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。我成功地证明了这一点。但我有两个问题

球越过屏幕
球的移动不平滑（看起来它消失并重新出现在屏幕上）

这是我的代码。是否有任何改变我需要做的是让我们在很多比赛中看到球的平稳和精确的运动。

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

这与您上一个问题的问题不同here?!您应该编辑/扩展原始问题，而不是开始新问题！

但基本上是为了让你想要通过使用x / y速度来移动球而不仅仅是改变位置。因此，您希望有一个绘制球的循环，并且您想知道当前循环与前一循环之间的时间差，那么您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).

在使用传感器输入设置加速度的情况下，只需将计算出的距离添加到球位置即可。

编辑 - 按要求编码。

你很幸运，你找到了一个无聊的游戏程序员！它不是完美的，但它为你工作。你应该给自己买一本游戏开发书，然后看看使用open GL，因为它会更好！

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);
}
}

Answer 2

我会将SENSOR_DELAY设为常量

SENSOR_DELAY_FASTEST

看看是否能修复它。这应该有助于解决口吃问题。另外我认为你的边界检查是错误的，因为xmax和ymax值给出了display.getWidth / getHeight 也许您应该将BitMap的宽度和高度边界提供给xmax和ymax值。

Android Accelerometer移动球

2 个答案: