Question

我有来自Github dzenbot/DZNPhotoPickerController的以下Objective-C块分配示例，我正在努力转换为Swift。 Controller是一个UIImagePickerController。

controller.finalizationBlock = ^(UIImagePickerController *picker, NSDictionary *info) {

    UIImage *image = info[UIImagePickerControllerEditedImage];
    weakSelf.imageView.image = image;

    // Dismiss when the crop mode was disabled
    if (picker.cropMode == DZNPhotoEditorViewControllerCropModeNone) {
        [weakSelf dismissController:picker];
    }
};

我尝试了以下方法，但无法弄清楚我哪里出错了。

controller.finalizationBlock = { (picker: UIImagePickerController, info: NSDictionary) -> UIImagePickerControllerFinalizationBlock! in
        var image = UIImagePickerControllerEditedImage(info)
        imageView.image = image

        // Dismiss when the crop mode was disabled
        if (picker.cropMode == .None) {
            dismissEditor(picker)
        }
    }

我得到的错误是：

“无法分配类型的值'（UIImagePickerController，NSDictionary） - ＆gt; UIImagePickerControllerFinalizationBlock！'输入'UIImagePickerControllerFinalizationBlock！'

Answer 1

Objective-C块不会返回任何内容，因此相同的闭包应如下所示：

controller.finalizationBlock = { (picker, info) in
        var image = UIImagePickerControllerEditedImage(info)
        imageView.image = image

        // Dismiss when the crop mode was disabled
        if (picker.cropMode == .None) {
            dismissEditor(picker)
        }
    }

Answer 2

Objective-C块没有返回任何内容，

controller.finalizationBlock = { (picker: UIImagePickerController, info: NSDictionary) -> (Void) in
        var image = UIImagePickerControllerEditedImage(info)
        imageView.image = image

        // Dismiss when the crop mode was disabled
        if (picker.cropMode == .None) {
            dismissEditor(picker)
        }
    }

注意1.如果您打算在其他函数中使用闭包，您可以声明一个Alias以提供更易读的代码（但这不是强制性的）

typealias UIImagePickerControllerFinalizationBlock = (picker: UIImagePickerController, info: NSDictionary) -> (Void)

注意2.也许您可以使用[String: AnyObject]或类型信息参数使用的更多信息参数类型“ Swifty ”。

Answer 3

试试这可能会对你有所帮助：

controller.finalizationBlock = {(picker: UIImagePickerController, info: [NSObject : AnyObject]) -> Void in
     var image: UIImage = info[UIImagePickerControllerEditedImage]
     weakSelf.imageView.image = image
    // Dismiss when the crop mode was disabled
     if picker.cropMode == DZNPhotoEditorViewControllerCropMode.None 
     {
         weakSelf.dismissController(picker)
     }
}

如何将Objective-C块转换为Swift Closure？

3 个答案: