Develop Reference

Canvas doesn't draw correctly my scale text

I see scale with only 0 written! As in the picture and two strange zeros out of the schema: (GALAXY NEXUS 4.2.1)
As in the example at http://mindtherobot.com/blog/272/android-custom-ui-making-a-vintage-thermometer/comment-page-1/#comment-106122%29 this is my custom view:
package com.wikibuyers.barometro;
import java.util.List;
import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.LightingColorFilter;
import android.graphics.LinearGradient;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RadialGradient;
import android.graphics.RectF;
import android.graphics.Shader;
import android.graphics.Typeface;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.os.Handler;
import android.os.Parcelable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
public class Barometro extends View implements SensorEventListener{
private static final String TAG = Barometro.class.getSimpleName();
private Handler handler;
// drawing tools
private RectF rimRect;
private Paint rimPaint;
private Paint rimCirclePaint;
private RectF faceRect;
private Bitmap faceTexture;
private Paint facePaint;
private Paint rimShadowPaint;
private Paint scalePaint;
private RectF scaleRect;
private Paint titlePaint;
private Path titlePath;
private Paint logoPaint;
private Bitmap logo;
private Matrix logoMatrix;
private float logoScale;
private Paint handPaint;
private Path handPath;
private Paint handScrewPaint;
private Paint backgroundPaint;
// end drawing tools
private Bitmap background; // holds the cached static part
// scale configuration
private static final int totalNicks = 100;
private static final float degreesPerNick = 360.0f / totalNicks;
private static final int centerDegree = 40; // the one in the top center (12 o'clock)
private static final int minDegrees = -30;
private static final int maxDegrees = 110;
// hand dynamics -- all are angular expressed in F degrees
private boolean handInitialized = false;
private float handPosition = centerDegree;
private float handTarget = centerDegree;
private float handVelocity = 0.0f;
private float handAcceleration = 0.0f;
private long lastHandMoveTime = -1L;
public Barometro(Context context) {
super(context);
init();
}
public Barometro(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public Barometro(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
#Override
protected void onAttachedToWindow() {
super.onAttachedToWindow();
attachToSensor();
}
#Override
protected void onDetachedFromWindow() {
detachFromSensor();
super.onDetachedFromWindow();
}
#Override
protected void onRestoreInstanceState(Parcelable state) {
Bundle bundle = (Bundle) state;
Parcelable superState = bundle.getParcelable("superState");
super.onRestoreInstanceState(superState);
handInitialized = bundle.getBoolean("handInitialized");
handPosition = bundle.getFloat("handPosition");
handTarget = bundle.getFloat("handTarget");
handVelocity = bundle.getFloat("handVelocity");
handAcceleration = bundle.getFloat("handAcceleration");
lastHandMoveTime = bundle.getLong("lastHandMoveTime");
}
#Override
protected Parcelable onSaveInstanceState() {
Parcelable superState = super.onSaveInstanceState();
Bundle state = new Bundle();
state.putParcelable("superState", superState);
state.putBoolean("handInitialized", handInitialized);
state.putFloat("handPosition", handPosition);
state.putFloat("handTarget", handTarget);
state.putFloat("handVelocity", handVelocity);
state.putFloat("handAcceleration", handAcceleration);
state.putLong("lastHandMoveTime", lastHandMoveTime);
return state;
}
#SuppressLint({ "NewApi", "InlinedApi" })
private void init() {
handler = new Handler();
setLayerType(View.LAYER_TYPE_SOFTWARE, null);
initDrawingTools();
}
private String getTitle() {
return "wikibuyers.com";
}
private SensorManager getSensorManager() {
return (SensorManager) getContext().getSystemService(Context.SENSOR_SERVICE);
}
private void attachToSensor() {
SensorManager sensorManager = getSensorManager();
List<Sensor> sensors = sensorManager.getSensorList(Sensor.TYPE_PRESSURE);
if (sensors.size() > 0) {
Sensor sensor = sensors.get(0);
sensorManager.registerListener(this, sensor, SensorManager.SENSOR_DELAY_NORMAL, handler);
} else {
Log.e(TAG, "No pressure sensor found");
}
}
private void detachFromSensor() {
SensorManager sensorManager = getSensorManager();
sensorManager.unregisterListener(this);
}
private void initDrawingTools() {
rimRect = new RectF(0.1f, 0.1f, 0.9f, 0.9f);
// the linear gradient is a bit skewed for realism
rimPaint = new Paint();
rimPaint.setFlags(Paint.ANTI_ALIAS_FLAG);
rimPaint.setShader(new LinearGradient(0.40f, 0.0f, 0.60f, 1.0f,
Color.rgb(0xf0, 0xf5, 0xf0),
Color.rgb(0x30, 0x31, 0x30),
Shader.TileMode.CLAMP));
