代码自动布局，及masonry

/* Create constraints explicitly.  Constraints are of the form "view1.attr1 = view2.attr2 * multiplier + constant"
If your equation does not have a second view and attribute, use nil and NSLayoutAttributeNotAnAttribute.
*/
+(instancetype)constraintWithItem:(id)view1
attribute:(NSLayoutAttribute)attr1
relatedBy:(NSLayoutRelation)relation
toItem:(nullable id)view2
attribute:(NSLayoutAttribute)attr2
multiplier:(CGFloat)multiplier
constant:(CGFloat)c;

参数说明：

第一个参数 view1: 要设置的视图；

第二个参数 attr1: view1要设置的属性，稍后详解；

第三个参数 relation: 视图view1和view2的指定属性之间的关系，稍后详解；

第四个参数 view2: 参照的视图；

第五个参数 attr2: 参照视图view2的属性，稍后详解；

第六个参数 multiplier: 视图view1的指定属性是参照视图view2制定属性的多少倍；

第七个参数 c: 视图view1的指定属性需要加的浮点数。

typedef NS_ENUM(NSInteger, NSLayoutAttribute) {
NSLayoutAttributeLeft = 1,
NSLayoutAttributeRight,
NSLayoutAttributeTop,
NSLayoutAttributeBottom,
NSLayoutAttributeLeading,
NSLayoutAttributeTrailing,
NSLayoutAttributeWidth,
NSLayoutAttributeHeight,
NSLayoutAttributeCenterX,
NSLayoutAttributeCenterY,
NSLayoutAttributeBaseline,
NSLayoutAttributeLastBaseline = NSLayoutAttributeBaseline,
NSLayoutAttributeFirstBaseline NS_ENUM_AVAILABLE_IOS(8_0),

NSLayoutAttributeLeftMargin NS_ENUM_AVAILABLE_IOS(8_0),
NSLayoutAttributeRightMargin NS_ENUM_AVAILABLE_IOS(8_0),
NSLayoutAttributeTopMargin NS_ENUM_AVAILABLE_IOS(8_0),
NSLayoutAttributeBottomMargin NS_ENUM_AVAILABLE_IOS(8_0),
NSLayoutAttributeLeadingMargin NS_ENUM_AVAILABLE_IOS(8_0),
NSLayoutAttributeTrailingMargin NS_ENUM_AVAILABLE_IOS(8_0),
NSLayoutAttributeCenterXWithinMargins NS_ENUM_AVAILABLE_IOS(8_0),
NSLayoutAttributeCenterYWithinMargins NS_ENUM_AVAILABLE_IOS(8_0),

NSLayoutAttributeNotAnAttribute = 0
};

分三部分解释 NSLayoutAttribute

第一部分：常用的

NSLayoutAttributeLeft: CGRectGetMinX(view.frame);

NSLayoutAttributeRight: CGRectGetMaxX(view.frame);

NSLayoutAttributeTop: CGRectGetMinY(view.frame);

NSLayoutAttributeBottom: CGRectGetMinY(view.frame);

NSLayoutAttributeWidth: CGRectGetWidth(view.frame);

NSLayoutAttributeHeight: CGRectGetHeight(view.frame);

NSLayoutAttributeCenterX: view.center.x;

NSLayoutAttributeCenterY:view.center.y ;

NSLayoutAttributeBaseline: 文本底标线，在大多数视图中等同于NSLayoutAttributeBottom； 在少数视图，如UILabel，是指字母的底部出现的位置;

NSLayoutAttributeLastBaseline: 相当于NSLayoutAttributeBaseline;

NSLayoutAttributeFirstBaseline: 文本上标线;

NSLayoutAttributeNotAnAttribute: None;

第二部分： 根据国家使用习惯不同表示的意思不同

NSLayoutAttributeLeading: 在习惯由左向右看的地区，相当于NSLayoutAttributeLeft；在习惯从右至左看的地区，相当于NSLayoutAttributeRight;

NSLayoutAttributeTrailing: 在习惯由左向右看的地区，相当于NSLayoutAttributeRight；在习惯从右至左看的地区，相当于NSLayoutAttributeLeft;

