Question

好。如果你有两个viewControllers，你从第一个到第二个进行模态Segue，那么你用[self dismissModalViewControllerAnimated：YES]解雇它;它似乎没有回忆起viewDidLoad。我有一个主页面（viewController），然后是各种选项页面，我希望在更改选项时更新主页面。当我刚刚做了两个模态分段（一个前进，一个后退）时，这很有用，但这似乎是非结构化的，并且可能导致大型项目中的代码混乱。

我听说过push segues。他们还好吗？

感谢。我感谢任何帮助:)。

Answer 1

那是因为UIViewController已经加载到内存中了。但是，您可以使用viewDidAppear:。

或者，您可以使推送视图控制器成为推送视图控制器的委托，并在推出的控制器退出屏幕时通知它更新。

后一种方法的好处是不需要重新运行viewDidAppear:的整个主体。例如，如果您只更新表格行，为什么要重新渲染整个表格？

编辑：仅供您使用，以下是使用代理的快速示例：

#import <Foundation/Foundation.h>

// this would be in your ModalView Controller's .h
@class ModalView;

@protocol ModalViewDelegate

- (void)modalViewSaveButtonWasTapped:(ModalView *)modalView;

@end

@interface ModalView : NSObject

@property (nonatomic, retain) id delegate;

@end

// this is in your ModalView Controller's .m
@implementation ModalView

@synthesize delegate;

- (void)didTapSaveButton
{
    NSLog(@"Saving data, alerting delegate, maybe");

    if( self.delegate && [self.delegate respondsToSelector:@selector(modalViewSaveButtonWasTapped:)])
    {
        NSLog(@"Indeed alerting delegate");

        [self.delegate modalViewSaveButtonWasTapped:self];
    }
}

@end

// this would be your pushing View Controller's .h
@interface ViewController : NSObject <ModalViewDelegate>

- (void)prepareForSegue;

@end;

// this would be your pushing View Controller's .m
@implementation ViewController

- (void)prepareForSegue
{
    ModalView *v = [[ModalView alloc] init];

    // note we tell the pushed view that the pushing view is the delegate
    v.delegate = self;

    // push it

    // this would be called by the UI
    [v didTapSaveButton];
}

- (void)modalViewSaveButtonWasTapped:(ModalView *)modalView
{
    NSLog(@"In the delegate method");
}

@end

int main(int argc, char *argv[]) {
    @autoreleasepool {

        ViewController *v = [[ViewController alloc] init];

        [v prepareForSegue];
    }
}

输出：

2012-08-30 10:55:42.061 Untitled[2239:707] Saving data, alerting delegate, maybe
2012-08-30 10:55:42.064 Untitled[2239:707] Indeed alerting delegate
2012-08-30 10:55:42.064 Untitled[2239:707] In the delegate method

示例是在CodeRunner中为OS X运行的，我与之没有任何关联。

如何在[self dismissModalViewControllerAnimated：YES]之后调用viewDidLoad;

1 个答案: