toga webview load local html file

[Jzhenli]

Hi, if it's possible for webview widget to load local html file? In some case we want to display a customized page before loading the remote web url.

[mhsmith]

As it says in the documentation:

Due to app security restrictions, WebView can only display http:// and https:// URLs, not file:// URLs. To serve local file content, run a web server on localhost using a background thread.

This could be as simple as using the standard library http.server module as shown here.

[Jzhenli]

@mhsmith thanks for your reply. Another little question, what's the web engine for toga webview widget on android, seems it's not mentioned in the doc.

[mhsmith]

It's the standard Android WebView.

[freakboy3742]

For completeness - another option for loading local content would be to read the HTML content as a text file, and set the HTML directly on the webview with set_content().

However, this only works if the HTML content is entirely self contained, or only contains references to external URLs. Local URL references won't resolve, so if your web page contains a reference to a separate CSS page, or to images, that won't work - you'll need to use the local web server approach.

[Jzhenli]

For completeness - another option for loading local content would be to read the HTML content as a text file, and set the HTML directly on the webview with set_content().

However, this only works if the HTML content is entirely self contained, or only contains references to external URLs. Local URL references won't resolve, so if your web page contains a reference to a separate CSS page, or to images, that won't work - you'll need to use the local web server approach.

@freakboy3742 thanks for your reply, I use the set_content() to load html, but I don't know how to change webview widget to remote url automatically after some seconds when the main_window.show() have run, if there are some call back method to do this? In my case, the remote url maybe very slow, so I want to display a customized html before loading.

[mhsmith]

In that case you'd probably need two WebViews, a visible one showing the local HTML, and an invisible one loading the remote URL, and then switch them when the remote URL has loaded.

For a fixed delay, you could use App.loop to call call_later for a regular function, or create_task for an async function which starts off with an async sleep.

Even better would be to use use the on_webview_load event, but unfortunately that isn't supported on Android yet.