Dictionary里面有关"Null"的判断方法。

if ((NSNull*)dic[@"email"]!=[NSNull null]) { }

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使__attribute__((annotate("xxx")))能作用于OC函数

diff -Naur orig/llvm-3.7.0.src/tools/clang/lib/CodeGen/CGBlocks.cpp llvm-3.7.0.src/tools/clang/lib/CodeGen/CGBlocks.cpp  --- orig/llvm-3.7.0.src/tools /clang/lib/CodeGen/CGBlocks.cpp    2015-06-23 01:07:51.000000000 +0200  +++ llvm-3.7.0.src/tools/clang/lib/CodeGen/CGBlocks.cpp 2015-11-13 13:05:44.000000000 +0100  @@ -1157,6 +1157,10 @@         fnLLVMType, llvm::GlobalValue::InternalLinkage, name, &CGM.getModule());     CGM.SetInternalFunctionAttributes(blockDecl, fn, fnInfo);  +  // Emit annotation attributes for ObjC blocks.  +  if (blockDecl->hasAttr<AnnotateAttr>())  +    CGM.AddGlobalAnnotations(blockDecl, fn);  +     // Begin generating the function.     StartFunction(blockDecl, fnType->getReturnType(), fn, fnInfo, args,                   blockDecl->getLocation(),  diff -Nau...
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viewWillAppear不执行的解决办法

UITableViewController或UIViewController中使() 后viewWillAppear:(BOOL)animated不执行 解决方法如下： 先在 *.h 头文件里加上<UINavigationControllerDelegate> 接着在*.m 文件里加上相关代码 self.navigationController.delegate=self; 再使用此时navigationController的代理函数，就OK了。 -(void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated { [viewController viewWillAppear:animated]; } -(void)viewWillAppear:(BOOL)animated { NSLog(@"现在可以使用了"); } 代码实例： MyOrders.h @interface MyOrders : UIViewControllerlegate>{ } @property(nonatomic,retain)IBOutlet UITableView *table; MyOrders.m - (void)viewDidLoad { [super viewDidLoad]; self.navigationController.delegate=self; } -(void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated { [viewController viewWillAppear:animated]; } -(void)viewWillAppear:(BOOL)a...
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iOS中使用xpc/xpc.h

sudo ln -s /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.13.sdk/usr/include/xpc /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS.sdk/usr/include/xpc sudo ln -s /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.13.sdk/usr/include/launch.h /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS.sdk/usr/include/launch.h #中间的MacOSX的版本号可能会有所不同。#
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