iOS多线程编程(一)NSThread
最后更新于：2022-04-01 22:59:00
## @NSThread的使用
### 1.显示调用的类为NSThread有两种直接创建方式：
**- (id)initWithTarget:(id)target selector:(SEL)selector object:(id)argument(手动开启)**
**+ (void)detachNewThreadSelector:(SEL)aSelector toTarget:(id)aTarget withObject:(id)anArgument(自动开启)**
~~~
1、[NSThread detachNewThreadSelector:@selector(doSomething:) toTarget:self withObject:nil];
2、NSThread* myThread = [[NSThread alloc] initWithTarget:self
selector:@selector(doSomething:)
object:nil];
[myThread start];
~~~
### 2\. 不显式创建线程的方法：
**通过NSObject的Category方法调用:**
**- (void)performSelectorOnMainThread:(SEL)aSelector withObject:(id)arg waitUntilDone:(BOOL)wait; //在主线程中运行方法，wait表示是否阻塞这个方法的调用，如果为YES则等待主线程中运行方法结束。一般可用于在子线程中调用UI方法。**
**- (void)performSelector:(SEL)aSelector onThread:(NSThread *)thread withObject:(id)arg waitUntilDone:(BOOL)wait;** //**在指定线程中执行，但该线程必须具备run loop。**
**- (void)performSelectorInBackground:(SEL)aSelector withObject:(id)arg;** //产生新线程。
**3.NSThread的其它一些常用的方法**
**1. + (NSThread *)currentThread; //获得当前线程**
**2. + (void)sleepForTimeInterval:(NSTimeInterval)ti; //线程休眠**
**3. + (NSThread *)mainThread; //主线程，亦即UI线程了**
**4. - (BOOL)isMainThread; + (BOOL)isMainThread; //当前线程是否主线程**
**5. - (BOOL)isExecuting; //线程是否正在运行**
**6. - (BOOL)isFinished; //线程是否已结束**
**7.- (void)cancel // 终止线程循环**
**8.- (void)start // 开启线程循环**
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