用KeyDown事件在畫布上的光滑元素運動UWP

Question

我想創建一種太空船遊戲，在這裏你用箭頭鍵控制圖像（顯然是飛船），以便向上/向下/向右移動。 爲此我使用了一個CoreWindow.KeyDown事件。

它實際上工作正常，但運動不夠流暢。 每當我按下其中一個箭頭鍵，圖像然後： 1.向該方向移動一步 2.凍結，爲半秒鐘（甚至更少） 3.然後繼續移動沒有麻煩。 （一個「步驟」，是一個'int'變量，它包含許多像素，比如20）。

當然，這是沒辦法運行一個遊戲。當我按下其中一個沒有「半秒」延遲的方向鍵時，我希望船能夠順利移動。 這是我的代碼：

public sealed partial class MainPage : Page 
{ 
    double playerYAxisPosition; 
    double playerXAxisPosition; 
    int steps = 20; 
    bool upMovement; 
    bool downMovement; 
    bool rightMovement; 
    bool leftMovement; 

    public MainPage() 
    { 
     this.InitializeComponent(); 
     Window.Current.CoreWindow.KeyDown += CoreWindow_KeyDown; 
     Window.Current.CoreWindow.KeyUp += CoreWindow_KeyUp; 
    } 

    // Recognizes the KeyDown press and sets the relevant booleans to "true" 
    private void CoreWindow_KeyDown(Windows.UI.Core.CoreWindow sender, Windows.UI.Core.KeyEventArgs args) { 
     playerYPosition = (double) playerShip.GetValue(Canvas.TopProperty); 
     playerXPosition = (double) playerShip.GetValue(Canvas.LeftProperty); 

     if (args.VirtualKey == Windows.System.VirtualKey.Up) { 
      upMovement = true; 
     } 
     else if (args.VirtualKey == Windows.System.VirtualKey.Down) { 
      downMovement = true; 
     } 
     else if (args.VirtualKey == Windows.System.VirtualKey.Left) { 
      leftMovement = true; 
     } 
     else if (args.VirtualKey == Windows.System.VirtualKey.Right) { 
      rightMovement = true; 
     } 
     movePlayer(); 
    } 

    // recognizes the KeyUp event and sets the relevant booleans to "false" 
    private void CoreWindow_KeyUp(Windows.UI.Core.CoreWindow sender, Windows.UI.Core.KeyEventArgs args) { 
     if (args.VirtualKey == Windows.System.VirtualKey.Up) { 
      upMovement = false; 
     } 
     else if (args.VirtualKey == Windows.System.VirtualKey.Down) { 
      downMovement = false; 
     } 
     else if (args.VirtualKey == Windows.System.VirtualKey.Left) { 
      leftMovement = false; 
     } 
     else if (args.VirtualKey == Windows.System.VirtualKey.Right) { 
      rightMovement = false; 
     } 
    } 

    // Calls the movement Methods of the relevant direction 
    private void movePlayer() { 
     if (upMovement) { 
      moveUp(); 
     } 
     if (downMovement) { 
      moveDown(); 
     } 
     if (rightMovement) { 
      moveRight(); 
     } 
     if (leftMovement) { 
      moveLeft(); 
     } 
    } 

    private void moveUp() { 
     playerShip.SetValue(Canvas.TopProperty, playerYPosition - stepsToMove); 
    } 

    private void moveDown() { 
     playerShip.SetValue(Canvas.TopProperty, playerYPosition + stepsToMove); 
    } 

    private void moveRight() { 
     playerShip.SetValue(Canvas.LeftProperty, playerXPosition + stepsToMove); 
    } 

    private void moveLeft() { 
     playerShip.SetValue(Canvas.LeftProperty, playerXPosition - stepsToMove); 
    } 

順便說一句，我創建了一個將設置爲「真」或「假」，在每一個KeyDown事件，而不是直接使用KeyDown事件的一些專用的布爾值的原因，是因爲該分隔允許元素（船圖像）也沿對角線移動，而使用「args.VirtualKey == Windows.System.VirtualKey.SomeArrowKey」直接不允許它由於某種原因。

感謝您的幫助。

Answer 1

如果你想創建一個遊戲，你應該在遊戲循環中移動playerShip。您可以使用DispatcherTimer或註冊CompositionTarget.Rendering事件來創建遊戲循環。

Windows.UI.Xaml.Media.CompositionTarget.Rendering += CompositionTarget_Rendering; 

變化CoreWindow_KeyDown事件處理程序如下：

private void CoreWindow_KeyDown(Windows.UI.Core.CoreWindow sender, Windows.UI.Core.KeyEventArgs args) 
{ 
    if (args.VirtualKey == Windows.System.VirtualKey.Up) 
    { 
     upMovement = true; 
    } 
    else if (args.VirtualKey == Windows.System.VirtualKey.Down) 
    { 
     downMovement = true; 
    } 
    else if (args.VirtualKey == Windows.System.VirtualKey.Left) 
    { 
     leftMovement = true; 
    } 
    else if (args.VirtualKey == Windows.System.VirtualKey.Right) 
    { 
     rightMovement = true; 
    } 
} 

接下來，移動你的船在CompositionTarget.Rendering事件處理程序。

private void CompositionTarget_Rendering(object sender, object e) 
{ 
    playerYPosition = (double)playerShip.GetValue(Canvas.TopProperty); 
    playerXPosition = (double)playerShip.GetValue(Canvas.LeftProperty); 
    movePlayer(); 
}