Masonry约束

最新推荐文章于 2021-11-08 13:39:17 发布

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最新推荐文章于 2021-11-08 13:39:17 发布

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本文链接：https://blog.youkuaiyun.com/MOONrunning/article/details/54907458

本文介绍如何使用Masonry库为iOS应用中的UIView添加自动布局约束。通过简单的代码示例，展示了如何实现视图的居中及尺寸设置，并强调了在添加约束前需将视图加入父视图的重要性。

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 @property (nonatomic, strong, readonly) MASConstraint *left;         //左侧

 @property (nonatomic, strong, readonly) MASConstraint *top;        //上侧

 @property (nonatomic, strong, readonly) MASConstraint *right;      //右侧

@property (nonatomic, strong, readonly) MASConstraint *bottom;   //下侧

@property (nonatomic, strong, readonly) MASConstraint *leading;   //首部

@property (nonatomic, strong, readonly) MASConstraint *trailing;   //尾部

@property (nonatomic, strong, readonly) MASConstraint *width;     //宽

@property (nonatomic, strong, readonly) MASConstraint *height;    //高

@property (nonatomic, strong, readonly) MASConstraint *centerX;  //横向居中

@property (nonatomic, strong, readonly) MASConstraint *centerY;  //纵向居中

@property (nonatomic, strong, readonly) MASConstraint *baseline; //文本基线

属性有了,接着我们应该怎么在视图中添加约束呢，Masonry给我们提供了3个方法

//新增约束
 - (NSArray *)mas_makeConstraints:(void(^)(MASConstraintMaker *make))block;

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

//清楚之前的所有约束,只会保留最新的约束
 - (NSArray *)mas_remakeConstraints:(void(^)(MASConstraintMaker *make))block;

 合理的利用这个3个函数，基本上可以应对任何情况了

2.居中一个view

  // 防止block中的循环引用
    __weak typeof (self) weakSelf = self
  // 初始化一个View
  UIView *bgView = [[UIView alloc]init];
  bgView.backgroundColor = [UIColor redColor];
  [self.view addSubview:bgView];
  // 使用mas_makeConstraints添加约束
  [bgView mas_makeConstraints:^(MASConstraintMaker *make) {  
  make.center.equalTo(weakSelf.view);       
  make.size.mas_equalTo(CGSizeMake(200, 200));
    }]；