How to use NSNumberFormatter to insert blank space to NSString? - ios

Question

I want to write a UITextField that can auto format a number to bank number.
For example: Input 1234567890098765 will be automatically displayed as 1234 5678 9009 8765.
I'll use textFieldDelegate to do it, but I don't know how to use NSNumberFormatter.
How can I do it?

Answer 1

Using NSNumberFormatter is simple.
NSNumber *number = [NSNumber numberWithLongLong:1234567890098765];
NSNumberFormatter *formatter = [NSNumberFormatter new];
[formatter setUsesGroupingSeparator:YES];
[formatter setGroupingSize:3];
// [formatter setGroupingSeparator:#"\u00a0"];
NSString *string = [formatter stringFromNumber:number];
I deliberately commented the line that sets the formatter's grouping separator as it may be better to use the default one, which is provided by the user's locale (e.g. , in the USA, . in Germany and ' in Switzerland). Also please note that iOS doesn't use a space as a separator but a non-breaking space (U+00A0).

Answer 2

Try this :-
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
NSString *text = [textField text];
NSCharacterSet *characterSet = [NSCharacterSet characterSetWithCharactersInString:#"0123456789\b"];
string = [string stringByReplacingOccurrencesOfString:#" " withString:#""];
if ([string rangeOfCharacterFromSet:[characterSet invertedSet]].location != NSNotFound) {
return NO;
}
text = [text stringByReplacingCharactersInRange:range withString:string];
text = [text stringByReplacingOccurrencesOfString:#" " withString:#""];
NSString *newString = #"";
while (text.length > 0) {
NSString *subString = [text substringToIndex:MIN(text.length, 4)];
newString = [newString stringByAppendingString:subString];
if (subString.length == 4) {
newString = [newString stringByAppendingString:#" "];
}
text = [text substringFromIndex:MIN(text.length, 4)];
}
newString = [newString stringByTrimmingCharactersInSet:[characterSet invertedSet]];
if (newString.length >= 20) {
return NO;
}
[textField setText:newString];
return NO;
}
Hope this helps you..

Answer 3

i have a c++ solution, maybe you can change your string to cstring and then change back
char s[50]={'\0'},ch[99]={'\0'};
int i,j,k,len;
printf("input a string:\n");
scanf("%s",s);
len=strlen(s);
k=0;
for(i=0;i<len;i+=4)
{
for(j=0;j<4;j++)
{
*(ch+k)=*(s+i+j);
k++;
}
*(ch+k)=' ';
k++;
}
printf("%s\n",ch);