rimCirclePaint = new Paint();
rimCirclePaint.setAntiAlias(true);
rimCirclePaint.setStyle(Paint.Style.STROKE);
rimCirclePaint.setColor(Color.argb(0x4f, 0x33, 0x36, 0x33));
rimCirclePaint.setStrokeWidth(0.005f);
float rimSize = 0.02f;
faceRect = new RectF();
faceRect.set(rimRect.left + rimSize, rimRect.top + rimSize,
rimRect.right - rimSize, rimRect.bottom - rimSize);
faceTexture = BitmapFactory.decodeResource(getContext().getResources(),
R.drawable.plastic);
BitmapShader paperShader = new BitmapShader(faceTexture,
Shader.TileMode.MIRROR,
Shader.TileMode.MIRROR);
Matrix paperMatrix = new Matrix();
facePaint = new Paint();
facePaint.setFilterBitmap(true);
paperMatrix.setScale(1.0f / faceTexture.getWidth(),
1.0f / faceTexture.getHeight());
paperShader.setLocalMatrix(paperMatrix);
facePaint.setStyle(Paint.Style.FILL);
facePaint.setShader(paperShader);
rimShadowPaint = new Paint();
rimShadowPaint.setShader(new RadialGradient(0.5f, 0.5f, faceRect.width() / 2.0f,
new int[] { 0x00000000, 0x00000500, 0x50000500 },
new float[] { 0.96f, 0.96f, 0.99f },
Shader.TileMode.MIRROR));
rimShadowPaint.setStyle(Paint.Style.FILL);
scalePaint = new Paint();
scalePaint.setStyle(Paint.Style.STROKE);
scalePaint.setColor(0x9f004d0f);
scalePaint.setStrokeWidth(0.005f);
scalePaint.setAntiAlias(true);
scalePaint.setTextSize(0.045f);
scalePaint.setTypeface(Typeface.SANS_SERIF);
scalePaint.setTextScaleX(0.8f);
scalePaint.setTextAlign(Paint.Align.CENTER);
float scalePosition = 0.10f;
scaleRect = new RectF();
scaleRect.set(faceRect.left + scalePosition, faceRect.top + scalePosition,
faceRect.right - scalePosition, faceRect.bottom - scalePosition);
titlePaint = new Paint();
titlePaint.setColor(0xaf946109);
titlePaint.setAntiAlias(true);
titlePaint.setTypeface(Typeface.DEFAULT_BOLD);
titlePaint.setTextAlign(Paint.Align.CENTER);
titlePaint.setTextSize(0.05f);
titlePaint.setTextScaleX(0.8f);
titlePath = new Path();
titlePath.addArc(new RectF(0.24f, 0.24f, 0.76f, 0.76f), -180.0f, -180.0f);
logoPaint = new Paint();
logoPaint.setFilterBitmap(true);
logo = BitmapFactory.decodeResource(getContext().getResources(), R.drawable.logo);
logoMatrix = new Matrix();
logoScale = (1.0f / logo.getWidth()) * 0.3f;;
logoMatrix.setScale(logoScale, logoScale);
handPaint = new Paint();
handPaint.setAntiAlias(true);
handPaint.setColor(0xff392f2c);
handPaint.setShadowLayer(0.01f, -0.005f, -0.005f, 0x7f000000);
handPaint.setStyle(Paint.Style.FILL);
handPath = new Path();
handPath.moveTo(0.5f, 0.5f + 0.2f);
handPath.lineTo(0.5f - 0.010f, 0.5f + 0.2f - 0.007f);
handPath.lineTo(0.5f - 0.002f, 0.5f - 0.32f);
handPath.lineTo(0.5f + 0.002f, 0.5f - 0.32f);
handPath.lineTo(0.5f + 0.010f, 0.5f + 0.2f - 0.007f);
handPath.lineTo(0.5f, 0.5f + 0.2f);
handPath.addCircle(0.5f, 0.5f, 0.025f, Path.Direction.CW);
handScrewPaint = new Paint();
handScrewPaint.setAntiAlias(true);
handScrewPaint.setColor(0xff493f3c);
handScrewPaint.setStyle(Paint.Style.FILL);
backgroundPaint = new Paint();
backgroundPaint.setFilterBitmap(true);
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
Log.d(TAG, "Width spec: " + MeasureSpec.toString(widthMeasureSpec));
Log.d(TAG, "Height spec: " + MeasureSpec.toString(heightMeasureSpec));
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int widthSize = MeasureSpec.getSize(widthMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
int heightSize = MeasureSpec.getSize(heightMeasureSpec);
int chosenWidth = chooseDimension(widthMode, widthSize);
int chosenHeight = chooseDimension(heightMode, heightSize);
int chosenDimension = Math.min(chosenWidth, chosenHeight);
setMeasuredDimension(chosenDimension, chosenDimension);
}
private int chooseDimension(int mode, int size) {
if (mode == MeasureSpec.AT_MOST || mode == MeasureSpec.EXACTLY) {
return size;
} else { // (mode == MeasureSpec.UNSPECIFIED)
return getPreferredSize();
}
}
// in case there is no size specified
private int getPreferredSize() {
return 300;
}
private void drawRim(Canvas canvas) {
// first, draw the metallic body
canvas.drawOval(rimRect, rimPaint);
// now the outer rim circle
canvas.drawOval(rimRect, rimCirclePaint);
}
private void drawFace(Canvas canvas) {
canvas.drawOval(faceRect, facePaint);
// draw the inner rim circle
canvas.drawOval(faceRect, rimCirclePaint);
// draw the rim shadow inside the face
canvas.drawOval(faceRect, rimShadowPaint);
}
private void drawScale(Canvas canvas) {
canvas.drawOval(scaleRect, scalePaint);
canvas.save(Canvas.MATRIX_SAVE_FLAG);
for (int i = 0; i < totalNicks; ++i) {
float y1 = scaleRect.top;
float y2 = y1 - 0.020f;
canvas.drawLine(0.5f, y1, 0.5f, y2, scalePaint);
if ((i % 5) == 0) {
int value = nickToDegree(i);
if ((value >= minDegrees) && (value <= maxDegrees)) {
String valueString = Integer.toString(value);
