Remove item from ArrayList, ArrayIndexOutOfBounds exception

Remove item from ArrayList, ArrayIndexOutOfBounds exception - android

I currently have an arraylist in which I add "blossom" objects ( which fall from the top of the screen ). When there is a collision between the blossom and a box at the bottom of the screen, I want to remove the blossom from the ArrayList. however, the way I'm doing it now (in the blossom class), I get an ArrayIndexOutOfBounds exception. Can anybody see where i'm going wrong? I know it has to do with my threads, I just can't figure out WHERE to put this method. (This is being performed in the "hit" method of my Blossom class).
BoardView
public BoardView(Context context){
super(context);
scorePaint.setColor(Color.BLACK);
scorePaint.setTextSize(12);
scorePaint.setTypeface(Typeface.MONOSPACE);
//surfaceHolder provides canvas that we draw on
getHolder().addCallback(this);
// controls drawings
thread = new BoardThread(getHolder(),this, blossomArrayList, box_x, box_y,
boxWidth, boxHeight);
timer = new Thread(){
public void run(){
//makes sure the player still has 3 lives left
while(game == false){
uiCallback.sendEmptyMessage(0);
try {
Thread.sleep(2000); // wait two seconds before drawing the next flower
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} //sleep for 2 seconds
}
}
};
timer.start();
//intercepts touch events
setFocusable(true);
}
#Override
public void onDraw(Canvas canvas){
canvas.drawColor(Color.WHITE);
score = "SCORE: " + currentScore;
//note: pay attention to order you draw things
//don't change order or else blossoms will fall
//on top of box, not "into" it.
//display the scoreboard
canvas.drawText(score,240,420,scorePaint);
// uses a synchronized method to prevent concurrent modification
DrawBlossoms(canvas);
canvas.drawBitmap(box, box_x, box_y, null);
}
#Override
public boolean onTouchEvent(MotionEvent event){
//handles movement of box
if(event.getAction() == MotionEvent.ACTION_DOWN){
if(event.getX() > box_x & event.getY() > box_y &
event.getX() < box_x + boxWidth & event.getY() < box_y + boxHeight)
{
mode = true;
}
}
if(event.getAction() == MotionEvent.ACTION_MOVE) {
if(event.getX() > box_x & event.getY() > box_y &
event.getX() < box_x + boxWidth & event.getY() < box_y + boxHeight)
{
mode = true;
}
if(mode == true){
box_x = (int)event.getX();
}
}
if(event.getAction() == MotionEvent.ACTION_UP){
mode = false;
}
invalidate();
return true;
}
#Override
public void surfaceChanged(SurfaceHolder holder,
int format, int width, int height ){
Log.v(TAG, "Surface Changed");
//somehow these don't seem to be working
}
#Override
public void surfaceCreated(SurfaceHolder holder){
thread.startRunning(true);
thread.start();
}
#Override
public void surfaceDestroyed(SurfaceHolder holder){
Log.v(TAG, "Surface Destroyed");
//somehow these don't seem to be working
thread.startRunning(false);
thread.stop();
timer.interrupt();
timer.stop();
}
private Handler uiCallback = new Handler(){
public synchronized void handleMessage(Message msg){
//add a new blossom to the blossom ArrayList!!
blossomArrayList.add(new Blossom(
(BitmapFactory.decodeResource
(getResources(), R.drawable.blossom))));
blossomNum++;
//remove neccesary blossoms from list
Log.v(TAG, "Number of Blossoms =" + blossomNum);
}
};
private synchronized void DrawBlossoms(Canvas c)
{
Canvas canvas = c;
for(Blossom blossom: blossomArrayList) // getting errors here
{
blossom.Draw(canvas);
blossom.hit(box_x,box_y, box_x + boxWidth, box_y + boxHeight, blossomArrayList);
}
}
}
Blossom class
public Blossom(Bitmap bitmap)
{
blossom = bitmap;
blossomWidth = blossom.getWidth();
blossomHeight = blossom.getHeight();
blossom_x = generator.nextInt(320-blossom.getWidth());
blossomRect = new RectF(blossom_x,blossom_y, blossom_x + blossomWidth, blossom_y + blossomHeight);
}
public Bitmap getBitmap()
{
return blossom;
}
public Boolean hit(int boxLeft, int boxTop, int boxRight,int boxBottom, ArrayList<Blossom> blossomArrayList)
{
if(remove == true)
{
Log.v(TAG, "Remove = true");
blossomArrayList.remove(removeInt);
remove = false;
}
if(blossom_x > boxLeft & blossom_y > boxTop
& blossom_x + blossom.getWidth() < boxRight
& blossom_y + blossom.getHeight() < boxBottom)
{
Log.v(TAG, "Collision Detected");
remove = true;
removeInt = blossomArrayList.indexOf(blossom);
return true;
}
else
{
return false;
}
}
public float getBlossomX()
{
return blossom_x;
}
public float getBlossomY()
{
return blossom_y;
}
public float getBlossomWidth()
{
return blossomWidth;
}
public float getBlossomHeight()
{
return blossomHeight;
}
public void Draw(Canvas canvas)
{
//draws the flower falling
if (hit == false)
{
canvas.drawBitmap(blossom, blossom_x,
blossom_y = blossom_y+5 , null);
}
}
public void UpdatePosition()
{
blossomRect.set(blossom_x, blossom_y, blossom_x + 25, blossom_y + 25);
}
}
Board Thread
public BoardThread(SurfaceHolder holder, BoardView boardView2,
ArrayList<Blossom> blossomArrayList1,
int box_x, int box_y, int boxW, int boxH) {
surfaceHolder = holder;
boardView=boardView2;
blossomArrayList = blossomArrayList1;
boxX = box_x;
boxY = box_y;
boxW = boxWidth;
boxH = boxHeight;
}
public void startRunning(boolean run) {
mrun=run;
}
#Override
public void run() {
super.run();
Canvas canvas;
while (mrun) {
canvas=null;
try {
canvas = surfaceHolder.lockCanvas(null);
synchronized (surfaceHolder) {
//update position
Position(blossomArrayList, boxX, boxY, boxWidth, boxHeight);
// draw flowers
boardView.onDraw(canvas); // and getting errors here - concurrent
}
} finally {
if (canvas != null) {
surfaceHolder.unlockCanvasAndPost(canvas);
}
}
}
}
private synchronized void Position(ArrayList<Blossom> blossomArrayList, int box_x, int box_y,
int boxWidth, int boxHeight)
{
for(Blossom blossom: blossomArrayList)
{
blossom.UpdatePosition();
}
}
}

