iOS 遍历AutoLayout约束

//遍历footerview约束(一般高,宽)

NSArray* constrains = self.footerView.constraints;

for (NSLayoutConstraint* constraint in constrains) {

if (constraint.firstAttribute ==NSLayoutAttributeHeight) {

constraint.constant = 0.0;

}

}

//遍历view约束，找到属于tableview的约束

NSArray* constrains2 = self.view.constraints;

for (NSLayoutConstraint* constraint in constrains2) {

if (constraint.secondItem == self.tableView) {

//据底部0

if (constraint.firstAttribute ==NSLayoutAttributeBottom) {

constraint.constant = 0.0;

}

}

}