概述

Masonry是一个非常轻量级的关于自动布局的库，这个相对于系统的AutoLayout的笨重给我这个习惯用纯代码来进行UI布局的人来说是一个非常不错的选择，好久没写笔记了所以特此记录下。
masnory下载地址:
OC版本: https://github.com/SnapKit/Masonry
Swift版本: https://github.com/SnapKit/SnapKit

属性

先来看看属性

  @property (nonatomic, strong, readonly) MASConstraint *left;
  @property (nonatomic, strong, readonly) MASConstraint *top;
  @property (nonatomic, strong, readonly) MASConstraint *right;
  @property (nonatomic, strong, readonly) MASConstraint *bottom;
  @property (nonatomic, strong, readonly) MASConstraint *leading;
  @property (nonatomic, strong, readonly) MASConstraint *trailing;
  @property (nonatomic, strong, readonly) MASConstraint *width;
  @property (nonatomic, strong, readonly) MASConstraint *height;
  @property (nonatomic, strong, readonly) MASConstraint *centerX;
  @property (nonatomic, strong, readonly) MASConstraint *centerY;
  @property (nonatomic, strong, readonly) MASConstraint *baseline;

这些属性与NSLayoutAttrubute的对照表如下：

36-1.png

使用

Masnory的绝大部分方法都放在UIViwe的类别里面:

  /**
 *  Creates a MASConstraintMaker with the callee view.
 *  Any constraints defined are added to the view or the appropriate superview once the block has finished executing
 *
 *  @param block scope within which you can build up the constraints which you wish to apply to the view.
 *
 *  @return Array of created MASConstraints
 */

- (NSArray *)mas_makeConstraints:(void(^)(MASConstraintMaker *make))block;

/**
 *  Creates a MASConstraintMaker with the callee view.
 *  Any constraints defined are added to the view or the appropriate superview once     the block has finished executing.
 *  If an existing constraint exists then it will be updated instead.
 *
 *  @param block scope within which you can build up the constraints which you wish to apply to the view.
 *
 *  @return Array of created/updated MASConstraints
 */
- (NSArray *)mas_updateConstraints:(void(^)(MASConstraintMaker *make))block;

/**
 *  Creates a MASConstraintMaker with the callee view.
 *  Any constraints defined are added to the view or the appropriate superview once     the block has finished executing.
 *  All constraints previously installed for the view will be removed.
 *
 *  @param block scope within which you can build up the constraints which you wish to apply to the view.
 *
 *  @return Array of created/updated MASConstraints
 */
- (NSArray *)mas_remakeConstraints:(void(^)(MASConstraintMaker *make))block;

增加约束的方法

 - (NSArray *)mas_makeConstraints:(void(^)(MASConstraintMaker *make))block;

更新约束的方法
- (NSArray *)mas_updateConstraints:(void(^)(MASConstraintMaker *make))block;

删除约束的方法
- (NSArray *)mas_remakeConstraints:(void(^)(MASConstraintMaker *make))block;

添加约束之前必须先实例化UIView 并且把其增加到父试图上面,否则会崩溃

Masnory进阶

Masonry为NSArray添加了两个特殊方法

/*
该方法只有存有UIView的NSArray数组可以调用，NSArray里面的UIView必须有共同的spuerView
该方法作用是UIView之间的水平等宽定距约束，或者垂直等高定距约束。
先确定间距，宽度或高度不确定，但相等
axisType只有MASAxisTypeHorizontal（水平间距类型）和MASAxisTypeVertical（垂直间距类型）
fixedSpacing是UIView两两之间的间距大小
leadSpacing是第一个UIView距离superView左(或上)边界的间距大小
tailSpacing是最后一个UIView距离superView右(或下)边界的间距大小
数组里的所有UIView水平宽度相等，或者垂直高度相等
*/
- (void)mas_distributeViewsAlongAxis:(MASAxisType)axisType 
                withFixedSpacing:(CGFloat)fixedSpacing 
                     leadSpacing:(CGFloat)leadSpacing 
                     tailSpacing:(CGFloat)tailSpacing;

/*
该方法只有存有UIView的NSArray数组可以调用，NSArray里面的UIView必须有共同的spuerView
该方法作用是UIView之间的水平定宽等距约束，或者垂直定高等距约束。
先确定宽度或高度，间距不确定，但相等
axisType只有MASAxisTypeHorizontal（水平间距类型）和MASAxisTypeVertical（垂直间距类型）
fixedSpacing是UIView两两之间的间距大小
leadSpacing是第一个UIView距离superView左(或上)边界的间距大小
tailSpacing是最后一个UIView距离superView右(或下)边界的间距大小
数组里的所有UIView间距相等
*/
- (void)mas_distributeViewsAlongAxis:(MASAxisType)axisType 
             withFixedItemLength:(CGFloat)fixedItemLength 
                     leadSpacing:(CGFloat)leadSpacing 
                     tailSpacing:(CGFloat)tailSpacing;