canvas.drawText(valueString, 0.5f, y2 - 0.015f, scalePaint);
}
}
canvas.rotate(degreesPerNick, 0.5f, 0.5f);
}
canvas.restore();
}
private int nickToDegree(int nick) {
int rawDegree = ((nick < totalNicks / 2) ? nick : (nick - totalNicks)) * 2;
int shiftedDegree = rawDegree + centerDegree;
return shiftedDegree;
}
private float degreeToAngle(float degree) {
return (degree - centerDegree) / 2.0f * degreesPerNick;
}
private void drawTitle(Canvas canvas) {
String title = getTitle();
canvas.drawTextOnPath(title, titlePath, 0.0f,0.0f, titlePaint);
}
private void drawLogo(Canvas canvas) {
canvas.save(Canvas.MATRIX_SAVE_FLAG);
canvas.translate(0.5f - logo.getWidth() * logoScale / 2.0f,
0.5f - logo.getHeight() * logoScale / 2.0f);
int color = 0x00000000;
float position = getRelativePressurePosition();
if (position < 0) {
color |= (int) ((0xf0) * -position); // blue
} else {
color |= ((int) ((0xf0) * position)) << 16; // red
}
//Log.d(TAG, "*** " + Integer.toHexString(color));
LightingColorFilter logoFilter = new LightingColorFilter(0xff338822, color);
logoPaint.setColorFilter(logoFilter);
canvas.drawBitmap(logo, logoMatrix, logoPaint);
canvas.restore();
}
private void drawHand(Canvas canvas) {
if (handInitialized) {
float handAngle = degreeToAngle(handPosition);
canvas.save(Canvas.MATRIX_SAVE_FLAG);
canvas.rotate(handAngle, 0.5f, 0.5f);
canvas.drawPath(handPath, handPaint);
canvas.restore();
canvas.drawCircle(0.5f, 0.5f, 0.01f, handScrewPaint);
}
}
private void drawBackground(Canvas canvas) {
if (background == null) {
Log.w(TAG, "Background not created");
} else {
canvas.drawBitmap(background, 0, 0, backgroundPaint);
}
}
#Override
protected void onDraw(Canvas canvas) {
drawBackground(canvas);
float scale = (float) getWidth();
canvas.save(Canvas.MATRIX_SAVE_FLAG);
canvas.scale(scale, scale);
drawLogo(canvas);
drawHand(canvas);
canvas.restore();
if (handNeedsToMove()) {
moveHand();
}
}
#Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
Log.d(TAG, "Size changed to " + w + "x" + h);
regenerateBackground();
}
private void regenerateBackground() {
// free the old bitmap
if (background != null) {
background.recycle();
}
background = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
Canvas backgroundCanvas = new Canvas(background);
float scale = (float) getWidth();
backgroundCanvas.scale(scale, scale);
drawRim(backgroundCanvas);
drawFace(backgroundCanvas);
drawScale(backgroundCanvas);
drawTitle(backgroundCanvas);
}
private boolean handNeedsToMove() {
return Math.abs(handPosition - handTarget) > 0.001f;
}
private void moveHand() {
if (! handNeedsToMove()) {
return;
}
if (lastHandMoveTime != -1L) {
long currentTime = System.currentTimeMillis();
float delta = (currentTime - lastHandMoveTime) / 1000.0f;
float direction = Math.signum(handVelocity);
if (Math.abs(handVelocity) < 90.0f) {
handAcceleration = 5.0f * (handTarget - handPosition);
} else {
handAcceleration = 0.0f;
}
handPosition += handVelocity * delta;
handVelocity += handAcceleration * delta;
if ((handTarget - handPosition) * direction < 0.01f * direction) {
handPosition = handTarget;
handVelocity = 0.0f;
handAcceleration = 0.0f;
lastHandMoveTime = -1L;
} else {
lastHandMoveTime = System.currentTimeMillis();
}
invalidate();
} else {
lastHandMoveTime = System.currentTimeMillis();
moveHand();
}
}
#Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
#Override
public void onSensorChanged(SensorEvent sensorEvent) {
if (sensorEvent.values.length > 0) {
float pressureAtm = sensorEvent.values[0]/20;
//Log.i(TAG, "*** Temperature: " + temperatureC);
float pressureMmg = (9.0f / 5.0f) * pressureAtm + 32.0f;
setHandTarget(pressureAtm);
} else {
Log.w(TAG, "Empty sensor event received");
}
}
private float getRelativePressurePosition() {
if (handPosition < centerDegree) {
return - (centerDegree - handPosition) / (float) (centerDegree - minDegrees);
} else {
return (handPosition - centerDegree) / (float) (maxDegrees - centerDegree);
}
}
private void setHandTarget(float pressure) {
if (pressure < minDegrees) {
pressure = minDegrees;
} else if (pressure > maxDegrees) {
pressure = maxDegrees;
}
handTarget = pressure;
handInitialized = true;
invalidate();
}
}
This is focus on drawScale() method:
private void drawScale(Canvas canvas) {
canvas.drawOval(scaleRect, scalePaint);
canvas.save(Canvas.MATRIX_SAVE_FLAG);
for (int i = 0; i < totalNicks; ++i) {
float y1 = scaleRect.top;
float y2 = y1 - 0.020f;
canvas.drawLine(0.5f, y1, 0.5f, y2, scalePaint);
if ((i % 5) == 0) {
int value = nickToDegree(i);
if ((value >= minDegrees) && (value <= maxDegrees)) {
String valueString = Integer.toString(value);
canvas.drawText(valueString, 0.5f, y2 - 0.015f, scalePaint);
}
}
canvas.rotate(degreesPerNick, 0.5f, 0.5f);
}
canvas.restore();
}

