Develop Reference

Collision Detection is Not Working

Basically I have been making a simple game in which I now want to create collision detection between the Player and the Enemy. I have made both a class of the player and the enemy and then also a separate GameView class. My issue is that there is simply no collision happening and I just don't understand why, I have changed the code various times but I still can't seem to crack it. I will leave my code below and if anyone sees where I have gone wrong it would be great help. Thank you.
GameView Class:
public class GameView extends SurfaceView implements Runnable {
Canvas canvas;
SurfaceHolder surfaceHolder;
Thread thread = null;
volatile boolean playing;
Paint paint;
Context context;
Player player;
int screenX, screenY, numberOfEnemies = 4, distanceBetweenEnemies;
int enemyX [] = new int[numberOfEnemies];
int enemyY [] = new int[numberOfEnemies];
private boolean paused = true;
Enemy enemy;
Enemy [] enemies;
Random random;
Rect [] enemyRectangle;
public GameView (Context context, int x, int y) {
super(context);
this.context = context;
surfaceHolder = getHolder();
paint = new Paint();
thread = new Thread();
screenX = x;
screenY = y;
player = new Player (context, screenX, screenY);
enemies = new Enemy[numberOfEnemies];
enemyRectangle = new Rect[numberOfEnemies];
enemy = new Enemy (context, screenX);
distanceBetweenEnemies = screenX * 3 / 4;
for (int i = 0; i < numberOfEnemies; i ++) {
enemies[i] = new Enemy(context, screenX);
enemyX[i] = screenX / 2 - enemy.getEnemyBitmap().getWidth() / 2 + i * distanceBetweenEnemies;
random = new Random();
enemyY[i] = random.nextInt(screenY - enemy.getEnemyBitmap().getHeight() / 2);
}
}
#Override
public void run() {
while (playing) {
draw();
if(!paused){
update();
}
}
}
private void draw () {
if (surfaceHolder.getSurface().isValid()) {
canvas = surfaceHolder.lockCanvas();
canvas.drawColor(Color.argb(255, 26, 128, 182));
canvas.drawBitmap(player.getPlayerBitmap(), player.getX(), player.getY(), null);
for (int i = 0; i < numberOfEnemies; i ++) {
canvas.drawBitmap(enemies[i].getEnemyBitmap(), enemyX[i], enemyY[i], null);
enemyRectangle [i] = new Rect(enemyX[i], enemyY[i], enemy.getEnemyBitmap().getWidth(),
enemy.getEnemyBitmap().getHeight());
enemyX[i] += enemy.getEnemySpeed();
}
update ();
surfaceHolder.unlockCanvasAndPost(canvas);
}
}
private void update () {
player.updatePlayerPosition();
player.noLeaveScreen();
for (int i = 0; i < numberOfEnemies; i ++) {
if (enemyX[i] < 0 - enemy.getEnemyBitmap().getWidth()) {
enemyY[i] = random.nextInt(screenY);
enemyRectangle [i] = new Rect(enemyX[i], enemyY[i], enemy.getEnemyBitmap().getWidth(),
enemy.getEnemyBitmap().getHeight());
enemyX[i] += numberOfEnemies * distanceBetweenEnemies;
} else {
enemyX[i] += enemy.getEnemySpeed();
}
if (Rect.intersects(player.getPlayerRectangle(), enemyRectangle[i])) {
Log.e("COLLISION:", "Detected");
enemyX[i] = - 200;
}
}
}
public void pause () {
playing = false;
try {
thread.join();
} catch (InterruptedException e) {
Log.e("Error:", "joining thread");
}
}
public void resume () {
playing = true;
thread = new Thread(this);
thread.start();
}
#Override
public boolean onTouchEvent (MotionEvent event) {
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
player.playerJump();
break;
}
return true;
}
}
Player Class:
public class Player {
Bitmap playerBitmap;
Rect playerRectangle;
int x, y, playerJumpSpeed, gravity, screenY;
boolean playerIsMoving;
public Player (Context context, int screenX, int screenY) {
this.screenY = screenY;
gravity = 2;
playerBitmap = BitmapFactory.decodeResource(context.getResources(), R.mipmap.ic_launcher);
x = screenX/2 - playerBitmap.getWidth()/2;
y = screenY/2 - playerBitmap.getHeight()/2;
playerRectangle = new Rect(x, y, playerBitmap.getWidth(), playerBitmap.getHeight());
playerJumpSpeed = - 1000;
playerIsMoving = true;
}
public void updatePlayerPosition () {
while (playerIsMoving) {
y += gravity;
break;
}
}
public void playerJump () {
while (playerIsMoving) {
y += playerJumpSpeed;
break;
}
}
public void noLeaveScreen () {
if (y < 0) {
playerJumpSpeed = 0;
} else {
playerJumpSpeed = - 40;
}
if (getY() > (screenY - playerBitmap.getHeight())) {
gravity = 0;
} else {
gravity = 2;
}
}
public int getX () {
return x;
}
public int getY () {
return y;
}
public Bitmap getPlayerBitmap () {
return playerBitmap;
}
public Rect getPlayerRectangle () {
return playerRectangle;
}
}
Enemy Class:
public class Enemy {
Bitmap enemyBitmap;
int enemySpeed, screenX;
boolean isEnemyMoving;
Random random;
public Enemy (Context context, int screenX) {
this.screenX = screenX;
enemyBitmap = BitmapFactory.decodeResource(context.getResources(), R.mipmap.ic_launcher);
random = new Random();
isEnemyMoving = true;
enemySpeed = - 3;
}
public int getEnemySpeed () {
return enemySpeed;
}
public Bitmap getEnemyBitmap () {
return enemyBitmap;
}
}
There are the classes, any help appreciated!

