혀가 길지 않은 개발자

Day.kt package com.jwsoft.kotlinproject enum class Day { MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY } activity_main.xml MainActivity.kt package com.jwsoft.kotlinproject import androidx.appcompat.app.AppCompatActivity import android.os.Bundle import android.view.View import android.widget.Toast import kotlinx.android.synthetic.main.activity_main.* class MainActivity : AppCompa..

T : 별도의 Wildcard 정의가 없이 read/write 모두 가능 in T : Java 의 ? super T 와 같음. input 의 약자이며 write 만 가능 out T : Java 의 ? extends T 와 같음. output 의 약자이며 read 만 가능 User.kt package com.jwsoft.kotlinproject class User ( var name: S, var age: I ) MainActivity.kt package com.jwsoft.kotlinproject import androidx.appcompat.app.AppCompatActivity import android.os.Bundle import android.util.Log class MainActivity :..

T : read/write 모두 가능 ? extends T : read 만 가능한 서브타입 와일드카드 ? super T : write 만 가능한 슈퍼 타입 와일드카드 User.java package com.jwsoft.javaproject; public class User { private S name; private I age; public User(S name, I age) { this.name = name; this.age = age; } public void setName(S name) { this.name = name; } public void setAge(I age) { this.age = age; } public S getName() { return this.name; } public I g..

common_toolbar.xml activity_main.xml activity_second.xml activity_third.xml ThirdActivity.java package com.jwsoft.javaproject; import androidx.appcompat.app.AppCompatActivity; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.widget.ImageButton; import android.widget.TextView; public class ThirdActivity extends AppCompatActivity { private ImageButt..

common_toolbar.xml activity_third.xml activity_second.xml activity_main.xml ThirdActivity.kt package com.jwsoft.kotlinproject import android.content.Intent import androidx.appcompat.app.AppCompatActivity import android.os.Bundle import android.view.View import android.widget.ImageButton import android.widget.TextView import kotlinx.android.synthetic.main.activity_third.* class ThirdActivity : Ap..