从一个UIViewController实例化一个UIView子类

Question

我找到了一个教程，正是我想在我现有的Objective-C项目中做的，但它是用Swift写的。我理解Swift中的一切，但我有一个噩梦般的时间"翻译"一个UIView's初始化器到Objective-C。这应该很简单，可我就是想不明白。

我的代码没有崩溃，但它没有加载任何东西。我把一个断点在我的UIViewController，看看发生了什么，当我试图加载UIView子类，这是我所看到的:

(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"的视图。

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 &目的- c UIViewControllers添加UIView:

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()
  }

这是我的"翻译"的Objective-C视图控制器:

- (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];
}

感谢您的阅读。

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];
}