@IntDef的使用

public class MainActivity extends Activity {  

    

    //先定义 常量  

    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;  

    

    //用 <span></span>@IntDef "包住" 常量；  

    // @Retention 定义策略  

    // 声明构造器  

    @IntDef({SUNDAY, MONDAY,TUESDAY,WEDNESDAY,THURSDAY,FRIDAY,SATURDAY})  

    @Retention()  

    public @interface WeekDays {}  

    

    @WeekDays int currentDay = SUNDAY;  

    

    @Override  

    protected void onCreate(Bundle savedInstanceState) {  

        super.onCreate(savedInstanceState);  

        setContentView(.activity_main);  

        setCurrentDay(WEDNESDAY);  

    

        //声明变量  

        @WeekDays int today = getCurrentDay();  

    

        switch (today){  

            case SUNDAY:  

                break;  

            case MONDAY:  

                break;  

            case TUESDAY:  

                break;  

            case WEDNESDAY:  

                break;  

            case THURSDAY:  

                break;  

            case FRIDAY:  

                break;  

            case SATURDAY:  

                break;  

            default:  

                break;  

        }  

    

    }  

    

    public void setCurrentDay(@WeekDays int currentDay) {  

        this.currentDay = currentDay;  

    }  

    

    @WeekDays  

    public int getCurrentDay() {  

        return currentDay;  

    }  

}