在iOS 8上共享NSURLCache和UIWebView [英] Shared NSURLCache and UIWebView on iOS 8

问题描述

在iOS 7中，我能够将共享URL缓存设置为 NSURLCache 的子类以及任何 UIWebView 我创建的会自动为每个请求使用该共享缓存。

In iOS 7, I was able to set a shared URL cache to a subclass of NSURLCache and any UIWebViews I created would automatically use that shared cache for each request.

// Set the URL cache and leave it set permanently
ExampleURLCache *cache = [[ExampleURLCache alloc] init];
[NSURLCache setSharedURLCache:cache];

但是，现在在iOS 8中，似乎UIWebView从共享缓存中拉出来并且 cachedResponseForRequest 永远不会被调用。

However, now in iOS 8 it doesn't seem like UIWebView pulls from the shared cache and cachedResponseForRequest never gets called.

是否有人找到此更改的文档或解决方法？

Has anyone found documentation for this change, or a workaround?

推荐答案

我今天遇到了同样的问题。它在ios7上没问题，在ios8上坏了。

I had same problem today. It was ok on ios7 and broken on ios8.

诀窍是在didFinishLaunchingWithOptions中创建自己的缓存。

The trick is to create your own cache as the first thing you do in didFinishLaunchingWithOptions.

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // IMPORTANT: call this line before anything else. Do not call [NSURLCache sharedCache] before this because that
    // creates a reference and then we can't create the new cache.
    NSURLCache *URLCache = [[NSURLCache alloc] initWithMemoryCapacity:4 * 1024 * 1024 diskCapacity:20 * 1024 * 1024 diskPath:nil];

    [NSURLCache setSharedURLCache:URLCache];

...

您可以在其他应用中看到这一点：

You can see this being done in other apps:

https： //github.com/AFNetworking/AFNetworking/blob/master/Example/AppDelegate.m

这个网站虽然陈旧，却有更多关于你为何的信息甚至不应该在上面的代码之前调用[NSURLCache sharedInstance]：
http：// inessential .com / 2007/02/28 / figured_it_the_heck_out

This site, while old, has more info on why you shouldn't even call [NSURLCache sharedInstance] before the above code: http://inessential.com/2007/02/28/figured_it_the_heck_out

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