The problem is that, you are providing an integer as a parameter to remove method while it is considering it as index of arrayList.
ArrayList provides two methods that are:
public E remove(int index)
public boolean remove(Object o)
What you can do is:
1) create an arrayList of type string.
2) cast your int to string and use it as-
blossomArrayList.remove(String.valueOf(removeInt));
Hope it helps..

Assuming that you get the error on blossomArrayList.remove(removeInt);, you could try to remove the object itself as .remove(..) can take an Object parameter.

Adding a cast to mark the int as an object worked for me.
blossomArrayList.remove((Object)myint);
this way it doesn't get confused with index.

Related

Drawing an animation circle in android

I am trying to create a circle animation, but the screen does not refresh itself and it draws many circles in different positions instead of drawing the movement. I want to use it this way instead of using invalidate() method because I want to use it for a real time application.
Here is the code:
public class activity_layout_animation extends SurfaceView implements Runnable {
Thread thread;
boolean CanDraw = false;
Paint red_fill;
int circle_x, circle_y;
Canvas canvas;
SurfaceHolder surfaceHolder;
public activity_layout_animation(Context context){
super(context);
surfaceHolder = getHolder();
circle_x= 130;
circle_y=130;
}
#Override
public void run(){
preparePaint();
while(CanDraw){
if ( !surfaceHolder.getSurface().isValid()){
continue;
}
canvas = surfaceHolder.lockCanvas();
motionCircle(10);
canvas.drawCircle(circle_x,circle_y,50, red_fill);
surfaceHolder.unlockCanvasAndPost(canvas);
}
}
public void pause(){
CanDraw = false;
while(true) {
try {
thread.join();
break;
} catch (InterruptedException e) {
e.printStackTrace();
}
}
thread = null;
}
public void resume(){
CanDraw = true;
thread = new Thread(this);
thread.start();
}
private void preparePaint(){
red_fill = new Paint();
red_fill.setColor(Color.RED);
red_fill.setStyle(Paint.Style.FILL);
}
private void motionCircle (int speed){
if ( (circle_y == 130) && ( circle_x < 650) ){
circle_x = circle_x + speed;
}
if ( (circle_y < 650) && ( circle_x ==650) ){
circle_y = circle_y + speed;
}
if ( (circle_y == 650) && ( circle_x > 130) ){
circle_x = circle_x - speed;
}
if ( (circle_y > 130) && ( circle_x== 130) ){
circle_y = circle_y - speed;
}
}
}
thank you!

