iOS: Core Data

File > New Project > Empty Application
Select "Core Data" checkbox

".xcdatamodeld" file created in project

select data model file, "Add Entity" at bottom left corner
"Add attributes" using the "+" sign

File > New File > Core Data > NSManagedObject
Select data model, and entity to create the NS managed object
.h and .m created in project

File > New File > UIViewController

AppDelegate.h (add View controller )

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

{

    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];

    // Override point for customization after application launch.

    self.window.backgroundColor = [UIColor whiteColor];

    // ADDED

    StartVC *vc = [[StartVC alloc] initWithNibName:@"StartVC" bundle:nil];

    // ADDED

    self.window.rootViewController = vc;

    // ADDED

    [vc release];

    

    [self.window makeKeyAndVisible];

    return YES;

}

VC .m

for adding/inserting data 

- (void)viewDidLoad

{

    [super viewDidLoad];

    // Do any additional setup after loading the view from its nib.

    

    AppDelegate *ad = [[UIApplication sharedApplication] delegate];

    Property *prop = (Property *)[NSEntityDescription insertNewObjectForEntityForName:@"Property" inManagedObjectContext:ad.managedObjectContext];

    prop.name = @"Sengkang";

    prop.seller = @"Beng";

    prop.price = (NSDecimalNumber *)[NSDecimalNumber numberWithInt: 100000];

    prop.address = @"123, Anchorvale #01-01";

    

    NSError *err;

    if(![ad.managedObjectContext save:&err])

        NSLog(@"error %@", [err domain]);

    else

        NSLog(@"Data added");

}

for reading data

// reading

    NSEntityDescription *desc = [NSEntityDescription entityForName:@"Property" inManagedObjectContext:ad.managedObjectContext];

    NSFetchRequest *req = [[NSFetchRequest alloc] init];

    [req setEntity:desc];

    

    NSArray *obj = [ad.managedObjectContext executeFetchRequest:req error:&err];

    

    for(Property *p in obj)

    {

        NSLog(@"-------------");

        NSLog(@"Property name: %@", p.name);

        NSLog(@"Price: %f", p.price.floatValue);

        NSLog(@"Seller: %@", p.seller);

    }

iOS: XML

Download TBXML http://www.tbxml.co.uk

Add "libz.dylib" into project. Project > main directory > Build phases > link Binary with Libraries > "+" > iOS 5.0 - "libz.dylib" > Add

import "TBXML.h"

- (void)viewDidLoad

{

    [super viewDidLoad];

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

    UITextView *tv = [[UITextView alloc] initWithFrame:CGRectMake(5, 50, self.view.frame.size.width-10, 300)];

    [self.view addSubview:tv];

    

    // load xml file

    TBXML *fileRead = [[TBXML alloc] initWithXMLFile:@"properties.xml"];

    // get root element "list"

    TBXMLElement *root = fileRead.rootXMLElement;

    

    NSString *str = [[NSString alloc] init];

    

    if(root)

    {

        NSLog(@"has root");

        

        // get first "property" child element from root element

        TBXMLElement *property = [TBXML childElementNamed:@"property" parentElement:root];

        

        while(property)

        {

            NSString *name = [TBXML textForElement:[TBXML childElementNamed:@"name" parentElement:property]];

            NSLog(@"name: %@", name);

            NSString *price = [TBXML textForElement:[TBXML childElementNamed:@"price" parentElement:property]];

            NSString *propertyID = [TBXML valueOfAttributeNamed:@"id" forElement:property];

            NSLog(@"id: %@", propertyID);

            

            // use current element "property" to fetch the next sibling "property"

            property = [TBXML nextSiblingNamed:@"property" searchFromElement:property];

            

            // append to string

            str = [str stringByAppendingFormat:@"%@: %@, $%@\n", propertyID, name, price];

        }

        // show on textview

        [tv setText:str];

    }

    

}

iOS: search bar with table view

// assuming table view is done
VC .h

@interface ViewController : UIViewController <UITableViewDelegate, UITableViewDataSource, UISearchBarDelegate>

{

    // ADDED

    NSMutableArray *tableData;

    NSArray *array;

    NSMutableArray *searchResults;

    

    IBOutlet UITableView *tableView;

}

@property (nonatomic, retain) NSArray *array;

