.kotlinproject.databinding.ActivityMainBinding
import java.util.*

class MainActivity : AppCompatActivity() {

    private lateinit var binding: ActivityMainBinding
    var liveVisible: MutableLiveData<Boolean> = MutableLiveData()
    var liveColor: MutableLiveData<Int> = MutableLiveData()

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

            btnVisible.setOnClickListener { liveVisible.value = true }
            btnInvisible.setOnClickListener { liveVisible.value = false }
            btnChange.setOnClickListener {
                val r = Random().nextInt(256)
                val g = Random().nextInt(256)
                val b = Random().nextInt(256)
                liveColor.value = Color.argb(255, r, g, b)
            }
        }
    }

}

실행 결과

 

 

 

 

 

색상 랜덤 추출 참고

stackoverflow.com/questions/5280367/android-generate-random-color-on-click

Android: Generate random color on click?