我有两个 Storyboard,每个 Storyboard都有自己各自的 View Controller ,但我需要根据第一个 View Controller 中按下的按钮更改第二个 Storyboard的外观。
在我的第一个 View Controller 中:
// First view controller .h
#import <UIKit/UIKit.h>
#import "SecondViewController.h"
@interface FirstViewController : UIViewController
@property (strong, nonatomic) IBOutlet UIButton *LevelOneButton; // tag 0
@property (strong, nonatomic) IBOutlet UIButton *LevelTwoButton; // tag 1
-(IBAction)selectLevel:(UIButton *)sender; // both buttons connected to this method
@property (assign, nonatomic) int levelSelect;
@end
然后在第一个.m文件中:
//FirstViewController.m
-(IBAction)selectLevel:(UIButton *)sender {
if (sender.tag == 0) {
_levelSelect = 0;
}
if (sender.tag == 1) {
_levelSelect = 1;
}
}
此代码工作正常,但问题出现在我拥有的 secondViewController 中。当我尝试访问 SecondViewController 中的 levelSelect 属性时,出现错误“在‘FirstViewController’类型的对象上找不到属性‘levelSelect’”或“意外的标识符 levelSelect”或这些行中的某些内容。我已经尝试了所有我能想到的事情以及我在 StackOverflow 上发现的与此相关的每个问题,但都没有解决问题。有人知道我做错了什么吗?
最佳答案
您应该在推送或继续时在第二个 View Controller 上设置属性。
所以在你的第一个 View Controller 中它应该看起来像这样:
#import "ViewController.h"
#import "SecondViewController.h"
@interface ViewController ()
@property (strong, nonatomic) IBOutlet UIButton *levelOne;
@property (strong, nonatomic) IBOutlet UIButton *levelTwo;
@property (assign, nonatomic) int selectedLevel;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.levelOne.tag = 1;
self.levelTwo.tag = 2;
}
- (IBAction)selectLevel:(UIButton *)sender
{
if (sender.tag == 1) {
self.selectedLevel = 1;
} else {
self.selectedLevel = 2;
}
[self performSegueWithIdentifier:@"pushToSecond" sender:self];
}
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
SecondViewController *dest = segue.destinationViewController;
dest.levelSelect = self.selectedLevel;
}
@end
现在,当在 SecondViewController
上调用 viewDidLoad
时,将设置该属性,您可以使用它。像这样:
#import "SecondViewController.h"
@interface SecondViewController ()
@property (strong, nonatomic) IBOutlet UILabel *levelLabel;
@end
@implementation SecondViewController
- (void)viewDidLoad
{
[super viewDidLoad];
self.levelLabel.text = [@(self.levelSelect) stringValue];
}
@end
快速编辑,如果你不使用 segues,你可以通过手动推送来做同样的事情。看起来像:
- (IBAction)selectLevel:(UIButton *)sender
{
if (sender.tag == 1) {
self.selectedLevel = 1;
} else {
self.selectedLevel = 2;
}
SecondViewController *secondVC = [[UIStoryboard storyboardWithName:@"Main" bundle:[NSBundle mainBundle]] instantiateViewControllerWithIdentifier:@"second"];
secondVC.levelSelect = self.selectedLevel;
[self.navigationController pushViewController:secondVC animated:YES];
}
关于ios - 如何访问不同 View Controller 中的属性?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/28078900/