iphone - 实现 shouldChangeCharactersInRange 方法时退格键不起作用 - iPhone Dev

Question

问题...我有一串允许的字符“0123456789”。我如何还允许键盘退格...当我从下面实现代码时...退格键不再有效...我该如何解决这个问题？

- (BOOL) textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string { 

    NSCharacterSet *nonNumberSet = [[NSCharacterSet characterSetWithCharactersInString:@"0123456789."] invertedSet];

    return ([string stringByTrimmingCharactersInSet:nonNumberSet].length > 0);

}

Answer 1

- (BOOL) textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    NSCharacterSet *nonNumberSet = [[NSCharacterSet characterSetWithCharactersInString:@"0123456789."] invertedSet];

    if (range.length == 1){
        return YES;
    }else{
        return ([string stringByTrimmingCharactersInSet:nonNumberSet].length > 0);
    }


}