Question

请教如何实现UITextField值变化的实时监视

Answer 1

1、KVO方式
[textField addObserver:self forKeyPath:@"text" options:0 context:nil];
2、直接添加监视
[textField addTarget:self action:@selector(valueChanged:) forControlEvents:UIControlEventAllEditingEvents];
3、注册消息通知
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textFieldChanged:) name:UITextFieldTextDidChangeNotification object:textField];