Objective C - Making UILabel update as user types text in UITextField

Question

How would I make a UILabel update as a user enters text in a UITextField. In my case, I have a quadratic equation solver for the iPhone and as the user enters the values of ab & c, I want a UILabel to update with the numbers given by the user.

Answer 1

[textField addTarget:self action:@selector(textFieldDidChange:) forControlEvents:UIControlEventEditingChanged];

然后，您的textFieldDidChange方法就像这样：

self.quadLabel.text = self.quadInput.text;