ios - how to set the data in second component based on first component selection in UIPickerview -

i using uipicker 3 components. want if select row in first component on basis of selected component shows value of corresponding data in second component. used array first component value @"uk",@"us",@"eu".now want if user selected uk in first component want load uksize1=[nsarray arraywithobjects:@"1",@"2",@"3",@"4",@"5", nil]; in second component , if user selected in first component want eusize2=[nsarray arraywithobjects:@"11",@"22",@"33",@"44",@"55", nil]; load in second component. same eu value want load ussize3=[nsarray arraywithobjects:@"111",@"222",@"333",@"444",@"555", nil];. want second component value changed based on first component , third component value fixed.

this code tried not getting exact value.

- (id)init  {     if (self = [super init]) {         notestodisplayforkey = [nsarray arraywithobjects: @"uk", @"us", @"eu", nil];         scalenames = [nsarray arraywithobjects: @"11", @"22", @"33", @"555",@"666",@"777",nil];         scalevalue=[nsarray arraywithobjects: @"1" ,@"2", @"3", @"4",@"5",@"6", @"7",@"8",@"9", @"10",@"11",nil];         uksize1=[nsarray arraywithobjects:@"1",@"2",@"3",@"4",@"5", nil];         eusize2=[nsarray arraywithobjects:@"11",@"22",@"33",@"44",@"55", nil];         ussize3=[nsarray arraywithobjects:@"111",@"222",@"333",@"444",@"555", nil];     }     return self; }  - (nsinteger)numberofcomponentsinpickerview:(uipickerview *)pickerview  {      return 3; }  - (nsinteger)pickerview:(uipickerview *)pickerview numberofrowsincomponent:(nsinteger)component {      // returns     switch (component) {         case 0: return [notestodisplayforkey count];         case 1:             if([selectedkey isequaltostring:@"uk" ])             {                  return [uksize1 count];             }             else if([selectedkey isequaltostring:@"us"] )             {                  return [ussize3 count];             }             else             {                  return [eusize2 count];             }             //return [scalenames count];         case 2: return [scalevalue count];         default:break;     }     return 0; }  - (nsstring *)pickerview:(uipickerview *)pickerview titleforrow:(nsinteger)row forcomponent:(nsinteger)component {     switch (component) {         case 0: return [notestodisplayforkey objectatindex:row];         case 1:if([selectedkey isequaltostring:@"uk" ])         {             selectedscale = [scalenames objectatindex:row];             return selectedscale;         }         else if([selectedkey isequaltostring:@"us"] )         {             selectedscale = [ussize3 objectatindex:row];             return selectedscale;         }         else         {             selectedscale = [eusize2 objectatindex:row];             return selectedscale;         }         case 2: return [scalevalue objectatindex:row];         default:break;     }     return nil; }  - (void)pickerview:(uipickerview *)pickerview didselectrow:(nsinteger)row incomponent:(nsinteger)component {   //  nslog(@"row %i selected in component %i", row, component);     switch (component) {         case 0:             selectedkey = [notestodisplayforkey objectatindex:row];             return;          case 1:             // selectedscale = [scalenames objectatindex:row];             if([selectedkey isequaltostring:@"uk" ])                   {                       selectedscale = [scalenames objectatindex:row];                       return;                   }                 else if([selectedkey isequaltostring:@"us"] )                  {                  selectedscale = [ussize3 objectatindex:row];                 return;                  }                 else                 {                  selectedscale = [eusize2 objectatindex:row];                  return;                 }             return;          case 2:             selectedvalue = [scalevalue objectatindex:row];             return;         default:break;     } } 

just check method .it work .

 - (void)pickerview:(uipickerview *)pickerview didselectrow:(nsinteger)row incomponent:(nsinteger)component     {       //  nslog(@"row %i selected in component %i", row, component);         switch (component) {             case 0:                 selectedkey = [notestodisplayforkey objectatindex:row];                   [pickerview reloadallcomponents];                 return;              case 1:                 // selectedscale = [scalenames objectatindex:row];                 if([selectedkey isequaltostring:@"uk" ])                       {                           selectedscale = [uksize1 objectatindex:row];                           return;                       }                     else if([selectedkey isequaltostring:@"us"] )                      {                      selectedscale = [ussize3 objectatindex:row];                     return;                      }                     else                     {                      selectedscale = [eusize2 objectatindex:row];                      return;                     }                 return;              case 2:                 selectedvalue = [scalevalue objectatindex:row];                 return;             default:break;         }     }