swift 3 - 未显示子类视图控制器

Question

在我的 Swift 3/Obj-C 应用程序中，我在显示 swift 视图控制器时遇到问题，该视图控制器是从 class 和 Obj-C class.

以下代码完美运行：

NavigationController.swift

func myMethod(){
    ...
    let vc = ParentViewController.init(someParameter: parameter) // << results in desired screen
    vc?.stringProperty = "someString"
    self.pushViewController(vc!, animated: true)
}

SuperParentViewController.h

@interface SuperParentViewController : UIViewController 
     @property (nonatomic, strong) NSString *stringProperty;
     - (instancetype)initWithSomeParameter:(SomeClass *)someParameter;
@end

ParentViewController.h

@interface ParentViewController : SuperParentViewController
     // numerous properties are declared here
@end

ParentViewController.m

@implementation ParentViewController
    ...

    - (void)viewDidLoad{
        [super viewDidLoad];
        // a bunch of properties are set
    }

    - (void)viewWillAppear:(BOOL)animated{
        [super viewWillAppear:animated];
        // more properties are set
    }

    ...
@end

但是，如果我子class ParentViewController 并尝试呈现子class、"SubclassViewController"，这会导致屏幕只显示导航栏项目；屏幕的其余部分是空白的：

NavigationController.swift

func myMethod(){
    ...
    let vc = SubClassedViewController.init(someParameter: parameter) // << results in blank screen
    vc?.stringProperty = "someString"
    self.pushViewController(vc!, animated: true)
}

SubClassedViewController.swift

class SubClassedViewController: ParentViewController
{
    // nothing in this file yet
}

有人能告诉我为什么 SubClassedViewController 无法显示与 ParentViewController 相同的内容吗？

Answer 1

问题是 ParentViewController 与 .xib 文件相关联（单击 .xib 文件 -> 转到识别检查器 -> 在自定义 Class 下，您会发现 "ParentViewController"）。因此，当 subclassing ParentViewController 创建 SubClassedViewController class 时，我还需要使用以下代码来初始化相同的 .xib 文件：

(Swift 3)

class SubClassedViewController: ParentViewController
{    
    override init(someParameter: someClass) {
        super.init(nibName: "ParentViewController", bundle: nil)
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }
}

swift 3 - 未显示子类视图控制器

swift 3 - subclassed view controller not being displayed

inheritance

subclass

objective-c

viewcontroller

swift3