[Java] ViewModel

ViewModel  +  DataBinding  +  LiveData  +  BindingAdapter

---

build.gradle (Module: app)

android {
    dataBinding {
        enabled = true
    }
}

 

 

 

 

 

 

 

MainViewModel.java

package com.jwsoft.javaproject;

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

public class MainViewModel extends ViewModel {
    public MutableLiveData<Integer> liveColor = new MutableLiveData<>();
}

 

 

 

 

 

 

 

BindingAdapters.java

package com.jwsoft.javaproject;

import android.view.View;

import androidx.annotation.ColorInt;
import androidx.databinding.BindingAdapter;

public class BindingAdapters {

    @BindingAdapter("android:colorJW")
    public static void setColor(View view, @ColorInt int color) {
        view.setBackgroundColor(color);
    }

}

코틀린은 build.gradle (Module: app) 안에 

apply plugin: 'kotlin-kapt' 추가해야

@BindingAdapter 어노테이션 사용 가능

 

 

 

 

 

 

 

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.javaproject.MainActivity" />
    </data>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:orientation="vertical"
        android:colorJW="@{mainActivity.mainViewModel.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.java

package com.jwsoft.javaproject;

import androidx.appcompat.app.AppCompatActivity;
import androidx.databinding.DataBindingUtil;
import androidx.lifecycle.ViewModelProvider;

import android.graphics.Color;
import android.os.Bundle;
import android.view.View;

import com.jwsoft.javaproject.databinding.ActivityMainBinding;

public class MainActivity extends AppCompatActivity {

    private ActivityMainBinding binding;
    public MainViewModel mainViewModel;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
        binding.setMainActivity(this);
        binding.setLifecycleOwner(this);

        mainViewModel = new ViewModelProvider(this, new ViewModelProvider.NewInstanceFactory()).get(MainViewModel.class);

        binding.btnRed.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mainViewModel.liveColor.setValue(Color.rgb(255, 121, 121));
            }
        });

        binding.btnGreen.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mainViewModel.liveColor.setValue(Color.rgb(121, 255, 121));
            }
        });

        binding.btnBlue.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mainViewModel.liveColor.setValue(Color.rgb(121, 121, 255));
            }
        });
    }

}

실행 결과