Newton's cradle on andengine, box2d

i'm trying to create something like Newton's cradle. But when one ball hits another, all balls move simultaneously in same direction. How can I decide this problem? Should i create another physical options of balls in createFixtureDef? Or I need to use some specific algorithm to transfer impuls between balls?
public class MainActivity extends SimpleBaseGameActivity implements IAccelerationListener,
IOnAreaTouchListener
{
private static final int CAMERA_WIDTH = 720;
private static final int CAMERA_HEIGHT = 480;
private BitmapTextureAtlas mBitmapTextureAtlas;
final String TAG = "States";
private Scene mScene;
protected ITiledTextureRegion mBoxFaceTextureRegion;
protected ITiledTextureRegion mCircleFaceTextureRegion;
protected PhysicsWorld mPhysicsWorld;
#Override
public EngineOptions onCreateEngineOptions() {
final Camera camera = new Camera(0, 0, CAMERA_WIDTH, CAMERA_HEIGHT);
return new EngineOptions(true, ScreenOrientation.LANDSCAPE_FIXED,
new RatioResolutionPolicy(CAMERA_WIDTH, CAMERA_HEIGHT), camera);
}
#Override
protected void onCreateResources() {
BitmapTextureAtlasTextureRegionFactory.setAssetBasePath("gfx/");
this.mBitmapTextureAtlas = new BitmapTextureAtlas(this.getTextureManager(), 64, 64, TextureOptions.BILINEAR);
this.mBoxFaceTextureRegion = BitmapTextureAtlasTextureRegionFactory.createTiledFromAsset(this.mBitmapTextureAtlas, this, "face_box_tiled.png", 0, 0, 2, 1); // 64x32
this.mCircleFaceTextureRegion = BitmapTextureAtlasTextureRegionFactory.createTiledFromAsset(this.mBitmapTextureAtlas, this, "face_circle_tiled.png", 0, 32, 2, 1); // 64x32
this.mBitmapTextureAtlas.load();
}
#Override
protected Scene onCreateScene() {
this.mEngine.registerUpdateHandler(new FPSLogger());
this.mScene = new Scene();
this.mScene.setBackground(new Background(0, 0, 0));
//this.mScene.setOnSceneTouchListener(this);
this.mPhysicsWorld = new PhysicsWorld(new Vector2(0, SensorManager.GRAVITY_EARTH), false);
this.initJoints(mScene);
this.mScene.registerUpdateHandler(this.mPhysicsWorld);
this.mScene.setOnAreaTouchListener(this);
return this.mScene;
}
private void initJoints(final Scene pScene) {
final float centerY = CAMERA_HEIGHT / 2;
final float spriteWidth = this.mBoxFaceTextureRegion.getWidth();
final float spriteHeight = this.mBoxFaceTextureRegion.getHeight();
final FixtureDef objectFixtureDef = PhysicsFactory.createFixtureDef(30, 0.2f, 0.2f);
for(int i = 0; i < 10; i++) {
final float anchorFaceX = 100 + i * spriteWidth ;
final float anchorFaceY = centerY;
final AnimatedSprite anchorFace = new AnimatedSprite(anchorFaceX, anchorFaceY,
this.mBoxFaceTextureRegion, this.getVertexBufferObjectManager());
final Body anchorBody = PhysicsFactory.createBoxBody(this.mPhysicsWorld,
anchorFace, BodyType.StaticBody,
objectFixtureDef);
