取得keyboard 座標和寬高（CGRect）

- (void) keyboardWillShow:(NSNotification*) notification

{

    NSDictionary* info = [notification userInfo];

    NSValue* aValue = [info objectForKey:UIKeyboardFrameEndUserInfoKey];

    CGRect keyboardRect = [aValue CGRectValue];

    NSLog(@"keyboardRect y:%f height:%f", keyboardRect.origin.y, keyboardRect.size.height);

}