如何在我的iOS应用程序中保留HTML文件？

Question

I have registered my app to be able to open HTML files. I would like the app to keep the last HTML file it opened... If I open a new HTML file, I would like it to overwrite the last one opened.

I have attempted to user the Documents directory and its not working for me. I have also tried using NSUserDefaults to no avail. Here is what i currently have:

-(BOOL)application:(UIApplication *)application handleOpenURL:(NSURL *)url
{
    ViewController *vc = (ViewController *)self.window.rootViewController;
    [vc loadFileWithUrl:url];

    [[NSUserDefaults standardUserDefaults] setURL:[url fileReferenceURL] forKey:@"amd"];
   return YES;
}

I kill the application entirely, then - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions is called. Here is how that method looks:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
NSURL *url = [[NSUserDefaults standardUserDefaults] URLForKey:@"amd"];
    if (url)
    {
        ViewController *vc = (ViewController *)self.window.rootViewController;
        [vc loadFileWithUrl:url];
    }

    return YES;
}

url is always nil :(

PS: I have also tried storing the HTML file in its string representation, and I am able to get that to persist in the Documents folder, but when I try to load that string using:

[webView loadHTMLString:htmlString]; the page never loads. I think that has something to do with the Javascript but I'm not too sure.

Answer 1

The user defaults are saved when the app goes to the background, or when you call -synchronize on the user defaults. When developing, you often don't put the app into background, but just kill it through XCode, in which case nothing gets saved. You can save the user defaults by pressing the home button on your iPhone/iPad, and killing the app in XCode 1second later.

Also, you should put a log statement into your first method, like NSLog(@"saving amd to %@", [url fileReferenceURL]); to be sure that it really gets saved!

Answer 2

It seems that you forgot to call

[[NSUserDefaults standardUserDefaults] synchronize];

Docs:

Writes any modifications to the persistent domains to disk and updates all unmodified persistent domains to what is on disk.