定位系统键盘

一.定位键盘视图

@implementation UIApplication(KeyboardView)

- (UIView*)keyboardView
{
    char* keyBoardViewClassName = NULL;
    if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 3.2)
    {
        keyBoardViewClassName = "UIPeripheralHostView";
    }
    else {
        keyBoardViewClassName = "UIKeyboard";
    }

    NSArray *windows = [self windows];
    for(UIWindow *window in [windows reverseObjectEnumerator])
    {
        for(UIView *view in [window subviews])
        {
            if(!strcmp(object_getClassName(view), keyBoardViewClassName))
            {
                return view;
            }

        }

    }
    return nil;
}

@end

二.定位firstResponder

UIView *firstResponder = [[[UIApplication sharedApplication] keyWindow] performSelector:@selector(firstResponder)];

参考：
Showing a “Loading…” message over the iPhone keyboard
UIKeyboardTypeNumberPad键盘增加Return键
object_getClassName
keyWindow