Fixed navigation bar not being entirely hidden on Android

[acsbendi]

Description

In full-screen mode on Android, the navigation bar was not entirely hidden which I tested on multiple devices. After changing a flag, the navigation bar started to behave as expected.

Also refer to the official sample about immersive mode.

Tasks

• Tested on Linux
• Tested on Windows
• Tested on macOS
• Tested on iOS
• Tested on Android

How to test this PR?

#include <SFML/Graphics.hpp>

using std::string;
using sf::Font;
using sf::Sprite;
using sf::Texture;

int main(int argc, char *argv[])
{
    sf::VideoMode screen(sf::VideoMode::getDesktopMode());

    sf::RenderWindow window(screen, "", sf::Style::Fullscreen);
    window.setFramerateLimit(30);

    sf::Texture texture;
    if(!texture.loadFromFile("image.png"))
        return EXIT_FAILURE;

    sf::Sprite image(texture);
    image.setPosition(screen.width / 2, screen.height / 2);
    image.setOrigin(texture.getSize().x/2, texture.getSize().y/2);

    sf::Font font;
    if (!font.loadFromFile("sansation.ttf"))
        return EXIT_FAILURE;

    sf::Text text("Tap anywhere to move the logo.", font, 64);
    text.setFillColor(sf::Color::Blue);
    text.setPosition(10, 10);

    // Loading canary.wav fails for me for now; haven't had time to test why

    /*sf::Music music;
    if(!music.openFromFile("canary.wav"))
        return EXIT_FAILURE;
    music.play();*/

    sf::View view = window.getDefaultView();

    sf::Color background = sf::Color::Black;

    // We shouldn't try drawing to the screen while in background
    // so we'll have to track that. You can do minor background
    // work, but keep battery life in mind.
    bool active = true;

    while (window.isOpen())
    {
        sf::Event event;

        while (active ? window.pollEvent(event) : window.waitEvent(event))
        {
            switch (event.type)
            {
                case sf::Event::Closed:
                    window.close();
                    break;
                case sf::Event::KeyPressed:
                    if (event.key.code == sf::Keyboard::Escape)
                        window.close();
                    break;
                case sf::Event::Resized:
                    view.setSize(event.size.width, event.size.height);
                    view.setCenter(event.size.width/2, event.size.height/2);
                    window.setView(view);
                    break;
                case sf::Event::LostFocus:
                    background = sf::Color::White;
                    break;
                case sf::Event::GainedFocus:
                    background = sf::Color::Black;
                    break;

                    // On Android MouseLeft/MouseEntered are (for now) triggered,
                    // whenever the app loses or gains focus.
                case sf::Event::MouseLeft:
                    active = false;
                    break;
                case sf::Event::MouseEntered:
                    active = true;
                    break;
                case sf::Event::TouchBegan:
                    if (event.touch.finger == 0)
                    {
                        image.setPosition(event.touch.x, event.touch.y);
                    }
                    break;
                default:
                    break;
            }
        }

        if (active)
        {
            window.clear(background);
            window.draw(image);
            window.draw(text);
            window.display();
        }
        else {
            sf::sleep(sf::milliseconds(100));
        }
    }
}

[eXpl0it3r]

Just realized we had a similar PR open #1538 but the author didn't provide an updated one. Looking at the two changes, what's the difference between yours and the other one: https://github.com/SFML/SFML/pull/1538/files#diff-a9064007c5b52fa9f173fdd52d3f0dc3R177 ?

[acsbendi]

@eXpl0it3r Apart from the other files changed in that PR, mine removes setting the other flag (SYSTEM_UI_FLAG_LOW_PROFILE) which doesn't have any effect after setting SYSTEM_UI_FLAG_HIDE_NAVIGATION and is therefore unnecessary.

[eXpl0it3r]

Seems like there are different options some comment from @MarioLiebisch or someone else might be useful, but I'm happy to get this merged regardless.