Android webview 中的缓存

Question

Android webview中加载移动网页和非移动网页哪一种更快；加载缓存还是根本不加载？

加载它的推荐样式是什么？

现在，当我不在所有非移动网站上加载缓存时，加载速度比在本机浏览器中加载它们时要慢得多。

Answer 1

不要使用这些：

viewer.getSettings().setAppCacheMaxSize(1024*1024*8);   
viewer.getSettings().setAppCachePath("/data/data/com.your.package.appname/cache"‌​);    
viewer.getSettings().setAppCacheEnabled(true);   

这些与默认的 webview 内部缓存无关。 Appcache 是一个完全不同的功能，它使您能够在没有互联网连接的情况下运行网站。它的效果不太好，可能您不想使用它。

通过设置：viewer.getSettings().setCacheMode(WebSettings.LOAD_DEFAULT)就足够了。

Answer 2

当然，缓存的方法应该更快。这就是缓存存在的确切原因。

但除非你专门禁用 webview 的缓存，否则应该没问题。如果不这样做 - 默认情况下它将使用缓存。

Answer 3

    /*
        public abstract void setAppCacheEnabled (boolean flag)
            Sets whether the Application Caches API should be enabled. The default is false.
            Note that in order for the Application Caches API to be enabled, a valid database
            path must also be supplied to setAppCachePath(String).

        Parameters
            flag : true if the WebView should enable Application Caches
    */
    // Enable the caching for web view
    mWebView.getSettings().setAppCacheEnabled(true);

    /*
        public abstract void setAppCachePath (String appCachePath)
        Sets the path to the Application Caches files. In order for the Application Caches
        API to be enabled, this method must be called with a path to which the application
        can write. This method should only be called once: repeated calls are ignored.

        Parameters
            appCachePath : a String path to the directory containing Application Caches files.
    */
    /*
        public abstract File getCacheDir ()
            Returns the absolute path to the application specific cache directory on the
            filesystem. These files will be ones that get deleted first when the device runs
            low on storage. There is no guarantee when these files will be deleted.

            Note: you should not rely on the system deleting these files for you; you should
            always have a reasonable maximum, such as 1 MB, for the amount of space you consume
            with cache files, and prune those files when exceeding that space.

            The returned path may change over time if the calling app is moved to an adopted
            storage device, so only relative paths should be persisted.

            Apps require no extra permissions to read or write to the returned path,
            since this path lives in their private storage.

        Returns
            The path of the directory holding application cache files.
    */
    /*
        public String getPath ()
            Returns the path of this file.
    */
    // Specify the app cache path
    mWebView.getSettings().setAppCachePath(mContext.getCacheDir().getPath());

    /*
        public abstract void setCacheMode (int mode)
            Overrides the way the cache is used. The way the cache is used is based on the
            navigation type. For a normal page load, the cache is checked and content is
            re-validated as needed. When navigating back, content is not re-validated, instead
            the content is just retrieved from the cache. This method allows the client to
            override this behavior by specifying one of
                LOAD_DEFAULT,
                LOAD_CACHE_ELSE_NETWORK,
                LOAD_NO_CACHE or
                LOAD_CACHE_ONLY.
            The default value is LOAD_DEFAULT.

        Parameters
            mode : the mode to use
    */
    /*
        public static final int LOAD_DEFAULT
            Default cache usage mode. If the navigation type doesn't impose any specific
            behavior, use cached resources when they are available and not expired, otherwise
            load resources from the network. Use with setCacheMode(int).

        Constant Value: -1 (0xffffffff)
    */
    /*
        public static final int LOAD_CACHE_ELSE_NETWORK
            Use cached resources when they are available, even if they have expired. Otherwise
            load resources from the network. Use with setCacheMode(int).

        Constant Value: 1 (0x00000001)
    */
    /*
        public static final int LOAD_NO_CACHE
            Don't use the cache, load from the network. Use with setCacheMode(int).

        Constant Value: 2 (0x00000002)
    */
    /*
        public static final int LOAD_CACHE_ONLY
            Don't use the network, load from the cache. Use with setCacheMode(int).

        Constant Value: 3 (0x00000003)
    */
    // Set the cache mode
    mWebView.getSettings().setCacheMode(WebSettings.LOAD_DEFAULT);

Answer 4

 mWebView.getSettings().setAppCacheEnabled(true);

这里 setAppCacheEnabled(true) 在 Target SDK 33 中已弃用。

请改用 settings.cacheMode = WebSettings.LOAD_DEFAULT。

Answer 5

利用这些设置；他们将帮助您缓存 WebView 内容：

with(webSettings) {
        javaScriptEnabled = true
        domStorageEnabled = true
        databaseEnabled = true
        mixedContentMode = WebSettings.MIXED_CONTENT_COMPATIBILITY_MODE
        setThirdPartyCookiesEnabled(true)
        allowFileAccess = false
        allowContentAccess = false
    }