iphone - 检测导航 Controller 何时弹出到根目录

Question

这是我的代码:

SignupController* signupController = [[SignupController alloc] initWithNibName:@"SignupController" bundle:nil];
    [window addSubview:[navigationController view]];
    [window makeKeyAndVisible];

    self.navigationController.title = @"MyNavController";

    [self.navigationController pushViewController:signupController animated:YES];
    [signupController release];

不幸的是，对我来说，调用pushViewController不是同步的，因此下一行([signupController release])会立即执行。

我需要检测signupController是否已弹出回根目录，以便我可以从注册 Controller 获取数据并进行注册或登录。

有什么想法吗？

谢谢

Answer 1

使用委托(delegate)模式回调主 Controller ，让它知道注册 Controller 即将退出。在导航 Controller 释放注册 Controller 之前复制其值。

// SignupController.h
@protocol SignupDelegate;
@interface SignupController : UIViewController {
    id <SignupDelegate> delegate;
    NSString *name;
}
@property (nonatomic, assign) id <SignupDelegate> delegate;
@property (nonatomic, retain) NSString *name;
@end
@protocol SignupDelegate
- (void) signupControllerDidFinish:(SignupController *)controller;
@end

// SignupController.m
@implementation SignupController
@synthesize delegate;
@synthesize name;

- (void) viewWillDisappear:(BOOL)animated {
    [self.delegate signupControllerDidFinish:self];
}
@end

// YourViewController.m
- (void) signupSelected {
    SignupController *signup = [[SignupController alloc] initWithNibName:NSStringFromClass([SignupController class]) bundle:nil];
    signup.delegate = self;
    [controller.navigationController pushViewController:signup animated:YES];
    [signup release];
}

- (void) signupControllerDidFinish:(SignupController *)signup {
    NSLog(@"Signup with name %@", signup.name);
}