iphone - 无法使用模型 segue 在 View 上设置标签

Question

problem StoryBoard

我想使用模型转场。通过单击“年”按钮，它应该转到“年 View Controller ”，单击表格单元格并将屏幕设置为初始 View Controller ，在 View Controller 中设置标签 1。

Person.h

#import <Foundation/Foundation.h>

@interface CarObj : NSObject

@property (nonatomic, strong) NSMutableString *Year;
@property (nonatomic, strong) NSMutableString* Name;

@end

点击名称按钮后，它应该转到名称 View Controller ，点击它应该将单元格的信息保存到 Person.h 的“名称”参数中。

如何实现？我无法设置标签 1 和标签 2....

对于 segue 我正在使用:

-(void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if([[segue identifier] isEqualToString:@"GrabYear"])
{
YearViewController *yvc = [segue destinationViewController];
[yvc setCurrentCar:currentCar];
}
}

对于我正在使用的行选择:

MenuViewController *mvc = [self.storyboard instantiateViewControllerWithIdentifier:@"MenuSB"];
NSIndexPath *path = [self.tableView indexPathForSelectedRow];
CarObj *c = [cars objectAtIndex:[path row]];
[mvc setCurrentCar:c];

[mvc viewDidLoad]; // I am not getting previous view loaded automatically
[self dismissViewControllerAnimated:YES completion:^{}];

我在 currentCar.year 中得到的字符串无法通过使用设置标签 [yearLabel setText:currentCar.year];

Answer 1

Controller 对 [controller view] 的调用没有发生在 api 的事件链中。 因此，您在未首先加载子控件的情况下在 View 的子控件上设置的任何值都将被覆盖，让您对这个谜团感到困惑。

-(void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{ 
    id vc = [segue destinationViewController];
    MyController *controller = (MyController*)vc;

    //You'll need lazy load controller child controls "now"! with this method call
    [controller view];

    //now you can set controls 
    controller.myLabel.text = @"Value will now persist";

    //note objects not owned by the "view" can be set here without the hack
   controller.myContextSting = @"This value will persist without the hack";
}