Block 传值

#import <UIKit/UIKit.h>

@interface OneViewController : UIViewController

@property(nonatomic,copy)void (^Block)(NSString * str);

@end

- (void)viewDidLoad

{

    [super viewDidLoad];

    

    UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];

    btn.backgroundColor = [UIColor yellowColor];

    btn.frame = CGRectMake(100, 100, 100, 100);

    [self.view addSubview:btn];

    [btn addTarget:self action:@selector(btnDown) forControlEvents:UIControlEventTouchUpInside];

    

    

    // Do any additional setup after loading the view.

}

-(void)btnDown

{

   NSString *string = @"Block传值";

    self.Block(string);

}

.A

OneViewController *one = [[OneViewController alloc]init];

    UINavigationController *nav = [[UINavigationController alloc]initWithRootViewController:one];

    

    

    one.Block = ^(NSString *string){

    

        NSLog(@"%@成功",string);

    };

    

    self.window.rootViewController = nav;