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。
我不确定一些答案在谈论什么，但我需要把这个答案放在这里，当我下次在谷歌中搜索时。关键词:“如何从一个nib加载一个UIView”或“如何从一个NSBundle加载一个UIView”
下面的代码几乎100%直接来自Apress Beginning iPhone 3的书籍(第247页，“使用新的表视图单元格”):
- (void)viewDidLoad {
[super viewDidLoad];
NSArray *bundle = [[NSBundle mainBundle] loadNibNamed:@"Blah"
owner:self options:nil];
Blah *blah;
for (id object in bundle) {
if ([object isKindOfClass:[Blah class]]) {
blah = (Blah *)object;
break;
}
}
assert(blah != nil && "blah can't be nil");
[self.view addSubview: blah];
}
这假设你有一个UIView子类叫Blah，一个nib叫Blah它包含一个UIView它的类设置为Blah。
类别:+ LoadFromNib NSObject
#import "NSObject+LoadFromNib.h"
@implementation NSObject (LoadFromNib)
+ (id)loadFromNib:(NSString *)name classToLoad:(Class)classToLoad {
NSArray *bundle = [[NSBundle mainBundle] loadNibNamed:name owner:self options:nil];
for (id object in bundle) {
if ([object isKindOfClass:classToLoad]) {
return object;
}
}
return nil;
}
@end
迅速扩展
extension UIView {
class func loadFromNib<T>(withName nibName: String) -> T? {
let nib = UINib.init(nibName: nibName, bundle: nil)
let nibObjects = nib.instantiate(withOwner: nil, options: nil)
for object in nibObjects {
if let result = object as? T {
return result
}
}
return nil
}
}
还有一个正在使用的例子:
class SomeView: UIView {
class func loadFromNib() -> SomeView? {
return self.loadFromNib(withName: "SomeView")
}
}
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..
谢谢大家。
我确实找到了做我想做的事的方法。
Create your UIView with the IBOutlets you need.
Create the xib in IB, design it to you liking and link it like this: The File's Owner is of class UIViewController (No custom subclass, but the "real" one). The File Owner's view is connected to the main view and its class is declared as the one from step 1).
Connect your controls with the IBOutlets.
The DynamicViewController can run its logic to decide what view/xib to load. Once its made the decission, in the loadView method put something like this:
NSArray* nibViews = [[NSBundle mainBundle] loadNibNamed:@"QPickOneView"
owner:self
options:nil];
QPickOneView* myView = [ nibViews objectAtIndex: 1];
myView.question = question;
就是这样!
主bundle的loadNibNamed方法将负责初始化视图和创建连接。
现在ViewController可以根据内存中的数据显示一个视图或另一个视图，而“父”屏幕不需要为这个逻辑而烦恼。
这是一个很好的问题(+1)，答案几乎是有帮助的;)抱歉，伙计们，虽然Gonso和AVeryDev都给出了很好的提示，但我花了很长时间才读完这篇文章。希望这个答案能帮助到其他人。
MyVC是持有这些东西的视图控制器。
MySubview是我们想从xib中加载的视图
In MyVC.xib, create a view of type MySubView that is the right size & shape & positioned where you want it.
In MyVC.h, have
IBOutlet MySubview *mySubView
// ...
@property (nonatomic, retain) MySubview *mySubview;
In MyVC.m, @synthesize mySubView; and don't forget to release it in dealloc.
In MySubview.h, have an outlet/property for UIView *view (may be unnecessary, but worked for me.) Synthesize & release it in .m
In MySubview.xib
set file owner type to MySubview, and link the view property to your view.
Lay out all the bits & connect to the IBOutlet's as desired
Back in MyVC.m, have
NSArray *xibviews = [[NSBundle mainBundle] loadNibNamed: @"MySubview" owner: mySubview options: NULL];
MySubview *msView = [xibviews objectAtIndex: 0];
msView.frame = mySubview.frame;
UIView *oldView = mySubview;
// Too simple: [self.view insertSubview: msView aboveSubview: mySubview];
[[mySubview superview] insertSubview: msView aboveSubview: mySubview]; // allows nesting
self.mySubview = msView;
[oldCBView removeFromSuperview];
对我来说棘手的一点是:其他答案中的提示从xib加载了我的视图，但没有替换MyVC中的视图(呸!)——我必须自己交换。
同样，为了访问mySubview的方法，.xib文件中的view属性必须设置为mySubview。否则，它会返回一个普通的UIView。
如果有一种方法来加载mySubview直接从它自己的xib，那将摇滚，但这让我在我需要的地方。
