Bank card formatted output and post four-bit display

#import <UIKit/UIKit.h>@interface  bankcardformat:uitextfield@end

#import "BankCardFormat.h"@interfaceBankcardformat () <UITextFieldDelegate>{nsstring*previoustextfieldcontent; Uitextrange*previousselection;}@end@implementationBankcardformat- (ID) initWithFrame: (cgrect) frame{ Self=[Super Initwithframe:frame]; if(self) {self.Delegate=Self ; [Self addtarget:self Action: @selector (reformatascardnumber:) Forcontrolevents:uico    Ntroleventeditingchanged]; }        returnSelf ;}- (void) Reformatascardnumber: (Uitextfield *) textfield{Nsuinteger targetcursorposition=[TextField offsetFromPosition:textField.beginningOfDocument ToPosition:textField.selectedTextRange.start]; NSString*cardnumberwithoutspaces =[self RemoveNonDigits:textField.text andpreservecursorposition:&Targetcursorposition]; if([cardnumberwithoutspaces length] > +) {[TextField settext:previoustextfieldcontent]; Textfield.selectedtextrange=previousselection; return; } nsstring*cardnumberwithspaces =[Self insertspaceseveryfourdigitsintostring:cardnumberwithoutspaces Andpreservecursorposition:&Targetcursorposition]; Textfield.text=cardnumberwithspaces; Uitextposition*targetposition =[TextField Positionfromposition:[textfield beginningofdocument]offset:targetcursorposition]; [TextField Setselectedtextrange:[textfield textrangefromposition:targetposition toposition:targetposition];}-(BOOL) TextField: (Uitextfield *) TextField Shouldchangecharactersinrange: (nsrange) range replacementstring: ( NSString *)string{previoustextfieldcontent=Textfield.text; Previousselection=Textfield.selectedtextrange; returnYES;}-(NSString *) removenondigits:(NSString *)stringAndpreservecursorposition: (Nsuinteger *) cursorposition{Nsuinteger originalcursorposition= *cursorposition; Nsmutablestring*digitsonlystring = [nsmutablestringNew];  for(Nsuinteger i =0; i < [stringLength]; i++) {Unichar Charactertoadd= [stringCHARACTERATINDEX:I]; if(IsDigit (Charactertoadd)) {NSString*stringtoadd =[nsstring stringwithcharacters:&charactertoadd Length:1];        [Digitsonlystring Appendstring:stringtoadd]; } Else {            if(I <originalcursorposition) {                (*cursorposition)--; }        }    }        returndigitsonlystring;}-(NSString *) insertspaceseveryfourdigitsintostring: (NSString *)stringAndpreservecursorposition:(Nsuinteger *) cursorposition{nsmutablestring*stringwithaddedspaces = [nsmutablestringNew]; Nsuinteger cursorpositioninspacelessstring= *cursorposition;  for(Nsuinteger i =0; i < [stringLength]; i++) {        if((i >0) && ((i%4) ==0) {[Stringwithaddedspaces appendString:@" "]; if(I <cursorpositioninspacelessstring) {                (*cursorposition) + +; }} Unichar Charactertoadd= [stringCHARACTERATINDEX:I]; NSString*stringtoadd =[NSString stringwithcharacters:&charactertoadd Length:1];    [Stringwithaddedspaces Appendstring:stringtoadd]; }        returnstringwithaddedspaces;}@end

//a four-bit space is required when entering a bank card number/*method of Use: Bankcardformat *bankcardnumber = [[Bankcardformat alloc]initwithframe:cgrectmake (60, 122, 230, 50)]; Bankcardnumber.borderstyle = Uitextborderstyleline; Bankcardnumber.placeholder = @ "Please enter your bank card number";  [Self.view Addsubview:bankcardnumber]; *///the bank card only shows the following four-bit practice/* Original card number NSString * Origincardno = [_weddata objectatindex:i][@ "Bankcardno"]; NSString *firstcardno = [Origincardno substringtoindex:origincardno.length-4];D log (@ "")//after four digits nsstring *lastfourC Ardno = [Origincardno substringfromindex:origincardno.length-4];D log (@ "%@", Lastfourcardno);D log ("%lu", unsigned Long) origincardno.length);D log ("%lu", (unsigned long) firstcardno.length); NSString *replacecardno = [Firstcardno stringbyreplacingoccurrencesofstring:firstcardno withString:@ "************** "];D log ("%lu ", (unsigned long) replacecardno.length); NSString *transform;if (replacecardno.length>firstcardno.length) {transform = [Replacecardno substringToIndex: Firstcardno.length];} DLog ("%lu", (unsigned long) transform.length);D log ("%@", Replacecardno); NSString *cardnumberstr = [NSString stringwithformat:@ "%@%@", Transform,lastfourcardno]; NSString *tmpstr = Cardnumberstr;dlog ("%@", Cardnumberstr);D log ("%@", tmpstr); int size = (int) TMPSTR.LENGTH/4; Nsmutablearray *tmpstrarr= [[Nsmutablearray alloc] init];for (int n = 0;n < size; n++) {[Tmpstrarr addobject:[tmpstr Substringwithrange:nsmak Erange (N*4, 4)];} [Tmpstrarr addobject:[tmpstr Substringwithrange:nsmakerange (size*4, (tmpstr.length% 4))]];tmpStr = [TMPSTRARR componentsjoinedbystring:@ ""];D log ("%lu", (unsigned long) tmpstr.length);D log ("%@", tmpstr);//  TMPSTR is the bank card number that finally shows only the last four digits.*/

Bank card formatted output and post four-bit display