WebView: how to avoid security alert from Google Play upon implementation of onReceivedSslError

To properly handle SSL certificate validation, change your code to
invoke SslErrorHandler.proceed() whenever the certificate presented by
the server meets your expectations, and invoke
SslErrorHandler.cancel() otherwise.

As email said, onReceivedSslError should handle user is going to a page with invalid cert, such like a notify dialog. You should not proceed it directly.

For example, I add an alert dialog to make user have confirmed and seems Google no longer shows warning.

@Override
public void onReceivedSslError(WebView view, final SslErrorHandler handler, SslError error) {
    final AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setMessage(R.string.notification_error_ssl_cert_invalid);
    builder.setPositiveButton("continue", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            handler.proceed();
        }
    });
    builder.setNegativeButton("cancel", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            handler.cancel();
        }
    });
    final AlertDialog dialog = builder.create();
    dialog.show();
}

More explain about the email.

Specifically, the implementation ignores all SSL certificate validation
errors, making your app vulnerable to man-in-the-middle attacks.

The email says the default implement ignored an important SSL security problem. So we need to handle it in our own app which used WebView. Notify user with a alert dialog is a simple way.