How about postInvalidate() - you can call it from background threads. You could also call canvas.drawColor(backgroundColor) to wipe out whole canvas from previous drawings.

redraw bitmap on the android canvas

In my app, I want to switch a bitmap image from one to another when I touch on that image. I keep getting NULLPOINTEREXCEPTION whenever I touch the image.
Is there any method that allows to switch from a bitmap to other bitmap?
#Override
protected void onDraw(Canvas canvas) {
canvas.drawColor(Color.BLACK);
this.cVas = canvas;
for(int i = 0; i < BSIZE; i++) {
for(int j = 0; j < BSIZE; j++) {
gameBoard[i][j] = new Cell(i*wCell, j*wCell+hCell);
if(gameBoard[i][j].getBitmap() == null) {
gameBoard[i][j].setBitmap(b3);
}
/*if(gameBoard[i][j].getTouch()) {
gameBoard[i][j].setBitmap(b4);
}else{
gameBoard[i][j].setBitmap(b3);
}*/
gameBoard[i][j].drawCell(canvas);
}
}
}
#Override
public boolean onTouchEvent(MotionEvent event) {
if(event.getAction() != MotionEvent.ACTION_DOWN) {
return super.onTouchEvent(event);
}
// Get the Cell's position.
selX = (int)((event.getX()) / wCell);
selY = (int)((event.getY() - hCell) / wCell);
if( selX > BSIZE || selY > BSIZE || selY < 0) {
return false;
}
else {
Log.d(TAG, "selX: " + selX + " selY: " + selY);
cellSelection(selX, selY);
}
return true;
}
// Redraw the image (switch to other bitmap).
private void cellSelection( int x, int y) {
if(gameBoard[x][y].getTouch()) {
gameBoard[x][y].setTouch(false);
gameBoard[x][y].setBitmap(b3);
} else {
gameBoard[x][y].setTouch(true);
gameBoard[x][y].setBitmap(b4);
}
gameBoard[x][y].drawCell(cVas);
invalidate();
}

