block块的用法

@interface aaa : UIView

- (IBAction)click;

@property(nonatomic,copy)void (^PushBlock)();

+(instancetype)header;

#import <QuartzCore/QuartzCore.h>

@implementation aaa

- (IBAction)click {

    if (_PushBlock) {

        _PushBlock();

    }

}

+(instancetype)header

{

    return [[NSBundle mainBundle]loadNibNamed:@"aaa" owner:nil options:nil][0];

}

#import "ViewController.h"

#import "aaa.h"

#import "FirstViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    

   UIView *view=[[UIView alloc]initWithFrame:[UIScreen mainScreen].applicationFrame];

//    view.backgroundColor=[UIColor whiteColor];

    [self.view addSubview:view];

    aaa *a=[aaa header];

    a.frame=CGRectMake(500, 500, 200, 200);

    [self.view addSubview:a];

 

       FirstViewController *first=[[FirstViewController alloc]init];

    

    a.PushBlock=^{

       [self.navigationController pushViewController:first animated:YES];

    };

    // Do any additional setup after loading the view, typically from a nib.

}

- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}