objective-c - 开始表 : block alternative?

Question

Snow Leopard 没有引入一些替代旧的 beginSheet: 方法来允许使用 block 来完成最后的工作吗？我不喜欢在另一个回调方法中使用它。

Answer 1

没关系。我在这两个网站找到了我要找的东西:

http://www.mikeash.com/pyblog/friday-qa-2009-08-14-practical-blocks.html , http://www.cocoabuilder.com/archive/cocoa/281058-sheets-blocks-and-garbage-collector.html

事实上，这就是代码，它与 GC 和非 GC 完全兼容:

@implementation NSApplication (SheetAdditions)

- (void)beginSheet:(NSWindow *)sheet modalForWindow:(NSWindow *)docWindow didEndBlock:(void (^)(NSInteger returnCode))block
{  
  [self beginSheet:sheet
    modalForWindow:docWindow
     modalDelegate:self
    didEndSelector:@selector(my_blockSheetDidEnd:returnCode:contextInfo:)
       contextInfo:Block_copy(block)];
}

- (void)my_blockSheetDidEnd:(NSWindow *)sheet returnCode:(NSInteger)returnCode contextInfo:(void *)contextInfo
{
  void (^block)(NSInteger returnCode) = contextInfo;
  block(returnCode);
  Block_release(block);
}

@end