IOS回调

在iOS 的设计中，至少存在两种方式的回调实现，一种是delegate,一种是CodeBlocks. 

blocks和delegate都含有转发并执行的逻辑;

blocks适合小而常用的逻辑，比如action，animation，

delegate适合重量级的转发，比如UIViewController之间的...，一般一个delegate涉及的接口会比较多。

delegate和block示例

DemoView.h

@protocol DemoViewDelegate <NSObject>

- (void)delegateApiOne:(id)sender;

@property (copy, nonatomic) void (^testBlock)(BOOL success);

@end

@interface DemoView

@property (weak, nonatomic) id<DemoViewDelegate> delegate;

@property (copy, nonatomic) void (^testBlock)(BOOL success);

@end

DemoView.m

@interface DemoView ()

//@property (strong, nonatomic) UIImage* testImage;

@end

@implementation DemoView

#pragma mark - private method

- (void)callDelegateApi:(id)sender {

    if ([self.delegate respondsToSelector:@selector(delegateApiOne:)]) {

        [self.delegate delegateApiOne];

    }

}

@end

ImplementDelegate.m

#import "DemoView.h"

@interface ImplementDelegate () <DemoViewDelegate>

@property (strong, nonatomic) DemoView* demoView;

@end

@implementation ImplementDelegate

#pragma mark - DemoViewDelegate

- (void)refreshBtnDidClicked:(id)sender {

    //todo

}

#pragma mark - private method

- (void)callBlock{

demoView.testBlock = ^(BOOL show) {

            NSLog(@"result = %d", success);

        };

}

@end