Android game in surfaceview lagg spikes

guys. I'm playing around with making my very first Android game, but stumbled into a problem. The framerate seems to have random lag spikes. If I comment the background(s) out the framerate gets much smoother. I've looked around SO and can't find anything to solve my problems. I have a feeling it has something to do with allocating a specific amount of time every time I draw, but I don't know how to properly implement such a feature. Any suggestions? Btw, tryed hardware ac, anti etc.
This is the class that starts the surfaceview :
package com.example.glassrunner;
Imports Here
public class Game extends Activity
{
MySurfaceView mySurfaceView;
public SoundPool spool;
private int soundID;
int length=0;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
this.setVolumeControlStream(AudioManager.STREAM_MUSIC);
mySurfaceView = new MySurfaceView(this);
setContentView(mySurfaceView);
}
#Override
protected void onResume()
{
// TODO Auto-generated method stub
super.onResume();
mySurfaceView.onResumeMySurfaceView();
}
#Override
protected void onPause()
{
// TODO Auto-generated method stub
super.onPause();
mySurfaceView.onPauseMySurfaceView();
}
#Override
protected void onDestroy()
{
super.onDestroy();
mySurfaceView = null;
}
}
This is the surfaceview class :
package com.example.glassrunner;
Imports here
public class MySurfaceView extends SurfaceView implements Runnable
{
public static boolean gameOver = false;
SurfaceHolder surfaceHolder;
Thread thread = null;
public Integer score=0;
public SoundPool spool;
private int soundID;
int length=0;
public static MediaPlayer mp;
volatile boolean running = false;
int Yposition = 450;
int Xposition = 50;
Paint textPaint;
long mLastTime;
Bitmap background;
Bitmap background2;
Bitmap lines;
Bitmap runSprite;
Bitmap box;
Paint bitmapPaint ;
Paint textPaint2;
Bitmap scaledBackground ;
Bitmap scaledBackground2 ;
Bitmap scaledLines ;
Bitmap scaledBox;
Canvas canvas;
Paint paint;
int SpX=0;
int SpY=0;
Bitmap[][] sprite;
/** Variables for the counter */
int frameSamplesCollected = 0;
int frameSampleTime = 0;
int fps = 0;
int speed = 5;
Toast GameOverToast;
Context context;
MediaPlayer mMediaPlayer;
public MySurfaceView(Context context)
{
super(context);
this.context = context;
// TODO Auto-generated constructor stub
surfaceHolder = getHolder();
surfaceHolder.setFormat(PixelFormat.RGB_565);
CharSequence text = "Game Over!";
int duration = Toast.LENGTH_SHORT;
GameOverToast = Toast.makeText(context, text, duration);
spool = new SoundPool(10, AudioManager.STREAM_MUSIC, 0);
soundID = spool.load(context, R.raw.jump, 1);
mp = MediaPlayer.create(context, R.raw.saturdaymorningfunk);
initialization();
}
public void initialization()
{
mp.setLooping(true);
mp.start();
Options options = new Options();
options.inSampleSize = 1/4;
options.inPreferredConfig = Bitmap.Config.RGB_565;
background=BitmapFactory.decodeResource(getResources(),R.drawable.background,options);
lines=BitmapFactory.decodeResource(getResources(),R.drawable.lines);// getting the png from drawable folder
background2=BitmapFactory.decodeResource(getResources(),R.drawable.background2,options);
runSprite=BitmapFactory.decodeResource(getResources(),R.drawable.runsprite);
box=BitmapFactory.decodeResource(getResources(),R.drawable.box);
bitmapPaint = new Paint(Paint.ANTI_ALIAS_FLAG); // tool for painting on the canvas
bitmapPaint.setAntiAlias(true);
bitmapPaint.setFilterBitmap(true);
textPaint = new Paint();
textPaint.setColor(Color.RED);
textPaint.setTextSize(32);
textPaint2 = new Paint();
textPaint2.setColor(Color.BLUE);
textPaint2.setTextSize(50);
scaledBackground = Bitmap.createScaledBitmap(background, 2560, 500, true);
scaledBackground2 = Bitmap.createScaledBitmap(background2, 2560, 400, true);
scaledLines = Bitmap.createScaledBitmap(lines, 2560, 30, true);