@end

// assuming table view is done

VC .m

// ADDED: to search

- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText

{

    NSLog(@"searching: %@", searchText);

    searchText = [searchText lowercaseString];

    // search for text in array

    if(searchText.length > 0)

    {

        [tableData removeAllObjects];// clear all data

        [searchResults removeAllObjects];

        for (NSString *ostr in array)

        {

            //NSLog(@"looping: %@", str);

            NSString *str = [ostr lowercaseString];

            NSRange range = [str rangeOfString:searchText];

            if(range.location != NSNotFound)

            {

                NSLog(@"matched: %@", searchText);

                [searchResults addObject:ostr];

            }

        }

        //[tableData removeAllObjects];

        [tableData addObjectsFromArray:searchResults];

        [tableView reloadData];

    }

    else

    {

        [tableData removeAllObjects];// clear all data

        [tableData addObjectsFromArray:array];

        [tableView reloadData];

    }

}

- (void)searchBarCancelButtonClicked:(UISearchBar *)searchBar

{

    NSLog(@"Cancel Button Clicked");

    [searchBar resignFirstResponder]; // close keyboard

}

- (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar

{

    NSLog(@"Search Button Clicked");

    [searchBar resignFirstResponder]; // close keyboard

}

- (void)viewDidLoad

{

    [super viewDidLoad];

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

    tableView.delegate = self;

    tableView.dataSource = self;

    

    // ADDED

    self.array = [NSArray arrayWithObjects:@"Beng", @"Seng", @"Lian", @"Beng2", @"Seng2", @"Lian2", nil];

    // must alloc and init. strange. cannot use arrayWithArray

    tableData = [[NSMutableArray alloc] init]; //[NSMutableArray arrayWithArray:self.array];

    searchResults = [[NSMutableArray alloc] init];//[NSMutableArray arrayWithArray:self.array];

    [tableData addObjectsFromArray:self.array];

    

    UISearchBar *searchBar = [[UISearchBar alloc] initWithFrame:CGRectMake(0, 0, tableView.frame.size.width,  0)];

    [searchBar sizeToFit];

    searchBar.delegate = self;

    [searchBar setShowsCancelButton:YES animated:YES];

    //[searchBar showsSearchResultsButton];

    [self.view addSubview:searchBar];

    

    // place tableview just below search bar. else, the first row of the table view will be hidden behind search bar

    // hence adjust the y and height in the (x,y,w,h) of the table view's frame

    [tableView setFrame:CGRectMake(0, searchBar.frame.size.height, tableView.frame.size.width, tableView.frame.size.height - searchBar.frame.size.height)];

}

iOS: Table View

// in table view controller .h

@interface ViewController : UIViewController <UITableViewDelegate, UITableViewDataSource>

{

    // ADDED

    NSArray *array;

    IBOutlet UITableView *tableView;

}

@property (nonatomic, retain) NSArray *array;

@end

// in table view controller .m

@implementation ViewController

@synthesize array;

// ADDED: method to handle table cell click

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath

{

    NSLog(@"click cell: %i", indexPath.row);

    // show another VC

    AboutVC *avc = [[AboutVC alloc] initWithNibName:@"AboutVC" bundle:nil];

    [self.view addSubview:avc.view];

}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {

    return [self.array count];

}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    static NSString *MyIdentifier = @"MyIdentifier";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:MyIdentifier];

    if (cell == nil) {

        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:MyIdentifier] autorelease];

    }

    // ADDED

    cell.textLabel.text = [self.array objectAtIndex:indexPath.row]; // text label of the cell

    cell.imageView.image = [UIImage imageNamed:@"myimage.gif"]; // image on the left

    cell.accessoryType = UITableViewCellAccessoryDetailDisclosureButton; // show a '>' button

    // end 

    

    return cell;

}

- (void)didReceiveMemoryWarning

{

    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.

