IOS/Objective-C:用于调用完成bloc的语法

块方法应该是这样的:

-(void)getMyBlock: (void (^)(NSString * yourString))completed {
    completed(@"HELLO");
}

你这样称呼它:

[self getMyBlock:^(NSString *yourString) {
    NSLog(@"%@", yourString);
}];

http://goshdarnblocksyntax.com/

你需要提供一个街区 completed

[self getMyBlock:^(NSString *result) {
    // this code is called when the asynchronous code inside getMyBlock is done
}];

在执行 getMyBlock 方法代码如下:

- (void)getMyBlock: (void (^)(NSString *))completed {
    // do some asynchronous stuff
    NSString *result = // some result string
    if (completed) {
        completed(result);
    }
}