我有这段代码是用 Objective c 写的:
NSRect textRect = NSMakeRect(42, 35, 117, 55);
{
NSString* textContent = @"Hello, World!";
NSMutableParagraphStyle* textStyle = NSMutableParagraphStyle.defaultParagraphStyle.mutableCopy;
textStyle.alignment = NSCenterTextAlignment;
NSDictionary* textFontAttributes = @{NSFontAttributeName: [NSFont fontWithName: @"Helvetica" size: 12], NSForegroundColorAttributeName: NSColor.blackColor, NSParagraphStyleAttributeName: textStyle};
[textContent drawInRect: NSOffsetRect(textRect, 0, 1 - (NSHeight(textRect) - NSHeight([textContent boundingRectWithSize: textRect.size options: NSStringDrawingUsesLineFragmentOrigin attributes: textFontAttributes])) / 2) withAttributes: textFontAttributes];
}
现在,我想用 swift 编写这段代码。这是我到目前为止所得到的:
let textRect = NSMakeRect(42, 35, 117, 55)
let textTextContent = NSString(string: "Hello, World!")
let textStyle = NSMutableParagraphStyle.defaultParagraphStyle().mutableCopy() as NSMutableParagraphStyle
textStyle.alignment = NSTextAlignment.CenterTextAlignment
let textFontAttributes = [NSFontAttributeName: NSFont(name: "Helvetica", size: 12), NSForegroundColorAttributeName: NSColor.blackColor(), NSParagraphStyleAttributeName: textStyle]
textTextContent.drawInRect(NSOffsetRect(textRect, 0, 1 - (NSHeight(textRect) - NSHeight(textTextContent.boundingRectWithSize(textRect.size, options: NSStringDrawingOptions.UsesLineFragmentOrigin, attributes: textFontAttributes))) / 2), withAttributes: textFontAttributes)
这一行是错误的:
let textFontAttributes = [NSFontAttributeName: NSFont(name: "Helvetica", size: 12), NSForegroundColorAttributeName: NSColor.blackColor(), NSParagraphStyleAttributeName: textStyle]
那一行有什么问题?
这是编译器的错误:
"Could not find an overload for “init” that accepts the supplied arguments".
最佳答案
Swift 的类型推断让您失望,因为您要添加到字典中的字体是可选的。 NSFont(name:size:)
返回一个可选的 NSFont?
,你需要一个未包装的版本。要进行防御性编码,您需要这样的东西:
// get the font you want, or the label font if that's not available
let font = NSFont(name: "Helvetica", size: 12) ?? NSFont.labelFontOfSize(12)
// now this should work
let textFontAttributes = [NSFontAttributeName: font, NSForegroundColorAttributeName: NSColor.blackColor(), NSParagraphStyleAttributeName: textStyle]
关于objective-c - 如何快速编写这段代码?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/26363268/