iOS多線程編程之NSOperation，nsoperation

iOS多線程編程之NSOperation，nsoperation

NSOperation有兩種方法:

1>.NSInvocationOperation:建立一個operation,並用selecter指向執行的程式碼片段

2>.NSBlockOperation:建立一個operation,並將執行的代碼放在block塊中.

1.NSInvocationOperation多線程方法:

建立方法:

- (void)invocationOperation {NSInvocationOperation *operation1 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(run1) object:nil];NSOperationQueue *queue = [[NSOperationQueue alloc] init];[queue addOperation:operation1];}

- (void)run1{NSLog(@"runing1---%@",[NSThread currentThread]);}

2.NSBlockOperation多線程方法:

建立方法:

- (void)blockOperation1 {NSBlockOperation *operation = [NSBlockOperation blockOperationWithBlock:^{NSLog(@"blockOperation---%@",[NSThread currentThread]);}];operation.completionBlock = ^{NSLog(@"finish!-----");};NSOperationQueue *queue = [[NSOperationQueue alloc] init];[queue addOperation:operation];}

3.從子線程回到主線程重新整理UI方法:

performSelectorOnMainThread: withObject: waitUntilDone:

4.多個operation在queue中的執行順序是可以設定的.

在添加到queue之前設定operation之間的依賴關係:

[operation2 addDependency:operation1];

operation2依賴於operation1=>2在1的後邊執行.此時如果queue中只有2個operation的話不會多建立一個子線程的,進程中只有主線程和operation1的那個子線程.畢竟順序執行多開一個子線程是浪費的嘛.

5.queue中可以設定同時最多的線程數量

queue.maxConcurrentOperationCount = 3;

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