7 
- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    ChildViewController *childviewcontroller = [[ChildViewController alloc] initWithNibName:@"ChildViewController" bundle:nil];


    [self addChildViewController:childviewcontroller];
    [self.view addSubview:childviewcontroller.view];
    [childviewcontroller willMoveToParentViewController:self];
    UIView *cview = [[UIView alloc] init];
    cview = childviewcontroller.view;
    [self.view removeConstraints:self.view.constraints];

    NSDictionary *viewsDictionary = NSDictionaryOfVariableBindings(cview);
    [self.view addConstraints:[NSLayoutConstraint 
                                constraintsWithVisualFormat:@"H:|-[cview]-|" 
                                                    options:0 metrics:nil                                        
                                                    views:viewsDictionary]];

}

我想在父视图上添加 childviewcontroller 视图。添加后我设置了约束，但它对我不起作用。

我也收到这样的警告

2013-07-25 10:47:30.564 neenah[1105:c07] Unable to simultaneously satisfy constraints.
    Probably at least one of the constraints in the following list is one you don't want. 
    Try this: (1) look at each constraint and try to figure out which you don't expect; 
    (2) find the code that added the unwanted constraint or constraints and fix it. 
    (Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't 
    understand, refer to the documentation for the UIView 
    property translatesAutoresizingMaskIntoConstraints) 
(
    "<NSLayoutConstraint:0x9256c90 H:|-(NSSpace(20))-[UIView:0x9256a00]   (Names: '|':UIView:0x92557a0 )>",
    "<NSAutoresizingMaskLayoutConstraint:0x755d690 h=--& v=--& H:[UIView:0x9256a00(320)]>",
    "<NSAutoresizingMaskLayoutConstraint:0x755d5a0 h=--& v=--& UIView:0x9256a00.midX == + 160>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x9256c90 H:|-(NSSpace(20))-[UIView:0x9256a00]   (Names: '|':UIView:0x92557a0 )>

Break on objc_exception_throw to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.
2013-07-25 10:47:30.567 neenah[1105:c07] Unable to simultaneously satisfy constraints.
    Probably at least one of the constraints in the following list is one you don't want. Try this: (1) look at each constraint and try to figure out which you don't expect; (2) find the code that added the unwanted constraint or constraints and fix it. (Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand, refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints) 
(
    "<NSLayoutConstraint:0x9256bb0 H:[UIView:0x9256a00]-(NSSpace(20))-|   (Names: '|':UIView:0x92557a0 )>",
    "<NSAutoresizingMaskLayoutConstraint:0x7561690 h=--- v=--- H:[UIWindow:0x92527c0(320)]>",
    "<NSAutoresizingMaskLayoutConstraint:0x755fe50 h=-&- v=-&- UIView:0x92557a0.width == UIWindow:0x92527c0.width>",
    "<NSAutoresizingMaskLayoutConstraint:0x755d690 h=--& v=--& H:[UIView:0x9256a00(320)]>",
    "<NSAutoresizingMaskLayoutConstraint:0x755d5a0 h=--& v=--& UIView:0x9256a00.midX == + 160>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x9256bb0 H:[UIView:0x9256a00]-(NSSpace(20))-|   (Names: '|':UIView:0x92557a0 )>

Break on objc_exception_throw to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.
4

1 回答 1

13

几点观察：

  1. 你应该关闭translatesAutoresizingMaskIntoConstraints：

    childviewcontroller.view.translatesAutoresizingMaskIntoConstraints = NO;

  2. 您也应该定义垂直约束：

    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-[cview]-|" 
                                                                  options:0
                                                                  metrics:nil                                        
                                                                    views:viewsDictionary]];

  3. 与您的问题无关，您不需要创建[[UIView alloc] init]for cview。你立即丢弃它。

  4. 我不确定您为什么要删除self.view. （我假设你在测试中撕掉头发时就这样做了。）你不必那样做。但是，如果您在这里发生了其他事情，让您认为您需要这样做，请告诉我们那是什么。

  5. 添加子控制器时，您调用didMoveToParentViewController，而不是willMoveToParentViewController。对你的addChildViewController呼唤willMoveToParentViewController。您只需要didMove...演绎版。

因此：

- (void)viewDidLoad {
    [super viewDidLoad];

    // instantiate the view controller

    ChildViewController *childViewController = [[ChildViewController alloc] initWithNibName:@"ChildViewController" bundle:nil];

    // or you can instantiate using storyboard
    //
    // ChildViewController *child = [self.storyboard instantiateViewControllerWithIdentifier:@"ChildIdentifier"];

    // now do the view controller containment calls to update the view controller hierarchy and add the view as appropriate

    [self addChildViewController:childViewController];
    childViewController.view.translatesAutoresizingMaskIntoConstraints = NO;
    [self.view addSubview:childViewController.view];
    [childViewController didMoveToParentViewController:self];
    UIView *childView = childViewController.view;

    NSDictionary *views = NSDictionaryOfVariableBindings(childView);
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-[childView]-|" options:0 metrics:nil views:views]];
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-[childView]-|" options:0 metrics:nil views:views]];
}
于 2013-07-25T05:24:01.680 回答