ochim

fun solution(N: Int): Int {
    // ２進数に変換
    val s = N.toString(2)
    // sが0を含まないなら0を返す
    if (!s.contains('0')) return 0

    var max = 0
    var count  = 0

ochim

• Best way to know if your Android app is currently in foreground

First

deprecated

public static boolean isApplicationInForeground(final Context context) {
    final ActivityManager activityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
    final List<RunningTaskInfo> tasks = activityManager.getRunningTasks(1);
    if (!tasks.isEmpty()) {
        final ComponentName topActivity = tasks.get(0).topActivity;

ochim

• Android 6.0 Marshmallow (android sdk 23)からはgetColorではなくContextCompat.getColorを使いましょう

// 新
ContextCompat.getColor(mContext, R.color.sample)

// 旧
mContext.getResources().getColor(R.color.sample)

// ContextCompat

ochim

• 日本語リファレンス
• オンラインIDE

Qiita

• はじめてのKotlin。Javaと比較してみた
• Kotlin のコレクション使い方メモ
• Kotlin: IntArray と Array の違い

ochim

https://stackoverflow.com/questions/46928874/android-oreo-notifications-check-if-specific-channel-enabled

if (!notificationManager.areNotificationsEnabled()) {
        openNotificationSettings();
        return;
}

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O &&
        isChannelBlocked(CHANNEL_1_ID)) {

ochim

Android Oreoから通知を送るにはまずチャンネルを登録するようになった。
https://feel-log.net/android/developer/o-notification-no-sound-vibration/

int importance = NotificationManager.IMPORTANCE_;
NotificationChannel channel = new NotificationChannel(CHANNEL_ID, name, importance);
NotificationManager manager =
            (NotificationManager) getSystemService(Service.NOTIFICATION_SERVICE);
manager.createNotificationChannel(channel);

ochim

Android Icon Size guide for Android 6 Marshmallow

Android Icon Size guide for App Interface Icons

-	MDPI (160dpi) Baseline	HDPI (240dpi) 1.5x	XHDPI (320dpi) 2x	XXHDPI (480dpi) 3x	XXXHDPI (640dpi) 4x
Launcher Icon	48px	72px	96px	166px	192px
Small Contextual icons	16px	24px	32px	48px	64px
Notification icons	22px icon in 24px area	33px icon in 36px area	44px icon in 48px area	66px icon in 72px area	88px icon in 96px area

ochim

[java] String.getBytes => [kotlin] String.toByteArray

fun String.toByteArray(
charset: Charset = Charsets.UTF_8
): ByteArray

Encodes the contents of this string using the specified character set and returns the resulting byte array.

ochim

import java.util.*;

// ハノイの塔の実装
class Main {
    /*
    piles：３本の杭をlistに格納
    名前なし：杭はLinkedList。円盤を格納
    名前なし：円盤の大きさを整数で表す。

ochim

How to programmatically set the width of the LinearLayout?

Display display = getActivity.getWindowManager().getDefaultDisplay();
Point size = new Point();
try {
    display.getRealSize(size);
} catch (NoSuchMethodError err) {
    display.getSize(size);
}