java不能在类中使用上下文？

Question

我目前正试图使用ContextCompact.getColor()将我的颜色资源xml中的颜色输入到我的应用程序中，但由于某些原因，我无法传递单一版本的上下文

我使用一个类作为处理程序，所以我不试图从活动中传入。在我的活动中，我可以使用它们，但在我的课堂上，我不能传递getActivityContext(){}等等。没有任何效果。我该怎么办

此外，我正在向画布添加颜色，因此无法在xml中添加颜色

canvas.drawColor(Color.BLACK);

是我目前被迫使用的。我想用xml中的颜色替换它。（我正在尝试设置画布的背景）

我的课程的完整代码：（我把这个应用程序做成一个“笔记”应用程序，这样我就可以在将来的项目中回顾它，从而得到所有的评论）

public class GameHandling {

    private SurfaceHolder holder;
    private Resources resources;

    private int screenWidth;
    private int screenHeight;

    private Ball ball;
    private Bat player;
    private Bat opponent;

    public GameHandling(int width, int height, SurfaceHolder holder, Resources resources){
        this.holder = holder;
        this.resources = resources;
        this.screenWidth = width;
        this.screenHeight = height;

        this.ball = new Ball(screenWidth, screenHeight, 400, 400);
        this.player = new Bat(screenWidth, screenHeight, 0, 0, Bat.Position.LEFT);
        this.opponent = new Bat(screenWidth, screenHeight, 0, 0, Bat.Position.RIGHT);
    }

    // setting the ball images to be drawn
    public void inIt(){

        Bitmap ballShadow = BitmapFactory.decodeResource(resources, R.mipmap.grey_dot);
        Bitmap ballImage = BitmapFactory.decodeResource(resources, R.mipmap.red_dot);
        Bitmap batPlayer = BitmapFactory.decodeResource(resources, R.mipmap.bat_player);
        Bitmap batOpponent = BitmapFactory.decodeResource(resources, R.mipmap.bat_opponent);

        ball.inIt(ballImage, ballShadow, 2, 0);
        player.inIt(batPlayer, batPlayer, 0, 0);
        opponent.inIt(batOpponent, batOpponent, 0, 0);
    }

    // calling Balls update method to update the ball
    public void update(long elapsed){
        ball.update(elapsed);
    }
    public void draw(){
        Canvas canvas = holder.lockCanvas(); // Making a canvas object to draw on - .lockcanvas locks canvas

        if(canvas != null) {
            // draw in area between locking and unlocking

            canvas.drawColor(Color.BLACK);
            ball.draw(canvas);
            player.draw(canvas);
            opponent.draw(canvas);

            holder.unlockCanvasAndPost(canvas); //-unlockcanvasandposts unlocks the canvas
        }


    }
}

Answer 1

我想出了一个解决办法，用我想要的颜色创建了一个图像，然后用它作为应用程序的背景

然而，这仍然是一个解决办法，所以它不能解决我的问题

Answer 2

将构造函数更改为此，并使用ContextCompat.getColor(context,...模式

无论在何处创建这个类（活动/片段），都要传递上下文调用getActivity()或getApplicationContext()

new GameHandling( getActivity()/getApplicationContext(), ...)

public GameHandling(Context context, int width, int height, SurfaceHolder holder, Resources resources){
    this.context = context;
    this.holder = holder;
    this.resources = resources;
    this.screenWidth = width;
    this.screenHeight = height;

    this.ball = new Ball(screenWidth, screenHeight, 400, 400);
    this.player = new Bat(screenWidth, screenHeight, 0, 0, Bat.Position.LEFT);
    this.opponent = new Bat(screenWidth, screenHeight, 0, 0, Bat.Position.RIGHT);
}