My onTouch method is not doing its proper fucntion

I am making a Android app. The objective is to make circles that when touched something happens. Here is the onTouch method
public boolean onTouch(View v, MotionEvent event) {
int x = (int) event.getX();
int y = (int) event.getY();
if(isInsideCircle(x, y) == true){
//Do your things here
if(redColor == lastColor){
Intent i = new Intent(v.getContext(), YouFailed.class);
v.getContext().startActivity(i);
} else {
addPoints++;
}
}else {
}
return true;
}
This part of the code is the thing that is not functioning properly here is the entire class below.
public class DrawingView extends View{
public DrawingView(Context context) {
super(context);
// TODO Auto-generated constructor stub
}
RectF rectf = new RectF(0, 0, 200, 0);
private static final int w = 100;
public static int lastColor = Color.BLACK;
private final Random random = new Random();
private final Paint paint = new Paint();
private final int radius = 230;
private final Handler handler = new Handler();
public static int redColor = Color.RED;
public static int greenColor = Color.GREEN;
int randomWidth = 0;
int randomHeight = 0;
public static int addPoints = 0;
private final Runnable updateCircle = new Runnable() {
#Override
public void run() {
lastColor = random.nextInt(2) == 1 ? redColor : greenColor;
paint.setColor(lastColor);
invalidate();
handler.postDelayed(this, 1000);
}
};
#Override
protected void onAttachedToWindow() {
super.onAttachedToWindow();
handler.post(updateCircle);
}
#Override
protected void onDetachedFromWindow() {
super.onDetachedFromWindow();
handler.removeCallbacks(updateCircle);
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
// your other stuff here
if(random == null){
randomWidth =(int) (random.nextInt(Math.abs(getWidth()-radius/2)) + radius/2f);
randomHeight = (random.nextInt((int)Math.abs((getHeight()-radius/2 + radius/2f))));
}else {
randomWidth =(int) (random.nextInt(Math.abs(getWidth()-radius/2)) + radius/2f);
randomHeight = (random.nextInt((int)Math.abs((getHeight()-radius/2 + radius/2f))));
}
canvas.drawCircle(randomWidth, randomHeight + radius/2f, radius, paint);
paint.setColor(Color.BLACK);
paint.setTextSize(150);
canvas.drawText("Score: " + addPoints, 120, 300, paint);
}
public boolean onTouch(View v, MotionEvent event) {
int x = (int) event.getX();
int y = (int) event.getY();
if(isInsideCircle(x, y) == true){
//Do your things here
if(redColor == lastColor){
Intent i = new Intent(v.getContext(), YouFailed.class);
v.getContext().startActivity(i);
} else {
addPoints++;
}
}else {
}
return true;
}
public boolean isInsideCircle(int x, int y){
if ((((x - randomWidth)*(x - randomWidth)) + ((y - randomHeight)*(y - randomHeight))) < ((radius)*(radius)))
return true;
return false;
}
}

