OC--多线程NSTheard OC--多线程NSTheard

NSThread.h

@interface NSThread : NSObject //当前线程 @property (class, readonly, strong) NSThread *currentThread; //使用类方法创建线程执行任务 + (void)detachNewThreadWithBlock:(void (^)(void))block API_AVAILABLE(macosx(10.12), ios(10.0), watchos(3.0), tvos(10.0)); + (void)detachNewThreadSelector:(SEL)selector toTarget:(id)target withObject:(nullable id)argument; //判断当前是否为多线程 + (BOOL)isMultiThreaded; //指定线程的线程参数，例如设置当前线程的断言处理器。 @property (readonly, retain) NSMutableDictionary *threadDictionary; //当前线程暂停到某个时间 + (void)sleepUntilDate:(NSDate *)date; //当前线程暂停一段时间 + (void)sleepForTimeInterval:(NSTimeInterval)ti; //退出当前线程 + (void)exit; //当前线程优先级 + (double)threadPriority; //设置当前线程优先级 + (BOOL)setThreadPriority:(double)p; //指定线程对象优先级 0.0～1.0，默认值为0.5 @property double threadPriority NS_AVAILABLE(10_6, 4_0); //服务质量 @property NSQualityOfService qualityOfService NS_AVAILABLE(10_10, 8_0); //线程名称 @property (nullable, copy) NSString *name NS_AVAILABLE(10_5, 2_0); //栈区大小 @property NSUInteger stackSize NS_AVAILABLE(10_5, 2_0); //是否为主线程 @property (class, readonly) BOOL isMainThread NS_AVAILABLE(10_5, 2_0); //获取主线程 @property (class, readonly, strong) NSThread *mainThread NS_AVAILABLE(10_5, 2_0); //初始化 - (instancetype)init NS_AVAILABLE(10_5, 2_0) NS_DESIGNATED_INITIALIZER; //实例方法初始化，需要再调用start方法 - (instancetype)initWithTarget:(id)target selector:(SEL)selector object:(nullable id)argument NS_AVAILABLE(10_5, 2_0); - (instancetype)initWithBlock:(void (^)(void))block API_AVAILABLE(macosx(10.12), ios(10.0), watchos(3.0), tvos(10.0)); //线程状态，正在执行 @property (readonly, getter=isExecuting) BOOL executing NS_AVAILABLE(10_5, 2_0); //线程状态，正在完成 @property (readonly, getter=isFinished) BOOL finished NS_AVAILABLE(10_5, 2_0); //线程状态，已经取消 @property (readonly, getter=isCancelled) BOOL cancelled NS_AVAILABLE(10_5, 2_0); //取消，仅仅改变线程状态，并不能像exist一样真正的终止线程 - (void)cancel NS_AVAILABLE(10_5, 2_0); //开始 - (void)start NS_AVAILABLE(10_5, 2_0); //线程需要执行的代码，一般写子类的时候会用到 - (void)main NS_AVAILABLE(10_5, 2_0); @end

【OC--多线程NSTheard】NSObject的分类各种performSelector方法

@interface NSObject (NSThreadPerformAdditions) //隐式的创建并启动线程，并在指定的线程（主线程或子线程）上执行方法。 - (void)performSelectorOnMainThread:(SEL)aSelector withObject:(nullable id)arg waitUntilDone:(BOOL)wait modes:(nullable NSArray *)array; - (void)performSelectorOnMainThread:(SEL)aSelector withObject:(nullable id)arg waitUntilDone:(BOOL)wait; - (void)performSelector:(SEL)aSelector onThread:(NSThread *)thr withObject:(nullable id)arg waitUntilDone:(BOOL)wait modes:(nullable NSArray *)array NS_AVAILABLE(10_5, 2_0); - (void)performSelector:(SEL)aSelector onThread:(NSThread *)thr withObject:(nullable id)arg waitUntilDone:(BOOL)wait NS_AVAILABLE(10_5, 2_0); - (void)performSelectorInBackground:(SEL)aSelector withObject:(nullable id)arg NS_AVAILABLE(10_5, 2_0); @end

一般用法

//方法1：使用对象方法 NSThread *thread1=[[NSThread alloc]initWithTarget:self selector:@selector(startNewThread1) object:nil]; //??注意1：启动一个线程并非就一定立即执行，而是处于就绪状态，当CUP调度时才真正执行 [thread1 start]; //方法2：使用类方法,自动start [NSThread detachNewThreadSelector:@selector(startNewThread1) toTarget:self withObject:nil]; //方法3：隐式创建并启动线程 [self performSelectorInBackground:@selector(run) withObject:nil];

解析注意
1.启动一个线程并非就一定立即执行，而是处于就绪状态，当CUP调度时才真正执行，如下图