Why does this UIWebView to UIImage code render a blank image?

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I know this is pretty common, but I just wanted to know why this very simple code doesn't work.

I have a breakpoint in the NSLog line inside the webViewDidFinishLoad method and I'm inspecting the resulting UIImage (using quick look). The result is a blank image where the UIWebView should be (and the black background I placed there for debugging purposes).

#import "KIViewController.h"

@interface KIViewController ()

@end

@implementation KIViewController

-(void)webViewDidStartLoad:(UIWebView *)webView {
    NSLog(@"start");
}

-(void)webViewDidFinishLoad:(UIWebView *)webView {

    UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, self.view.opaque, 0.0);
    [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage * img = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    NSLog(@"webview did finish load");

}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    UIWebView *wv = [[UIWebView alloc] initWithFrame:CGRectMake(0,0,640,200)];
    wv.delegate = self;

    NSString *url=@"http://www.google.com";
    NSURL *nsurl=[NSURL URLWithString:url];
    NSURLRequest *nsrequest=[NSURLRequest requestWithURL:nsurl];
    [wv loadRequest:nsrequest];
    self.view.backgroundColor = [UIColor blackColor];
    [self.view addSubview:wv];

}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

Why is this happening and how can I prevent it?

asked 10 secs ago

Hal

1,134

Why does this UIWebView to UIImage code render a blank image?