objective c - How to format UITextField with NSNumberFormatter? -

hope helps others, since haven't seen similar post on web shows how format text field using nsnumberformatter @ same time keep uitextfield cursor position should naturally be. those, because after formatting, nsstring inside uitextfield , setting field end cursor placed end of field. nice convert swift needs it.

and here answer issue, using uikeyboardtypenumberpad, work fine uikeyboardtypedecimalpad, if other keyboard types used, feel free add regex before using next code:

- (int)getcharoccurencies:(nsstring *)character instring:(nsstring *)string{      nsmutablearray *characters = [[nsmutablearray alloc] initwithcapacity:[string length]];     (int i=0; < [string length]; i++) {         nsstring *ichar  = [nsstring stringwithformat:@"%c", [string characteratindex:i]];         [characters addobject:ichar];     }      int count = 0;     (nsstring *ichar in characters) {         if ([ichar isequaltostring:character]) {             count++;         }     }     return count;  }  - (void)selecttextforinput:(uitextfield *)input atrange:(nsrange)range {     uitextposition *start = [input positionfromposition:[input beginningofdocument]                                                  offset:range.location];     uitextposition *end = [input positionfromposition:start                                                offset:range.length];     [input setselectedtextrange:[input textrangefromposition:start toposition:end]]; }  - (bool)textfield:(uitextfield *)textfield shouldchangecharactersinrange:(nsrange)range replacementstring:(nsstring *)string{      nsstring *charusedtoformat = @",";      nsmutablestring *textstring = [nsmutablestring stringwithstring:[textfield text]];     [textfield settintcolor:[uicolor darkgraycolor]];      if ([string isequaltostring:charusedtoformat]) {         return no;     }      if (range.location == 0 && [string isequaltostring:@"0"]) {         return no;     }      if ([[textstring stringbyreplacingcharactersinrange:range withstring:string] length] == 0) {         textfield.text = @"";         [self selecttextforinput:textfield atrange:nsmakerange(0, 0)];         return no;     }      nsstring *replaceblestring = [textstring substringwithrange:range];      if (string.length == 0 && [replaceblestring isequaltostring:charusedtoformat]) {          nsrange newrange = nsmakerange( range.location - 1, range.length);         range = newrange;         textstring = [nsmutablestring stringwithstring:[textstring stringbyreplacingcharactersinrange:newrange withstring:string]];     }else{          textstring = [nsmutablestring stringwithstring:[textstring stringbyreplacingcharactersinrange:range withstring:string]];     }       int commmacountbefore = [self getcharoccurencies:charusedtoformat instring:textstring];      textstring = [nsmutablestring stringwithstring:[textstring stringbyreplacingoccurrencesofstring:charusedtoformat withstring:@""]];     nsnumber *firstnumber = [nsnumber numberwithdouble:[textstring doublevalue]];     nsnumberformatter *formatter = [[nsnumberformatter alloc] init];     [formatter setnumberstyle:nsnumberformatterdecimalstyle];     //just in case     [formatter setformatterbehavior:nsnumberformatterbehavior10_4];     [formatter setgroupingseparator:charusedtoformat];     [formatter setdecimalseparator:@""];     [formatter setmaximumfractiondigits:0];     textstring = [nsmutablestring stringwithstring:[formatter stringforobjectvalue:firstnumber]];     textfield.text = textstring;      int commmacountafter = [self getcharoccurencies:charusedtoformat instring:textstring];     int commadif = commmacountafter - commmacountbefore;       int cursorpossition = (int)range.location + (int)string.length + commadif;      //set cursor position     nslog(@"cursorpossition: %d", cursorpossition);       [self selecttextforinput:textfield atrange:nsmakerange(cursorpossition, 0)];      return no;  }