Masonry約束

2019-11-09 18:12:24

字體：大中小

來源：轉載

供稿：網友

@PRoperty (nonatomic, strong, readonly) MASConstraint *left; //左側 @property (nonatomic, strong, readonly) MASConstraint *top; //上側 @property (nonatomic, strong, readonly) MASConstraint *right; //右側@property (nonatomic, strong, readonly) MASConstraint *bottom; //下側@property (nonatomic, strong, readonly) MASConstraint *leading; //首部@property (nonatomic, strong, readonly) MASConstraint *trailing; //尾部@property (nonatomic, strong, readonly) MASConstraint *width; //寬@property (nonatomic, strong, readonly) MASConstraint *height; //高@property (nonatomic, strong, readonly) MASConstraint *centerX; //橫向居中@property (nonatomic, strong, readonly) MASConstraint *centerY; //縱向居中@property (nonatomic, strong, readonly) MASConstraint *baseline; //文本基線

屬性有了,接著我們應該怎么在視圖中添加約束呢，Masonry給我們提供了3個方法

//新增約束 - (NSArray *)mas_makeConstraints:(void(^)(MASConstraintMaker *make))block;//更新約束 - (NSArray *)mas_updateConstraints:(void(^)(MASConstraintMaker *make))block;//清楚之前的所有約束,只會保留最新的約束 - (NSArray *)mas_remakeConstraints:(void(^)(MASConstraintMaker *make))block; 合理的利用這個3個函數，基本上可以應對任何情況了2.居中一個view // 防止block中的循環引用 __weak typeof (self) weakSelf = self // 初始化一個View UIView *bgView = [[UIView alloc]init]; bgView.backgroundColor = [UIColor redColor]; [self.view addSubview:bgView]; // 使用mas_makeConstraints添加約束 [bgView mas_makeConstraints:^(MASConstraintMaker *make) { make.center.equalTo(weakSelf.view); make.size.mas_equalTo(CGSizeMake(200, 200)); }]；

是不是很簡單，這里有一點要必須注意下，添加約束前必須要把view添加到視圖上。

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