혀가 길지 않은 개발자

import java.util.HashSet; import java.util.Iterator; public class JavaTest { public static void main(String[] args) { HashSet set = new HashSet(); set.add(3); set.add(2); set.add(1); set.add(2); set.add(2); set.add(2); Iterator iterator = set.iterator(); while (iterator.hasNext()) { System.out.println(iterator.next()); } } } 중복되는 값은 허용하지 않음. 자동 정렬이 돼서 출력됨. 원래 TreeSet 이 자동 정렬되는데 HashSet 도 자동 정렬되네..

import java.util.HashSet fun main() { var set: HashSet = HashSet() set.add("3") set.add("2") set.add("1") set.add("2") set.add("2") set.add("2") for (i in set) { println(i) } } 중복되는 값은 허용하지 않음. 자동 정렬이 돼서 출력됨. 원래 TreeSet 이 자동 정렬되는데 HashSet 도 자동 정렬되네 ㅋㅋ fun main() { val set1: HashSet = HashSet() val set2: HashSet = HashSet() set1.add("James Kim") set1.add("Kevin Jang") set1.add("Jason Park") set2...

Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK activity_main.xml activity_sub.xml SubActivity.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.Button; public class SubActivity extends AppCompatActivity { private Button btnSub; @Override p..

Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK activity_main.xml activity_sub.xml SubActivity.kt package com.jwsoft.kotlinproject import android.content.Intent import androidx.appcompat.app.AppCompatActivity import android.os.Bundle import kotlinx.android.synthetic.main.activity_main.* class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?)..

build.gradle (Project: KotlinProject) allprojects { repositories { google() jcenter() maven { url 'https://jitpack.io' } } } maven { url 'https://jitpack.io' } 추가 build.gradle (Module: app) dependencies { // MPAndroidChart implementation 'com.github.philJay:MPAndroidChart:v3.1.0' } 해당 라이브러리 사용 https://github.com/PhilJay/MPAndroidChart PhilJay/MPAndroidChart A powerful 🚀 Android chart view / grap..

lateinit vs Delegates.notNull() MainActivity.kt package com.jwsoft.kotlinproject import androidx.appcompat.app.AppCompatActivity import android.os.Bundle class MainActivity : AppCompatActivity() { private lateinit var longValue: Long private lateinit var intValue: Int private lateinit var stringValue: String private lateinit var arrLong: ArrayList private lateinit var arrInt: ArrayList private l..

cardview_item.xml MyAdapter.kt package com.jwsoft.kotlinproject import android.view.LayoutInflater import android.view.View import android.view.ViewGroup import android.widget.TextView import androidx.recyclerview.widget.RecyclerView class MyAdapter : RecyclerView.Adapter() { inner class MyViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) { private val tvPosition: TextView = itemVie..

MainActivity.kt package com.jwsoft.kotlinproject import androidx.appcompat.app.AppCompatActivity import android.os.Bundle import kotlinx.android.synthetic.main.activity_main.* class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) etJames.requestFocus() // 포커스가 있어야 키보드 노출. } } activ..

activity_main.xml MainActivity.java package com.jwsoft.javaproject; import androidx.appcompat.app.AppCompatActivity; import android.content.Context; import android.os.Bundle; import android.view.View; import android.view.inputmethod.InputMethodManager; import android.widget.Button; import android.widget.EditText; public class MainActivity extends AppCompatActivity { private Button btnShowKeyboar..