| 水平或垂直 | H: V: |
V:[view1]-15-[view2] 设置view2的顶部距离view1的底部15距离 |
| 视图 | [item] |
［view1］ 匹配与字典里的key为view1的视图实例 |
| 父视图 | | |
H:|[view1]| view1的宽度等于父视图的宽度 |
| 关系 | == <= >= |
H:[view1]-(>=20)-[view2] view1的右边距离view2的左边的距离最小为20 |
| 度量 | metric |
H:[view1(<=someWidth)] someWidthz在度量字典中，为number值， |
| 水平堆砌 | [item][item] |
H:[view1(<=someWidth)] someWidthz在度量字典中，为number值， |
| 灵活间隔 | [item]-(>=0)-[item] | |