如何在 iOS 的数字键盘上添加完成按钮

这是在iOS7数字键盘中投影完成按钮的简单方法.在UITextField的下面的委托方法中，添加键盘显示的通知.

-(void)textFieldDidBeginEditing:(UITextField *)textField {
    
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWillShow:)
                                                 name:UIKeyboardWillShowNotification
                                               object:nil];
}

现在实现方法keyboardWillShow，如下所示.在这里，我们需要特别注意iOS7.

- (void)keyboardWillShow:(NSNotification *)note {
    // create custom button
    UIButton *doneButton = [UIButton buttonWithType:UIButtonTypeCustom];
    doneButton.frame = CGRectMake(0, 163, 106, 53);
    doneButton.adjustsImageWhenHighlighted = NO;
    [doneButton setImage:[UIImage imageNamed:@"doneButtonNormal.png"] forState:UIControlStateNormal];
    [doneButton setImage:[UIImage imageNamed:@"doneButtonPressed.png"] forState:UIControlStateHighlighted];
    [doneButton addTarget:self action:@selector(doneButton:) forControlEvents:UIControlEventTouchUpInside];
    
    if (SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"7.0")) {
        dispatch_async(dispatch_get_main_queue(), ^{
            UIView *keyboardView = [[[[[UIApplication sharedApplication] windows] lastObject] subviews] firstObject];
            [doneButton setFrame:CGRectMake(0, keyboardView.frame.size.height - 53, 106, 53)];
            [keyboardView addSubview:doneButton];
            [keyboardView bringSubviewToFront:doneButton];
            
            [UIView animateWithDuration:[[note.userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] floatValue]-.02
                                  delay:.0
                                options:[[note.userInfo objectForKey:UIKeyboardAnimationCurveUserInfoKey] intValue]
                             animations:^{
                                 self.view.frame = CGRectOffset(self.view.frame, 0, 0);
                             } completion:nil];
        });
    } else {
        // locate keyboard view
        dispatch_async(dispatch_get_main_queue(), ^{
            UIWindow* tempWindow = [[[UIApplication sharedApplication] windows] objectAtIndex:1];
            UIView* keyboard;
            for(int i=0; i<[tempWindow.subviews count]; i++) {
                keyboard = [tempWindow.subviews objectAtIndex:i];
                // keyboard view found; add the custom button to it
                if([[keyboard description] hasPrefix:@"UIKeyboard"] == YES)
                    [keyboard addSubview:doneButton];
            }
        });
    }
}

现在将此宏添加到适当的标头以检测SYSTEM_VERSION

#define SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(v)  ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedAscending)