self.delegate = self;这样做有什么问题？ [英] self.delegate = self; what's wrong in doing that?

问题描述

self.delegate = self;这样做有什么问题？
和正确的方法是什么？

谢谢Nir。

代码：

 （UITextField *）initWith：（id）sender：（float）X：（float）Y：（float）width： （float）hieght：（int）textFieldTag {
 if（self = [super initWithFrame：CGRectMake（X，Y，width，hieght）]）{
 finalText = [[NSMutableString alloc] initWithString：@ ]; 
 senderObject = sender; 
 self.textColor = [UIColor blackColor]; 
 self.font = [UIFont systemFontOfSize：17.0]; 
 self.backgroundColor = [UIColor whiteColor]; 
 self.autocorrectionType = UITextAutocorrectionTypeNo; 
 self.keyboardType = UIKeyboardTypeDefault; 
 self.returnKeyType = UIReturnKeyDone; 
 self.clearButtonMode = UITextFieldViewModeWhileEditing; 
 self.tag = textFieldTag; 
 self.delegate = self; 
 [sender addSubview：self]; 
} 
 return self; 
} 
  

备注：这是一个文本字段，当我将代理设置为另一个对象（self.delegate = mainView）时，一切都可以正常工作，但是我将不得不在mainView中实现委托方法，我想将它们放在self（一个我创建的uiTextField类中） ）。如果我设置self.delegate = self，我会得到一个textField，但键盘不显示。

解决方案

查看此主题

http：//www.cocoabuilder。 com / archive / cocoa / 241465-iphone-why-can-a-uitextfield-be-its-own-delegate.html＃241505

基本上，当您单击UITextField作为委托时，冻结的原因是 respondToSelector 正在调用自身 - >无限递归。

UITextField是唯一的AFAIK。你通常可以使用一个类作为自己的委托，没有特别的问题。对于UITextField，您必须创建一个实际的委托（当然可以在UITextField上调用它的代理方法，只要注意避免保留循环，即使你使用ARC ）。

self.delegate = self; what's wrong in doing that? and what is the correct way of doing it?

Thanks, Nir.

Code:

(UITextField*)initWith:(id)sender:(float)X:(float)Y:(float)width:(float)hieght:(int)textFieldTag { 
    if (self = [super initWithFrame:CGRectMake(X, Y,width, hieght)]) {
        finalText = [[NSMutableString alloc] initWithString:@""];
        senderObject = sender;
        self.textColor = [UIColor blackColor]; 
        self.font = [UIFont systemFontOfSize:17.0]; 
        self.backgroundColor = [UIColor whiteColor]; 
        self.autocorrectionType = UITextAutocorrectionTypeNo;   
        self.keyboardType = UIKeyboardTypeDefault;     
        self.returnKeyType = UIReturnKeyDone; 
        self.clearButtonMode = UITextFieldViewModeWhileEditing;    
        self.tag = textFieldTag;        
        self.delegate = self;    
        [sender addSubview:self];
    }
    return self;
} 

Notes: This is a text field, and when I am setting the delegate to another object (self.delegate = mainView) everything works fine, but then I will have to implement the delegate methods in mainView, and I would like to put them in self (a uiTextField class wich I have created). If I am setting self.delegate = self, I do get a textField but the keyboard doesn't show up.

解决方案

See this thread

http://www.cocoabuilder.com/archive/cocoa/241465-iphone-why-can-a-uitextfield-be-its-own-delegate.html#241505

Basically, the reason for the "freeze" when you click on your UITextField with itself as a delegate is that respondsToSelector is calling itself -> infinite recursion.

UITextField is unique AFAIK. You can usually use a class as its own delegate with no particular problems. For UITextField you must create an actual delegate (that could, of course, call methods on the UITextField for which it's a delegate. Just be careful to avoid retain loops, even if you're using ARC).

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