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
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
<pre style="margin: 0px; padding: 0px; overflow: auto;">make.width.greaterThanOrEqualTo(@200);
make.width.lessThanOrEqualTo(@400)</pre>
<pre style="margin: 0px; padding: 0px; overflow: auto;"><2>//creates view.left = view.superview.left + 10</pre>
<pre style="margin: 0px; padding: 0px; overflow: auto;">make.left.lessThanOrEqualTo(@10)</pre>
<pre style="margin: 0px; padding: 0px; overflow: auto;">代替NSNumber，使用原始的数据或者结构体设置约束数据</pre>
<pre style="margin: 0px; padding: 0px; overflow: auto;">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));</pre>
<pre style="margin: 0px; padding: 0px; overflow: auto;">使用数组NSArray设置约束</pre>
<pre style="margin: 0px; padding: 0px; overflow: auto;">make.height.equalTo(@[view1.mas_height, view2.mas_height]);
make.height.equalTo(@[view1, view2]);
make.left.equalTo(@[view1, @100, view3.right]);</pre>
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
<pre style="margin: 0px; padding: 0px; overflow: auto;">make.left.greaterThanOrEqualTo(label.mas_left).with.priorityLow();
make.top.equalTo(label.mas_top).with.priority(600);</pre>
使用MASCompositeConstraints添加约束
edges：边缘
<pre style="margin: 0px; padding: 0px; overflow: auto;">// 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))</pre>
<pre style="margin: 0px; padding: 0px; overflow: auto;">// All edges but the top should equal those of the superview
make.left.right.and.bottom.equalTo(superview);
make.top.equalTo(otherView);</pre>
size：大小
<pre style="margin: 0px; padding: 0px; overflow: auto;">// 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))</pre>
center：中心
<pre style="margin: 0px; padding: 0px; overflow: auto;">// 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))</pre>
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
<pre style="margin: 0px; padding: 0px; overflow: auto;">// 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];</pre>
<pre style="margin: 0px; padding: 0px; overflow: auto;">2.更新约束 mas_updateConstraints</pre>
<pre style="margin: 0px; padding: 0px; overflow: auto;">- (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];
}</pre>
<pre style="margin: 0px; padding: 0px; overflow: auto;">3.重新设置mas_remakeConstraints</pre>
<pre style="margin: 0px; padding: 0px; overflow: auto;">- (void)changeButtonPosition {</pre>
<pre style="margin: 0px; padding: 0px; overflow: auto;"> [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);
}
}];
}</pre>
