经常在项目中，使用强制更新的功能，我们可以使用UIAlertview跳转到APPStore进行更新，但是同时也可以点击左上方的小箭头，返回到之前的APP.这时候，UIAlertview已经消失，我们需要让他依然在，一直在！
import "DGAlertView.h"
#import <UIKit/UIKit.h>
@interface DGAlertView : UIAlertView
- (void)dismissWithClickedButtonIndex:(NSInteger)buttonIndex animated:(BOOL)animated;
@end
DGAlertView.m
#import "DGAlertView.h"
@implementation DGAlertView
/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
// Drawing code
}
*/
- (void)dismissWithClickedButtonIndex:(NSInteger)buttonIndex animated:(BOOL)animated{
if (buttonIndex == 0) {
//[super dismissWithClickedButtonIndex:buttonIndex animated:animated]; // 消失
}else{
// ...
// 不消失
}
}
@end
重写系统的这个方法，就OK了
- (void)dismissWithClickedButtonIndex:(NSInteger)buttonIndex animated:(BOOL)animated
