how to identify the visible keyboard is whether numberpad or default keyboard?

How can one identify if the visible keyboard is a nu开发者_运维问答mberpad or the default keyboard?

You should ask the UITextInputTraits for its keyboardType-propery. Both UITextField and UITextView implements this protocol.

An example would be:

if(myTextField.keyboardType == UIKeyboardTypeURL) {
    // do something if it wants URLs
}

Check the documentations for more.