第三部分：ios8新增属性，各种间距

NSLayoutAttributeLeftMargin，

NSLayoutAttributeRightMargin，

NSLayoutAttributeTopMargin，

NSLayoutAttributeBottomMargin，

NSLayoutAttributeLeadingMargin，

NSLayoutAttributeTrailingMargin，

NSLayoutAttributeCenterXWithinMargins，

NSLayoutAttributeCenterYWithinMargins，

下面拿上两段，自定义View 的适配

UIView *superview = self;

UIView *view1 = [[UIView alloc] init];
view1.translatesAutoresizingMaskIntoConstraints = NO;
view1.backgroundColor = [UIColor greenColor];
[superview addSubview:view1];

[superview addConstraints:@[
//view1 constraints
[NSLayoutConstraint constraintWithItem:view1
attribute:NSLayoutAttributeTop
relatedBy:NSLayoutRelationEqual
toItem:superview
attribute:NSLayoutAttributeTop
multiplier:1.0
constant:10],

[NSLayoutConstraint constraintWithItem:view1
attribute:NSLayoutAttributeLeft
relatedBy:NSLayoutRelationEqual
toItem:superview
attribute:NSLayoutAttributeLeft
multiplier:1.0
constant:10],

[NSLayoutConstraint constraintWithItem:view1
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:nil
attribute:NSLayoutAttributeNotAnAttribute
multiplier:1.0 constant:90],

[NSLayoutConstraint constraintWithItem:view1
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:nil
attribute:NSLayoutAttributeNotAnAttribute
multiplier:1.0 constant:90],
]];

UILabel *lab = [[UILabel alloc] init];
[superview addSubview:lab];
lab.numberOfLines = 0;
lab.backgroundColor = [UIColor yellowColor];
lab.translatesAutoresizingMaskIntoConstraints = NO;
[superview addConstraints:@[
//view1 constraints
[NSLayoutConstraint constraintWithItem:lab
attribute:NSLayoutAttributeTop
relatedBy:NSLayoutRelationEqual
toItem:view1
attribute:NSLayoutAttributeTop
multiplier:1.0
constant:0],

[NSLayoutConstraint constraintWithItem:lab
attribute:NSLayoutAttributeLeft
relatedBy:NSLayoutRelationEqual
toItem:view1
attribute:NSLayoutAttributeRight
multiplier:1.0 constant:10],

[NSLayoutConstraint constraintWithItem:lab
attribute:NSLayoutAttributeRight
relatedBy:NSLayoutRelationEqual
toItem:superview
attribute:NSLayoutAttributeRight
multiplier:1.0 constant:-10],
]];

lab.text = @"adsadasdasdasadsadasdasdasadsadasdasdasadsadasdasdasadsadasdasdasadsadasdasdasadsadasdasdasadsadasdasdasadsadasdasdasadsadasdasdas";

masonry

UIView *superview = self;

UIView *view1 = [[UIView alloc] initWithFrame:CGRectZero];
[superview addSubview:view1];
view1.backgroundColor = [UIColor greenColor];

[view1 mas_makeConstraints:^(MASConstraintMaker *make) {
make.top.equalTo(superview.mas_top).with.offset(10);
make.left.equalTo(superview.mas_left).with.offset(10);
make.size.mas_equalTo(CGSizeMake(90, 90));
}];

UILabel *lab = [[UILabel alloc] initWithFrame:CGRectZero];
[superview addSubview:lab];
lab.text = @"adsadasdasdasadsadasdasdasadsadasdasdasadsadasdasdasadsadasdasdasadsadasdasdasadsadasdasdasadsadasdasdasadsadasdasdasadsadasdasdas";
lab.numberOfLines = 0;
lab.backgroundColor = [UIColor yellowColor];
[lab mas_makeConstraints:^(MASConstraintMaker *make) {
make.top.equalTo(view1.mas_top).with.offset(0);
make.left.equalTo(view1.mas_right).with.offset(10);
make.right.equalTo(self.mas_right).with.offset(-10);
}];

效果图是一样上面的



讲解一下masonry