iPhone键盘，自定义处理

Question

I need to react in a way specific to my iPhone app when the user is typing inside some UITextView field.

Three examples :

1. I want to dismiss the keyboard if the user types in: 'E'.
2. I want to jump to a new input line if the user types in: 'nN'.
3. I want to ignore if the user types in: 'A' or 'b'.

I am sure there must be a quite simple way to do what I want. But after browsing for a while on the net, I do not find a clear answer.

What is the way to go?

Thanks for any tip.

Answer 1

If you are using a UITextField , give the text field a delegate (implementing the UITextFieldDelegate protocol), and in the delegate, implement textField:shouldChangeCharactersInRange:replacementString: . Examine the replacement string and take action based on whether it contains the characters you're looking for.

If you are using a UITextView , give the text view a delegate (implementing the UITextViewDelegate protocol), and in the delegate, implement textView:shouldChangeTextInRange:replacementText: .

Answer 2

You could try implementing this in your UITextViewDelegate:

https://developer.apple.com/library/ios/#documentation/uikit/reference/UITextViewDelegate_Protocol/Reference/UITextViewDelegate.html

Check the replacementText . If it's @"e", call resignFirstResponder on the UITextView and return NO.

If it's @"A" or @"b", return NO.

I'm not exactly sure about the other one, but you can probably handle it here also and return NO.

Answer 3

I simple way to just flat out deny A and B is to do a simple thing like this (You would get up a check timer to run the void)

- (void) something {

if([statusString isEqualToString:@"a"]){
    statusString == @"";
}

}

This would simply delete every thing if the user types a. This may not be exactly what you want but I wanted to give a start