当按下键时，窗口停止刷新

每当我按下一个键来移动一个精灵时，屏幕将不会更新，直到我释放这个键。我能够解决这个问题的唯一方法是在每个按键循环中清除，绘制和显示窗口。

独立于任何按键一次完成这些事情会更有意义。我不知道为什么这不起作用，或者修复这个问题的最好方法是什么。

在下面的程序中，我在多个不同的地方张贴了清除/绘制/显示代码，希望把它放在正确的地方会起作用。到目前为止还没有。否则冗余是没有意义的。

#include <SFML/Window.hpp>
#include <iostream>
#include <SFML/Graphics.hpp>
#include <SFML/System.hpp>
using namespace std;
int main()
{
int windowx = 800;
int windowy = 600;
float playerx = 400.0;
float playery = 300.0;
sf::Sprite playersprite;
sf::Sprite enemysprite;
float playerspeedx = 0;
float playerspeedy = 0;
float playerspeedx2 = 0;
float playerspeedy2 = 0;
float accelerationx = 50.0;
float accelerationy = 50.0;
float deccelerationx = 50.0;
float deccelerationy = 50.0;
float frictionx = 25.0;
float frictiony = 25.0;
float playermaxspeedx = 500.0;
float playermaxspeedy = 200.0;
sf::Texture hoverdrone; //player's sprite
if (!hoverdrone.loadFromFile("hoverdrone.png"))
    {
        cout << "error loading image";
    }
sf::Texture floatdrone; //for sprite enemysprite
    if (!floatdrone.loadFromFile("floatdrone.png"))
    {
        cout << "error loading image";
    }
    playersprite.setTexture(hoverdrone);
    enemysprite.setTexture(floatdrone);
    enemysprite.setPosition(sf::Vector2f(400, 400));
    playersprite.setPosition(sf::Vector2f(400, 300));

sf::RenderWindow mywindow(sf::VideoMode(windowx, windowy), "FishTank");
//sf::Clock clock; //Begin clock.
//sf::Int32 baseclock = clock.getElapsedTime().asMilliseconds();
// run the program as long as the window is open
while (mywindow.isOpen())
{
    // check all the window's events that were triggered since the last iteration of the loop
    sf::Event event;
    while (mywindow.pollEvent(event))
    {
        // "close requested" event: we close the window
        if (event.type == sf::Event::Closed)
            {
                cout <<"You have closed the window."<<endl;
                mywindow.close();
            }
        mywindow.clear(sf::Color::Black);
        mywindow.draw(playersprite);
        mywindow.draw(enemysprite);
        playersprite.setPosition(sf::Vector2f(playerx, playery));
        mywindow.display();
        sf::sleep(sf::microseconds(5));
        // left key is pressed: move our character
        if (sf::Keyboard::isKeyPressed(sf::Keyboard::Left))
            {
                sf::Clock leftclock;
                while (sf::Keyboard::isKeyPressed(sf::Keyboard::Left))
                {
                    playerx -= 0.01; //will replace later with time based movement
                    sf::Int32 leftclock1 = leftclock.getElapsedTime().asMilliseconds();
                    cout << leftclock1 << endl;
                    /*mywindow.clear(sf::Color::Black);
                    mywindow.draw(playersprite);
                    mywindow.draw(enemysprite);
                    playersprite.setPosition(sf::Vector2f(playerx, playery));
                    mywindow.display();*/
                }
            }
        // right key is pressed: move our character
        if (sf::Keyboard::isKeyPressed(sf::Keyboard::Right))
            {
                sf::Clock rightclock;
                while (sf::Keyboard::isKeyPressed(sf::Keyboard::Right))
                {
                    playerx += 0.01; //will replace later with time based movement
                    sf::Int32 rightclock1 = rightclock.getElapsedTime().asMilliseconds();
                    cout << rightclock1 << endl;
                    /*mywindow.clear(sf::Color::Black);
                    mywindow.draw(playersprite);
                    mywindow.draw(enemysprite);
                    playersprite.setPosition(sf::Vector2f(playerx, playery));
                    mywindow.display();*/
                }
            }
        if (sf::Keyboard::isKeyPressed(sf::Keyboard::Up))
            {
                // up key is pressed: move our character
                //will replace later with time based movement
                (playery--);
            }
        if (sf::Keyboard::isKeyPressed(sf::Keyboard::Down))
            {
                // down key is pressed: move our character
                // currently just resets sprite position for testing purposes
                    playerx = 400.0;
                    playery = 300.0;
            }
        if (playerx < 0) //Player cannot leave screen x left boundary
            {
                playerx = 0;
            }
        if (playerx > windowx) //Player cannot leave screen x right boundary
            {
                playerx = windowx - 10;
            }
    }
    mywindow.clear(sf::Color::Black);
    mywindow.draw(playersprite);
    mywindow.draw(enemysprite);
    playersprite.setPosition(sf::Vector2f(playerx, playery));
    mywindow.display();
    sf::sleep(sf::microseconds(5));
}
mywindow.clear(sf::Color::Black);
mywindow.draw(playersprite);
mywindow.draw(enemysprite);
playersprite.setPosition(sf::Vector2f(playerx, playery));
mywindow.display();
sf::sleep(sf::microseconds(5));
return 0;

}