Masonry的链式编成思想
mas_makeConstraints 给控件设置布局
参数是一个block
返回值是一个NSArray
- (NSArray *)mas_makeConstraints:(void(^)(MASConstraintMaker *))block {
self.translatesAutoresizingMaskIntoConstraints = NO;
MASConstraintMaker *constraintMaker = [[MASConstraintMaker alloc] initWithView:self];
block(constraintMaker);
return [constraintMaker install];
}
个人理解: 拿我特别喜欢吃的木屋烧烤举例子.
1.创建一个约束制造者
- 拿下菜单.
2.调用block(maker) 让外界把约束加好
- 把点菜那个单给顾客, 想吃啥自己往上面写.
3.[constraintMaker install]; 遍历约束制造者的所有约束并返回.
- 上菜给顾客
- install是老板烤串,把串烤好在return
MASConstraintMaker 约束制造者类 (点菜单) 在Masonry里也封装了些添加约束的方法. 通过链式编成思想,使得添加约束简单明了.
- 点菜时候各种菜名很复杂,或许有不认识的字,所以顾客点菜时候不用写菜的全名,只要把相应的编号写上去就好 比如想点3L的朝日啤酒 就写2310.
另外关于链式编成思想.我以Masonry的源码为基础 写了一个简单的图文混排,以便更好的理解链式编成思想.
- (void)viewDidLoad {
[super viewDidLoad];
NSString *str = @"Sniper";
NSMutableAttributedString *waterStr = [str makeString:^(ZNStringMaker *maker) {
maker.addStr(@" is").addStr(@" a").addStr(@" Developer ").addImgName(@"water").addStr(@" yo~!");
}];
UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(30, 50, 240, 40)];
[self.view addSubview:label];
label.attributedText = waterStr;
label.backgroundColor = [UIColor orangeColor];
}
结果:
屏幕快照 2016-07-26 下午5.53.18.png
代码:
#import <Foundation/Foundation.h>
#import "ZNStringMaker.h"
@interface NSString (ZNAdd)
- (NSMutableAttributedString *)makeString:(void (^)(ZNStringMaker *maker))block;
@end
#import "NSString+ZNAdd.h"
@implementation NSString (ZNAdd)
- (NSMutableAttributedString *)makeString:(void (^)(ZNStringMaker *maker))block; {
ZNStringMaker *maker = [[ZNStringMaker alloc] initWithStr:self];
block(maker);
return [maker makeAttrStr];
}
@end
#import <Foundation/Foundation.h>
@interface ZNStringMaker : NSObject
- (ZNStringMaker * (^)(NSString *str))addStr;
- (ZNStringMaker * (^)(NSString *imgNameStr))addImgName;
- (instancetype)initWithStr:(NSString *)str;
- (NSMutableAttributedString *)makeAttrStr;
@end
#import "ZNStringMaker.h"
#import <UIKit/UIKit.h>
@interface ZNStringMaker ()
@property (nonatomic, copy)NSMutableString *strResult;
@property (nonatomic, copy)NSMutableAttributedString *attrStrResult;
@end
@implementation ZNStringMaker
- (ZNStringMaker * (^)(NSString *str))addStr {
return ^(NSString *str) {
if (str) {
if (_attrStrResult) {
NSAttributedString *attrStr = [[NSAttributedString alloc] initWithString:str];
[_attrStrResult appendAttributedString:attrStr];
} else {
[_strResult appendString:str];
}
}
return self;
};
}
-(ZNStringMaker *(^)(NSString *))addImgName {
return ^(NSString *str) {
if (str) {
NSTextAttachment *textAttach = [[NSTextAttachment alloc] init];
NSString *imgName = str;
textAttach.image = [UIImage imageNamed:imgName];
NSAttributedString *attrImg = [NSAttributedString attributedStringWithAttachment:textAttach];
_attrStrResult = [[NSMutableAttributedString alloc] initWithString:_strResult];
[_attrStrResult appendAttributedString:attrImg];
}
return self;
};
}
- (instancetype)initWithStr:(NSString *)str {
self = [super init];
if (self) {
_strResult = [[NSMutableString alloc] initWithString:str];
}
return self;
}
- (NSMutableAttributedString *)makeAttrStr {
return _attrStrResult;
}
@end