final AnimatedSprite movingFace = new AnimatedSprite(anchorFaceX, anchorFaceY + 150,
this.mCircleFaceTextureRegion, this.getVertexBufferObjectManager()) ;
// movingFace.setScale(1.2f);
final Body movingBody = PhysicsFactory.createCircleBody(this.mPhysicsWorld,
movingFace, BodyType.DynamicBody, objectFixtureDef);
movingFace.setUserData(movingBody);
// anchorFace.setScale(1.2f);
anchorFace.animate(200);
anchorFace.animate(200);
final Line connectionLine = new Line(anchorFaceX + spriteWidth / 2,
anchorFaceY + spriteHeight / 2,
anchorFaceX + spriteWidth / 2,
anchorFaceY + spriteHeight / 2,
this.getVertexBufferObjectManager());
pScene.registerTouchArea(movingFace);
pScene.attachChild(connectionLine);
pScene.attachChild(anchorFace);
pScene.attachChild(movingFace);
this.mPhysicsWorld.registerPhysicsConnector(new PhysicsConnector(anchorFace,
anchorBody, true, true){
#Override
public void onUpdate(final float pSecondsElapsed) {
super.onUpdate(pSecondsElapsed);
final Vector2 movingBodyWorldCenter = movingBody.getWorldCenter();
connectionLine.setPosition(connectionLine.getX1(), connectionLine.getY1(),
movingBodyWorldCenter.x * PhysicsConstants.PIXEL_TO_METER_RATIO_DEFAULT,
movingBodyWorldCenter.y * PhysicsConstants.PIXEL_TO_METER_RATIO_DEFAULT);
}
});
this.mPhysicsWorld.registerPhysicsConnector(new PhysicsConnector(movingFace, movingBody, true, true));
final RevoluteJointDef revoluteJointDef = new RevoluteJointDef();
revoluteJointDef.initialize(anchorBody, movingBody, anchorBody.getWorldCenter());
this.mPhysicsWorld.createJoint(revoluteJointDef);
}
}
#Override
public void onAccelerationAccuracyChanged(final AccelerationData pAccelerationData) {
}
#Override
public void onAccelerationChanged(final AccelerationData pAccelerationData) {
final Vector2 gravity = Vector2Pool.obtain(pAccelerationData.getX(), pAccelerationData.getY());
this.mPhysicsWorld.setGravity(gravity);
Vector2Pool.recycle(gravity);
}
public boolean onAreaTouched( final TouchEvent pSceneTouchEvent,
final ITouchArea pTouchArea,final float pTouchAreaLocalX,
final float pTouchAreaLocalY) {
if(pSceneTouchEvent.isActionMove())
{
float touchX = pSceneTouchEvent.getX();
float touchY = pSceneTouchEvent.getY();
Log.d(TAG, "move to in X" +touchX + "n Y " +touchY);
final AnimatedSprite anchorFace = (AnimatedSprite) pTouchArea;
final Body tochedBody = (Body)anchorFace.getUserData();
//move sprite to xy
final float x = pSceneTouchEvent.getX();
final float y = pSceneTouchEvent.getY();
final float widthD2 = anchorFace.getWidth() / 2;
final float heightD2 = anchorFace.getHeight() / 2;
final float angle = tochedBody.getAngle(); // keeps the body angle
final Vector2 v2 = Vector2Pool.obtain((x + widthD2) / 32, (y + heightD2) / 32);
tochedBody.setTransform(v2, angle);
Vector2Pool.recycle(v2);
return true;
}
return false;
}
}

