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; 
        }


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