[Kotlin] @JvmOverloads

CustomView.java

package com.jwsoft.javaproject;

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;

import androidx.annotation.Nullable;

public class CustomView extends View {

    public CustomView(Context context) {
        super(context);
    }

    public CustomView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    public CustomView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

}

생성자 3개 만들어야 에러 발생 안함.

 

 

 

 

 

 

CustomView.java

package com.jwsoft.javaproject;

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;

import androidx.annotation.Nullable;

public class CustomView extends View {

    public CustomView(Context context) {
        this(context, null);
    }

    public CustomView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public CustomView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

}

this 를 이용하여 이렇게 사용 가능.

 

 

 

 

 

 

 

CustomView.kt

package com.jwsoft.kotlinproject

import android.content.Context
import android.util.AttributeSet
import android.view.View

class CustomView : View {

    constructor(context: Context) : this(context, null)

    constructor(context: Context, attrs: AttributeSet?) : this(context, attrs, 0)

    constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int) : super(context, attrs, defStyleAttr)

}

코틀린 소스로 바꿔보면 이렇게 됨.

소스가 너무 길어서 뭔가 비효율적이다. 

 

 

 

 

 

 

CustomView.kt

package com.jwsoft.kotlinproject

import android.content.Context
import android.util.AttributeSet
import android.view.View

class CustomView @JvmOverloads constructor(context: Context,
                                           attrs: AttributeSet? = null,
                                           defStyleAttr: Int = 0)
    : View(context, attrs, defStyleAttr) {

}

@JvmOverloads 를 이용하여 효율적으로 표현

 

 

 

 

 

 

참고

medium.com/@futureofdev/코틀린-kotlin-customview-774e236ca034

코틀린(Kotlin) CustomView