添加 topLayoutGuide 后无法更改视图的框架

Question

我在导航控制器视图的超级视图中添加了一个topLayoutGuide约束，然后当我尝试更改导航控制器视图的框架时，例如：从（0,0,320,568）的当前框架到（200， 0, 320, 568) 使用

[[navigationController view] setFrame:CGRectMake(200, 0, 320, 568)];

动画结束后自动设置为 (0, 0, 320, 568)。

topLayoutGuide 约束是由这段代码添加的：

- (void)viewDidLoad { // of subclassed UINavigationController class .m file
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 7.0f) {
        [[self view] setTranslatesAutoresizingMaskIntoConstraints:NO];

        id topGuide = [self topLayoutGuide];
        UIView * selfView = [self view];
        NSDictionary *viewsDictionary = NSDictionaryOfVariableBindings (selfView, topGuide);
        [[[self view] superview] addConstraints:
         [NSLayoutConstraint constraintsWithVisualFormat:@"V:[topGuide]-0-[selfView]"
                                             options:0
                                             metrics:nil
                                               views:viewsDictionary]];
        [[[self view] superview] layoutSubviews]; // Must call this method here or the system raises an exception
    }
}

Answer 1

Autolayout 力求满足所有约束条件。在您的动画之后，此约束被破坏，并且在下一个布局周期中，它将满足您的约束并改回帧。 考虑动画布局约束更改或关闭自动布局。