title: Show data in UIPickerView second component based on first component selection
body: <p>I am using a picker with two components. I want if I select a row in first component on the basis of selected component it shows the value of the corresponding data.</p>
  
  <p><img src="https://i.stack.imgur.com/O6m5O.png" alt="enter image description here"></p>
  
  <p>As Picker is showing that England has corresponding clubs when England is selected. I want to do same for the other countries. But I am not getting which approach to follow.</p>
  
  <p>Here is my code:</p>
  
  <pre><code>- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)thePickerView 
  {
  
      return 2;
  }
  
  - (NSInteger)pickerView:(UIPickerView *)thePickerView numberOfRowsInComponent:(NSInteger)component 
  {
  
      if(component ==0)
      {
          return [Nations count];
      }
  
      else{
          if(country_flag==0)
          {
          return [England count];
          }
          else if (country_flag==1)
          {
              return [Espana count];
          }
          else if (country_flag==2)
          {
              return [Netherlands count];
          }
          else if (country_flag==3)
          {
              return [Germany count];
          }
          else if (country_flag==4)
          {
              return [Italy count];
          }
      }
  
      return 0;
  }
  - (NSString *)pickerView:(UIPickerView *)thePickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
  {
      if(component ==0)
      {
          return [Nations objectAtIndex:row];
      }
  
      else{
          if(country_flag==0)
          {
              return [England objectAtIndex:row];
          }
          else if (country_flag==1)
          {
              return [Espana objectAtIndex:row];
          }
          else if (country_flag==2)
          {
              return [Netherlands objectAtIndex:row];
          }
          else if (country_flag==3)
          {
              return [Germany objectAtIndex:row];
          }
          else if (country_flag==4)
          {
              return [Italy objectAtIndex:row];
          }
      }
  
      return 0;
  
  }
  - (void)pickerView:(UIPickerView *)thePickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
  {
  
      label.text=[Nations objectAtIndex:row];
  
      str = [[NSString alloc]init];
  
      if (country_flag==0) {
          str=@"England";
          label_1.text=[NSString stringWithFormat:@"%@",str];
          NSLog(@"%@",label_1);
          str=@"";
          country_flag =1;
          [picker reloadAllComponents];
      }
      else if (country_flag==1)
      {
          str=@"Espana";
          label_1.text=[NSString stringWithFormat:@"%@",str];
          NSLog(@"%@",label_1);
          str=@"";
          country_flag =2;
          [picker reloadAllComponents];
      }
      else if (country_flag==2)
      {
          str=@"Netherlands";
          label_1.text=[NSString stringWithFormat:@"%@",str];
          NSLog(@"%@",label_1);
          str=@"";
          country_flag =3;
          [picker reloadAllComponents];
      }
      else if (country_flag==3)
      {
          str=@"Germany";
          label_1.text=[NSString stringWithFormat:@"%@",str];
          NSLog(@"%@",label_1);
          str=@"";
          country_flag =4;
          [picker reloadAllComponents];
      }
      else if (country_flag==4)
      {
          str=@"Germany";
          label_1.text=[NSString stringWithFormat:@"%@",str];
          NSLog(@"%@",label_1);
          str=@"";
        //  country_flag =4;
          [picker reloadAllComponents];
      }
  
  }
  </code></pre>
  
  <p><strong>EDIT:</strong></p>
  
  <p>Here is the data</p>
  
  <pre><code>Nations = [[NSMutableArray alloc]initWithObjects:@"England",@"Espana",@"Germany",@"Netherlands",@"Germany",@"Italy", nil];
  
      England=[[NSMutableArray alloc]initWithObjects:@"Arsenal",@"Chelsea",@"Manchester City",@"Manchester United",@"Liverpool",@"Tottenham",@"Fulham City",@"Stoke City",@"Sunderland",@"NewCastle United",@"Blackburn Rovers",@"Southampton",@"Wolvers",@"Aston Villa", nil];
  
      Espana = [[NSMutableArray alloc]initWithObjects:@"Barcelona",@"Real Madrid",@"Valencia",@"Athletico Madrid",@"Athletico Balbao",@"Getafe CF",@"Sevilla CF", nil];
  
      Netherlands = [[NSMutableArray alloc]initWithObjects:@"Celtics",@"Ajax",@"Amesterdam", nil];
  
      Germany = [[NSMutableArray alloc]initWithObjects:@"Bayern Munich",@"Bermen",@"Fiorentina",@"Pampas",@"Nord", nil];
  
      Italy = [[NSMutableArray alloc]initWithObjects:@"AC Milan",@"Inter Milan",@"Juventus", nil];
  </code></pre>