UIAlertView category

Scenario:

Create the custom alert view like this....


Solution:

By using the category file [Note: Apple does not allow to   subclass  the UIAlertView ] we can achieve this...

.h file:

#import <UIKit/UIKit.h>

@interface UIAlertView (Custom)
+ (void) setBackgroundColor:(UIColor *) background
            withStrokeColor:(UIColor *) stroke;

- (void) drawRoundedRect:(CGRect) rect inContext:(CGContextRef)
context withRadius:(CGFloat) radius;

+(void) showAlertWithTitile:(NSString*)title withContent:(NSString*)content;
@end

.m file:

#import "UIAlertView+Custom.h"

@implementation UIAlertView (Custom)

static UIColor *fillColor = nil;
static UIColor *borderColor = nil;


+ (void) setBackgroundColor:(UIColor *) background
            withStrokeColor:(UIColor *) stroke
{
    if(fillColor != nil)
    {
        fillColor=nil;
        borderColor=nil;
    }
   
    fillColor = background;
    borderColor = stroke;
}

- (id)initWithFrame:(CGRect)frame
{
    if((self = [super initWithFrame:frame]))
    {
        if(fillColor == nil)
        {
            fillColor = [UIColor blackColor] ;
            borderColor = [UIColor colorWithHue:0.625
                                      saturation:0.0 brightness:0.8 alpha:0.8]
                           ;
        }
    }
   
    return self;
}

- (void)layoutSubviews
{
    for (UIView *sub in [self subviews])
    {
        if([sub class] == [UIImageView class] && sub.tag == 0)
        {
            // The alert background UIImageView tag is 0,
            // if you are adding your own UIImageView's
            // make sure your tags != 0 or this fix
            // will remove your UIImageView's as well!
            [sub removeFromSuperview];
            break;
        }
    }
}

- (void)drawRect:(CGRect)rect
{   
    CGContextRef context = UIGraphicsGetCurrentContext();
   
    CGContextClearRect(context, rect);
    CGContextSetAllowsAntialiasing(context, true);
    CGContextSetLineWidth(context, 0.0);
    CGContextSetAlpha(context, 0.8);
    CGContextSetLineWidth(context, 2.0);
    CGContextSetStrokeColorWithColor(context, [borderColor CGColor]);
    CGContextSetFillColorWithColor(context, [fillColor CGColor]);
   
    // Draw background
    CGFloat backOffset = 2;
    CGRect backRect = CGRectMake(rect.origin.x + backOffset,
                                 rect.origin.y + backOffset,
                                 rect.size.width - backOffset*2,
                                 rect.size.height - backOffset*2);
   
    [self drawRoundedRect:backRect inContext:context withRadius:8];
    CGContextDrawPath(context, kCGPathFillStroke);
   
    // Clip Context
    CGRect clipRect = CGRectMake(backRect.origin.x + backOffset-1,
                                 backRect.origin.y + backOffset-1,
                                 backRect.size.width - (backOffset-1)*2,
                                 backRect.size.height - (backOffset-1)*2);
   
    [self drawRoundedRect:clipRect inContext:context withRadius:8];
    CGContextClip (context);
   
    //Draw highlight
    CGGradientRef glossGradient;
    CGColorSpaceRef rgbColorspace;
    size_t num_locations = 2;
    CGFloat locations[2] = { 0.0, 1.0 };
    CGFloat components[8] = { 1.0, 1.0, 1.0, 0.35, 1.0, 1.0, 1.0, 0.06 };
    rgbColorspace = CGColorSpaceCreateDeviceRGB();
    glossGradient = CGGradientCreateWithColorComponents(rgbColorspace,
                                                        components, locations, num_locations);
   
    CGRect ovalRect = CGRectMake(-130, -115, (rect.size.width*2),
                                 rect.size.width/2);
   
    CGPoint start = CGPointMake(rect.origin.x, rect.origin.y);
    CGPoint end = CGPointMake(rect.origin.x, rect.size.height/5);
   
    CGContextSetAlpha(context, 1.0);
    CGContextAddEllipseInRect(context, ovalRect);
    CGContextClip (context);
   
    CGContextDrawLinearGradient(context, glossGradient, start, end, 0);
   
    CGGradientRelease(glossGradient);
    CGColorSpaceRelease(rgbColorspace);
}

- (void) drawRoundedRect:(CGRect) rrect inContext:(CGContextRef) context
              withRadius:(CGFloat) radius
{
    CGContextBeginPath (context);
   
    CGFloat minx = CGRectGetMinX(rrect), midx = CGRectGetMidX(rrect),
    maxx = CGRectGetMaxX(rrect);
   
    CGFloat miny = CGRectGetMinY(rrect), midy = CGRectGetMidY(rrect),
    maxy = CGRectGetMaxY(rrect);
   
    CGContextMoveToPoint(context, minx, midy);
    CGContextAddArcToPoint(context, minx, miny, midx, miny, radius);
    CGContextAddArcToPoint(context, maxx, miny, maxx, midy, radius);
    CGContextAddArcToPoint(context, maxx, maxy, midx, maxy, radius);
    CGContextAddArcToPoint(context, minx, maxy, minx, midy, radius);
    CGContextClosePath(context);
}


+(void) showAlertWithTitile:(NSString*)title withContent:(NSString*)content
{
    UIAlertView *theAlert = [[UIAlertView alloc] initWithTitle:title
                                                       message: content
                                                      delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil] ;
   
    [theAlert show];
   
    UILabel *theTitle = [theAlert valueForKey:@"_titleLabel"];
    [theTitle setTextColor:[UIColor redColor]];
   
    UILabel *theBody = [theAlert valueForKey:@"_bodyTextLabel"];
    [theBody setTextColor:[UIColor blueColor]];
   
    UIImage *theImage = [UIImage imageNamed:@"pattern2.jpg"];//nil;   
    theImage = [theImage stretchableImageWithLeftCapWidth:16 topCapHeight:16];
    CGSize theSize = [theAlert frame].size;
   
    UIGraphicsBeginImageContext(theSize);   
    [theImage drawInRect:CGRectMake(0, 0, theSize.width, theSize.height)];   
    theImage = UIGraphicsGetImageFromCurrentImageContext();   
    UIGraphicsEndImageContext();
   
    CGImageRef img=theImage.CGImage;
    [[theAlert layer] setContents: ( id)img];
}

@end

Call will be.....

UIAlertView *alert=[[UIAlertView alloc ]initWithTitle:@"Welcome To Category" message:@"Hi" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles: nil];
    [UIAlertView setBackgroundColor:[UIColor colorWithPatternImage:[UIImage imageNamed:@"red.jpg"]] withStrokeColor:[UIColor magentaColor]];
    [alert show];
    [alert release];

The source code available here