更改AlertView背景

UIAlertView *theAlert = [[[UIAlertViewalloc] initWithTitle:@"Atention"
                                                     message: @"I'm a Chinese!"
                                                    delegate:nil
                                            cancelButtonTitle:@"Cancel"
                                            otherButtonTitles:@"Okay",nil] autorelease];
   [theAlert show];
   UIImage *theImage = [UIImageimageNamed:@"loveChina.png"];
   theImage = [theImage stretchableImageWithLeftCapWidth:0topCapHeight:];
   CGSize theSize = [theAlert frame].size;
    UIGraphicsBeginImageContext(theSize);
   [theImage drawInRect:CGRectMake(, , theSize.width-, theSize.height-)];// 这个地方的大小要自己调整，以适应 alertview 的背景颜色的大小。
   theImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
   theAlert.layer.contents = (id)[theImage CGImage];