UINavigationController和UINavigationBarDelegate.ShouldPopItem()与MonoTouch

这实现了“你确定要退出吗？当按下后退按钮时发出警报,请从代码修改：http://www.hanspinckaers.com/custom-action-on-back-button-uinavigationcontroller/

原来,如果您在CustomNavigationController中实现UINavigationBarDelegate,可以使用shouldPopItem方法：

CustomNavigationController.h：

#import <Foundation/Foundation.h>

@interface CustomNavigationController : UINavigationController <UIAlertViewDelegate,UINavigationBarDelegate> {

BOOL alertViewClicked;
BOOL regularPop;
}

@end

CustomNavigationController.m：

#import "CustomNavigationController.h"
#import "SetTingsTableController.h"

@implementation CustomNavigationController


- (BOOL)navigationBar:(UINavigationBar *)navigationBar shouldPopItem:(UINavigationItem *)item {

if (regularPop) {
    regularPop = falSE;
    return YES;
}

if (alertViewClicked) {
    alertViewClicked = falSE;
    return YES;
}

if ([self.topViewController isMemberOfClass:[SetTingsTableViewController class]]) {
    UIAlertView * exitAlert = [[[UIAlertView alloc] initWithtitle:@"Are you sure you want to quit?" message:nil delegate:self cancelButtontitle:@"Cancel" otherButtontitles:@"Yes",nil] autorelease];

    [exitAlert show];

    return NO;

}   
else {
    regularPop = TRUE;
    [self popViewControllerAnimated:YES];
    return NO;
}   
}

-(void)alertView:(UIAlertView *)alertView clickedButtonATindex:(NSInteger)buttonIndex {
if (buttonIndex == 0) {
    //Cancel button
}

else if (buttonIndex == 1) {    
        //Yes button
    alertViewClicked = TRUE;
    [self popViewControllerAnimated:YES];
}           
}

@end

“regularPop”bool的奇怪的逻辑是因为某些原因只是在shouldPopItem上返回“YES”只会弹出导航栏,而不是与navBar关联的视图 – 为此,您必须直接调用popViewControllerAnimated(然后调用shouldPopItem为其逻辑的一部分)