When developing Android, I encountered an Https page loaded with http js and css, prompting a Mixed Content error, preventing the loading
solution:
Android below:
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) { webView.getSettings().setMixedContentMode(WebSettings.MIXED_CONTENT_ALWAYS_ALLOW); }
Solve through the web page: automatically upgrade the unsafe request of http to https, which requires HTTPS support in the background
<meta http-equiv="Content-Security-Policy" content="upgrade-insecure-requests">