我如何在旧版本的OS X上使用[SAlert beginSheetModalForWindow：completionhandler：](How can I use [SAlert beginSheetModalForWindow:completionhandler:] on older versi of OS X)

我如何在旧版本的OS X上使用[SAlert beginSheetModalForWindow：completionhandler：](How can I use [SAlert beginSheetModalForWindow:completionhandler:] on older versi of OS X)

OS X Mavericks实现了一个新的API，以更方便地显示SAlert ：

- (void)beginSheetModalForWindow:(SWindow *)sheetWindow completionHandler:(void (^)(SModalRespe returnCode))handler

是否有一种简单的方法可以在OS X 10.8及更早版本中支持的类别中创建类似的方法？

OS X Mavericks implemented a new API for more convenient displaying of SAlert:

- (void)beginSheetModalForWindow:(SWindow *)sheetWindow completionHandler:(void (^)(SModalRespe returnCode))handler

Is there an easy way to create a similar method in a category that does the same thing but supported on OS X 10.8 and earlier?

最满意答案

是的，您可以使用基于委托的API来模拟类似的API。 唯一棘手的部分是让所有演员合适，因此它适用于ARC。 以下是SAlert的一个类别，它提供了一个向后兼容的基于块的API：

SAlert + BlockMethods.h

#import <Cocoa/Cocoa.h> @interface SAlert (BlockMethods) -(void)compatibleBeginSheetModalForWindow: (SWindow *)sheetWindow completionHandler: (void (^)(SInteger returnCode))handler; @end

SAlert +

#import "SAlert+BlockMethods.h" @implementation SAlert (BlockMethods) -(void)compatibleBeginSheetModalForWindow: (SWindow *)sheetWindow completionHandler: (void (^)(SInteger returnCode))handler { [self beginSheetModalForWindow: sheetWindow modalDelegate: self didEndSelector: @selector(blockBasedAlertDidEnd:returnCode:contextInfo:) contextInfo: (__bridge_retained void*)[handler copy] ]; } -(void)blockBasedAlertDidEnd: (SAlert *)alert returnCode: (SInteger)returnCode contextInfo: (void *)contextInfo { void(^handler)(SInteger) = (__bridge_transfer void(^)(SInteger)) contextInfo; if (handler) handler(returnCode); } @end

欲了解更多信息，请参阅我的SAlertBlockMethods Github回购 。

Yes, you can simulate a similar API using the delegate based API. The only tricky part is getting all the casts right so it works with ARC. Here's a category on SAlert that provides a backward compatible block-based API:

SAlert+BlockMethods.h

#import <Cocoa/Cocoa.h> @interface SAlert (BlockMethods) -(void)compatibleBeginSheetModalForWindow: (SWindow *)sheetWindow completionHandler: (void (^)(SInteger returnCode))handler; @end

SAlert+

#import "SAlert+BlockMethods.h" @implementation SAlert (BlockMethods) -(void)compatibleBeginSheetModalForWindow: (SWindow *)sheetWindow completionHandler: (void (^)(SInteger returnCode))handler { [self beginSheetModalForWindow: sheetWindow modalDelegate: self didEndSelector: @selector(blockBasedAlertDidEnd:returnCode:contextInfo:) contextInfo: (__bridge_retained void*)[handler copy] ]; } -(void)blockBasedAlertDidEnd: (SAlert *)alert returnCode: (SInteger)returnCode contextInfo: (void *)contextInfo { void(^handler)(SInteger) = (__bridge_transfer void(^)(SInteger)) contextInfo; if (handler) handler(returnCode); } @end

For more info, see my SAlertBlockMethods Github repo.