SurfaceView Game step-by-step: react device movement/orientation using accelerometer

With the help of accelerometer on Android device(Get detail info of Accelerometer), we can react device movement/orientation for our SurfaceView Game(Implement onTouchEvent() to handle user touch on SurfaceView). After finished, the the Sprite will move once user move the device.


Implement new class - MyAccelerometer.java.

package com.MyGame;

import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;

public class MyAccelerometer implements SensorEventListener{

 private SensorManager sensorManager;
 private Sensor sensorAccelerometer;
 private MyGameActivity parent;
 
 private float maximumRange;
 
 public MyAccelerometer(Context c) {
  parent = (MyGameActivity)c;
 }
 
 void registerListener(){
  sensorManager = (SensorManager)parent.getSystemService(Context.SENSOR_SERVICE);
      sensorAccelerometer = sensorManager.getDefaultSensor(
        Sensor.TYPE_ACCELEROMETER);
    
      maximumRange = sensorAccelerometer.getMaximumRange();
    
  sensorManager.registerListener(this,
    sensorAccelerometer,
    SensorManager.SENSOR_DELAY_NORMAL);
 }
 
 void unregisterListener(){
  sensorManager.unregisterListener(this);
 }

 @Override
 public void onAccuracyChanged(Sensor sensor, int accuracy) {
  // TODO Auto-generated method stub
  
 }

 @Override
 public void onSensorChanged(SensorEvent event) {
  // TODO Auto-generated method stub
  /*
   * event.values[0]: azimuth, rotation around the Z axis.
   * event.values[1]: pitch, rotation around the X axis.
   * event.values[2]: roll, rotation around the Y axis.
   */
  
  float valueAzimuth = event.values[0];
  float valuePitch = event.values[1];
  
  parent.updateAccelerometer(
    valueAzimuth/maximumRange, -valuePitch/maximumRange);
  
 }

}

Modify MyGameActivity.java to instance MyAccelerometer object in onCreate(), init it in onResume(), unregisterListener it in onPause(), and also implement updateAccelerometer().

package com.MyGame;

import android.app.Activity;
import android.graphics.PixelFormat;
import android.os.Bundle;

public class MyGameActivity extends Activity {
 
 MyGameSurfaceView myGameSurfaceView1;
 MyForeground myForeground;
 
 MyAccelerometer myAccelerometer;
 
  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.main);
      myGameSurfaceView1 = (MyGameSurfaceView)findViewById(R.id.myview1);
      myForeground = (MyForeground)findViewById(R.id.myforeground);
    
      //Set myForeground using transparent background
      myForeground.setZOrderOnTop(true);
      myForeground.getHolder().setFormat(PixelFormat.TRANSPARENT);
    
      myAccelerometer = new MyAccelerometer(this);
    
  }

 @Override
 protected void onResume() {
  // TODO Auto-generated method stub
  super.onResume();
  myGameSurfaceView1.MyGameSurfaceView_OnResume();
  myForeground.MyGameSurfaceView_OnResume();
  
  myAccelerometer.registerListener();

 }

 @Override
 protected void onPause() {
  // TODO Auto-generated method stub
  super.onPause();
  myGameSurfaceView1.MyGameSurfaceView_OnPause();
  myForeground.MyGameSurfaceView_OnPause();
  
  myAccelerometer.unregisterListener();
 }
 
 void updateAccelerometer(float tx, float ty){
  int w = myForeground.getWidth();
  int h = myForeground.getHeight();
  
  float x = ((w/2) * tx) + (w/2);
  float y = ((h/2) * ty) + (h/2);
  myForeground.updateAccelerometer(x, y);
 }

}

Update MyForeground.java.

package com.MyGame;

import android.content.Context;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.PorterDuff.Mode;
import android.util.AttributeSet;

public class MyForeground extends MyGameSurfaceView {
 
 Sprite mySprite;

 public MyForeground(Context context) {
  super(context);
  init();
 }

 public MyForeground(Context context, AttributeSet attrs) {
  super(context, attrs);
  init();
 }

 public MyForeground(Context context, AttributeSet attrs, int defStyle) {
  super(context, attrs, defStyle);
  init();
 }
 
 private void init(){
  mySprite = new Sprite(
    BitmapFactory.decodeResource(getResources(), R.drawable.icon_me),
    100, 100);
 }

 @Override
 protected void onDraw(Canvas canvas) {
  //Clear Canvas with transparent background
  canvas.drawColor(Color.TRANSPARENT, Mode.CLEAR);
  
  mySprite.draw(canvas);
 }

 @Override
 public void updateStates() {
  // TODO Auto-generated method stub
  mySprite.update();
 }
 
 void updateAccelerometer(float tx, float ty){
  mySprite.setX((int)tx);
  mySprite.setY((int)ty);
 }

}

Update Sprite.java to remove un-used code.

package com.MyGame;

import android.graphics.Bitmap;
import android.graphics.Canvas;

public class Sprite {
 private Bitmap bitmap;
 private int x;
 private int y;
 float bitmap_halfWidth, bitmap_halfHeight;
 
 public Sprite(Bitmap bm, int tx, int ty){
  bitmap = bm;
  x = tx;
  y = ty;
  bitmap_halfWidth = bitmap.getWidth()/2;
  bitmap_halfHeight = bitmap.getHeight()/2;  
 }
 
 public void setX(int tx){
  x = tx;
 }
 
 public void setY(int ty){
  y = ty;
 }
 
 public int getX(){
  return x;
 }
 
 public int getY(){
  return y;
 }
 
 public void draw(Canvas canvas){
  canvas.drawBitmap(bitmap, x-bitmap_halfWidth, y-bitmap_halfHeight, null);
 }
 
 public void update(){

 }

}

The code can be download here: https://sites.google.com/site/helloandroidingcoding/download/MyGame_20120307.zip?attredirects=0&d=1