runSprite = Bitmap.createScaledBitmap(runSprite, 1400, 1000, true);
scaledBox = Bitmap.createScaledBitmap(box, 100, 100, true);
sprite = new Bitmap[4][7];
for(int row=0;row<=3;row++)
{
for(int col=0;col<=6;col++)
{
sprite[row][col] = Bitmap.createBitmap(runSprite, SpX, SpY, 200, 250);
SpX+=200;
}
SpX=0;
SpY+=250;
}
}
public void onResumeMySurfaceView()
{
mp.seekTo(length);
mp.start();
running = true;
thread = new Thread(this);
thread.start();
}
public void onPauseMySurfaceView()
{
mp.pause();
length=mp.getCurrentPosition();
boolean retry = true;
running = false;
while(retry){
try {
thread.join();
retry = false;
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public void onDestroyMySurfaceView()
{
mp.stop();
running = false;
thread = null;
thread.stop();
}
private void fps()
{
long now = System.currentTimeMillis();
if (mLastTime != 0)
{
//Time difference between now and last time we were here
int time = (int) (now - mLastTime);
frameSampleTime += time;
frameSamplesCollected++;
//After 10 frames
if (frameSamplesCollected == 10)
{
//Update the fps variable
fps = (int) (10000 / frameSampleTime);
//Reset the sampletime + frames collected
frameSampleTime = 0;
frameSamplesCollected = 0;
}
}
mLastTime = now;
}
public boolean pressDown = false;
public long pressTime;
public boolean onTouchEvent(MotionEvent event)
{
if (event != null)
{
if (event.getAction() == MotionEvent.ACTION_DOWN)
{ if(Yposition == orgPos)
{
spool.play(soundID, 15, 15, 1, 0, 1f);
pressDown = true;
pressTime = System.currentTimeMillis();
}
}else if (event.getAction() == MotionEvent.ACTION_UP)
{
pressDown = false;
}
}
return true;
}
int x=0;
int y=100;
int x2=0;
int y2=20;
int row=0;
int col=0;
int limit = 100;
int orgPos = 450;
int Xbox = 1280;
int Ybox = 580;
Random r = new Random();
int RBox;
public static String Fscore;
boolean onTop = false;
long now;
long start;
long stop;
long time ;
int spritePosition = 0 ;
int spriteSize;
#Override
public void run()
{
while(running)
{
canvas = null;
if(surfaceHolder.getSurface().isValid())
{
canvas = surfaceHolder.lockCanvas();
fps(); // fps
// Update screen parameters
update();
draw();
surfaceHolder.unlockCanvasAndPost(canvas);
}
}
}
public void update()
{
if(score<500)
{
speed = 7;
}
else if(score%500 == 0)
{
speed = 7 + (score / 500);
}
if(col==6)
{
row++;
col=0;
}
if(row==4)
{
row=0;
}
score++;
Fscore = score.toString();
if(x>-1280)
{
x-=speed;
}else if(x<=-1280)
{
x=0;
}
if(x2>-1280)
{
x2-=5;
}else if(x2<=-1280)
{
x2=-0;
}
RBox = r.nextInt(999)+1280;
if(Xbox > -100)
{
Xbox-=speed;
}else if(Xbox<=-100)
{
Xbox=RBox;
}
if( (Xposition + 200 == Xbox +40 )&&(Yposition + 250 > Ybox+20)||( Xposition+200<=Xbox+70)&&( Xposition+200>=Xbox+20)&&(Yposition + 250 > Ybox+30) ) // collision
{
GameOverToast.show();
running = false;
spool.release();
mp.release();
Looper.prepare();
Intent database = new Intent(context, MainHighscore.class);
database.putExtra("score", Fscore);
context.startActivity(database);
onDestroyMySurfaceView();
}
now = System.currentTimeMillis();
if(( now - pressTime) <= 600)
{
if(Yposition > limit)
{
Yposition -= 10;
}
}
onTop = false;
if((now - pressTime) >= 600 && (now - pressTime) <= 1200)
{
if(!(Yposition == orgPos))
{
if(Yposition+250 >= Ybox && Xposition+200>=Xbox+70 && Xposition <= Xbox+40)
{
onTop=true;
Yposition = 340;
}else
{
Yposition += 10;
}
}
}
if((now - pressTime) >= 1200)
{
if(Yposition < 450) Yposition +=10;
else Yposition = 450;
}
}
public void draw()
{
canvas.drawColor(Color.WHITE);
//canvas.drawBitmap(scaledBackground, x2,y2, bitmapPaint);
canvas.drawBitmap(scaledBackground2, x,y, bitmapPaint);
canvas.drawBitmap(scaledLines, x,650, bitmapPaint);
canvas.drawText(Fscore, 1050, 50, textPaint2);
canvas.drawText(fps + " fps", getWidth() / 2, getHeight() / 2, textPaint);
canvas.drawBitmap(sprite[row][col],Xposition,Yposition,bitmapPaint );
canvas.drawBitmap(scaledBox,Xbox,Ybox,bitmapPaint);
col++;
}
}