}

#pragma mark - View lifecycle

- (void)viewDidLoad

{

    [super viewDidLoad];

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

    tableView.delegate = self;

    tableView.dataSource = self;

    

    // ADDED

    self.array = [NSArray arrayWithObjects:@"Beng", @"Seng", @"Lian", nil];

}

iOS: UITabBarController

// in root view controller .m

- (void)viewDidLoad

{

    [super viewDidLoad];

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

    UITabBarController *tbc = [[UITabBarController alloc] init];

    

    // create VC instances

    AboutVC *avc = [[AboutVC alloc] initWithNibName:@"AboutVC" bundle:nil];

    ContactVC *cvc = [[ContactVC alloc] initWithNibName:@"ContactVC" bundle:nil];

    

    // set tab bar properties if necessary. use system defined tab if necessary

    UITabBarItem *tbitem = [[UITabBarItem alloc] initWithTabBarSystemItem:UITabBarSystemItemFavorites tag:1];

    // link VC to this tab bar item

    [cvc setTabBarItem:tbitem];

    

    // interesting that if title is set in VC, it overrides the title here

    UITabBarItem *tbitem2 = [[UITabBarItem alloc] initWithTitle:@"Hmm" image:[UIImage imageNamed:@"myimage.gif"] tag:2];

    // link VC to this tab bar item

    [avc setTabBarItem:tbitem2];

    

    // create array storing all the VCs

    NSArray *arr = [NSArray arrayWithObjects:avc, cvc, nil] ;

    

    // link array to tab bar controller. if title is set in VC, it will show in tab bar

    [tbc setViewControllers:arr];

    

    // set the view bounds of tab bar

    [tbc.view setFrame:self.view.bounds];

    

    // add tab bar to current view

    [self.view addSubview:tbc.view];

}

iOS: UINavigationController

// in app delegate .m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

{

    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];

    // Override point for customization after application launch.

    self.viewController = [[[ViewController alloc] initWithNibName:@"ViewController" bundle:nil] autorelease];

    

    //NEW - start

    UINavigationController *nc = [[UINavigationController alloc] initWithRootViewController:self.viewController];

    self.window.rootViewController = nc;

    [nc release];

    // end

    [self.window makeKeyAndVisible];

    return YES;

}

// in viewcontroller .m ; assume IBAction to a button to click to go to another VC

-(IBAction) m1:(id)sender

{

    NSLog(@"about us");
    // NEW: create VC instance and push into nav controller

    AboutVC *about = [[AboutVC alloc] initWithNibName:@"AboutVC" bundle:nil];

    [self.navigationController pushViewController:about animated:YES];

}

// in AboutVC.m

- (void)viewDidLoad

{

    [super viewDidLoad];

    // Do any additional setup after loading the view from its nib.
    // NEW: set title on title bar of nav controller

    [self setTitle:@"About Us"];

}

iOS: Delegates

it works like an interface
Example:

@interface myVC:UIViewController <UIWebViewDelegate>
{
}
@end

// assume webViewToLoad IBOutlet
[webViewToLoad setDelegate:self];

// implement methods of delegate
-void webViewDidStartLoad: (UIWebView *) webview
{
  NSLog(@"started loading...");
}

-void webViewDidFinishLoad: (UIWebView *) webview

{

  NSLog(@"finished loading...");

}

iOS: Memory management

retain - increment reference count by 1
release - decrement by 1
retainCount - reference count
autorelease

tool
xcode > product > analyze

iOS: UIWebView

Assuming that IBOutlet urlTxtField and webViewToLoad
NSString *urlToLoad = [NSString stringWithString : @"http://www.google.com"];
[self.webViewToLoad loadRequest : [NSURLRequest requestWithURL : [NSURL URLWithString : urlToLoad]]];
[urlTxtField setText : urlToLoad];

// assume button IBAction
[urlTxtField resignFirstResponder]; //dismiss keyboard
[self.webViewToLoad loadRequest : [NSURLRequest requestWithURL : [NSURL URLWithString : urlTxtField.text]]];

iOS: View Programming

Eg.:

UILabel *label = [[UILabel alloc] init];
CGRect bounds = CGRectMake(10, 20, 300, 200);
[label setText:@"This is a label"]; // put some text, if not, nothing seen on screen
[label setFrame:bounds];
[self.view addSubview:label];

// loading image

UIImage *img = [UIImage imageNamed:@"image.jpg"];    

UIImageView *imgView = [[UIImageView alloc] initWithImage:img];

// add to view with the same steps as above

...

