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Make Background of UIView a Gradient Without Sub Classing



Is there a way to make the background of a UIView a gradient without subclassing it? I'd rather not use an image file to accomplish this either. It just seems obtuse to have to subclass UIView just to draw a gradient for the background.





Source: Tips4all

Comments

  1. You can use +[UIColor colorWithPatternImage:] to produce a patterned background. Example (bring your own CGGradient):

    // Allocate color space
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    // Allocate bitmap context
    CGContextRef bitmapContext = CGBitmapContextCreate(NULL, 320, 480, 8, 4 * 320, colorSpace, kCGImageAlphaNoneSkipFirst);
    // Draw Gradient Here
    CGContextDrawLinearGradient(bitmapContext, myGradient, CGPointMake(0.0f, 0.0f), CGPointMake(320.0f, 480.0f), );
    // Create a CGImage from context
    CGImageRef cgImage = CGBitmapContextCreateImage(bitmapContext);
    // Create a UIImage from CGImage
    UIImage *uiImage = [UIImage imageWithCGImage:cgImage];
    // Release the CGImage
    CGImageRelease(cgImage);
    // Release the bitmap context
    CGContextRelease(bitmapContext);
    // Release the color space
    CGColorSpaceRelease(colorSpace);
    // Create the patterned UIColor and set as background color
    [targetView setBackgroundColor:[UIColor colorWithPatternImage:image]];


    It will probably be simpler to just create a UIView subclass though. It will use less memory as well.

    ReplyDelete
  2. As of iPhone SDK 3.0, there's a much simpler solution that relies on the new CAGradientLayer and doesn't require subclassing or images.

    ReplyDelete
  3. I agree with rpetrich, it would be cleaner to just do the UIView subclass. For an example of how to do this, see my response in this question. If you wanted, you could create a generic gradient UIView subclass and simply place that behind the views you want to have gradient backgrounds.

    ReplyDelete

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