I think your problem might be actually the moving part. Your just drawing too much stuff, and the surfaceView is not meant for that.

Called From Wrong Thread Exception

I am getting an exception here when I try to bring another view to the front. It happens in the last method of my BoardView class where it says if(lives == 0). Can anybody see where I should be calling this bringToFront method from??
public class BoardView extends SurfaceView implements SurfaceHolder.Callback{
Context mContext;
// thread initialization
private BoardThread thread;
Thread timer;
// box variables
Bitmap box =
(BitmapFactory.decodeResource
(getResources(), R.drawable.box));
private int box_x = 140;
private int box_y = 378;
private int boxWidth = box.getWidth();
private int boxHeight = box.getHeight();
// storage
private Vector<Blossom> blossomVector = new Vector<Blossom>();
Iterator<Blossom> dataIterator = blossomVector.iterator();
// counters
private int blossomNum = 0;
private String score;
private int currentScore = 0;
private int lives = 3;
boolean mode = false;
boolean game = false;
OutputStreamWriter out = null;
FileOutputStream fOut = null;
private static final String TAG = "Debug";
final Paint scorePaint = new Paint();
public BoardView(Context context){
super(context);
scorePaint.setColor(Color.BLACK);
scorePaint.setTextSize(12);
scorePaint.setTypeface(Typeface.MONOSPACE);
//surfaceHolder provides canvas that we draw on
getHolder().addCallback(this);
// controls drawings
thread = new BoardThread(getHolder(),this, blossomVector, dataIterator, box_x, box_y,
boxWidth, boxHeight);
timer = new Thread(){
public void run(){
//makes sure the player still has 3 lives left
while(game == false){
uiCallback.sendEmptyMessage(0);
try {
Thread.sleep(2000); // wait two seconds before drawing the next flower
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} //sleep for 2 seconds
}
}
};
timer.start();
//intercepts touch events
setFocusable(true);
}
#Override
public void onDraw(Canvas canvas){
canvas.drawColor(Color.WHITE);
score = "SCORE: " + currentScore;
//note: pay attention to order you draw things
//don't change order or else blossoms will fall
//on top of box, not "into" it.
//display the scoreboard
canvas.drawText(score,240,420,scorePaint);
// uses a synchronized method to prevent concurrent modification
DrawBlossoms(canvas);
canvas.drawBitmap(box, box_x, box_y, null);
}
#Override
public boolean onTouchEvent(MotionEvent event){
//handles movement of box
if(event.getAction() == MotionEvent.ACTION_DOWN){
if(event.getX() > box_x & event.getY() > box_y &
event.getX() < box_x + boxWidth & event.getY() < box_y + boxHeight)
{
mode = true;
}
}
if(event.getAction() == MotionEvent.ACTION_MOVE) {
if(event.getX() > box_x & event.getY() > box_y &
event.getX() < box_x + boxWidth & event.getY() < box_y + boxHeight)
{
mode = true;
}
if(mode == true){
box_x = (int)event.getX();
}
}
if(event.getAction() == MotionEvent.ACTION_UP){
mode = false;
}
invalidate();
return true;
}
#Override
public void surfaceChanged(SurfaceHolder holder,
int format, int width, int height ){
Log.v(TAG, "Surface Changed");
//somehow these don't seem to be working
}
#Override
public void surfaceCreated(SurfaceHolder holder){
thread.startRunning(true);
thread.start();
}
#Override
public void surfaceDestroyed(SurfaceHolder holder){
Log.v(TAG, "Surface Destroyed");
//somehow these don't seem to be working
thread.startRunning(false);
thread.stop();
timer.interrupt();
timer.stop();
}
private Handler uiCallback = new Handler(){
public synchronized void handleMessage(Message msg){
//add a new blossom to the blossom Vector!!
blossomVector.add(new Blossom(
(BitmapFactory.decodeResource
(getResources(), R.drawable.blossom))));
dataIterator = blossomVector.iterator();
blossomNum++;
Log.v(TAG, "Number of Blossoms =" + blossomNum);
}
};
private synchronized void DrawBlossoms(Canvas c) // method to draw flowers on screen and test for collision
{
Canvas canvas = c;
dataIterator = blossomVector.iterator();
while (dataIterator.hasNext())
{
Blossom tempBlossom = dataIterator.next();
tempBlossom.Draw(canvas);
if (tempBlossom.hit(box_x,box_y, box_x + boxWidth, box_y + boxHeight, blossomVector) == true)
{
Log.v(TAG, "ITERATOR WORKS!");
dataIterator.remove();
currentScore += 100;
}
if (tempBlossom.dropped() == true)
{
dataIterator.remove();
Log.v(TAG, "Blossom dropped");
lives--;
}
if (lives == 0)
{
// END THE GAME!!!
((BoardView) getParent()).findViewById(1).bringToFront();
}
}
}
public void writeFile()
{
}
}
public class BoardThread extends Thread {
private SurfaceHolder surfaceHolder;
private BoardView boardView;
private Vector<Blossom> blossomVector;
private int boxX;
private int boxY;
private int boxWidth;
private int boxHeight;
private boolean mrun =false;
private Iterator<Blossom> iterator;
private static final String TAG = "Debug";
public BoardThread(SurfaceHolder holder, BoardView boardView2,
Vector<Blossom> blossomVector1, Iterator<Blossom> dataIterator,
int box_x, int box_y, int boxW, int boxH) {
surfaceHolder = holder;
boardView=boardView2;
blossomVector = blossomVector1;
iterator = dataIterator;
boxX = box_x;
boxY = box_y;
boxW = boxWidth;
boxH = boxHeight;
}
public void startRunning(boolean run) {
mrun=run;
}
#Override
public void run() {
super.run();
Canvas canvas;
while (mrun) {
canvas=null;
try {
canvas = surfaceHolder.lockCanvas(null);
synchronized (surfaceHolder) {
//update position
//Position(blossomVector, boxX, boxY, boxWidth, boxHeight);
// draw flowers
boardView.onDraw(canvas);
}
} finally {
if (canvas != null) {
surfaceHolder.unlockCanvasAndPost(canvas);
}
}
}
}
private synchronized void Position(Vector<Blossom> blossomVector,int box_x, int box_y,
int boxWidth, int boxHeight)
{
//for(Blossom blossom: blossomVector)
iterator = blossomVector.iterator();
while (iterator.hasNext())
{
Blossom tempBlossom = iterator.next();
tempBlossom.UpdatePosition();
}
}
}
public class Board extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
//use a frame layout so you can also display a dialog box
// allows more than one view to be used
FrameLayout f1 = new FrameLayout(this);
LinearLayout l1 = new LinearLayout(this);
EditText edit = new EditText(this);
l1.setOrientation(LinearLayout.VERTICAL);
l1.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT));
edit.setText("Enter your name!");
l1.setId(1);
l1.addView(edit);
f1.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT,
LayoutParams.FILL_PARENT));
f1.addView(l1);
f1.addView(new BoardView(this));
setContentView(f1);
//setContentView(new BoardView(this));
}
}

You need to run the bring to front on the right thread. Try this:
final View v = ((BoardView) getParent()).findViewById(1);
v.post(new Runnable(){ public void run(){ v.bringToFront(); } });
See if that works.

