不能让UITextFieldDelegate工作

Question

我编写了一个自定义视图CustomViewA : UIView<UITextFieldDelegate>并实现了委托的方法。

在CustomViewA的init中，我写道：

- (id)initWithFrame:(CGRect)frame {
    self = [[[NSBundle mainBundle] loadNibNamed:@"CustomViewA" owner:self options:nil] objectAtIndex:0];
    if (self) {
        //the txtfieldA is a IBOutlet property linked to the nib file.
        self.txtfieldA.delegate = self; //not work
    }
    return  self;
}

在这个xib文件中包含一个UITextField控件，当我运行它并编辑textfield时，我在init method.But中设置了它的委托，委托的方法是而不是 called.Can，有人告诉我为什么吗？我怎样才能修好它？

Answer 1

要从xib文件加载一个UIView子类的视图，可以这样做：

// Reusable method to load a class which subclass UIView from a xib.
+ (id)loadNibNamed:(NSString *)nibName ofClass:(Class)objClass andOwner:(id)owner {
    if (nibName && objClass) {
        NSArray *objects = [[NSBundle mainBundle] loadNibNamed:nibName owner:owner options:nil];

        for (id currentObject in objects ){
            if ([currentObject isKindOfClass:objClass])
                return currentObject;
        }
    }

    return nil;
}

然后在控制器中添加视图：

myCustomViewA = [self loadNibNamed:@"customviewA" ofClass:[CustomViewA class] andOwner:self];

myCustomViewA.delegate = self; // Or do this in the xib file
[self.view addSubview:myCustomViewA];

Answer 2

确保UITextField被正确地连接到IBOutlet of CustomViewA。否则，尝试在init中设置委托将一无所获，

//if self.myTextField is nil, then this does nothing
self.myTextField.delegate = self;

Answer 3

只要从xib文件中输入视图，就不要使用-(id)init。

并在- (void)awakeFromNib.中设置UITextField的委托方法。