textField 监听事件(可以防止键盘联想)

- (void)viewWillAppear:(BOOL)animated {

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(infoAction:)name:UITextFieldTextDidChangeNotification object:nil];

}

- (void)viewWillDisappear:(BOOL)animated {

[[NSNotificationCenter defaultCenter] removeObserver:self name:UITextFieldTextDidChangeNotification object:nil];

}

- (void)infoAction:(NSNotification *)notification {

// notification.object 这个对象是传进来的 textfield 这个方法的目的是为了解决键盘联想的问题.

}