iPhone 键盘、完成按钮和 resignFirstResponder

问题描述

这可能是一个愚蠢的问题，但我在文档中找不到答案.弹出式键盘上的完成"按钮是否总是导致键盘消失?我在网上看到很多这样的代码:

This is probably a dumb question, but I can't find the answer in the docs. Did the "Done" button on the pop-up keyboard always cause the keyboard to disappear? I see a lot of code around the web like this:

- (BOOL)textFieldShouldReturn:(UITextField *)theTextField {
    [theTextField resignFirstResponder];
    return YES;
}

当我按下完成"按钮时，键盘弹出，UITextField 退出第一响应者.

When I press the "Done" button, the keyboard pops down and the UITextField resigns first responder.

我假设按下完成"按钮不会导致 UITextField 变为 resignFirstResponder，但这种行为有时会发生变化.

I'm presuming that pressing the "Done" button didn't used to cause a UITextField to resignFirstResponder, but that behavior changed at some time.

我在 OS 3.0 - 3.1.3 上调试

I'm debugging on OS 3.0 - 3.1.3

推荐答案

我做了一个小测试项目，只有一个 UITextField 和这段代码

I made a small test project with just a UITextField and this code

#import <UIKit/UIKit.h>
@interface TextFieldTestViewController : UIViewController
<UITextFieldDelegate>
{
    UITextField *textField;
}
@property (nonatomic, retain) IBOutlet UITextField *textField;
@end

#import "TextFieldTestViewController.h"
@implementation TextFieldTestViewController
@synthesize textField;

- (void)viewDidLoad
{
    [self.textField setDelegate:self];
    [self.textField setReturnKeyType:UIReturnKeyDone];
    [self.textField addTarget:self
                  action:@selector(textFieldFinished:)
        forControlEvents:UIControlEventEditingDidEndOnExit];
    [super viewDidLoad];
}
- (IBAction)textFieldFinished:(id)sender
{
    // [sender resignFirstResponder];
}

- (void)dealloc {
    [super dealloc];
}
@end

文本字段是一个未修改的 UITextField，拖到 NIB 上，插座已连接.
加载应用程序后，单击文本字段会弹出键盘.按下完成"按钮会使文本字段失去焦点并动画键盘.请注意，网络上的建议是始终使用 [sender resignFirstResponder] 但没有它也可以.

The text field is an unmodified UITextField dragged onto the NIB, with the outlet connected.
After loading the app, clicking in the text field brings up the keyboard. Pressing the "Done" button makes the text field lose focus and animates out the keyboard. Note that the advice around the web is to always use [sender resignFirstResponder] but this works without it.

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