Android @IntDef注解取代Java enum枚举提高性能

￡神魔★判官ぃ 2023-10-17 21:28 20阅读 0赞

**Android @IntDef注解取代Java enum枚举提高性能**

为提高Android性能，Android官方建议使用@IntDef注解替代Java的enum枚举。@IntDef的使用给出一个例子，先建立@IntDef数据结构模型，例如MyDay.java：

package zhangphil.test;
    
    import android.support.annotation.IntDef;
    
    import java.lang.annotation.Retention;
    import java.lang.annotation.RetentionPolicy;
    
    public class MyDay {
        public static final int SUNDAY = 0;
        public static final int MONDAY = 1;
        public static final int TUESDAY = 2;
        public static final int WEDNESDAY = 3;
        public static final int THURSDAY = 4;
        public static final int FRIDAY = 5;
        public static final int SATURDAY = 6;
    
        @IntDef({SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY})
        @Retention(RetentionPolicy.SOURCE)
        public @interface WeekDays {
    
        }
    
        @WeekDays
        private int mCurDay = SUNDAY;
    
        public void setCurrentDay(@WeekDays int currentDay) {
            this.mCurDay = currentDay;
        }
    
        @WeekDays
        public int getCurrentDay() {
            return mCurDay;
        }
    }

使用：

MyDay days = new MyDay();
    
            days.setCurrentDay(MyDay.TUESDAY);
    
            @MyDay.WeekDays int day = days.getCurrentDay();
    
            switch (day) {
                case MyDay.SUNDAY:
                    break;
    
                case MyDay.MONDAY:
                    break;
    
                case MyDay.TUESDAY:
                    break;
    
                case MyDay.WEDNESDAY:
                    break;
    
                case MyDay.THURSDAY:
                    break;
    
                case MyDay.FRIDAY:
                    break;
    
                case MyDay.SATURDAY:
                    break;
    
                default:
                    break;
            }