CN.setScreenSaverEnabled(false); and MediaPlayer

问题

Oddly when I play a video using MediaPlayer in a non-native way, after a few seconds (depending on the mobile phone settings) the power saving mode starts, which turns the screen off. This is an unwanted behavior, because when playing a video the screen must never turn off or dim. I don't understand if this is a Codename One bug or a feature, however it happens both on Android and iOS.

Apparently I fixed the problem using CN.setScreenSaverEnabled(false);. My problem, however, is that it doesn't work all the time. The following code sometimes makes the screen stay active, sometimes it doesn't. I don't understand why sometimes it works and sometimes it doesn't.

To better understand the following code, videoUrl is an HLS stream.

    private void playVideo(Form parent, String videoUrl) {
        CN.setScreenSaverEnabled(false);
        Form player = new Form(new BorderLayout());
        player.getToolbar().setBackCommand("Back", Toolbar.BackCommandPolicy.ALWAYS, e -> {
            if (mp != null) {
                mp.getMedia().cleanup();
            }
            CN.setScreenSaverEnabled(true);
            parent.showBack();
        });
        player.add(BorderLayout.CENTER, FlowLayout.encloseCenterMiddle(
                new SpanLabel("Stream will start playing automatically when it is live")));

        player.addShowListener(l -> {
            while (!Util.downloadUrlToStorage(videoUrl, "temp.m3u8", false)) {
                CN.invokeAndBlock(() -> Util.sleep(1000));
            }
            try {
                // note that we cannot play the locally downloaded m3u8
                Media video = MediaManager.createMedia(videoUrl, true, () -> {
                    // completion handler, it's invoked when the stream connection is lost
                    if (mp != null) {
                        mp.getMedia().cleanup();
                    }
                    CN.setScreenSaverEnabled(true);
                    parent.showBack();
                });
                video.setNativePlayerMode(false);
                if (mp != null) {
                    mp.getMedia().cleanup();
                }
                mp = new MediaPlayer(video);
                mp.setAutoplay(true);
                mp.setHideNativeVideoControls(true);
                mp.setMaximize(false);
                player.removeAll();
                player.add(BorderLayout.CENTER, mp);
                player.revalidate();
            } catch (Exception err) {
                Log.e(err);
                ToastBar.showErrorMessage("Error loading straming");
            }
        });

        player.show();
    }

来源：https://stackoverflow.com/questions/63007943/cn-setscreensaverenabledfalse-and-mediaplayer