View+MASAdditions.m
查找两个view的公共父视图Superview；
第一个view是自身self，第二个view是传进来的view；
第一层遍历，找到第二个view的superView；
第二层遍历，找到第一个view的superView，并判断和第二个view的superView是否相等，
若相等赋值给closestCommonSuperview；
如果closestCommonSuperview有值了，就跳出循环了；先跳出里面的while，在外面的while；
- (instancetype)mas_closestCommonSuperview:(MAS_VIEW *)view {
MAS_VIEW *closestCommonSuperview = nil;
MAS_VIEW *secondViewSuperview = view;
while (!closestCommonSuperview && secondViewSuperview) {
MAS_VIEW *firstViewSuperview = self;
while (!closestCommonSuperview && firstViewSuperview) {
if (secondViewSuperview == firstViewSuperview) {
closestCommonSuperview = secondViewSuperview;
}
firstViewSuperview = firstViewSuperview.superview;
}
secondViewSuperview = secondViewSuperview.superview;
}
return closestCommonSuperview;
}
NSArray+MASAdditions.m
查找数组中的子view的公共superView;
首先遍历这个数组，只有UIView的class才继续遍历；
前一个view(previousView)不为空，查找和previousView的公共父视图；
循环依次进行下去；
- (MAS_VIEW *)mas_commonSuperviewOfViews
{
MAS_VIEW *commonSuperview = nil;
MAS_VIEW *previousView = nil;
for (id object in self) {
if ([object isKindOfClass:[MAS_VIEW class]]) {
MAS_VIEW *view = (MAS_VIEW *)object;
if (previousView) {
commonSuperview = [view mas_closestCommonSuperview:commonSuperview];
} else {
commonSuperview = view;
}
previousView = view;
}
}
NSAssert(commonSuperview, @"Can't constrain views that do not share a common superview. Make sure that all the views in this array have been added into the same view hierarchy.");
return commonSuperview;
}
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转载自：https://blog.csdn.net/weixin_33843409/article/details/87472709