How to get a circle to display only once for the animation for the circle [duplicate]

I have an app that displays multiple circles and animates the radius from 0 to 300. The problem I am having is that it displays multiple circles slowly increasing the radius with each circle. I want only one circle drawn that increases the radius. Here is my code.
public class SplashLaunch extends View{
Handler cool = new Handler();
DrawingView v;
Paint newPaint = new Paint();
int randomWidthOne = 0;
int randomHeightOne = 0;
private float radiusOne = 300;
final int redColorOne = Color.RED;
final int greenColorOne = Color.GREEN;
private static int lastColorOne;
ObjectAnimator radiusAnimator;
private final Random theRandom = new Random();
public SplashLaunch(Context context) {
super(context);
// TODO Auto-generated constructor stub
}
private final Runnable circleUpdater = new Runnable() {
#Override
public void run() {
lastColorOne = theRandom.nextInt(2) == 1 ? redColorOne : greenColorOne;
newPaint.setColor(lastColorOne);
startAnimation(100);
cool.postDelayed(this, 1000);
invalidate();
}
};
#Override
protected void onAttachedToWindow(){
super.onAttachedToWindow();
cool.post(circleUpdater);
}
protected void onDetachedFromWindow(){
super.onDetachedFromWindow();
cool.removeCallbacks(circleUpdater);
}
#Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
super.onDraw(canvas);
if(theRandom == null){
randomWidthOne =(int) (theRandom.nextInt((int) Math.abs(getWidth()-radiusOne/2)) + radiusOne/2f);
randomHeightOne = (theRandom.nextInt((int)Math.abs((getHeight()-radiusOne/2 + radiusOne/2f))));
}else {
randomWidthOne =(int) (theRandom.nextInt((int) Math.abs(getWidth()-radiusOne/2)) + radiusOne/2f);
randomHeightOne = (theRandom.nextInt((int)Math.abs((getHeight()-radiusOne/2 + radiusOne/2f))));
}
canvas.drawCircle(randomWidthOne, randomHeightOne, radiusOne, newPaint);
}
public void setRadiusOne(float value){
this.radiusOne = value;
invalidate();
}
public int startAnimation(int animationDuration) {
if (radiusAnimator == null || !radiusAnimator.isRunning()) {
// Define what value the radius is supposed to have at specific time values
Keyframe kf0 = Keyframe.ofFloat(0f, 0f);
Keyframe kf2 = Keyframe.ofFloat(0.5f, 180f);
Keyframe kf1 = Keyframe.ofFloat(1f, 360f);
// If you pass in the radius, it will be calling setRadius method, so make sure you have it!!!!!
PropertyValuesHolder pvhRotation = PropertyValuesHolder.ofKeyframe("radiusOne", kf0, kf1, kf2);
radiusAnimator = ObjectAnimator.ofPropertyValuesHolder(this, pvhRotation);
radiusAnimator.setInterpolator(new LinearInterpolator());
radiusAnimator.setDuration(animationDuration);
radiusAnimator.start();
}
else {
Log.d("Circle", "I am already running!");
}
return animationDuration;
}
public void stopAnimation() {
if (radiusAnimator != null) {
radiusAnimator.cancel();
radiusAnimator = null;
}
}
public boolean getAnimationRunning() {
return radiusAnimator != null && radiusAnimator.isRunning();
}
}

Try using
canvas.drawColor(Color.WHITE);
for clearing whole view display after super.onDraw(canvas);