You must update the View using the UI thread (not the SurfaceView thread). If you would like to make some View change from within the SurfaceView thread you must create a new RunOnUiThread which performs the View updating.
// From within SurfaceView thread
new Thread() {
public void run() {
activity.runOnUiThread(new Runnable() {
#Override
public void run() {
// Update view here
}
});
}
}.start();

Collision Detection/Remove object from ArrayList

I am currently trying to test collision between a falling object and a box. I understand basic collision detection, but my problem here is that I have to test it for an indefinite number of falling objects. When these objects(blossoms) are created, they are stored in an ArrayList. The ArrayList handles the drawing of the object on the canvas (using a for each to update the position). My problem comes when a blossom is "caught" in the box. How do I make it disappear from the screen/removed from the array list without a null reference happening? I can show you the logic I have so far...please let me know what you think. I am REALLY stuck, but feel like I'm so close to figuring this out.
Blossom Class
public class Blossom{
private Bitmap blossom;
private int blossom_x = 0;
private int blossom_y = 0;
private int blossomWidth = 0;
private int blossomHeight = 0;
private boolean hit = false;
private Random generator = new Random();
RectF blossomRect;
private static final String TAG = "Debug";
public Blossom(Bitmap bitmap)
{
blossom = bitmap;
blossomWidth = blossom.getWidth();
blossomHeight = blossom.getHeight();
blossom_x = generator.nextInt(320-blossom.getWidth());
blossomRect = new RectF(blossom_x,blossom_y, blossom_x + blossomWidth, blossom_y + blossomHeight);
}
public Bitmap getBitmap()
{
return blossom;
}
public Boolean hit(int boxLeft, int boxTop, int boxRight,int boxBottom)
{
if(blossom_x > boxLeft & blossom_y > boxTop
& blossom_x + blossom.getWidth() < boxRight
& blossom_y + blossom.getHeight() < boxBottom)
{
Log.v(TAG, "Collision Detected");
return true;
}
else
{
return false;
}
}
public float getBlossomX()
{
return blossom_x;
}
public float getBlossomY()
{
return blossom_y;
}
public float getBlossomWidth()
{
return blossomWidth;
}
public float getBlossomHeight()
{
return blossomHeight;
}
public void Draw(Canvas canvas)
{
//draws the flower falling
if (hit == false)
{
canvas.drawBitmap(blossom, blossom_x,
blossom_y = blossom_y+5 , null);
}
}
public void UpdatePosition()
{
blossomRect.set(blossom_x, blossom_y, blossom_x + 25, blossom_y + 25);
}
}
BoardView
public class BoardView extends SurfaceView implements SurfaceHolder.Callback{
Context mContext;
Bitmap box =
(BitmapFactory.decodeResource
(getResources(), R.drawable.box));
private BoardThread thread;
private int box_x = 140;
private int box_y = 378;
private int boxWidth = box.getWidth();
private int boxHeight = box.getHeight();
private ArrayList<Blossom> blossomArrayList = new ArrayList<Blossom>();
private int blossomNum = 0;
private String score;
private int currentScore = 0;
Thread timer;
boolean mode = false;
boolean game = false;
private static final String TAG = "Debug";
final Paint scorePaint = new Paint();
public BoardView(Context context){
super(context);
scorePaint.setColor(Color.BLACK);
scorePaint.setTextSize(12);
scorePaint.setTypeface(Typeface.MONOSPACE);
//surfaceHolder provides canvas that we draw on
getHolder().addCallback(this);
// controls drawings
thread = new BoardThread(getHolder(),this, blossomArrayList, box_x, box_y,
boxWidth, boxHeight);
timer = new Thread(){
public void run(){
//makes sure the player still has 3 lives left
while(game == false){
uiCallback.sendEmptyMessage(0);
try {
Thread.sleep(2000); // wait two seconds before drawing the next flower
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} //sleep for 2 seconds
}
}
};
timer.start();
//intercepts touch events
setFocusable(true);
}
#Override
public void onDraw(Canvas canvas){
canvas.drawColor(Color.WHITE);
score = "SCORE: " + currentScore;
//note: pay attention to order you draw things
//don't change order or else blossoms will fall
//on top of box, not "into" it.
//display the scoreboard
canvas.drawText(score,240,420,scorePaint);
//draw box and set start location
for(Blossom blossom: blossomArrayList) // getting errors here
{
blossom.Draw(canvas);
blossom.hit(box_x,box_y, box_x + boxWidth, box_y + boxHeight);
}
canvas.drawBitmap(box, box_x, box_y, null);
}
#Override
public boolean onTouchEvent(MotionEvent event){
//handles movement of box
if(event.getAction() == MotionEvent.ACTION_DOWN){
if(event.getX() > box_x & event.getY() > box_y &
event.getX() < box_x + boxWidth & event.getY() < box_y + boxHeight)
{
mode = true;
}
}
if(event.getAction() == MotionEvent.ACTION_MOVE) {
if(event.getX() > box_x & event.getY() > box_y &
event.getX() < box_x + boxWidth & event.getY() < box_y + boxHeight)
{
mode = true;
}
if(mode == true){
box_x = (int)event.getX();
}
}
if(event.getAction() == MotionEvent.ACTION_UP){
mode = false;
}
invalidate();
return true;
}
#Override
public void surfaceChanged(SurfaceHolder holder,
int format, int width, int height ){
Log.v(TAG, "Surface Changed");
//somehow these don't seem to be working
}
#Override
public void surfaceCreated(SurfaceHolder holder){
thread.startRunning(true);
thread.start();
}
#Override
public void surfaceDestroyed(SurfaceHolder holder){
Log.v(TAG, "Surface Destroyed");
//somehow these don't seem to be working
thread.startRunning(false);
thread.stop();
timer.interrupt();
timer.stop();
}
private Handler uiCallback = new Handler(){
public void handleMessage(Message msg){
//add a new blossom to the blossom ArrayList!!
blossomArrayList.add(new Blossom(
(BitmapFactory.decodeResource
(getResources(), R.drawable.blossom))));
blossomNum++;
//remove neccesary blossoms from list
Log.v(TAG, "Number of Blossoms =" + blossomNum);
}
};
}
BoardThread
public class BoardThread extends Thread {
private SurfaceHolder surfaceHolder;
private BoardView boardView;
private ArrayList<Blossom> blossomArrayList;
private int boxX;
private int boxY;
private int boxWidth;
private int boxHeight;
private boolean mrun =false;
public BoardThread(SurfaceHolder holder, BoardView boardView2,
ArrayList<Blossom> blossomArrayList1,
int box_x, int box_y, int boxW, int boxH) {
surfaceHolder = holder;
boardView=boardView2;
blossomArrayList = blossomArrayList1;
boxX = box_x;
boxY = box_y;
boxW = boxWidth;
boxH = boxHeight;
}
public void startRunning(boolean run) {
mrun=run;
}
#Override
public void run() {
super.run();
Canvas canvas;
while (mrun) {
canvas=null;
try {
canvas = surfaceHolder.lockCanvas(null);
synchronized (surfaceHolder) {
//test for collision
Collision(blossomArrayList, boxX, boxY, boxWidth, boxHeight);
// draw flowers
boardView.onDraw(canvas); // and getting errors here - concurrent
}
} finally {
if (canvas != null) {
surfaceHolder.unlockCanvasAndPost(canvas);
}
}
}
}
public void Collision(ArrayList<Blossom> blossomArrayList, int box_x, int box_y,
int boxWidth, int boxHeight)
{
for(Blossom blossom: blossomArrayList)
{
blossom.UpdatePosition();
if(blossom.hit(box_x,box_y, box_x + boxWidth, box_y + boxHeight) == true)
{
///if flower is caught, add to score
//currentScore += 100;
}
}
}
}

