我试着做一些复杂的事情,但应该是可能的。所以这里有一个对你们所有专家的挑战(这个论坛是由你们很多人组成的:))。
我正在创建一个问卷“组件”,我想加载在一个navigationcontroller(我的QuestionManagerViewController)。“组件”是一个“空的”UIViewController,它可以根据需要回答的问题加载不同的视图。
我的做法是:
Create Question1View object as a UIView subclass, defining some IBOutlets.
Create (using Interface Builder) the Question1View.xib (HERE IS WHERE MY PROBLEM PROBABLY IS). I set both the UIViewController and the UIView to be of class Question1View.
I link the outlets with the view's component (using IB).
I override the initWithNib of my QuestionManagerViewController to look like this:
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
if (self = [super initWithNibName:@"Question1View" bundle:nibBundleOrNil]) {
// Custom initialization
}
return self;
}
当我运行代码时,我得到这个错误:
2009-05-14 15:05:37.152 iMobiDines[17148:20b] ***由于未捕获异常'NSInternalInconsistencyException'而终止应用程序,原因:'-[UIViewController _loadViewFromNibNamed:bundle:] loaded the "Question1View" nib but the view outlet was not set.'
我确信有一种方法可以使用nib文件加载视图,而不需要创建一个viewController类。
还有一种更简单的方法来访问视图,而不是将nib作为数组处理。
1)创建一个自定义的View子类,其中包含你以后想要访问的任何出口。——MyView
2)在你想要加载和处理nib的UIViewController中,创建一个IBOutlet属性来保存加载的nib的视图
在MyViewController中(一个UIViewController子类)
@property (nonatomic, retain) IBOutlet UIView *myViewFromNib;
(别忘了合成它并在你的。m文件中发布它)
3)在IB中打开你的nib(我们称之为'myViewNib.xib'),设置你文件的所有者为MyViewController
4)现在连接你的文件的所有者出口myViewFromNib到nib的主视图。
5)现在在MyViewController中,写以下一行:
[[NSBundle mainBundle] loadNibNamed:@"myViewNib" owner:self options:nil];
当你这样做的时候,把你的财产称为“自我”。myViewFromNib”将让你从你的nib访问视图!
下面是一种在Swift中实现的方法(目前正在XCode 7 beta 5中编写Swift 2.0)。
从你在接口构建器中设置为“自定义类”的UIView子类中创建一个像这样的方法(我的子类叫做RecordingFooterView):
class func loadFromNib() -> RecordingFooterView? {
let nib = UINib(nibName: "RecordingFooterView", bundle: nil)
let nibObjects = nib.instantiateWithOwner(nil, options: nil)
if nibObjects.count > 0 {
let topObject = nibObjects[0]
return topObject as? RecordingFooterView
}
return nil
}
然后你可以像这样调用它:
let recordingFooterView = recordingFooterView . loadfromnib ()
你不应该在Interface Builder中将视图控制器的类设置为UIView的子类。这肯定是你的部分问题。保留它为UIViewController,它的子类,或者其他自定义类。
As for loading only a view from a xib, I was under the assumption that you had to have some sort of view controller (even if it doesn't extend UIViewController, which may be too heavyweight for your needs) set as the File's Owner in Interface Builder if you want to use it to define your interface. I did a little research to confirm this as well. This is because otherwise there would be no way to access any of the interface elements in the UIView, nor would there be a way to have your own methods in code be triggered by events.
If you use a UIViewController as your File's Owner for your views, you can just use initWithNibName:bundle: to load it and get the view controller object back. In IB, make sure you set the view outlet to the view with your interface in the xib. If you use some other type of object as your File's Owner, you'll need to use NSBundle's loadNibNamed:owner:options: method to load the nib, passing an instance of File's Owner to the method. All its properties will be set properly according to the outlets you define in IB.
这是一件应该比较容易的事情。我最终扩展了UIViewController并添加了一个loadNib:inPlaceholder: selector。现在我可以说
self.mySubview = (MyView *)[self loadNib:@"MyView" inPlaceholder:mySubview];
下面是这个类别的代码(它和Gonso描述的一样):
@interface UIViewController (nibSubviews)
- (UIView *)viewFromNib:(NSString *)nibName;
- (UIView *)loadNib:(NSString *)nibName inPlaceholder:(UIView *)placeholder;
@end
@implementation UIViewController (nibSubviews)
- (UIView *)viewFromNib:(NSString *)nibName
{
NSArray *xib = [[NSBundle mainBundle] loadNibNamed:nibName owner:self options:nil];
for (id view in xib) { // have to iterate; index varies
if ([view isKindOfClass:[UIView class]]) return view;
}
return nil;
}
- (UIView *)loadNib:(NSString *)nibName inPlaceholder:(UIView *)placeholder
{
UIView *nibView = [self viewFromNib:nibName];
[nibView setFrame:placeholder.frame];
[self.view insertSubview:nibView aboveSubview:placeholder];
[placeholder removeFromSuperview];
return nibView;
}
@end
对于那些需要管理多个自定义视图实例的人,也就是Outlet Collection,我合并并定制了@Gonso, @AVeryDev和@Olie的答案:
Create a custom MyView : UIView and set it as "Custom Class" of the root UIView in the desired XIB;
Create all outlets you need in MyView (do it now because after point 3 the IB will propose you to connect outlets to the UIViewController and not to the custom view as we want);
Set your UIViewController as "File's Owner" of the custom view XIB;
In the UIViewController add a new UIViews for each instance of MyView you want, and connect them to UIViewController creating an Outlet Collection: these views will act as "wrapper" views for the custom view instances;
Finally, in the viewDidLoad of your UIViewController add the following lines:
NSArray *bundleObjects;
MyView *currView;
NSMutableArray *myViews = [NSMutableArray arrayWithCapacity:myWrapperViews.count];
for (UIView *currWrapperView in myWrapperViews) {
bundleObjects = [[NSBundle mainBundle] loadNibNamed:@"MyView" owner:self options:nil];
for (id object in bundleObjects) {
if ([object isKindOfClass:[MyView class]]){
currView = (MyView *)object;
break;
}
}
[currView.myLabel setText:@"myText"];
[currView.myButton setTitle:@"myTitle" forState:UIControlStateNormal];
//...
[currWrapperView addSubview:currView];
[myViews addObject:currView];
}
//self.myViews = myViews; if need to access them later..