Display number value to the max number of decimal places

iPhone SDK Tips & Tricks

float x = 1.23;
NSLog(@"%g", x); //1.23
NSLog(@"%f", x); //1.23000000

Rate this app

iPhone SDK Tips & Tricks

[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"http://itunes.apple.com/WebObjects/MZStore.woa/wa/viewContentsUserReviews?id=374892313&onlyLatestVersion=false&type=Purple+Software"]];

Replace id with the application ID from itunesconnect.

Get User Currency Code and Symbol

iPhone SDK Tips & Tricks

NSString *currencyCode = [[NSLocale currentLocale] objectForKey: NSLocaleCurrencyCode];

NSString *currencySymbol = [[NSLocale currentLocale] objectForKey: NSLocaleCurrencySymbol];

Number of days in current month

iPhone SDK Tips & Tricks

NSDate *today = [NSDate date]; //Get a date object for today's date

NSCalendar *c = [NSCalendar currentCalendar];

NSRange days = [c rangeOfUnit:NSDayCalendarUnit

inUnit:NSMonthCalendarUnit

forDate:today];

Resize UIImage

iPhone SDK Tips & Tricks


-(UIImage *)resizeImage:(UIImage *)image {

CGImageRef imageRef = [image CGImage];
CGImageAlphaInfo alphaInfo = CGImageGetAlphaInfo(imageRef);
CGColorSpaceRef colorSpaceInfo = CGColorSpaceCreateDeviceRGB();

if (alphaInfo == kCGImageAlphaNone)
alphaInfo = kCGImageAlphaNoneSkipLast;

int width, height;

width = 200;
height = 200;

CGContextRef bitmap;

if (image.imageOrientation == UIImageOrientationUp | image.imageOrientation == UIImageOrientationDown) {
bitmap = CGBitmapContextCreate(NULL, width, height, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, alphaInfo);

} else {
bitmap = CGBitmapContextCreate(NULL, height, width, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, alphaInfo);

}

if (image.imageOrientation == UIImageOrientationLeft) {
NSLog(@"image orientation left");
CGContextRotateCTM (bitmap, radians(90));
CGContextTranslateCTM (bitmap, 0, -height);

} else if (image.imageOrientation == UIImageOrientationRight) {
NSLog(@"image orientation right");
CGContextRotateCTM (bitmap, radians(-90));
CGContextTranslateCTM (bitmap, -width, 0);

} else if (image.imageOrientation == UIImageOrientationUp) {
NSLog(@"image orientation up");

} else if (image.imageOrientation == UIImageOrientationDown) {
NSLog(@"image orientation down");
CGContextTranslateCTM (bitmap, width,height);
CGContextRotateCTM (bitmap, radians(-180.));

}

CGContextDrawImage(bitmap, CGRectMake(0, 0, width, height), imageRef);
CGImageRef ref = CGBitmapContextCreateImage(bitmap);
UIImage *result = [UIImage imageWithCGImage:ref];

CGContextRelease(bitmap);
CGImageRelease(ref);

return result;
}

NSDateFormatter

iPhone SDK Tips & Tricks

NSDateFormatter *dateFormat = [[[NSDateFormatter alloc] init] autorelease];

[dateFormat setDateFormat:@"dd MMM yyyy"];

NSLog(@"%@", [dateFormat stringFromDate:[NSDate date]]);

    x           number
   xx          two digit number
   xxx         abbreviated name
   xxxx        full name

   a           AM/PM
   A           millisecond of day
   c           day of week (c,cc,ccc,cccc)
   d           day of month
   e           day of week (e,EEE,EEEE)
   F           week of month
   g           julian day (since 1/1/4713 BC)
   G           era designator (G=GGG,GGGG)
   h           hour (1-12, zero padded)
   H           hour (0-23, zero padded)
   L           month of year (L,LL,LLL,LLLL)
   m           minute of hour (0-59, zero padded)
   M           month of year (M,MM,MMM,MMMM)
   Q           quarter of year (Q,QQ,QQQ,QQQQ)
   s           seconds of minute (0-59, zero padded)
   S           fraction of second
   u           zero padded year
   v           general timezone (v=vvv,vvvv)
   w           week of year (0-53, zero padded)
   y           year (y,yy,yyyy)
   z           specific timezone (z=zzz,zzzz)
   Z           timezone offset +0000

   sql         y-M-d H:m:s
   rss         [E, ]d MMM y[y] H:m:s Z|z[zzz]