【转】iOS：Masonry小记

转自：https://www.cnblogs.com/XYQ-208910/p/5011483.html

Masonry练习详解

添加约束的方式：

1.通过使用NSLayoutConstraints添加约束到约束数组中,之前必须设置translatesAutoresizingMaskIntoConstraints = NO,即取消自动布局;

2.通过使用MASConstraintMaker在block中添加约束,不需要再设置translatesAutoresizingMaskIntoConstraintst 属性,block内部已经帮助完成;

约束的关系：

equalTo <=======> NSLayoutRelationEqual 等于

lessThanOrEqualTo <======> NSLayoutRelationLessThanOrEqual 小于或等于

greaterThanOrEqualTo <=======> NSLayoutRelationGreaterThanOrEqual 大于或等于

MASViewAttribute：视图约束属性

image

UIView/NSView

这两个约束完全相同，都是view左边大于等于label的左边位置

make.left.greaterThanOrEqualTo(label）;

make.left.greaterThanOrEqualTo(label.mas_left）;

NSNumber给约束设置具体的值

<1>//width >= 200 && width <= 400

make.width.greaterThanOrEqualTo(@200);
 make.width.lessThanOrEqualTo(@400)

<2>//creates view.left = view.superview.left + 10

make.left.lessThanOrEqualTo(@10)

代替NSNumber，使用原始的数据或者结构体设置约束数据

make.top.mas_equalTo(42);
 make.height.mas_equalTo(20);
 make.size.mas_equalTo(CGSizeMake(50, 100));
 make.edges.mas_equalTo(UIEdgeInsetsMake(10, 0, 10, 0));
 make.left.mas_equalTo(view).mas_offset(UIEdgeInsetsMake(10, 0, 10, 0));

使用数组NSArray设置约束

make.height.equalTo(@[view1.mas_height, view2.mas_height]);
 make.height.equalTo(@[view1, view2]);
 make.left.equalTo(@[view1, @100, view3.right]);

使用优先级设置约束

.priorityHigh <======> UILayoutPriorityDefaultHigh 高优先级

.priorityMedium <========> between high and low ** 介于高/低之间**

.priorityLow <=========> UILayoutPriorityDefaultLow 低优先级

make.left.greaterThanOrEqualTo(label.mas_left).with.priorityLow();
 make.top.equalTo(label.mas_top).with.priority(600);

使用MASCompositeConstraints添加约束

edges：边缘

// make top, left, bottom, right equal view2
 make.edges.equalTo(view2);

// make top = superview.top + 5, left = superview.left + 10,
 // bottom = superview.bottom - 15, right = superview.right - 20
 make.edges.equalTo(superview).insets(UIEdgeInsetsMake(5, 10, 15, 20))

// All edges but the top should equal those of the superview
 make.left.right.and.bottom.equalTo(superview);
 make.top.equalTo(otherView);

size：大小

// make width and height greater than or equal to titleLabel
 make.size.greaterThanOrEqualTo(titleLabel)

// make width = superview.width + 100, height = superview.height - 50
 make.size.equalTo(superview).sizeOffset(CGSizeMake(100, -50))

center：中心

// make centerX and centerY = button1
 make.center.equalTo(button1)

// make centerX = superview.centerX - 5, centerY = superview.centerY + 10
 make.center.equalTo(superview).centerOffset(CGPointMake(-5, 10))

有时候，你需要修改现有的约束，以动画或删除/替换约束。在砌体中有几个不同的方法来更新约束。

1.使用设置References

// in public/private interface
 @property (nonatomic, strong) MASConstraint *topConstraint;
 ...
 // when making constraints
 [view1 mas_makeConstraints:^(MASConstraintMaker *make) {
 self.topConstraint = make.top.equalTo(superview.mas_top).with.offset(padding.top);
 make.left.equalTo(superview.mas_left).with.offset(padding.left);
 }];
 ...
 // then later you can call
 [self.topConstraint uninstall];

2.更新约束 mas_updateConstraints

- (void)updateConstraints {
 [self.growingButton mas_updateConstraints:^(MASConstraintMaker *make) {
 make.center.equalTo(self);
 make.width.equalTo(@(self.buttonSize.width)).priorityLow();
 make.height.equalTo(@(self.buttonSize.height)).priorityLow();
 make.width.lessThanOrEqualTo(self);
 make.height.lessThanOrEqualTo(self);
 }];

//according to apple super should be called at end of method

[super updateConstraints];
 }

3.重新设置mas_remakeConstraints

- (void)changeButtonPosition {

 [self.button mas_remakeConstraints:^(MASConstraintMaker *make) {
 make.size.equalTo(self.buttonSize);

    if (topLeft) {
        make.top.and.left.offset(10);
    } else {
        make.bottom.and.right.offset(-10);
    }
}];

}