How to implement a multiple conversions in pickerView in objective-c - objective-c

Question

I am trying to create a conversion app. I have three units to convert: temperature (fahrenheit, pounds and miles to their metric counterparts).
I want to use a picker view, but I am having difficulties connecting the pickerView to the functionality and actually selecting each unit.
I have been able to implement this in a segmented control, but would like a pickerView to be able to add more conversions in the future.
Thanks!
ViewControlle.m
#import "ViewController.h"
#interface ViewController (){
NSArray *devices;
}
#end
//CONVERSIONS
// convert pounds to kilograms
double convertLbsToKgs(double poundsValue){
double kilogramsValue;
kilogramsValue = poundsValue / 2.205;
return kilogramsValue;
}
//convert fahrenheit to celcius
double convertFarenheitToCelcius(double farenheitValue){
double celciusValue;
celciusValue = (farenheitValue - 32) * 0.555;
return celciusValue;
}
//convert miles to kilometers
double convertMilesToKilometers(double milesValue){
double kilometersValue;
kilometersValue = milesValue * 1.609;
return kilometersValue;
}
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
devices = #[#"Pounds", #"Fahernheit", #"Miles"];
self.pickerView.dataSource = self;
self.pickerView.delegate = self;
}
// pickerView datascource & delegate methods
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{
return 1;
}
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{
return devices.count;
}
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{
return devices[row];
}
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{
self.outputTextBox.text = devices[row];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end
ViewController.h
#import <UIKit/UIKit.h>
#interface ViewController : UIViewController<UIPickerViewDataSource, UIPickerViewDelegate>
#property (weak, nonatomic) IBOutlet UITextField *inputField;
#property (weak, nonatomic) IBOutlet UILabel *outputTextBox;
#property (weak, nonatomic) IBOutlet UIPickerView *pickerView;
#end

Answer 1

Add this code in didselect method.
if ([devices[row] isEqualToString: #"Pounds"]) {
double kgs =[self convertLbsToKgs:[inputField.text doubleValue]];
outputTextBox.text=[NSString stringWithFormat:#"%f",kgs];
}else if ([devices[row] isEqualToString: #"Fahernheit"]){
double celcious =[self convertFarenheitToCelcius:[inputField.text doubleValue]];
outputTextBox.text=[NSString stringWithFormat:#"%f",celcious];
}else if ([devices[row] isEqualToString: #"Miles"]){
double kms=[self convertMilesToKilometers:[inputField.text doubleValue]];
outputTextBox.text=[NSString stringWithFormat:#"%f",kms];
}