情節提要中ViewController的訪問屬性

Question

     NSString * storyboardName = @"Main";
     UIStoryboard *storyboard = [UIStoryboard storyboardWithName:storyboardName bundle: nil];
     UIViewController * vc = [storyboard instantiateViewControllerWithIdentifier:@"drawingboard"];

我想訪問vc.property，但是我要訪問的屬性無法訪問，即使該屬性位於.h文件中並且具有非原子的assign屬性。 無論如何，我可以訪問嗎？ 請幫忙！ 提前致謝。

Answer 1

vc必須強制轉換為特定類，該特定類是UIViewController的子類。

例如：

Drawingboard *vc = [storyboard instantiateViewControllerWithIdentifier:@"drawingboard"];

Answer 2

實現prepareForSegue:方法如下：-

可以說CommentsViewController是您要推送的viewController的類名。

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.

    if ([segue.destinationViewController isKindOfClass:[CommentsViewController class]]) { // Your viewControllerclass 

        CommentsViewController *controller = [segue destinationViewController];
        controller.propertyName = @"Write value here";
    }
}

Answer 3

如果在.h文件中定義屬性，則無需在.m中重新定義屬性。 否則，您將訪問.m對象而不是.h屬性。

    @property (nonatomic) UIViewController *vc;

上面是您的標頭，下面是實現

 NSString * storyboardName = @"Main";
 UIStoryboard *storyboard = [UIStoryboard storyboardWithName:storyboardName bundle: nil];
 _vc = [storyboard instantiateViewControllerWithIdentifier:@"drawingboard"];

_vc也可以根據自己的喜好用self.vc替換，但這將是以后使用它的方式。 希望這有所幫助