Question

I have a simple utility app, with a MainViewController.m & h and a FlipsideViewController.m & h. Within my storyboard I have a button on MainViewController. I want to be able to click the button and run a method in FlipsideViewController.m is this possible? this is my first app and I am a total novice. all comments / suggestion welcome.

enter code here

i have this in my FlipsideViewController.m this is what i want to call when i click the button.

- (void)SaveFPQData
{
NSLog(@"Data Saved");
}

and this is what i have in MainViewController.m

- (IBAction)saveButton:(id)sender
{

}

This is the code I have so far;

MainViewController.h

#import "FlipsideViewController.h"
#import "sqlite3.h"
#import "FPQCheck.h"

@interface MainViewController : UIViewController <FlipsideViewControllerDelegate>

@property (weak, nonatomic) IBOutlet UITextField *nameField;
@property (weak, nonatomic) IBOutlet UITextField *checkField;
@property (weak, nonatomic) IBOutlet UITextField *commentsField;
@property (weak, nonatomic) FlipsideViewController *flipsidecontroller;

- (IBAction)saveButton:(id)sender;
- (IBAction)showHistoryButton:(id)sender;


@end

MainViewController.m

#import "MainViewController.h"
#import "FlipsideViewController.h"
#import "sqlite3.h"


@interface MainViewController ()

@end


@implementation MainViewController

- (void)viewDidLoad
{


[super viewDidLoad];
}

// Do any additional setup after loading the view, typically from a nib.


- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

#pragma mark - Flipside View

- (void)flipsideViewControllerDidFinish:(FlipsideViewController *)controller
{
[self dismissViewControllerAnimated:YES completion:nil];
}

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if ([[segue identifier] isEqualToString:@"showAlternate"]) {
    [[segue destinationViewController] setDelegate:self];
}
}


- (IBAction)saveButton:(id)sender
{
[self.flipsidecontroller SaveFPQData];


//[[NSNotificationCenter defaultCenter] postNotificationName:@"SaveFPQData" object:nil];
}

- (IBAction)showHistoryButton:(id)sender

{

}
@end

FlipSideViewController.h

#import <UIKit/UIKit.h>
#import "FPQCheck.h"

@class FlipsideViewController;

@protocol FlipsideViewControllerDelegate

- (void)flipsideViewControllerDidFinish:(FlipsideViewController *)controller;


@end

@interface FlipsideViewController : UIViewController <UITableViewDelegate, UITableViewDataSource>


@property (weak, nonatomic) IBOutlet UITableView *myTableView;

@property (weak, nonatomic) id <FlipsideViewControllerDelegate> delegate;

-(void)SaveFPQData;


- (IBAction)done:(id)sender;
- (IBAction)deleteEntry:(id)sender;



@end

FlipSideViewController.m

#import "FlipsideViewController.h"
#import "MainViewController.h"


@interface FlipsideViewController ()
{
NSMutableArray *arrayOfCheck;
sqlite3 *fpqDB;
NSString *dbPathString;

}

@end

@implementation FlipsideViewController

- (void)viewDidLoad
{

/*
[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(SaveFPQData)
                                             name:@"SaveFPQData"
                                           object:nil];
 */


[super viewDidLoad];
arrayOfCheck = [[NSMutableArray alloc]init];
[self creatOrOpenDB];
[[self myTableView]setDelegate:self];
[[self myTableView]setDataSource:self];

// Do any additional setup after loading the view, typically from a nib.

}

- (void)SaveFPQData
{
NSLog(@"Data Saved");

}


-(void)creatOrOpenDB
{
NSArray *path = NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES);
NSString *docPath = [path objectAtIndex:0];
dbPathString = [docPath stringByAppendingPathComponent:@"FPQ.db"];

char *error;

NSFileManager *fileManager = [NSFileManager defaultManager];
if (![fileManager fileExistsAtPath:dbPathString]) {
    const char *dbPath = [dbPathString UTF8String];

    //create db

    if (sqlite3_open(dbPath, &fpqDB)==SQLITE_OK) {
        const char *sql_stmt = "CREATE TABLE IF NOT EXISTS FPQ (ID INTEGER PRIMARY KEY AUTOINCREMENT, NAME TEXT, CHECK INTEGER, COMMENTS TEXT)";
        sqlite3_exec(fpqDB, sql_stmt, NULL, NULL, &error);
        sqlite3_close(fpqDB);            
    }
}
}


- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

#pragma mark - Actions

- (IBAction)done:(id)sender
{
[self.delegate flipsideViewControllerDidFinish:self];}

- (IBAction)deleteEntry:(id)sender {

}


-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
} 

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

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

if (!cell){
    cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
}

FPQCheck *fpqCheck = [arrayOfCheck objectAtIndex:indexPath.row];

NSString *nameANDcheck = [NSString stringWithFormat:@"%@%d", fpqCheck.name, fpqCheck.check];

cell.textLabel.text = nameANDcheck;
cell.detailTextLabel.text = fpqCheck.comments;

return cell;

}

@end

Answer 1

You have mainly two ways:

1. add a property (eg. self.flipSideController) to your MainViewController to store a reference to the FlipsideViewController; then call SaveFPQData though it (eg. [self.flipSideController SaveFPQData]; or

2. use notification center to post a notification from saveButton: that triggers SaveFPQData; this would go like this:

   //-- in flipsidecontroller `viewDidLoad`:
   [[NSNotificationCenter defaultCenter] addObserver:self
                                        selector:@selector(SaveFPQData)
                                            name:@"SaveFPQData"
                                          object:nil];
   
   //-- in saveButton:
   [[NSNotificationCenter defaultCenter] postNotificationName:@"SaveFPQData" object:nil];
   

The second method is the simplest to implement, IMO, and it allows for the loosest coupling, at the expense of some clock cycles.

EDIT:

It is not entirely clear to me what you are trying to do (specifically, I don’t understand fully how you can push the button in MainViewController once you FlipsideViewController is displayed; on the other hand, if you do not segue to the FlipsideViewController, then it is not there, so you cannot send a message to it), anyway you could try and initialise your self.flipsideViewController property in prepareForSegue:

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
  if ([[segue identifier] isEqualToString:@"showAlternate"]) {
    UIViewController* controller = [segue destinationViewController];
    [controller setDelegate:self];
    if ([controller isKindOfClass:[FlipsideViewController class]])
         self.flipsideViewController = (id)controller;
  }
}

after doing that, your MainViewController will be able to send the saveFPQ message to the FlipsideViewController.

If you mean you would like to send the saveFPQ message before segue-ing to the FlipsideViewController, you should make the saveButton segue to it and the call the saveFPQ method.

What I suspect is you need some kind of “model” object accessible both from the main view and the flipside view controller.

Hope this helps.