C++ SFML Text flickers when drawn - c++

Question

I have an SFML RenderWindow, and when it closes, it'll display a confirmation message. I've run into this same problem a lot of times: the confirmation message (an sf::Text) is drawn when the Event::Closed is called, but it only stays when the event is called; I think till the click on the close button is registered (calling the close event); disappears in a flash (does that have something to do with the speed of C++?). How can I solve this? The text should be displayed after it's drawn, and shouldn't disappear, after calling the close event.
Here is the code (in main.cpp):
while (app.isOpen())
{
// Process events
sf::Event event;
while (app.pollEvent(event))
{
// Close window : exit
if (event.type == sf::Event::Closed)
{
app.clear();
Text close("Are you sure you want to close this?", Arial);
app.draw(close);
close.setCharacterSize(40);
close.setPosition(300, 300);
app.display();
}
}
// Clear screen
app.clear();
// Draw the sprite
app.draw(sprite);
app.draw(text);
text.setPosition(500, 500);
// Update the window
app.display();
}
The workaround gives me an error:
I made a function to do the work, but it gives me this error:
error: use of deleted function 'sf::RenderWindow::RenderWindow(const sf::RenderWindow&)'.
Here is the code. What am I doing wrong?

Answer 1

Keep an explicit variable with the state of the game, and change your game code based on that:
enum class GameState { Playing, Closing };
GameState phase = GameState::Playing;
while (app.isOpen()) {
// Process events
sf::Event event;
while (app.pollEvent(event)) {
// Close window : exit
if (event.type == sf::Event::Closed) {
phase = GameState::Closing;
}
}
// Clear screen
app.clear();
if (phase == GameState::Closing) {
Text close("Are you sure you want to close this?", Arial);
close.setCharacterSize(40);
close.setPosition(300, 300);
app.draw(close);
} else if (phase == GameState::Playing) {
app.draw(sprite);
app.draw(text);
text.setPosition(500, 500);
}
// Update the window
app.display();
}