How to get a circle to display only once for the animation

I have an app that displays multiple circles and animates the radius from 0 to 300. The problem I am having is that it displays multiple circles slowly increasing the radius with each circle. I want only one circle drawn that increases the radius. Here is my code.
public class SplashLaunch extends View{
Handler cool = new Handler();
DrawingView v;
Paint newPaint = new Paint();
int randomWidthOne = 0;
int randomHeightOne = 0;
private float radiusOne = 300;
final int redColorOne = Color.RED;
final int greenColorOne = Color.GREEN;
private static int lastColorOne;
ObjectAnimator radiusAnimator;
private final Random theRandom = new Random();
public SplashLaunch(Context context) {
super(context);
// TODO Auto-generated constructor stub
}
private final Runnable circleUpdater = new Runnable() {
#Override
public void run() {
lastColorOne = theRandom.nextInt(2) == 1 ? redColorOne : greenColorOne;
newPaint.setColor(lastColorOne);
startAnimation(100);
cool.postDelayed(this, 1000);
invalidate();
}
};
#Override
protected void onAttachedToWindow(){
super.onAttachedToWindow();
cool.post(circleUpdater);
}
protected void onDetachedFromWindow(){
super.onDetachedFromWindow();
cool.removeCallbacks(circleUpdater);
}
#Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
super.onDraw(canvas);
if(theRandom == null){
randomWidthOne =(int) (theRandom.nextInt((int) Math.abs(getWidth()-radiusOne/2)) + radiusOne/2f);
randomHeightOne = (theRandom.nextInt((int)Math.abs((getHeight()-radiusOne/2 + radiusOne/2f))));
}else {
randomWidthOne =(int) (theRandom.nextInt((int) Math.abs(getWidth()-radiusOne/2)) + radiusOne/2f);
randomHeightOne = (theRandom.nextInt((int)Math.abs((getHeight()-radiusOne/2 + radiusOne/2f))));
}
canvas.drawCircle(randomWidthOne, randomHeightOne, radiusOne, newPaint);
}
public void setRadiusOne(float value){
this.radiusOne = value;
invalidate();
}
public int startAnimation(int animationDuration) {
if (radiusAnimator == null || !radiusAnimator.isRunning()) {
// Define what value the radius is supposed to have at specific time values
Keyframe kf0 = Keyframe.ofFloat(0f, 0f);
Keyframe kf2 = Keyframe.ofFloat(0.5f, 180f);
Keyframe kf1 = Keyframe.ofFloat(1f, 360f);
// If you pass in the radius, it will be calling setRadius method, so make sure you have it!!!!!
PropertyValuesHolder pvhRotation = PropertyValuesHolder.ofKeyframe("radiusOne", kf0, kf1, kf2);
radiusAnimator = ObjectAnimator.ofPropertyValuesHolder(this, pvhRotation);
radiusAnimator.setInterpolator(new LinearInterpolator());
radiusAnimator.setDuration(animationDuration);
radiusAnimator.start();
}
else {
Log.d("Circle", "I am already running!");
}
return animationDuration;
}
public void stopAnimation() {
if (radiusAnimator != null) {
radiusAnimator.cancel();
radiusAnimator = null;
}
}
public boolean getAnimationRunning() {
return radiusAnimator != null && radiusAnimator.isRunning();
}
}

Try using
canvas.drawColor(Color.WHITE);
for clearing whole view display after super.onDraw(canvas);

