david blogs: iPhone: create UITabBarController + UINavigationController + UITableViewController

programmatically create a TabBarController application

We can create application by choose File->New Project ,and select 'window-based application'

Give a name (say tabbarsample) and save the project

create tableviewcontroller file to display when click on tab
File->New File, select UIViewController subclass, and check the UITableViewController subclass
give a name (example MyTableViewController)

create an instance of NSObject file to retrieve data from that class
File->New File, select Objective-C class, and select subclass of NSObject
give file name example DataAccess

After doing these steps, we can see six files in our classes folder

This is the final product :

Its better to show the code in all six files, it will tell the remaining part..

//
//  tabbarsampleAppDelegate.h
//  tabbarsample

#import &amp;lt;UIKit/UIKit.h&amp;gt;

@interface tabbarsampleAppDelegate : NSObject &amp;lt;UIApplicationDelegate, UITabBarControllerDelegate&amp;gt; {
    UIWindow *window;
    
    
    UITabBarController *mytabBarController;
}

@property (nonatomic, retain) IBOutlet UIWindow *window;

@property (nonatomic, retain) UITabBarController *mytabBarController;

@end


//
//  tabbarsampleAppDelegate.m
//  tabbarsample
//

#import "tabbarsampleAppDelegate.h"
#import "MyTableViewController.h"

@implementation tabbarsampleAppDelegate

@synthesize window;
@synthesize mytabBarController;

- (void)applicationDidFinishLaunching:(UIApplication *)application {    

    
    mytabBarController = [[UITabBarController alloc] init];
    
    NSMutableArray *array = [[NSMutableArray alloc] init];
    
    
    MyTableViewController *myTableViewController1 = [[MyTableViewController alloc] initWithParam:1];
    
    UINavigationController *myTableNavController1 = [[UINavigationController alloc] initWithRootViewController:myTableViewController1] ;
    [array addObject:myTableNavController1];
    
    [myTableViewController1 release];
    [myTableNavController1 release];
    myTableViewController1 = nil;
    myTableNavController1 = nil;
    
    
    MyTableViewController *myTableViewController2 = [[MyTableViewController alloc] initWithParam:3];
    
    UINavigationController *myTableNavController2 = [[UINavigationController alloc] initWithRootViewController:myTableViewController2] ;
    [array addObject:myTableNavController2];
    
    [myTableViewController2 release];
    [myTableNavController2 release];
    myTableViewController2 = nil;
    myTableNavController2 = nil;

    
    MyTableViewController *myTableViewController = [[MyTableViewController alloc] initWithParam:6];
    
    UINavigationController *myTableNavController = [[UINavigationController alloc] initWithRootViewController:myTableViewController] ;
    [array addObject:myTableNavController];
    
    [myTableViewController release];
    [myTableNavController release];
    myTableViewController = nil;
    myTableNavController = nil;
    
    
    
    window.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
    mytabBarController.view.autoresizingMask =  UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
    mytabBarController.viewControllers = array;
    [window setBackgroundColor:[UIColor whiteColor]];
    [window addSubview:mytabBarController.view];
    mytabBarController.delegate = self;
    [array release];
    
    // Override point for customization after application launch
    [window makeKeyAndVisible];
}


- (void)dealloc {
    [mytabBarController release];
    [window release];
    [super dealloc];
}


#pragma mark UITabBarControllerDelegate

- (void)tabBarController:(UITabBarController *)tabBarController didEndCustomizingViewControllers:(NSArray *)viewControllers changed:(BOOL)changed{
    
    if(changed){
        //write the object to persistent stroe to retrive on next launch
    }
    
}


- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController{
    
    NSLog(@"clicked index at %i",tabBarController.selectedIndex);
    
}
@end




//
//  MyTableViewController.h
//  tabbarsample
//


#import 


@interface MyTableViewController : UITableViewController {

    
    NSArray *arrayData;
}

@property(nonatomic, retain) NSArray *arrayData;


- (id)initWithParam:(NSUInteger)param;

@end





//
//  MyTableViewController.m
//  tabbarsample
//

#import "MyTableViewController.h"
#import "DataAccess.h"

@implementation MyTableViewController

@synthesize arrayData;


- (id)initWithParam:(NSUInteger)param {
    // Override initWithStyle: if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad.
    if (self = [super init]) {
        
        DataAccess *dataAccess = [[DataAccess alloc]init];
        self.arrayData = [dataAccess getDataForType:param];
        [dataAccess release];
        
        
        self.title = [NSString stringWithFormat:@"type_%i", param];
        self.tabBarItem.image = [UIImage imageNamed:@"images.png"];
        //self.tabBarItem.tag = param;//can use for CustomizingViewControllers
    }
    return self;
}


- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];
    
    // Release any cached data, images, etc that aren't in use.
}

- (void)viewDidUnload {
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}


#pragma mark Table view methods

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


// Customize the number of rows in the table view.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
            NSUInteger countt = [arrayData count];
 if(countt>0){
  return [arrayData count];
 }
 else{
  return 4;//to show "No Items" on 4rd cell
 }
}


// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    
    UITableViewCell *cell = nil;
 if([arrayData count] > 0){
  
  static NSString *CellIdentifier = @"Cell";
  
  cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
  if (cell == nil) {
   cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
   
  }
  
  // Set up the cell...
  cell.textLabel.text = [arrayData objectAtIndex:indexPath.row];
 }else{
  
  static NSString *CellIdentifier = @"NoData";
  
  cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
  if (cell == nil) {
   cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
   
  }
  cell.selectionStyle = UITableViewCellSelectionStyleNone;
  // Set up the cell...
  if(indexPath.row == 3){
   cell.textLabel.text= @"No Items";
   cell.textLabel.textAlignment= UITextAlignmentCenter;
   cell.textLabel.textColor= [UIColor lightGrayColor];
  }else{
   cell.textLabel.text = @"";
  }
 }
    return cell;

}


- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
 
}
- (void)dealloc {
    [arrayData release];
    [super dealloc];
}


@end





//
//  DataAccess.h
//  tabbarsample
//

#import 

@interface DataAccess : NSObject {    
}

-(NSArray *)getDataForType:(NSUInteger)typeOfData;

@end





//
//  DataAccess.m
//  tabbarsample
//


#import "DataAccess.h"


@implementation DataAccess

-(NSArray *)getDataForType:(NSUInteger)typeOfData{
    
     //to test "No Items"
 if(typeOfData == 6){
  NSMutableArray *array = [[NSMutableArray alloc] init];
  return [array autorelease];
 }else
    if(typeOfData == 1){
        
        NSArray *array = [NSArray arrayWithObjects:@"type1 cell0",@"type1 cell1",@"type1 cell2",@"type1 cell3",nil];
        return array;
    }else{
        
        NSMutableArray *array = [[NSMutableArray alloc] init];
        for(int i=0 ; i&lt;3*typeofdata&gt;
            
            [array addObject:[NSString stringWithFormat:@"type%i cell_%i",typeOfData,i]];
        }
        return [array autorelease];
    }
}

@end