简单的链式语法及实际运用（链式编程的基本原理）

不管在什么项目中总会有一些控件，它们样式相似却根据不同场景又有所不同。虽然也写了一些便利构造函数来快速的创建一些控件，但总感觉不尽人意，想用更少的代码来创建它们。

所以想到了链式语法，在查询部分资料和尝试后有了这篇日记。
直接百度的参考文章：
http://www.jianshu.com/p/a1458a69f72b

作者的总结很精髓
>首先获得实例中的一个block，然后执行block并返回实例本身，然后再执行实例的另一个block，而在这个block中同样返回实例本身，按此规律通过点语法一直往下执行。

接着我试着写了一个简单的可以用于快速创建UIButton的类：

.h文件内容

// Created by chizheng 

#import <UIKit/UIKit.h>

@interface CHZButton : UIButton

@property (nonatomic, copy) CHZButton * (^setTitle)(NSString *,UIControlState);

@property (nonatomic, copy) CHZButton * (^setTitleColor)(UIColor *,UIControlState);

@property (nonatomic, copy) CHZButton * (^setFont)(CGFloat);

@property (nonatomic, copy) CHZButton * (^setBackgroundColor)(UIColor *);

@property (nonatomic, copy) CHZButton * (^setCornerRadius)(CGFloat);

@property (nonatomic, copy) CHZButton * (^setImage)(NSString *,UIControlState);

@property (nonatomic, copy) CHZButton * (^addAction)(id,SEL,UIControlEvents);

@end

// Created by chizheng 

#import "CHZButton.h"


@implementation CHZButton

- (CHZButton * (^)(NSString * title,UIControlState state))setTitle{
return ^(NSString * title,UIControlState state){

[self setTitle:title forState:state];

return self;
};
}

- (CHZButton * (^)(UIColor * titleColor,UIControlState state))setTitleColor{
return ^(UIColor * titleColor,UIControlState state){

[self setTitleColor:titleColor forState:state];

return self;
};
}

- (CHZButton * (^)(CGFloat font))setFont{
return ^(CGFloat font){

self.titleLabel.font = [UIFont systemFontOfSize:font];

return self;
};
}

- (CHZButton * (^)(UIColor * backgroundColor))setBackgroundColor{
return ^(UIColor * backgroundColor){

[self setBackgroundColor:backgroundColor];

return self;
};
}

- (CHZButton * (^)(CGFloat cornerRadius))setCornerRadius{
return ^(CGFloat cornerRadius){

self.layer.cornerRadius = cornerRadius;
self.clipsToBounds = YES;

return self;
};
}

- (CHZButton * (^)(NSString * imageName,UIControlState state))setImage{
return ^(NSString * imageName,UIControlState state){

[self setImage:[UIImage imageNamed:imageName] forState:state];

return self;
};
}

- (CHZButton * (^)(id target,SEL selector,UIControlEvents events))addAction{
return ^(id target,SEL selector,UIControlEvents events){

[self addTarget:target action:selector forControlEvents:events];

return self;
};
}
@end

创建按钮时只需要如下代码

CHZButton * btn = [CHZButton new];
btn.frame = CGRectMake(Margin_leading, 64, screenW-2*Margin_leading, 44);
btn.setFont(18).setTitle(@"测试按钮", UIControlStateNormal).setBackgroundColor(btn_Color).setCornerRadius(4);
btn.addAction(self, @selector(btnAction:), UIControlEventTouchUpInside);
[self.view addSubview:btn];

后来感觉还是写成UIButton的分类会更好用