Appledocs假设我可以通过捕获对self的弱引用来避免强引用循环，如下所示:-(void)configureBlock{XYZBlockKeeper*__weakweakSelf=self;self.block=^{[weakSelfdoSomething];//capturetheweakreference//toavoidthereferencecycle}}然而当我写这段代码时，编译器告诉我:Dereferencinga__weakpointerisnotallowedduetopossiblenullvaluecausedbyracecondition,assignitt
Appledocs假设我可以通过捕获对self的弱引用来避免强引用循环，如下所示:-(void)configureBlock{XYZBlockKeeper*__weakweakSelf=self;self.block=^{[weakSelfdoSomething];//capturetheweakreference//toavoidthereferencecycle}}然而当我写这段代码时，编译器告诉我:Dereferencinga__weakpointerisnotallowedduetopossiblenullvaluecausedbyracecondition,assignitt
我正在使用dispatch_sync执行一个block，并且该block已正确执行。但是这个block是在主线程上执行的。根据Apple文档:Serialqueues(alsoknownasprivatedispatchqueues)executeonetaskatatimeintheorderinwhichtheyareaddedtothequeue.Thecurrentlyexecutingtaskrunsonadistinctthread(whichcanvaryfromtasktotask)thatismanagedbythedispatchqueue.这意味着(或者我的理解)
我正在使用dispatch_sync执行一个block，并且该block已正确执行。但是这个block是在主线程上执行的。根据Apple文档:Serialqueues(alsoknownasprivatedispatchqueues)executeonetaskatatimeintheorderinwhichtheyareaddedtothequeue.Thecurrentlyexecutingtaskrunsonadistinctthread(whichcanvaryfromtasktotask)thatismanagedbythedispatchqueue.这意味着(或者我的理解)
我正在尝试理解NSOperationQueue，并尝试创建尽可能简单的示例。我有以下内容:NSOperationQueue*myOQ=[[NSOperationQueuealloc]init];[myOQaddOperationWithBlock:^(void){NSLog(@"hereissomethingforjt2");}];[myOQaddOperationWithBlock:^(void){NSLog(@"ohisthisgoingtowork2");}];但是想这样做:void(^jt)()=^void(){NSLog(@"hereissomethingforjt");};
我正在尝试理解NSOperationQueue，并尝试创建尽可能简单的示例。我有以下内容:NSOperationQueue*myOQ=[[NSOperationQueuealloc]init];[myOQaddOperationWithBlock:^(void){NSLog(@"hereissomethingforjt2");}];[myOQaddOperationWithBlock:^(void){NSLog(@"ohisthisgoingtowork2");}];但是想这样做:void(^jt)()=^void(){NSLog(@"hereissomethingforjt");};
1.执行gitclone报错错误提示：fatal:unabletoaccess'https://github.com/****.git/':GnuTLSrecverror(-110):TheTLSconnectionwasnon-properlyterminated.2.解决方案imaginemiracle@im-Linux:~$sudoapt-getupdateimaginemiracle@im-Linux:~$sudoapt-getinstallgnutls-binimaginemiracle@im-Linux:~$gitconfig--globalhttp.sslVerifyfalsei
我正在尝试从UIImage对象创建渐进式jpeg，这是我的代码NSMutableData*data=[NSMutableDatadata];NSString*path=[NSHomeDirectory()stringByAppendingPathComponent:@"Library/Caches/test.jpg"];CFURLRefurl=CFURLCreateWithString(NULL,(CFStringRef)[NSStringstringWithFormat:@"file://%@",path],NULL);CGImageDestinationRefdestination
我正在尝试从UIImage对象创建渐进式jpeg，这是我的代码NSMutableData*data=[NSMutableDatadata];NSString*path=[NSHomeDirectory()stringByAppendingPathComponent:@"Library/Caches/test.jpg"];CFURLRefurl=CFURLCreateWithString(NULL,(CFStringRef)[NSStringstringWithFormat:@"file://%@",path],NULL);CGImageDestinationRefdestination
苹果的文档中是这样说的:block文字(即^{...})是表示block的堆栈本地数据结构的地址。因此，堆栈本地数据结构的范围是封闭的复合语句，因此您应该避免以下示例中显示的模式:voiddontDoThis(){void(^blockArray[3])(void);//anarrayof3blockreferencesfor(inti=0;i1000){block=^{printf("gotiat:%d\n",i);};//WRONG:Theblockliteralscopeisthe"then"clause.}//...}我不知道应该避免哪些模式。似乎我可以调用与block定义具有
