在Android的WebView中，`DomStorage`、`Database`、`AppCache`之间有什么区别？

发布于 2025-01-08 10:38:10 字数 1310 浏览 6 评论 0原文

Android的WebView中，DomStorage、Database和AppCache有什么区别？

我对这三个设置感到困惑。现在我需要一个可以在 JavaScript 中使用 localStorage 的 WebView 实例。

这是一个例子：

        if (localStorage['avatar_user_' + nick]) {
        obj.src = localStorage['avatar_user_' + nick];
    } else {
        var url = avatar_path + nick + '/avatar.jpg';
        new Oauth().img("jpeg", url,
            function(data) {
                if (data != '') {
                    obj.src = data;
                    localStorage['avatar_user_' + nick] = data;
                }
            }, function() {}
        );
    }

在上面的代码中，我确实从网络上获取了图像，下次我需要它时将从 localStorage 加载它，但存储只持续与应用程序的生命周期一样长。

如果我重新启动我的应用程序，那么图像将再次从网络加载。

我按如下方式设置 WebView：

    mWebSettings.setAppCacheEnabled(true);
    mWebSettings.setDomStorageEnabled(true);
    mWebSettings.setDatabaseEnabled(true);
    mWebSettings.setDatabasePath("file:///data/data/com.xxx/databases");

但是当我向 localStorage 添加内容时，我可以看到 file:///data/data/com.xxx/databases 中的文件保持不变。

所以我的问题是如何让我的网页存储数据并在应用程序关闭后保留它们？

如果我在应用程序中使用多个WebView并指向DatabasePath，这是否重要？到同一个文件夹？

如果您能告诉我 DomStorage、Database 和 AppCache 之间的区别那就更好了！

原文

In Android's WebView, what's the difference between DomStorage, Database and AppCache?

I'm confused about these three settings. Now I need a instance of WebView that I can use localStorage in JavaScript.

Here is an example:

        if (localStorage['avatar_user_' + nick]) {
        obj.src = localStorage['avatar_user_' + nick];
    } else {
        var url = avatar_path + nick + '/avatar.jpg';
        new Oauth().img("jpeg", url,
            function(data) {
                if (data != '') {
                    obj.src = data;
                    localStorage['avatar_user_' + nick] = data;
                }
            }, function() {}
        );
    }

In the above code I really get the image from the web, and it will be loaded from the localStorage the next time I need it, but the storage only lasts as long as the app's lifetime.

If I restart my app, then the image will be loaded from the web again.

I setup my WebView as follows:

    mWebSettings.setAppCacheEnabled(true);
    mWebSettings.setDomStorageEnabled(true);
    mWebSettings.setDatabaseEnabled(true);
    mWebSettings.setDatabasePath("file:///data/data/com.xxx/databases");

but I can see the files in file:///data/data/com.xxx/databases remain unchanged when I'm adding something into localStorage.

So my question is how to make my webpages store data and keep them after the app is closed?

And does it matters if I use multiple WebView in a app and point the DatabasePath to the same folder?

And if you can tell me the difference between DomStorage, Database and AppCache it would be so much better!

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