One way you could do this is to have a field on the Blossom that indicates whether it is active or not, then only draw it if it is active. If it is inactive, another Blossom could replace it in the list.

Setting a visibility flag is one way to go, however I'd recommend against it since you are adding an indeterminate amount of Bitmaps to an ArrayList...you'll find yourself running out of memory pretty quickly. Change your collision detection iterator from a foreach to a handwritten loop, this will avoid concurrency issues you may run to in the code you have listed above.
for (int i = 0; i < blossomArrayList.size(); i++)
{
if(blossom.hit(box_x,box_y, box_x + boxWidth, box_y + boxHeight)) {
blossomArrayList.remove(i);
}
}
Additionally, I'd recommend changing all your ArrayList foreach iterators to hand written for loops, as iterating ArrayLists (but not any other object) is relatively slow on Android and can lead to unexpected concurrency issues.
Thirdly, it seems as though you only need to run your Collision() method once after your UpdatePositions loop has completed since you're already checking every Blossom in your Collision() method.

Develop Reference

The Android operating system is a mobile operating system that was developed by Google (GOOGL?) to be primarily used for touchscreen devices, cell phones, and tablets.

Remove item from ArrayList, ArrayIndexOutOfBounds exception - android

Assuming that you get the error on blossomArrayList.remove(removeInt);, you could try to remove the object itself as .remove(..) can take an Object parameter.

Adding a cast to mark the int as an object worked for me. blossomArrayList.remove((Object)myint); this way it doesn't get confused with index.

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Collision Detection/Remove object from ArrayList

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