Question

我正在玩Android sample app Snake。原始蛇移动方向数学的代码如下。这很简单。方向由基于屏幕中心的触摸所在的象限确定。然而，这很粗糙。有时候蛇在屏幕的右边缘，我想向左移动，但如果我的触摸位于蛇的左侧但仍在右边的象限内，它的方向仍然是正确的。所以我需要一个以Snake头为中心而不是屏幕中心的更新方向数学。我没有成功进行这样的更新。有人擅长数学请帮助。请注意，4个象限被2条对角线分开。

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        if (mSnakeView.getGameState() == SnakeView.RUNNING) {
            // Normalize x,y between 0 and 1
            float x = event.getX() / v.getWidth();
            float y = event.getY() / v.getHeight();

            // Direction will be [0,1,2,3] depending on quadrant
            int direction = 0;
            direction = (x > y) ? 1 : 0;
            direction |= (x > 1 - y) ? 2 : 0;

            // Direction is same as the quadrant which was clicked
            mSnakeView.moveSnake(direction);

        } else {
            // If the game is not running then on touching any part of the screen
            // we start the game by sending MOVE_UP signal to SnakeView
            mSnakeView.moveSnake(MOVE_UP);
        }
        return false;
    }

Answer 1

修改

@Override public boolean onTouch(View v, MotionEvent event) { if (mSnakeView.getGameState() == SnakeView.RUNNING) { // Normalize x,y between 0 and 1 float x = event.getX() / v.getWidth(); float y = event.getY() / v.getHeight(); Coordinate head = mSnakeTrail.get(0); // Direction will be [0,1,2,3] depending on quadrant int direction = 0; //This probably won't work very well //direction = (x > head.x) ? 1 : 0; //Right or left //direction = (y > head.y) ? 2 : 3; //Down or up //this will make sort of quadrants as well, but looked from the head direction = (x > head.x + 10) ? 1:(nowhere); //Right or nowhere (you'll have to see what to fill in instead of 0) direction = (x < head.x - 10) ? 0:(nowhere); //Left or nowhere direction = (y > head.y + 10) ? 2:(nowhere); //Down or nowhere direction = (y < head.y - 10) ? 3:(nowhere); //Up or nowhere // Direction is same as the quadrant which was clicked mSnakeView.moveSnake(direction); } else { // If the game is not running then on touching any part of the screen // we start the game by sending MOVE_UP signal to SnakeView mSnakeView.moveSnake(MOVE_UP); } return false; }

无论如何，我认为将蛇划向你想要的方向会更好。这是在手机上移动蛇的最简单方法。

因此，我建议添加一个gestureOverlay，而不是添加一个touchListener。你可以在这里查看如何添加手势：

http://developer.android.com/reference/android/gesture/GestureOverlayView.html

您也可以使用GestureDetector。以下是GestureDetector的功能：

http://developer.android.com/reference/android/view/GestureDetector.html

这是一个例子：

https://stackoverflow.com/a/938657/2767703

Android示例应用程序Snake的新方向数学

1 个答案: