ios - 添加哪些视图约束是否重要？

Question

我发现收集整个视图层次结构的所有约束并将它们全部添加到本地根视图很方便。与向适当的视图添加约束相比，这是不鼓励和/或一个坏主意吗？

下面是我使用的常见模式的简化。视图通常更复杂，有多个存储的约束，需要在添加或删除视图时更新。

- (void)updateViewConstraints
{
    UIView *content = ...;
    UIView *panel = ...;
    UILabel *label = ...;
    [self.view addSubview:content];
    [content addSubview:panel];
    [panel addSubview:label];

    NSMutableArray *constraints = [NSMutableArray new];
    [constraints addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"|[content]|"
                                                                             options:0
                                                                             metrics:nil
                                                                               views:NSDictionaryOfVariableBindings(content)]];
    [constraints addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"|[panel]|"
                                                                             options:0
                                                                             metrics:nil
                                                                               views:NSDictionaryOfVariableBindings(panel)]];
    [constraints addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"|[label]|"
                                                                             options:0
                                                                             metrics:nil
                                                                               views:NSDictionaryOfVariableBindings(label)]];

    [self.view addConstraints:constraints]
    self.storedConstraints = constraints;

    [super updateViewConstraints];
}

- (void)invalidateConstraints
{
    [self.view removeConstraints:self.storedConstraints];
    [self.view needsUpdateConstraints];
}