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

Question

好的.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？

谢谢.我感谢任何帮助:).

Answer 1

那是因为UIViewController已经加载到内存中了.但是你可以使用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整个机体viewDidAppear:.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:只为你,这是一个使用代表的快速示例:

#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OSR的CodeRunner中运行的,我与之没有任何关联.