Unfortunately Box2D is not really suitable for this.
In my experience, you can get one or two swing-thrus to work as long as the balls are not touching each other to start with. That is, each ball starts with a very small gap between it and the neighbor on each side. This means that when they collide each collision is solved using just two balls at a time, for a total of 4 separate collisions for the impact to travel to the other side (for 5 balls), instead of solving all 5 balls as a single 'island'.
Trouble is, the positioning needs to be very precise, and after a few swings the balls stray from that, so that you end up with collisions involving more than two balls at a time. I only ever saw at most 2-3 swings work as desired...

PhysicsHandler not working as expected - AndEngine

Guys am a complete newbie to AndEngine. I wanted to use the physics handler and went through the examples of andengine. So in my case i have a "ball" sprite which i can move by touching and a second "square" animated sprite which i expect to bounce of the walls. But it is just leaving the screen. Help me out...
package com.Escapo;
import org.anddev.andengine.engine.Engine;
import org.anddev.andengine.engine.camera.Camera;
import org.anddev.andengine.engine.handler.physics.PhysicsHandler;
import org.anddev.andengine.engine.options.EngineOptions;
import org.anddev.andengine.engine.options.EngineOptions.ScreenOrientation;
import org.anddev.andengine.engine.options.resolutionpolicy.RatioResolutionPolicy;
import org.anddev.andengine.entity.scene.Scene;
import org.anddev.andengine.entity.scene.Scene.IOnSceneTouchListener;
import org.anddev.andengine.entity.scene.background.ColorBackground;
import org.anddev.andengine.entity.sprite.AnimatedSprite;
import org.anddev.andengine.entity.sprite.Sprite;
import org.anddev.andengine.entity.util.FPSLogger;
import org.anddev.andengine.input.touch.TouchEvent;
import org.anddev.andengine.opengl.texture.TextureOptions;
import org.anddev.andengine.opengl.texture.atlas.bitmap.BitmapTextureAtlas;
import org.anddev.andengine.opengl.texture.atlas.bitmap.BitmapTextureAtlasTextureRegionFactory;
import org.anddev.andengine.opengl.texture.region.TextureRegion;
import org.anddev.andengine.opengl.texture.region.TiledTextureRegion;
import org.anddev.andengine.ui.activity.BaseGameActivity;
import android.view.Display;
public class EscapoActivity extends BaseGameActivity {
private Camera mCamera;
private Scene mMainScene;
//main ball variables
private BitmapTextureAtlas mBitmapTextureAtlas;
private TextureRegion mPlayerTextureRegion;
private Sprite player;
//square
private BitmapTextureAtlas mBitmapTextureAtlas2;
private static final float DEMO_VELOCITY = 100.0f;
private TiledTextureRegion mFaceTextureRegion;
private static int cameraWidth;
private static int cameraHeight;
private Sprite square;
#Override
public void onLoadComplete() {
}
#Override
public Engine onLoadEngine() {
final Display display = getWindowManager().getDefaultDisplay();
cameraWidth = display.getWidth();
cameraHeight = display.getHeight();
mCamera = new Camera(0, 0, cameraWidth, cameraHeight);
return new Engine(new EngineOptions(true, ScreenOrientation.LANDSCAPE,
new RatioResolutionPolicy(cameraWidth, cameraHeight), mCamera));
}
#Override
public void onLoadResources() {
mBitmapTextureAtlas = new BitmapTextureAtlas(512, 512,
TextureOptions.BILINEAR_PREMULTIPLYALPHA);
//square
mBitmapTextureAtlas2 = new BitmapTextureAtlas(512, 512,
TextureOptions.BILINEAR_PREMULTIPLYALPHA);
BitmapTextureAtlasTextureRegionFactory.setAssetBasePath("gfx/");
mPlayerTextureRegion = BitmapTextureAtlasTextureRegionFactory
.createFromAsset(this.mBitmapTextureAtlas, this, "ball.png",
0, 0);
//square
this.mFaceTextureRegion = BitmapTextureAtlasTextureRegionFactory.createTiledFromAsset(this.mBitmapTextureAtlas2, this, "square.png", 0, 0, 1, 1);
mEngine.getTextureManager().loadTextures(mBitmapTextureAtlas,mBitmapTextureAtlas2);
}
#Override
public Scene onLoadScene() {
mEngine.registerUpdateHandler(new FPSLogger());
mMainScene = new Scene();
mMainScene
.setBackground(new ColorBackground(0.09804f, 0.6274f, 0.8784f));
final int PlayerX =(int) ((mCamera.getWidth() - mPlayerTextureRegion
.getWidth()) / 2);
final int PlayerY = (int) ((mCamera.getHeight() - mPlayerTextureRegion
.getHeight()) / 2);
player = new Sprite(PlayerX, PlayerY, mPlayerTextureRegion) {
public boolean onAreaTouched(TouchEvent pSceneTouchEvent,float pTouchAreaLocalX, float pTouchAreaLocalY) {
this.setPosition(pSceneTouchEvent.getX()- this.getWidth() / 2, pSceneTouchEvent.getY()- this.getHeight() / 2);
return true;
}
};
mMainScene.registerTouchArea(player);
mMainScene.setTouchAreaBindingEnabled(true);
mMainScene.attachChild(player);
//square
final Ball ball = new Ball(2, 2, this.mFaceTextureRegion);
final PhysicsHandler physicsHandler = new PhysicsHandler(ball);
ball.registerUpdateHandler(physicsHandler);
physicsHandler.setVelocity(DEMO_VELOCITY, DEMO_VELOCITY);
mMainScene.getLastChild().attachChild(ball);
return mMainScene;
}
private static class Ball extends AnimatedSprite {
private final PhysicsHandler mPhysicsHandler;
public Ball(final float pX, final float pY, final TiledTextureRegion pTextureRegion) {
super(pX, pY, pTextureRegion);
this.mPhysicsHandler = new PhysicsHandler(this);
this.registerUpdateHandler(this.mPhysicsHandler);
}
#Override
protected void onManagedUpdate(final float pSecondsElapsed) {
if(this.mX < 0) {
this.mPhysicsHandler.setVelocityX(DEMO_VELOCITY);
} else if(this.mX + this.getWidth() > cameraWidth) {
this.mPhysicsHandler.setVelocityX(-DEMO_VELOCITY);
}
if(this.mY < 0) {
this.mPhysicsHandler.setVelocityY(DEMO_VELOCITY);
} else if(this.mY + this.getHeight() > cameraHeight) {
this.mPhysicsHandler.setVelocityY(-DEMO_VELOCITY);
}
super.onManagedUpdate(pSecondsElapsed);
}
}
}
I have just tried to integrate the moving ball example http://code.google.com/p/andengineexamples/source/browse/src/org/anddev/andengine/examples/MovingBallExample.java
Where am i going wrong?

