Simple iPhone examples

Will continuously update some simple and useful iPhone examples here.

1. Logging
In Xcode, click Run > Console to see NSLog statements.

NSLog(@"log: %@", aString);
Nslog(@"log: %f", afloat);
Nslog(@"log: %i", anint);

2. Set an image as background in UIViewController
[1] Use [UIColor colorWithPatternImage]

self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"background.png"]];

[2] Add an image view to the view, and then send the image view to background.
This method is common used and recommended.

UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"background.png"]];

imageView.frame = self.view.frame;

[self.view addSubview: imageView];

[self.view sendSubviewToBack: imageView];

[imageView release];

3. Conversion between "NSString" and "char *"

[1] From NSString to char *

myString = [NSString stringWithUTF8String:myChars];

[2] From char * to NSString

myChars = [myString UTF8String];

4. Constant NSString

#define URL_SERVER @"http://www.example.com"

NSString *const URL_1 = URL_SERVER@"/a.php";

NSString *const URL_2 = URL_SERVER@"/b.php";