Duplicate Method Issue - ios

Question

I'm very new to Objective-C and the syntax and everything. I wrote two separate methods, but ran into the error: Duplicate declaration of method webView:shouldStartLoadWithRequest:navigationType:
So, it looks like I need to combine both of my webView:shouldStartLoadWithRequest:navigationType: methods. The only issue is, they both contain if statements and return values, and that super confused me. These are the two methods:
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
{
NSString *full = [request.URL absoluteString];
if ([full isEqualToString:#"ExampleURL.com"] || [full isEqualToString:#"ExampleURL.com"]
|| [full isEqualToString:#"ExampleURL.com"] ) {
return YES;
}
else
return NO;
}
And:
-(BOOL) webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
NSString *full = [request.URL absoluteString];
if ([full isEqualToString:#"ExampleURL.com"]) {
_backButton.hidden = YES;
return NO;
} else {
_backButton.hidden = NO;
}
return YES;
}
I've been trying to combine these two methods into one for a long time now, and am at a loss. It's the if statements that are tripping me up. Does anyone know how I could do this or what it would look like?
Side note: My desired goal is to only allow specific URLs to load. At the same time, I need the back button to be hidden only when one website is loaded. Does anyone know if there would be a way to hide / show the back button based on a URL by avoiding this method all together? I think I may be going about this wrong.

Answer 1

What's your desired logic here? One method will be called when the WebView starts loading. You will do some stuff, then return YES or NO based on whether you want the loading to proceed. You can't tell it it's ok to load and then tell it that it's not ok to load at the same time.
In your two methods you have this:
if ([full isEqualToString:#"ExampleURL.com"] || ...snipped... ) {
return YES;
}
And then this
if ([full isEqualToString:#"ExampleURL.com"]) {
// ...
return NO;
}
Which check the same thing but then return opposite values.
So I'll answer generally. This is sort of the general form of this method.
-(BOOL) webView:(UIWebView *)webView
shouldStartLoadWithRequest:(NSURLRequest *)request
navigationType:(UIWebViewNavigationType)navigationType
{
// alter application state
// return YES or NO
}
Lets say you want to do this, which I'm not sure is what you want, but this is the general idea:
if loading ExampleURL.com, then show the back button and allow the load
otherwise, hide the button and do not allow the load.
Then you might implement this method like so:
-(BOOL) webView:(UIWebView *)webView
shouldStartLoadWithRequest:(NSURLRequest *)request
navigationType:(UIWebViewNavigationType)navigationType
{
if ([[request.URL host] isEqualToString:#"ExampleURL.com"]) {
_backButton.hidden = NO;
return YES;
} else {
_backButton.hidden = YES;
return NO;
}
}
Now adjust that to reflect the logic you actually want.

Answer 2

I think you are trying to do something like this:
-(BOOL) webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request
navigationType:(UIWebViewNavigationType)navigationType {
NSString *full = [request.URL absoluteString];
if([full isEqualToString:#"hidebackbuttonforthiswebsite.com"])
_backButton.hidden = YES;
if ([full isEqualToString:#"AcceptedURL1.com"] ||
[full isEqualToString:#"AcceptedURL2.com"] ||
[full isEqualToString:#"AcceptedURL3.com"])
{
// Good URL, load it
return YES;
}
else
{
// Bad URL, so don't load it
return NO;
}
}
This will hide the back button for the specific URL, and then allow only a specific set of URLS to load. It sounded like this is what you want, but it's hard to understand your explanation.

Answer 3

I general, you might consider an additional conditional inside the method to determine what condition tree to use.
That could be another method called within this one.
You might also consider adding an additional argument to the method parameters if you need some criterion to determine conditional logic inside the method.
Another option, if you have two methods that cannot be merged because they do different things, but they have the same argument list, you should change the selectors (method signature) to distinguish them and make sure the selector indicates what they do differently.