I'm not sure PhysicsHandler will solve your problems, because I think it's just supposed to help you move your Entity.
Try the Box2d extension to AndEngine.
From the AndEngine Examples, there's PhysicsJumpExample.java (called "Combining Physics and Touch" in the launcher) which basically makes an object jump if you touch it, so I guess it's near to what you want.
Here's some code from that file, to make walls:
//onCreateScene
final VertexBufferObjectManager vertexBufferObjectManager = this.getVertexBufferObjectManager();
final Rectangle ground = new Rectangle(0, CAMERA_HEIGHT - 2, CAMERA_WIDTH, 2, vertexBufferObjectManager);
final Rectangle roof = new Rectangle(0, 0, CAMERA_WIDTH, 2, vertexBufferObjectManager);
final Rectangle left = new Rectangle(0, 0, 2, CAMERA_HEIGHT, vertexBufferObjectManager);
final Rectangle right = new Rectangle(CAMERA_WIDTH - 2, 0, 2, CAMERA_HEIGHT, vertexBufferObjectManager);
final FixtureDef wallFixtureDef = PhysicsFactory.createFixtureDef(0, 0.5f, 0.5f);
PhysicsFactory.createBoxBody(this.mPhysicsWorld, ground, BodyType.StaticBody, wallFixtureDef);
PhysicsFactory.createBoxBody(this.mPhysicsWorld, roof, BodyType.StaticBody, wallFixtureDef);
PhysicsFactory.createBoxBody(this.mPhysicsWorld, left, BodyType.StaticBody, wallFixtureDef);
PhysicsFactory.createBoxBody(this.mPhysicsWorld, right, BodyType.StaticBody, wallFixtureDef);
this.mScene.attachChild(ground);
this.mScene.attachChild(roof);
this.mScene.attachChild(left);
this.mScene.attachChild(right);
To make the object jump, just set a set the velocity to negative gravity. Gravity pulls it back after it eventually reaches 0:
final Vector2 velocity = Vector2Pool.obtain(this.mGravityX * -50, this.mGravityY * -50);
faceBody.setLinearVelocity(velocity);
Vector2Pool.recycle(velocity);

Shooting a bullet from wrong starting point

I created a racing game in andengine.There is a player which is size 100x30px,like a rectangle.And there is fire() function to shoot bullet, code is below.It works fine.but problem is when player is rotating.player is a car image.so they rotating by directionButton().When I shoot a bullet,it starting 0x0px of car.But i want it must be start to move in front of car like 100x15px of car.How can I do?
public void fire() {
float startBulletX=player.getX();
float startBulletY=player.getY();
Sprite bullet=new Sprite(startBulletX,startBulletY,bulletRegion);
final float xComp = (float) Math.cos(MathUtils.degToRad(this.player.getRotation() + 90));
final float yComp = (float) Math.sin(MathUtils.degToRad(this.player.getRotation() + 90));
final Vector2 velocity = Vector2Pool.obtain(xComp * 10, yComp * 10);
bullet.setRotation(this.player.getRotation());
final FixtureDef bulletFixtureDef1 = PhysicsFactory.createFixtureDef(0, 0, 0);
this.mBulletBody = PhysicsFactory.createBoxBody(this.mPhysicsWorld, bullet, BodyType.KinematicBody, bulletFixtureDef1);
this.mBulletBody.setLinearVelocity(velocity);
Vector2Pool.recycle(velocity);
this.mPhysicsWorld.registerPhysicsConnector(new PhysicsConnector(bullet, this.mBulletBody, true, false));
this.scene.attachChild(bullet);
}
//on screen control button
public void addDirectionButton() {
player = new AnimatedSprite(centerX, centerY, this.playerTextureRegion);
final AnalogOnScreenControl analogOnScreenControl = new AnalogOnScreenControl(0, CAMERA_HEIGHT - this.mOnScreenControlBaseTextureRegion.getHeight(), this.mBoundChaseCamera, this.mOnScreenControlBaseTextureRegion, this.mOnScreenControlKnobTextureRegion, 0.1f, 200, new IAnalogOnScreenControlListener() {
public void onControlChange(final BaseOnScreenControl pBaseOnScreenControl, final float pValueX, final float pValueY) {
final Body carBody = DeffenseActivity.this.mCarBody;
final Vector2 velocity = Vector2Pool.obtain(pValueX * 5, pValueY * 5);
carBody.setLinearVelocity(velocity);
Vector2Pool.recycle(velocity);
final float rotationInRad = (float)Math.atan2(-pValueX, pValueY);
player.setRotation(MathUtils.radToDeg(rotationInRad));
}
public void onControlClick(final AnalogOnScreenControl pAnalogOnScreenControl) {
}
});
analogOnScreenControl.getControlBase().setBlendFunction(GL10.GL_SRC_ALPHA, GL10.GL_ONE_MINUS_SRC_ALPHA);
analogOnScreenControl.getControlBase().setAlpha(0.5f);
analogOnScreenControl.getControlBase().setScaleCenter(0, 128);
analogOnScreenControl.getControlBase().setScale(1.25f);
analogOnScreenControl.getControlKnob().setScale(1.25f);
analogOnScreenControl.refreshControlKnobPosition();
this.scene.setChildScene(analogOnScreenControl);
this.mBoundChaseCamera.setChaseEntity(player);
a=new Sprite(0,0,bulletRegion);
player.attachChild(a);
final FixtureDef carFixtureDef = PhysicsFactory.createFixtureDef(1, 0.5f, 0.5f);
this.mCarBody = PhysicsFactory.createBoxBody(this.mPhysicsWorld, player, BodyType.DynamicBody, carFixtureDef);
this.mPhysicsWorld.registerPhysicsConnector(new PhysicsConnector(player, this.mCarBody, true, false));
this.scene.attachChild(player);
}

how to move body of sprite using andEngine?

