Segmented Controllers - ios5

Question

Trying to set an int value using a Segmented Controller. I've seen several tuts on how to change labels, but I need to set an int value.
#import "SecondViewController.h"
#interface SecondViewController ()
#end
#implementation SecondViewController
#synthesize caseCost;
#synthesize dilution;
#synthesize returnMsg;
#synthesize opcValue;
//synthesize opc; < -- Tried
//int opc; <--- tried
- (IBAction)opcView:(id)sender {
if (opcValue.selectedSegmentIndex == 0) {
int opc = 320;
}
if (opcValue.selectedSegmentIndex == 1) {
int opc = 128;
}
if (opcValue.selectedSegmentIndex == 2) {
int opc = 135;
}
if (opcValue.selectedSegmentIndex == 3) {
int opc = 88;
}
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
//int opc; <--- tried
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (IBAction)finishBtn:(id)sender {
//int opc = 320;
float case_cost = ([caseCost.text floatValue]);
float dilutionValue = ([dilution.text floatValue]);
float gpc = (opc / dilutionValue);
float gCost = (case_cost / gpc);
float bCost = (gCost / 4);
float bpc = (gpc * 4);
NSNumberFormatter *formatterCur = [[NSNumberFormatter alloc] init];
NSNumberFormatter *formatterInt = [[NSNumberFormatter alloc] init];
[formatterCur setNumberStyle:NSNumberFormatterCurrencyStyle];
[formatterInt setNumberStyle:NSNumberFormatterDecimalStyle];
NSString *bottlesCost = [formatterCur stringFromNumber:[NSNumber numberWithFloat:bCost]];
NSString *gallons = [formatterInt stringFromNumber:[NSNumber numberWithInt:gpc]];
NSString *gallonsCost = [formatterCur stringFromNumber:[NSNumber numberWithFloat:gCost]];
NSString *bottles = [formatterInt stringFromNumber:[NSNumber numberWithInt:bpc]];
returnMsg.text = [NSString stringWithFormat:#"%# gallons per case at %# per gallon and %# - 32 oz bottles at %# per bottle.", gallons, gallonsCost, bottles, bottlesCost];
}
- (IBAction)opcView:(id)sender {
}
#end
in the line "float gpc = (opc / dilutionValue);" is shows as an unknown value of opc, even though I think it should from the segmented controller. I'm using the segmented controller instead of Radio Buttons i've used in Java. I used the "//int opc=320" to make sure the rest of the code worked.

Answer 1

In each of the if blocks in your method - (IBAction)opcView:(id)sender you are creating a local int variable named opc. So when execution leaves the if block, the local variable disappears. Thus, in - (IBAction)finishBtn:(id)sender there is no variable named opc in scope.
You should declare opc to be a property as well. You will set this property when the segment control changes selection. Later, you can read the property's value in your finish button's handler.
#import "SecondViewController.h"
#interface SecondViewController()
#property (nonatomic) int opc;
#end
#implementation SecondViewController
// this method is wired to the segment control's UIControlEventValueChanged event
- (IBAction)opcView:(id)sender
{
if (opcValue.selectedSegmentIndex == 0) {
self.opc = 320;
}
if (opcValue.selectedSegmentIndex == 1) {
self.opc = 128;
}
if (opcValue.selectedSegmentIndex == 2) {
self.opc = 135;
}
if (opcValue.selectedSegmentIndex == 3) {
self.opc = 88;
}
}
- (IBAction)finishBtn:(id)sender
{
float case_cost = ([caseCost.text floatValue]);
float dilutionValue = ([dilution.text floatValue]);
float gpc = (self.opc / dilutionValue);
// lots more code
}