Android Open Source - FallingBall Pad View

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Back to project page FallingBall.
License

The source code is released under:
GNU General Public License
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Java Source Code

package edu.fmi.android.brickpong.view;
/*from w  w  w.ja  v  a2 s  .c om*/
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.view.Display;
import android.view.Surface;
import android.view.View;
import android.view.WindowManager;
import edu.fmi.android.brickpong.GameItem;
import edu.fmi.android.brickpong.listeners.OnPositionChangedListener;

public class PadView extends View implements SensorEventListener {

  /**
   * {@value}
   */
  public static final String TAG = PadView.class.getSimpleName();

  /**
   * {@value}
   */
  private static final int PADDLE_HEIGHT = 10;

  /**
   * {@value}
   */
  private static final float PADDLE_WIDTH = 0.015f;

  /**
   * {@value}
   */
  private static final float NANOSECONDS_IN_A_SECOND = 1000000000.0f;

  /**
   * {@value}
   */
  private static final float METRES_IN_INCH = 0.0254f;

  private float positionX;

  private float positionY;

  private float accelerationX;

  private float accelerationY;

  private float horizontalBound;

  private float verticalBound;

  private float startX;

  private long lastRenderTime;

  private float metersToPixelsX;

  private float sensorX;

  private float sensorY;

  private long sensorTimeStamp;

  private long cpuTimeStamp;

  private final Paint shipPaint;

  private final RectF boundingRect;

  private OnPositionChangedListener listener;

  public PadView(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);

    final WindowManager windowManager = (WindowManager) context
        .getSystemService(Context.WINDOW_SERVICE);

    DisplayMetrics metrics = new DisplayMetrics();
    windowManager.getDefaultDisplay().getMetrics(metrics);
    metersToPixelsX = metrics.xdpi / METRES_IN_INCH;

    final SensorManager sensorManager = (SensorManager) context
        .getSystemService(Context.SENSOR_SERVICE);
    sensorManager.registerListener(this,
        sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER),
        SensorManager.SENSOR_DELAY_UI);

    shipPaint = new Paint();
    shipPaint.setColor(Color.CYAN);

    boundingRect = new RectF();
  }

  public PadView(Context context, AttributeSet attrs) {
    this(context, attrs, 0);
  }

  public PadView(Context context) {
    this(context, null);
  }

  @Override
  protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);

    final long renderTime = sensorTimeStamp
        + (System.nanoTime() - cpuTimeStamp);

    if (lastRenderTime != 0) {
      final float renderDelta = (renderTime - lastRenderTime)
          / NANOSECONDS_IN_A_SECOND;
      if (renderDelta != 0) {
        positionX = positionX + accelerationX * renderDelta
            * renderDelta;
        positionY = positionY + accelerationY * renderDelta
            * renderDelta;
        accelerationX = -sensorX;
        accelerationY = -sensorY;
      }
    }

    lastRenderTime = renderTime;

    if (positionX > horizontalBound) {
      positionX = horizontalBound;
    } else if (positionX < -horizontalBound) {
      positionX = -horizontalBound;
    }
    if (positionY > verticalBound) {
      positionY = verticalBound;
    } else if (positionY < -verticalBound) {
      positionY = -verticalBound;
    }

    final float x = startX + positionX * metersToPixelsX;
    boundingRect.set(Math.max(0, x), verticalBound - PADDLE_HEIGHT,
        Math.round(x + PADDLE_WIDTH * metersToPixelsX), verticalBound);
    canvas.drawRect(boundingRect, shipPaint);
    listener.onPositionChanged(GameItem.PAD, boundingRect);
  }

  @Override
  public void onAccuracyChanged(Sensor sensor, int accuracy) {
    // blank
  }

  @Override
  public void onSensorChanged(SensorEvent event) {
    final WindowManager windowManager = (WindowManager) getContext()
        .getSystemService(Context.WINDOW_SERVICE);
    final Display display = windowManager.getDefaultDisplay();

    switch (display.getRotation()) {
    case Surface.ROTATION_0:
      sensorX = event.values[0];
      sensorY = event.values[1];
      break;
    case Surface.ROTATION_90:
      sensorX = -event.values[1];
      sensorY = event.values[0];
      break;
    case Surface.ROTATION_180:
      sensorX = -event.values[0];
      sensorY = -event.values[1];
      break;
    case Surface.ROTATION_270:
      sensorX = event.values[1];
      sensorY = -event.values[0];
      break;
    }

    sensorTimeStamp = event.timestamp;
    cpuTimeStamp = System.nanoTime();
  }

  public void setDimensions(final int width, final int height) {
    startX = Math.round(width - PADDLE_WIDTH * metersToPixelsX) * 0.5f;
    horizontalBound = (width / metersToPixelsX - PADDLE_WIDTH) * 0.5f;
    verticalBound = height;
  }

  public void setOnPositionChangedListener(
      final OnPositionChangedListener listener) {
    this.listener = listener;
  }

}
Java Source Code List