I want to move body of the sprite along with line in some portion of line, just i able to move sprite only but body is not moving.
public Scene onLoadScene() {
this.mEngine.registerUpdateHandler(new FPSLogger());
final Scene scene = new Scene(2);
scene.setBackground(new ColorBackground(0.09804f, 0.00274f, 0.0784f));
this .enableAccelerometerSensor(this );
this.sPhysicsWorld = new PhysicsWorld(new Vector2(0, SensorManager.GRAVITY_EARTH), false);
final Shape ground = new Rectangle(0, CAMERA_HEIGHT - 2, CAMERA_WIDTH,2);
final Shape roof = new Rectangle(0, 0, CAMERA_WIDTH, 2);
final Shape left = new Rectangle(0, 0, 2, CAMERA_HEIGHT);
final Shape right = new Rectangle(CAMERA_WIDTH-2, 0,2, CAMERA_HEIGHT);
PhysicsFactory.createBoxBody(this.sPhysicsWorld, ground,
BodyType.StaticBody, wallFixtureDef);
PhysicsFactory.createBoxBody(this.sPhysicsWorld, roof,
BodyType.StaticBody, wallFixtureDef);
PhysicsFactory.createBoxBody(this.sPhysicsWorld, left,
BodyType.StaticBody, wallFixtureDef);
PhysicsFactory.createBoxBody(this.sPhysicsWorld, right,
BodyType.StaticBody, wallFixtureDef);
scene.getFirstChild().attachChild(ground);
scene.getFirstChild().attachChild(roof);
scene.getFirstChild().attachChild(left);
scene.getFirstChild().attachChild(right);
final int centerX = (CAMERA_WIDTH - this.mFaceTextureRegion.getWidth()) / 2;
final int centerY = (CAMERA_HEIGHT - this.mFaceTextureRegion.getHeight()) / 2;
final AnimatedSprite face = new AnimatedSprite(centerX - 100, centerY, this.mFaceTextureRegion);
final Body bodyRedBall = PhysicsFactory.createCircleBody(this.sPhysicsWorld, face,
BodyType.DynamicBody, wallFixtureDef);
this.sPhysicsWorld.registerPhysicsConnector(new PhysicsConnector(face, bodyRedBall, true, true));
scene.attachChild(face);
final AnimatedSprite face2 = new AnimatedSprite(100, 100, this.mFaceTextureRegion);
final Body bodyRedBall2 = PhysicsFactory.createCircleBody(this.sPhysicsWorld, face2,
BodyType.KinematicBody, wallFixtureDef);
final Path path4 = new Path(3).to(682, 223).to(482, 223).to(682, 223);
face2.registerEntityModifier(new LoopEntityModifier(new PathModifier(30, path4, null, new IPathModifierListener() {
#Override
public void onWaypointPassed(final PathModifier pPathModifier, final IEntity pEntity, final int pWaypointIndex) {
}
})));
this.sPhysicsWorld.registerPhysicsConnector(new PhysicsConnector(face2, bodyRedBall2, true, true){
#Override
public void onUpdate(final float pSecondsElapsed) {
super.onUpdate(pSecondsElapsed);
face2.setPosition(face2.getX(), face2.getY());
}
});
scene.attachChild(face2);
scene.registerUpdateHandler(this.sPhysicsWorld);
return scene;
}
#Override
public void onLoadComplete() {
}
#Override
public void onAccelerometerChanged(AccelerometerData pAccelerometerData) {
// TODO Auto-generated method stub
final Vector2 gravity = Vector2Pool.obtain(pAccelerometerData.getY(), pAccelerometerData.getX());
this.sPhysicsWorld.setGravity(gravity);
Vector2Pool.recycle(gravity);
}

You can use body.setLinearVelocity(); to move the body, the sprite will automatically follow the body because you have specified a physics connector.

public class MoveBodyModifier extends MoveModifier {
private Body mBody;
public MoveBodyModifier(float pDuration, float pFromX, float pToX, float pFromY, float pToY, Body body) {
super(pDuration, pFromX, pToX, pFromY, pToY);
mBody = body;
}
#Override
protected void onSetInitialValues(IEntity pEntity, float pX, float pY) {
mBody.setTransform(pX/ PhysicsConnector.PIXEL_TO_METER_RATIO_DEFAULT,
pY/ PhysicsConnector.PIXEL_TO_METER_RATIO_DEFAULT, mBody.getAngle());
}
#Override
protected void onSetValues(IEntity pEntity, float pPercentageDone, float pX, float pY) {
mBody.setTransform(pX/ PhysicsConnector.PIXEL_TO_METER_RATIO_DEFAULT,
pY/ PhysicsConnector.PIXEL_TO_METER_RATIO_DEFAULT, mBody.getAngle());
}
}

to move the body must use the setTransform
yourBody.setTransform(new Vector2(x/32,y/32), 0);
and remember that you have to divide x and y default by 32

you can also go
yourBody.setTransform(x/32,y/32), 0);
and you need to divide by 32 because box2d does not operates in pixels so to get it to pixels you need to divide by 32