为什么此视图控制器无法设置下一个视图控制器的文本字段? [英] Why can't this view controller set the text fields of the next view controller?

问题描述

我有一个视图控制器，该控制器具有带完成按钮的导航栏和两个文本字段.按下完成按钮时，将调用方法 postInfo .这是实现:

I have a view controller that has navigation bar with a done button, and two text fields. When the done button is pressed, the method postInfo is called. Here is the implementation:

- (void)postInfo{
ListingViewController* lvc = [[ListingViewController alloc] init];

NSString* listingName = listingNameField.text;
NSString* listingPrice = listingPriceField.text;

NSLog(@"%@", listingName);
NSLog(@"%@", listingPrice); 

[lvc.titleLabel setText:listingName];
[lvc.priceLabel setText:listingPrice];

[self.navigationController pushViewController:lvc animated:YES]; 

}

此处 ListingViewController.h :

#import <UIKit/UIKit.h>

@interface ListingViewController : UIViewController

@property (weak, nonatomic) IBOutlet UILabel *priceLabel;
@property (weak, nonatomic) IBOutlet UILabel *titleLabel;

@end

UILabel是通过xib文件设置的，并且为空.将根据要求发布所需的任何其他代码.

The UILabel's are set through a xib file and are empty. Will post whatever other code is needed upon request.

推荐答案

在您执行该推送时，尚未加载下一个控制器的视图，因此您无法访问其视图.您需要在ListingViewController中创建NSString属性，并将字符串传递给postnfo方法中的那些属性.然后在ListingViewController的viewDidLoad方法中，使用这些属性填充标签(这些标签将在viewDidLoad运行时加载).

At the time you do that push, the next controller's view hasn't been loaded yet, so you can't access its views. You need to create NSString properties in ListingViewController and pass a string to those in your postnfo method. Then in ListingViewController's viewDidLoad method, use those properties to populate the labels (which will have been loaded by the time viewDidLoad runs).

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