textField到相应字段执行方法

[_tel_tf addTarget:self action:@selector(textFiledDidChange:) forControlEvents:UIControlEventEditingChanged];
- (void) textFiledDidChange:(UITextField *)text
{
    if( _tel_tf.text.length == 11){
       
        [_tel_tf restorationIdentifier];
        tele = [NSString stringWithString:_tel_tf.text];
    //须知行的方法
    }
}
//限制舒服字符的长度
- (BOOL) textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    //用户名
    if (textField == _tel_tf) {
        if (_tel_tf.text.length > 6) {
            if (string.length > 0) {
                return NO;
            }else{
                return YES;
            }
        }
    }
    return YES;
}