Question

this is I think basic problem because stackoverflow is full of it and ofc google too. But nothing helped me. I need to pass integer vaule which says which row is selected, to another class. Here is my code:

TableViewController.h

#import <UIKit/UIKit.h>

@interface TableViewController : UIViewController <UITableViewDataSource, UITableViewDelegate>

{
    NSArray *tabledata;
}
@property (nonatomic, retain) NSArray *tabledata;
@property (strong, nonatomic) IBOutlet UITableView *tableView;
@property(nonatomic) NSInteger selectedRow;

@end

TableViewController.m

#import "Instruments.h"

@interface Instruments ()

@end

@implementation Instruments
@synthesize tabledata;
@synthesize tableView;
@synthesize selectedRow;

- (void)viewDidLoad
{
    [super viewDidLoad];
    tabledata = [[NSArray alloc] initWithObjects:@"Row1", @"Row2", @"Row3", nil];
    self.selectedRow = 0;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return [tabledata count];
}

- (UITableViewCell *)tableView:(UITableView *)tableview cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *cell = nil;
    cell = [tableview dequeueReusableCellWithIdentifier:@"Row1"];
    if (cell == nil)
    {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"Row1"];
    }

    cell.textLabel.text = [tabledata objectAtIndex:indexPath.row];

    if (indexPath.row == self.selectedRow)
    {
        cell.accessoryType = UITableViewCellAccessoryCheckmark;
    } else {
        cell.accessoryType = UITableViewCellAccessoryNone;
    }

    return cell;
}

- (void)tableView:(UITableView *)tableview didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (indexPath.row != self.selectedRow) {
        self.selectedRow = indexPath.row;
    }

    [tableView reloadData];
}


- (void)viewDidUnload {
    [self setTableView:nil];
    [super viewDidUnload];
}
@end

FirstViewController.h

//Some code which calls my variable 'selectedrow'
...

FirstViewController.m

...
if selectedrow = 0 {
//some code
}
if selectedrow = 1 {
//some code
}
if selectedrow = 2 {
//some code
}
...

How should I declare my variable ‘selectedrow’ to be able to use it in FirstViewController?

Answer 1

In the MVC world, everything that you intend to share among multiple view controllers belongs in the model. Your model class is globally available; one controller sets the value; the other reads it.

Header: MyAppModel.h

@interface MyAppModel // <<<=== Use an appropriate name here
+(MyAppModel*)instance;
@property (readwrite) NSInteger selectedRow;
@end

Implementation: MyAppModel.m

@implementation MyAppModel
+(MyAppModel*)instance {
    static MyAppModel *statInst;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        statInst = [[MyAppModel alloc] init];
    });
    return statInst;
}
@synthesize selectedRow;
@end

Usage: your view controllers

// Set the selected row
[MyAppModel instance].selectedRow = indexPath.row;

// Access the last selected row
switch ([MyAppModel instance].selectedRow) {
    case 1: // some code
    break;
    case 2: // some code
    break;
    case 3: // some code
    break;
}