ios - 从 UIViewController 实例化 UIView 子类

Question

我找到了一个教程，它完全符合我想在我现有的 Objective-C 项目中执行的操作，但它是用 Swift 编写的。我了解 Swift 中的所有内容，但我正在经历一段噩梦般的时间，将 UIView 的 初始化程序“翻译”为 Objective-C。这应该很简单，但我想不通。

我的代码没有崩溃，但它没有加载任何东西。我在我的 UIViewController 中放置了一个断点，以查看当我尝试加载 UIView 子类时发生了什么，这就是我所看到的:

(lldb) po self.boxSize
75

(lldb) po self.holderView.frame
(origin = (x = 0, y = 0), size = (width = 0, height = 0))
 (origin = (x = 0, y = 0), size = (width = 0, height = 0))

(lldb) po self.holderView
 nil

这是我试图在 Objective-C 中“复制”的 View 。

HolderView.swift:

class HolderView: UIView {

    var parentFrame :CGRect = CGRectZero

    weak var delegate:HolderViewDelegate?

    override init(frame: CGRect) {
        super.init(frame: frame)
        backgroundColor = Colors.clear
    }

    required init(coder: NSCoder) {
        super.init(coder: coder)
    }
    // A bunch of class methods
}

这是我“翻译的”Objective-C .h/.m 文件:

HolderView.h:

#import <UIKit/UIKit.h>

@protocol HolderViewDelegate <NSObject>
// delegate methods
@ end

@interface HolderView : UIView

@property (nonatomic, weak) id <HolderViewDelegate> delegate;

@property (nonatomic) CGRect frame;
@property (nonatomic) CGRect parentFrame;

HolderView.m:

- (instancetype)initWithFrame:(CGRect)frame
{
    self.parentFrame = CGRectZero;
    self = [super initWithFrame:frame];
    if (self) {
        [super setFrame:self.parentFrame];
        self.backgroundColor = [UIColor orangeColor]; // Added to see if it's working
        NSLog(@"anyone home?");
    }
    return self;
}

这是 Swift 和 Objective-C UIViewControllers 添加 UIView 的代码:

ViewController.swift

  func addHolderView() {
    let boxSize: CGFloat = 75.0
    holderView.frame = CGRect(x: view.bounds.width / 2 - boxSize / 2,
                              y: view.bounds.height / 2 - boxSize / 2,
                              width: boxSize,
                              height: boxSize)
    holderView.parentFrame = view.frame
    holderView.delegate = self
    view.addSubview(holderView)
    holderView.addOval()
  }

这是我“翻译的”Objective-C View Controller :

- (void)addHolderView {
    self.boxSize = 75.0; // I added as a global variable, as local returned NULL when I tried locally
    self.holderView.frame = CGRectMake(self.view.bounds.size.height / 2 - self.boxSize / 2,
                                       self.view.bounds.size.width / 2 - self.boxSize / 2,
                                       self.boxSize,
                                       self.boxSize);

    self.holderView.parentFrame = self.view.frame;
    self.holderView = [self.holderView initWithFrame:self.holderView.frame];    

    self.holderView.delegate = self;

    NSLog(@"addHolderView called");
    [self.view addSubview:self.holderView];
}

感谢阅读。

Answer 1

这段代码怎么样..

- (void)addHolderView {
    self.boxSize = 75.0; // I added as a global variable, as local returned NULL when I tried locally
    CGRect frame = CGRectMake(self.view.bounds.size.height / 2 - self.boxSize / 2,
                                       self.view.bounds.size.width / 2 - self.boxSize / 2,
                                       self.boxSize,
                                       self.boxSize);

    self.holderView = [[HolderView alloc] initWithFrame: frame];   
    self.holderView.parentFrame = self.view.frame;

    self.holderView.delegate = self;

    NSLog(@"addHolderView called");
    [self.view addSubview:self.holderView];
}