iPhone Development Tutorials for Beginners

I am posting in my blog new tutorials for beginners who are going to start iPhone developement.
https://github.com/gopinathdev/iPhone-Development-Tutorials

Keep visiting i will post new tutorials ..

Setting Image for TabBar

UIImage *tabBackground = [[UIImage imageNamed:@"tab_bg"] 
    resizableImageWithCapInsets:UIEdgeInsetsMake(0, 0, 0, 0)];
[[UITabBar appearance] setBackgroundImage:tabBackground];
[[UITabBar appearance] setSelectionIndicatorImage:
        [UIImage imageNamed:@"tab_select_indicator"]];

Setting Image for NavigationBar

UIImage *gradientImage44 = [[UIImage imageNamed:@"surf_gradient_textured_44"] 
        resizableImageWithCapInsets:UIEdgeInsetsMake(0, 0, 0, 0)];

[[UINavigationBar appearance] setBackgroundImage:gradientImage44 
        forBarMetrics:UIBarMetricsDefault];

Adding Image to UIView with out UIImageView

Setting the Image to UIView with out UIImageView.   

[[self view] setBackgroundColor:[UIColor colorWithPatternImage:[UIImage imageNamed:@"bg_sand"]]];    

Show or Hide StatusBar

In Application's Resource  folder have app-info.plist file, set the
property Status bar is initially hidden make yes/no.

Changing status bar style

In AppDelegate's "didFinishLaunchingWithOptions" method we can usually set this method for status bar visibulity.

[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleBlackOpaque];

Solving Webview bounces problem

for (id subview in webView.subviews)

if ([[subview class] isSubclassOfClass: [UIScrollView class]])

((UIScrollView *)subview).bounces = NO;

Reading Text fille content from Application Bundle

NSString *filePath = [[NSBundle mainBundle] pathForResource:@"EAP" ofType:@"txt"];

NSString *strData = [[NSString alloc] initWithContentsOfFile:filePath];

NSLog(@"Info :%@",strData);

TBXML Parser Sample

TBXML is the best XML parser with memory and performance aspectives.You can download sample source at https://github.com/gopinathdev/TBXML-Parser 

Lazy Loading sample

Best sample for lazy loading for images in Table View. If you want more details with source code visit at https://github.com/gopinathdev/lazyload

Objective-C XML Parsers

Before we begin, I wanted to make sure everyone is aware of the most important difference between XML parsers: whether the parser is a SAX or a DOM parser.

• A SAX parser is one where your code is notified as the parser walks through the XML tree, and you are responsible for keeping track of state and constructing any objects you might want to keep track of the data as the parser marches through.
• A A DOM parser reads the entire document and builds up an in-memory representation that you can query for different elements. Often, you can even construct XPath queries to pull out particular pieces.

TBXML is the best one parsers avialble in Objective C with performance and memory prospectives.

For more details visit at --http://www.raywenderlich.com/553/how-to-chose-the-best-xml-parser-for-your-iphone-project

Synchronous and Asynchronous Request Processing

Synchronous Request Handling:

responseData = [[NSMutableData data] retain];

NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://localhost/json"]];

NSURLResponse *response = nil;

NSError *error = nil;

//getting the data

NSData *newData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];

//json parse

NSString *responseString = [[NSString alloc] initWithData:newData encoding:NSUTF8StringEncoding];

NSDictionary *jsonObject = [responseString JSONValue];

//Accessing JSON content

NSLog(@"type :  %@", [jsonObject objectForKey:@"Type"] );

Some explanations :

- response is the url response for the json call

- error is error returned by NSURLConnection

- newData is data returned by the server

Notice that you can cast the JSON deserialized data into a NSDictionnary or anNSMutuableArray.

Asynchronous Request Handling:

To make an Asynchronous call we’ll need to use NSURLConnection withinitWithRequest method, then we need to implement differents other methods to handle the finish of data loading, error handling etc.

//in the viewDidLoad

responseData = [[NSMutableData data] retain];

NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://localhost/json"]];//asynchronous call

[[NSURLConnection alloc] initWithRequest:request delegate:self];

Implementing delegate methods :

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {

[responseData setLength:0];

}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {

[responseData appendData:data];

}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {

NSLog(@"%@", error);

}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {

NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];

[responseData release];

NSDictionary *jsonObject = [responseString JSONValue];

NSLog(@"type :  %@", [jsonObject objectForKey:@"Type"] );

[connection release];

}