for loop does not "grow" the circle. I need to "grow" a circle

I am trying to write an android application that draws Circles at random positions over and over forever. This is already done in my code. The next objective for me is to slowly animate these circles to make them "grow" onto the screen. Basically increment the radius of the circle from 0 to 300 very fast I did this by creating a for loop like this.
for(int i = 0;i< 300; i++){
canvas.drawCircle(randomWidthOne, randomHeightOne,i, newPaint);
}
unfortunately this does not perform the desired result. Instead it just displays the circles at the end radius of 300. Here is my code for the class that draws the circles. Please let me know if there is anything in the class that is interfering with what I am trying to accomplish.
public class SplashLaunch extends View{
Handler cool = new Handler();
DrawingView v;
Paint newPaint = new Paint();
int randomWidthOne = 0;
int randomHeightOne = 0;
private float radiusNsix = 10;
private float radiusNfive = 25;
private float radiusNfour = 50;
private float radiusNthree = 100;
private float radiusNtwo = 150;
private float radiusNone = 200;
private float radiusZero = 250;
private float radiusOne = 300;
final int redColorOne = Color.RED;
final int greenColorOne = Color.GREEN;
private static int lastColorOne;
double startTime = System.currentTimeMillis();
ObjectAnimator radiusAnimator;
private final Random theRandom = new Random();
public SplashLaunch(Context context) {
super(context);
// TODO Auto-generated constructor stub
}
private final Runnable circleUpdater = new Runnable() {
#Override
public void run() {
lastColorOne = theRandom.nextInt(2) == 1 ? redColorOne : greenColorOne;
newPaint.setColor(lastColorOne);
cool.postDelayed(this, 1000);
invalidate();
}
};
#Override
protected void onAttachedToWindow(){
super.onAttachedToWindow();
cool.post(circleUpdater);
}
protected void onDetachedFromWindow(){
super.onDetachedFromWindow();
cool.removeCallbacks(circleUpdater);
}
#Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
super.onDraw(canvas);
canvas.drawColor(Color.WHITE);
if(theRandom == null){
randomWidthOne =(int) (theRandom.nextInt((int) Math.abs(getWidth()-radiusOne/2)) + radiusOne/2f);
randomHeightOne = (theRandom.nextInt((int)Math.abs((getHeight()-radiusOne/2 + radiusOne/2f))));
}else {
randomWidthOne =(int) (theRandom.nextInt((int) Math.abs(getWidth()-radiusOne/2)) + radiusOne/2f);
randomHeightOne = (theRandom.nextInt((int)Math.abs((getHeight()-radiusOne/2 + radiusOne/2f))));
}
for(int i = 0;i< 300; i++){
canvas.drawCircle(randomWidthOne, randomHeightOne,i, newPaint);
}
}
public void setRadiusOne(float value){
this.radiusOne = value;
invalidate();
}
public int startAnimation(int animationDuration) {
if (radiusAnimator == null || !radiusAnimator.isRunning()) {
// Define what value the radius is supposed to have at specific time values
Keyframe kf0 = Keyframe.ofFloat(0f, 0f);
Keyframe kf2 = Keyframe.ofFloat(0.5f, 180f);
Keyframe kf1 = Keyframe.ofFloat(1f, 360f);
// If you pass in the radius, it will be calling setRadius method, so make sure you have it!!!!!
PropertyValuesHolder pvhRotation = PropertyValuesHolder.ofKeyframe("radiusOne", kf0, kf1, kf2);
radiusAnimator = ObjectAnimator.ofPropertyValuesHolder(this, pvhRotation);
radiusAnimator.setInterpolator(new LinearInterpolator());
radiusAnimator.setDuration(animationDuration);
radiusAnimator.start();
}
else {
Log.d("Circle", "I am already running!");
}
return animationDuration;
}
public void stopAnimation() {
if (radiusAnimator != null) {
radiusAnimator.cancel();
radiusAnimator = null;
}
}
public boolean getAnimationRunning() {
return radiusAnimator != null && radiusAnimator.isRunning();
}
}

Call this.invalidate() to force redraw on next frame:
private int x = -1;
private int y = -1;
private int r = -1;
private int stepsLeft = 300;
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (x < 0) { // generate new circle
int[] xy = generateXY();
x = xy[0];
y = xy[1];
r = 0;
}
if (stepsLeft > 0) {
canvas.drawColor(Color.WHITE);
canvas.drawCircle(x, y, r, newPaint); // draw circle with new radius
r++; // increment radius
stepsLeft--; // decrement steps
this.invalidate(); // invalidate the view
}
}
private int[] generateXY() {
if (theRandom == null) {
randomWidthOne =(int) (theRandom.nextInt((int) Math.abs(getWidth()-radiusOne/2)) + radiusOne/2f);
randomHeightOne = (theRandom.nextInt((int)Math.abs((getHeight()-radiusOne/2 + radiusOne/2f))));
} else {
randomWidthOne =(int) (theRandom.nextInt((int) Math.abs(getWidth()-radiusOne/2)) + radiusOne/2f);
randomHeightOne = (theRandom.nextInt((int)Math.abs((getHeight()-radiusOne/2 + radiusOne/2f))));
}
return new int[]{randomWidthOne, randomHeightOne};
}

Have a look at the property animator.