IOS block

@implementation ViewController

- (void)viewDidLoad
{
[super
viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
NSLog(@"我在完手机");
NSLog(@"手机没电了");
//调用手机充电方法，块内容为回调代码。
[self
chargeMyiPhone:^{
NSLog(@"出去逛街");
}];
NSLog(@"我在看电视");
}
/*!
* 给手机充电方法
*
* @param finishBlock 充电完成后的回调方法：void表示返回类型为void,(^)表示块类型,(void)表示无参数，finishBlock就是块的名字，理解为实参
*
* @since V1.0
*/
-(void)chargeMyiPhone:(void(^)(void))finishBlock
{
double delayInSeconds =
10.0;
dispatch_time_t popTime =
dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds *
NSEC_PER_SEC));
//10秒后调用
dispatch_after(popTime,
dispatch_get_main_queue(), ^(void){
NSLog(@"充好电了");
finishBlock();
});
}