尝试初始化 annotationView 时出现问题

Question

我想将用 Obj-C 编写的自定义 MKAnnotationView 转换为 Swift，但当我想 initWithAnnotation 时出现错误。

下面我将提供 ObjC 和 Swift 代码：

class JPThumbnailAnnotationView: MKAnnotationView,JPThumbnailAnnotationViewProtocol {


var coordinate :CLLocationCoordinate2D
var imageView : UIImageView
var titleLabel : UILabel
var subtitleLabel : UILabel
var disclosureBlock : JPThumbnail.SequencerNext

func initWithAnnotation(annotation : MKAnnotation) {

    self = MKAnnotationView(annotation: annotation, reuseIdentifier: kJPSThumbnailAnnotationViewReuseID) //HERE IS WHERE I GET THE ERROR

        self.canShowCallout = true
        self.frame = CGRectMake(0, 0, kJPSThumbnailAnnotationViewStandardWidth, kJPSThumbnailAnnotationViewStandardHeight)
        self.centerOffset = CGPointMake(0, -kJPSThumbnailAnnotationViewVerticalOffset)


}

Objective-C 版本是

- (id)initWithAnnotation:(id<MKAnnotation>)annotation {
  self = [super initWithAnnotation:annotation reuseIdentifier:kJPSThumbnailAnnotationViewReuseID];

  if (self) {
    self.canShowCallout = NO;
    self.frame = CGRectMake(0, 0, kJPSThumbnailAnnotationViewStandardWidth, kJPSThumbnailAnnotationViewStandardHeight);
    self.backgroundColor = [UIColor clearColor];
    self.centerOffset = CGPointMake(0, -kJPSThumbnailAnnotationViewVerticalOffset);

    _state = JPSThumbnailAnnotationViewStateCollapsed;

    [self setupView];
}

return self;

}

我得到的错误是：Can not assign self in a method

有没有办法我仍然可以在我的情况下分配 self 或者我应该只创建一个类型为 MKAnnotationView 的变量，将它分配给初始化程序的结果并更改函数的返回类型，或者是否有另一种方法可以做到这一点?

Answer 1

你在init方法中做错了，你应该像这样调用超类初始化器，

func initWithAnnotation(annotation : MKAnnotation) {

   super.init(annotation: annotation, reuseIdentifier: kJPSThumbnailAnnotationViewReuseID) //HERE IS WHERE I GET THE ERROR
   self.canShowCallout = true
   self.frame = CGRectMake(0, 0, kJPSThumbnailAnnotationViewStandardWidth, kJPSThumbnailAnnotationViewStandardHeight)
   self.centerOffset = CGPointMake(0, -kJPSThumbnailAnnotationViewVerticalOffset)
}