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  • iOS开发线程之NSThread

    1、初始化

    - (instancetype)init API_AVAILABLE(macos(10.5), ios(2.0), watchos(2.0), tvos(9.0)) NS_DESIGNATED_INITIALIZER;
    - (instancetype)initWithTarget:(id)target selector:(SEL)selector object:(nullable id)argument API_AVAILABLE(macos(10.5), ios(2.0), watchos(2.0), tvos(9.0));
    - (instancetype)initWithBlock:(void (^)(void))block API_AVAILABLE(macosx(10.12), ios(10.0), watchos(3.0), tvos(10.0));

    2、开启线程

    + (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;
    - (void)start API_AVAILABLE(macos(10.5), ios(2.0), watchos(2.0), tvos(9.0));
    - (void)main API_AVAILABLE(macos(10.5), ios(2.0), watchos(2.0), tvos(9.0));    // thread body method

      特点:main

    //执行start方法后会自动调用main方法。
    //main是默认的初始化和调用selector的方法。如果要继承NSThread,可以重写main方法来执行新线程的主要部分。重写的mian方法不需要调用super。不要直接调用mian方法,而是通过start方法来调用。

    3、停止线程

    + (void)sleepUntilDate:(NSDate *)date;//休眠到指定时间
    + (void)sleepForTimeInterval:(NSTimeInterval)ti;//休眠多久
    + (void)exit;//退出所有线程
    - (void)cancel API_AVAILABLE(macos(10.5), ios(2.0), watchos(2.0), tvos(9.0));//取消线程

      特点:exit

    //exit方法先执行currentThread类方法来获取当前线程。
    //由于退出线程前给默认通知中心发送NSThreadWillExitNotification通知,并把当前线程作为参数,因为post通知是同时发送的,所以所有NSThreadWillExitNotification 通知的观察者都会收到通知,导致所有线程都退出。

    4、描述线程状态

    @property (readonly, getter=isExecuting) BOOL executing;//是否在执行
    @property (readonly, getter=isFinished) BOOL finished ;//是否执行完毕
    @property (readonly, getter=isCancelled) BOOL cancelled;//是否已经取消,此时finished可能为NO

    5、主线程和多线程

    @property (readonly) BOOL isMainThread ;//是否是主线程
    @property (class, readonly, strong) NSThread *mainThread ;//获取当前主线程
    
    + (BOOL)isMultiThreaded;//是否是多线程
    @property (class, readonly, strong) NSThread *currentThread;//当前线程 1为主线程
    @property (class, readonly, copy) NSArray<NSNumber *> *callStackReturnAddresses;//线程函数地址
    @property (class, readonly, copy) NSArray<NSString *> *callStackSymbols;//当前线程的调用栈

    6、属性设置

    //可以使用返回的字典来保存线程的特定数据。这只是一个普通的字典,用来保存所有开发者感兴趣的数据。
    @property (readonly, retain) NSMutableDictionary *threadDictionary;
    //线程的堆内存大小字节数。必须是4KB的倍数。要使设置有用,必须在start方法调用前设置。
    @property NSUInteger stackSize;
    @property (nullable, copy) NSString *name;//线程名字

    7、优先级

    + (double)threadPriority;//当前线程优先级【0.0--1.0】默认0.5
    + (BOOL)setThreadPriority:(double)p;//设置优先级成功返回YES
    
    @property double threadPriority API_AVAILABLE(macos(10.6), ios(4.0), watchos(2.0), tvos(9.0)); // To be deprecated; use qualityOfService below
    @property NSQualityOfService qualityOfService API_AVAILABLE(macos(10.10), ios(8.0), watchos(2.0), tvos(9.0)); // read-only after the thread is started
    typedef NS_ENUM(NSInteger, NSQualityOfService) {
        /* 最高优先级,主要用于提供交互UI的操作,比如处理点击事件,绘制图像到屏幕上 */
        NSQualityOfServiceUserInteractive = 0x21,
        /* 次高优先级,主要用于执行需要立即返回的任务 */
        NSQualityOfServiceUserInitiated = 0x19,
        /* 普通优先级,主要用于不需要立即返回的任务*/
        NSQualityOfServiceUtility = 0x11,
        /* 后台优先级,用于完全不紧急的任务*/
        NSQualityOfServiceBackground = 0x09,
        /* 默认优先级,当没有设置优先级的时候,线程默认优先级*/
        NSQualityOfServiceDefault = -1
    } API_AVAILABLE(macos(10.10), ios(8.0), watchos(2.0), tvos(9.0));

    8、通知

    FOUNDATION_EXPORT NSNotificationName const NSWillBecomeMultiThreadedNotification;//由当前线程派生出第一个其他线程时发送,一般一个线程只发送一次
    FOUNDATION_EXPORT NSNotificationName const NSDidBecomeSingleThreadedNotification;//未知。
    FOUNDATION_EXPORT NSNotificationName const NSThreadWillExitNotification;//当线程对象获取到exit消息时,广播这个通知。

    9、NSThreadPerformAdditions类别

    @interface NSObject (NSThreadPerformAdditions)
    
    - (void)performSelectorOnMainThread:(SEL)aSelector withObject:(nullable id)arg waitUntilDone:(BOOL)wait modes:(nullable NSArray<NSString *> *)array;//用于线程通信,子线程传到主线程
    - (void)performSelectorOnMainThread:(SEL)aSelector withObject:(nullable id)arg waitUntilDone:(BOOL)wait;// 用于线程通信,子线程传到主线程,默认的运行时模式: kCFRunLoopCommonModes
    - (void)performSelector:(SEL)aSelector onThread:(NSThread *)thr withObject:(nullable id)arg waitUntilDone:(BOOL)wait modes:(nullable NSArray<NSString *> *)array API_AVAILABLE(macos(10.5), ios(2.0), watchos(2.0), tvos(9.0));//用于线程之间的通信
    - (void)performSelector:(SEL)aSelector onThread:(NSThread *)thr withObject:(nullable id)arg waitUntilDone:(BOOL)wait API_AVAILABLE(macos(10.5), ios(2.0), watchos(2.0), tvos(9.0));//用于线程之间的通信
    - (void)performSelectorInBackground:(SEL)aSelector withObject:(nullable id)arg API_AVAILABLE(macos(10.5), ios(2.0), watchos(2.0), tvos(9.0));// 隐式创建线程,默认的运行时模式 kCFRunLoopCommonModes
    
    @end
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  • 原文地址:https://www.cnblogs.com/xianfeng-zhang/p/9360288.html
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