## @NSThread的使用 ### 1.顯示調用的類為NSThread有兩種直接創建方式： **- (id)initWithTarget:(id)target?selector:(SEL)selector?object:(id)argument(手動開啟)** **+ (void)detachNewThreadSelector:(SEL)aSelector?toTarget:(id)aTarget?withObject:(id)anArgument(自動開啟)** ~~~ 1、[NSThread detachNewThreadSelector:@selector(doSomething:) toTarget:self withObject:nil]; 2、NSThread* myThread = [[NSThread alloc] initWithTarget:self selector:@selector(doSomething:) object:nil]; [myThread start]; ~~~ ### 2\. 不顯式創建線程的方法： **通過NSObject的Category方法調用:** **- (void)performSelectorOnMainThread:(SEL)aSelector withObject:(id)arg waitUntilDone:(BOOL)wait;?//在主線程中運行方法，wait表示是否阻塞這個方法的調用，如果為YES則等待主線程中運行方法結束。一般可用于在子線程中調用UI方法。** **- (void)performSelector:(SEL)aSelector onThread:(NSThread *)thread withObject:(id)arg waitUntilDone:(BOOL)wait;**?//**在指定線程中執行，但該線程必須具備run loop。** **- (void)performSelectorInBackground:(SEL)aSelector withObject:(id)arg;**?//產生新線程。 **3.NSThread的其它一些常用的方法** **1.?+ (NSThread?*)currentThread;?//獲得當前線程** **2.?+ (void)sleepForTimeInterval:(NSTimeInterval)ti;?//線程休眠** **3.?+ (NSThread *)mainThread;?//主線程，亦即UI線程了** **4.?- (BOOL)isMainThread;?+ (BOOL)isMainThread;?//當前線程是否主線程** **5.?- (BOOL)isExecuting;?//線程是否正在運行** **6.?- (BOOL)isFinished;?//線程是否已結束** **7.- (void)cancel ?//?終止線程循環** **8.- (void)start ?// 開啟線程循環**