PrivacyPolicyActivity WebView does not route non http(s) links out of the WebView

[jim-daf]

PrivacyPolicyActivity (opencloudApp/src/main/java/eu/opencloud/android/presentation/settings/privacypolicy/PrivacyPolicyActivity.kt) sets up its WebViewClient with only an onReceivedError override:

webViewClient = object : WebViewClient() {
    override fun onReceivedError(view: WebView, errorCode: Int, description: String, failingUrl: String) {
        showMessageInSnackbar(message = getString(R.string.privacy_policy_error) + description)
    }
}

Because shouldOverrideUrlLoading is not overridden, every link the privacy policy page renders is loaded by the WebView itself. That has two visible effects:

1. A mailto: link in the policy text opens nothing. The WebView fails to load mailto:foo@example.com and the user sees a blank state.
2. A non http(s) scheme that some other app on the device claims (tel:, geo:, intent:, market:) is just swallowed by the WebView instead of handing it to that app.

This is a normal pre-API-24 default, but on a modern build the privacy policy view stops being a useful escape hatch into the system browser / mail app.

Suggested fix

Override shouldOverrideUrlLoading so http(s) navigations stay in the WebView and any other scheme is routed out via Intent.ACTION_VIEW, with a try/catch for ActivityNotFoundException so a missing handler does not crash the Activity:

override fun shouldOverrideUrlLoading(view: WebView?, request: WebResourceRequest?): Boolean {
    val url = request?.url ?: return false
    val scheme = url.scheme?.lowercase()
    if (scheme == "http" || scheme == "https") return false
    return try {
        startActivity(Intent(Intent.ACTION_VIEW, url).apply {
            addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
        })
        true
    } catch (e: ActivityNotFoundException) {
        false
    }
}

A PR with the change is at #165.