Android加速度计移动球

Question

我已经在网上发布的教程的帮助下开发了一个示例应用程序。我的目标是访问加速度计并根据手机方向移动球。我在某种程度上是成功的。但是我有两个问题

1. 球出界了
2. 小球运动不流畅(看起来消失又重新出现在屏幕上)

这是我的代码。我是否需要做任何改变才能像我们在很多比赛中看到的那样平稳准确地移动球。

public class Accelerometer extends Activity implements SensorEventListener{
    /** Called when the activity is first created. */
    CustomDrawableView mCustomDrawableView = null;
    ShapeDrawable mDrawable = new ShapeDrawable();
    public static int x;
    public static int y;
       private Bitmap mBitmap;
       private Bitmap mWood;
    private SensorManager sensorManager = null;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState)
    {

        super.onCreate(savedInstanceState);
        // Get a reference to a SensorManager
        sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
        mCustomDrawableView = new CustomDrawableView(this);
        setContentView(mCustomDrawableView);
        // setContentView(R.layout.main);

    }

    // This method will update the UI on new sensor events
    public void onSensorChanged(SensorEvent sensorEvent)
    {
        {
           /* if (sensorEvent.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
                // the values you were calculating originally here were over 10000!
                x = (int) Math.pow(sensorEvent.values[0], 2); 
                y = (int) Math.pow(sensorEvent.values[1], 2);

            }*/

            if (sensorEvent.sensor.getType() == Sensor.TYPE_ORIENTATION) {
                  Display display = getWindowManager().getDefaultDisplay(); 
                  int xmax = display.getWidth();
                  int ymax = display.getHeight();
                  x = (int) Math.pow(sensorEvent.values[1], 2); 
                  y = (int) Math.pow(sensorEvent.values[2], 2);
                  if (x > xmax) {
                      x = xmax;
                  } else if (x < -xmax) {
                      x = -xmax;
                  }
                  if (y > ymax) { 
                      y = ymax;
                  } else if (y < -ymax) {
                      y = -ymax;
                  }

            }
        }
    }

    // I've chosen to not implement this method
    public void onAccuracyChanged(Sensor arg0, int arg1)
    {
        // TODO Auto-generated method stub

    }

    @Override
    protected void onResume()
    {
        super.onResume();
        // Register this class as a listener for the accelerometer sensor
        sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER),
                SensorManager.SENSOR_DELAY_GAME);
        // ...and the orientation sensor
        sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION),
                SensorManager.SENSOR_DELAY_NORMAL); 
    }

    @Override
    protected void onStop()
    {
        // Unregister the listener
        sensorManager.unregisterListener(this);
        super.onStop();
    }

    public class CustomDrawableView extends View
    {


        public CustomDrawableView(Context context)
        {
            super(context);

          Bitmap ball = BitmapFactory.decodeResource(getResources(), R.drawable.ball);
          final int dstWidth = 50; 
          final int dstHeight = 50; 
          mBitmap = Bitmap.createScaledBitmap(ball, dstWidth, dstHeight, true);
          mWood = BitmapFactory.decodeResource(getResources(), R.drawable.wood);

        }

        protected void onDraw(Canvas canvas)
        {

            final Bitmap bitmap = mBitmap;

            canvas.drawBitmap(mWood, 0, 0, null);
            canvas.drawBitmap(bitmap, x, y, null);

            invalidate();
        }
    }
}

Answer 1

这和你上一个问题不是同一个问题吗here?!您应该只编辑/扩展您的原始问题，而不是开始一个新问题!

但基本上，为了让它更逼真，您希望通过使用 x/y 速度来移动球，而不是仅仅改变位置。所以你想要一个绘制球的循环并且你想知道当前循环和前一个循环之间的时间差，那么你可以使用简单的运动学方程来计算位置变化。

例如:

newspeed = oldSpeed + (acceleration * time)
distance = (original speed*time) + (0.5 * acceleration * time^2).

在您使用传感器输入设置加速度的地方，只需将计算出的距离添加到球的位置即可。

---

编辑 - 根据要求编写代码。

你很幸运，你找到了一个无聊的游戏程序员!它无论如何都不是完美的，但它适合你。您应该给自己买一本游戏开发书籍，看看为此使用 Open GL，因为它会好得多!

public class test2 extends Activity implements SensorEventListener{

CustomDrawableView mCustomDrawableView = null;
ShapeDrawable mDrawable = new ShapeDrawable();
public float xPosition, xAcceleration,xVelocity = 0.0f;
public float yPosition, yAcceleration,yVelocity = 0.0f;
public float xmax,ymax;
private Bitmap mBitmap;
private Bitmap mWood;
private SensorManager sensorManager = null;
public float frameTime = 0.666f;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{

    super.onCreate(savedInstanceState);

    //Set FullScreen & portrait
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);

    // Get a reference to a SensorManager
    sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
    sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION),
            SensorManager.SENSOR_DELAY_GAME);

    mCustomDrawableView = new CustomDrawableView(this);
    setContentView(mCustomDrawableView);
    // setContentView(R.layout.main);

    //Calculate Boundry
    Display display = getWindowManager().getDefaultDisplay();
    xmax = (float)display.getWidth() - 50;
    ymax = (float)display.getHeight() - 50;
}

// This method will update the UI on new sensor events
public void onSensorChanged(SensorEvent sensorEvent)
{
    {
        if (sensorEvent.sensor.getType() == Sensor.TYPE_ORIENTATION) {
            //Set sensor values as acceleration
            yAcceleration = sensorEvent.values[1]; 
            xAcceleration = sensorEvent.values[2];
            updateBall();
        }
    }
}

private void updateBall() {


    //Calculate new speed
    xVelocity += (xAcceleration * frameTime);
    yVelocity += (yAcceleration * frameTime);

    //Calc distance travelled in that time
    float xS = (xVelocity/2)*frameTime;
    float yS = (yVelocity/2)*frameTime;

    //Add to position negative due to sensor 
    //readings being opposite to what we want!
    xPosition -= xS; 
    yPosition -= yS;

    if (xPosition > xmax) {
        xPosition = xmax;
    } else if (xPosition < 0) {
        xPosition = 0;
    }
    if (yPosition > ymax) { 
        yPosition = ymax;
    } else if (yPosition < 0) {
        yPosition = 0;
    }
}

// I've chosen to not implement this method
public void onAccuracyChanged(Sensor arg0, int arg1)
{
    // TODO Auto-generated method stub
}

@Override
protected void onResume()
{
    super.onResume();
    sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION),
            SensorManager.SENSOR_DELAY_GAME); 
}

@Override
protected void onStop()
{
    // Unregister the listener
    sensorManager.unregisterListener(this);
    super.onStop();
}

public class CustomDrawableView extends View
{
    public CustomDrawableView(Context context)
    {
        super(context);
        Bitmap ball = BitmapFactory.decodeResource(getResources(), R.drawable.ball);
        final int dstWidth = 50; 
        final int dstHeight = 50; 
        mBitmap = Bitmap.createScaledBitmap(ball, dstWidth, dstHeight, true);
        mWood = BitmapFactory.decodeResource(getResources(), R.drawable.wood);

    }

    protected void onDraw(Canvas canvas)
    {
        final Bitmap bitmap = mBitmap;
        canvas.drawBitmap(mWood, 0, 0, null);
        canvas.drawBitmap(bitmap, xPosition, yPosition, null);
        invalidate();
    }
}

@Override
public void onConfigurationChanged(Configuration newConfig) {
    // TODO Auto-generated method stub
    super.onConfigurationChanged(newConfig);
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
}
}