// set color

[self.view setBackgroundColor:[UIColor colorWithRed:0.1 green:0.7 blue:0.3 alpha:1]];

Note:

UIButton has a class method to create a button. [UIButton buttonWithType:UIButtonTypeRoundedRect]

To programmatically add an action to a button, use addTarget:action:forControlEvents: of the UIControl

Example:

[button addTarget:self action:@selector(btnPressed:) forControlEvents:UIControlEventTouchUpInside];

...

-(void) btnPressed:(id) sender
{
   UIButton *btn = (UIButton *) sender;
   if([btn.titleLabel.text isEqual:@"button label"])
   {
      // code to do something
   }
}

// to remove
[self.view removeFromSuperview];

To load and display a ViewController from XIB file

Screen01ViewController.m

Screen02ViewController *next = [[Screen02ViewController alloc] initWithNibName:@"Screen02ViewController" bundle:nil];    

[self.view addSubview:next.view]; // will put the new view on top of this current view

...

Screen02ViewController.m

[self.view removeFromSuperview]; // if you are done with this view and wants to close it

iOS: more basics

Random numbers
random() // gives you 0-(2^31-1)
to generate random number from 0 to 9: random() % 10
3 to 18: random() % ( 18-3 +1) + 3

if need numeric pad for textfield, interface builder > text input trait > num pad

Timer
NSTimer
[NSTimer timerWithTimeInterval:0.5 /* seconds */ invocation: invocation repeats:YES]

NSDate
NSDate *now = [[NSDate alloc] init];
[date2 timeIntervalSinceDate:date1]; returns seconds
[date1 release];

iOS basics

- Variables: int, float, double
- Operators: +, -, *, /, %
- Conditional statements: if-else, switch-case
- Loops: for, while, do-while
- printf() function
- viewDidLoad event


Example:
int i = 1;
float f = 2.3;
printf("This is a string with integer: %d and a floating point number: %f", i, f);
NSLog(@"This is a string with integer: %d and a floating point number: %f", i, f);


Constants:
.h
extern const int MY_NUMBER;
.m
const int MY_NUMBER = 123;


Outlets
in .h
UITextField *tf;
@property (nonatomic, retain) IBOutlet UITextField *tf;

in .m
@synthesize tf;
tf.text = @"Hello textfield";

in .xib
Reload class files, if necessary
File's Owner > Ctrl+Click and drag to textfield in "View" > New reference (outlet)

Actions
in .h
-(IBAction) whatToDoWhenButtonClicked:(id)sender;

in .m
-(IBAction) whatToDoWhenButtonClicked:(id)sender {
// do what ever
tf.text = @"button clicked";
}

in .xib
Reload class files, if necessary
Ctrl+click button in "View" and drag to "File's Owner" > "whatToDoWhenButtonClicked" (Action) TouchUpInside

NSString
NSString *str = [NSString stringWithFormat: @"string %@ with %d and %f", someWords, i, f]
float f = [str floatValue]
int i = [str intValue]


Object-Oriented Programming (OOP)
@interface
@property
@implementation
@synchronise
@end
methods

---

Creating a custom class, MyClass

1. MyClass.h
   @interface MyClass : NSObject {
      float myfloat;
      int myint;
   }
   @property float myfloat;
   @property int myint;
   -(void) myMethodWithParameter:(float) param1
   @end
2. MyClass.m
   #import "MyClass.m"
   @implementation MyClass
   @synthesize myfloat;
   @synthesize myint;
   -(void) myMethodWithParameter:(float) param1
   {
      NSLog(@"this is my method with %f", param1);
   }
   @end

Instantiation of an object and using the object

MyClass *myObject = [MyClass alloc];
[myObject init]; // or [[MyClass alloc] init];
[myObject myMethodWithParameter:4.5];
[myObject release];

---

NSNumber
NSNumber *fNum = [NSNumber numberWithFloat:12.3];
float f = [fNum floatValue];
NSString *str = [fNum stringValue];
NSNumber reference

NSArray & NSMutableArray
NSArray *names01 = [NSArray arrayWithObjects: @"Beng", @"Siti", @"Dinesh"];
NSMutableArray *names02 = [NSMutableArray arrayWithObjects: @"Beng", @"Siti", @"Dinesh"];
int number = [names01 count];
NSString *firstName = [names01 objectAtIndex:0];
OR for fast enumeration
for(NSString *n in names01)
{
NSLog(@"The name is %@", n);
}