i'm trying to fix this problem for more than 2 days now and have become quite desperate.
I want to write a 'Checkers-like' board game for android. The game engine itself is kinda complete but i have problems with updating the views.
I wrote a little example class to demonstrate my problem:
public class GameEngineView extends View {
private static final String TAG = GameEngineView.class.getSimpleName();
private int px;
private int py;
private int cx;
private int cy;
private boolean players_move;
private int clickx;
private int clicky;
Random rgen;
private RefreshHandler mRedrawHandler = new RefreshHandler();
class RefreshHandler extends Handler {
#Override
public void handleMessage(Message msg) {
GameEngineView.this.update();
GameEngineView.this.invalidate();
Log.d(TAG, "invalidate()");
}
public void sleep(long delayMillis) {
this.removeMessages(0);
sendMessageDelayed(obtainMessage(0), delayMillis);
}
};
public GameEngineView(Context context) {
super(context);
setFocusable(true);
players_move = true;
rgen = new Random();
}
public void update() {
updateGame();
Log.d(TAG, "update -> sleep handler");
mRedrawHandler.sleep(100);
}
public void updateGame() {
if(players_move) {
px = clickx;
py = clicky;
} else {
calcAIMove();
switchMove();
}
}
public void switchMove() {
players_move = !players_move;
}
public void calcAIMove() {
for(int i = 0; i < 20000; i++) {
cx = rgen.nextInt(getWidth());
cy = rgen.nextInt(getHeight());
}
}
#Override
public boolean onTouchEvent(MotionEvent event) {
Log.d(TAG, "event");
int eventaction = event.getAction();
if(eventaction == MotionEvent.ACTION_DOWN) {
Log.d(TAG, "action_down");
clickx = (int) event.getX();
clicky = (int) event.getY();
switchMove();
update();
}
return super.onTouchEvent(event);
}
#Override
public void onDraw(Canvas canvas) {
super.onDraw(canvas);
Paint green = new Paint();
green.setColor(Color.GREEN);
Paint red = new Paint();
red.setColor(Color.RED);
canvas.drawColor(Color.BLACK);
canvas.drawCircle(px, py, 25, green);
canvas.drawCircle(cx, cy, 25, red);
}
}
The function calcAIMove() just burns time to simulate a real evaluation of the position in a board game.
Now my Problem is: If the player clicks(makes a move) the green ball is first drawn when the ai move calculation has been complete. So both moves are drawn at the same time.
I wonder HOW to accomplish this:
-Player clicks
-green Ball is drawn
-AI calculates
-red ball is drawn
-and so on..
When searching the web i found a lot of game loop examples but they all need a Thread with constant polling.. it should be possible without this since the whole program runs sequentially .. right?
Hoping for advice.
thanks,
Dave
Here is how your game could work:
user makes a move
game view is updated
game switches to CPU's turn
sleep to simulate CPU player thinking (if move computation is trivial)
compute CPU's move
game view is updated
game switches to player's turn
There is no need for constant polling in a turn-based game like this. The only place you should have sleep is in step 4, so you can remove it from the other areas (no need for the old update() method which is just a delayed call to updateGame()).
One way to implement this is to simply delay the call to calcAIMove() and switchMove() by putting it into a Runnable and using Handler.postDelayed() or similar.
I don't see how you are disabling touch events when it is the CPU's turn, which can lead to a host of other problems if switchMove() and update() are still being called...
In your game loop you can use a instance of TimerTask to ensure certain delay between greenBall and some other drawing task. Game tutorials like Snake and LunarLander are great references on when and if you need to invalidate your View. Hope this helps a little!
ok so the answer provided by antonyt helped me solve this.. I provide the corrected code for other interested ones.
public class GameEngineView extends View {
private static final String TAG = GameEngineView.class.getSimpleName();
private int px;
private int py;
private int cx;
private int cy;
private boolean players_move;
private int clickx;
private int clicky;
Random rgen;
/**
* Create a simple handler that we can use to cause animation to happen. We
* set ourselves as a target and we can use the sleep()
* function to cause an update/invalidate to occur at a later date.
*/
private RefreshHandler mRedrawHandler = new RefreshHandler();
class RefreshHandler extends Handler {
#Override
public void handleMessage(Message msg) {
GameEngineView.this.update();
}
public void sleep(long delayMillis) {
this.removeMessages(0);
sendMessageDelayed(obtainMessage(0), delayMillis);
}
};
public GameEngineView(Context context) {
super(context);
setFocusable(true);
players_move = true;
rgen = new Random();
}
public void update() {
if(players_move) {
Log.d(TAG, "new player x");
px = clickx;
py = clicky;
GameEngineView.this.invalidate();
switchMove();
mRedrawHandler.sleep(100);
} else {
Log.d(TAG, "new ai x");
calcAIMove();
GameEngineView.this.invalidate();
switchMove();
}
Log.d(TAG, "update -> sleep handler");
}
public void switchMove() {
players_move = !players_move;
}
public void calcAIMove() {
for(int i = 0; i < 100000; i++) {
cx = rgen.nextInt(getWidth());
cy = rgen.nextInt(getHeight());
}
}
#Override
public boolean onTouchEvent(MotionEvent event) {
Log.d(TAG, "event");
int eventaction = event.getAction();
if(players_move && eventaction == MotionEvent.ACTION_DOWN) {
Log.d(TAG, "action_down");
clickx = (int) event.getX();
clicky = (int) event.getY();
update();
}
return super.onTouchEvent(event);
}
#Override
public void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawColor(Color.BLACK);
Paint green = new Paint();
green.setColor(Color.GREEN);
Paint red = new Paint();
red.setColor(Color.RED);
canvas.drawCircle(px, py, 25, green);
canvas.drawCircle(cx, cy, 25, red);
}
}
Related
I am trying to draw bullets on the screen when the player presses, but
after a few bullets I get the following error: FATAL EXCEPTION: Thread-2
Here is the classes of the bullet and of the gameView
public class Bullet {
private int x;
private int y;
private int speed;
private Bitmap bitmap;
public Bullet(Context context,int PositionX,int PositionY) {
Log.v("i am in bullet"," come on!!!");
speed = 10;
x = PositionX;
y = PositionY;
bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.flash);
}
public void update() {
//Log.v("i am in update bullet"," come on!!!");
//animating the star horizontally right side
//by increasing x coordinate with player speed
x += 20;
}
public Bitmap getBitmap(){return bitmap;}
public int getX() {
return x;
}
public int getY() {
return y;
}
}
returns
public class GameView extends SurfaceView implements Runnable {
private long fps;
private long timeThisFrame;
volatile boolean playing;
private Thread gameThread = null;
private Player player;
//a screenX holder
int screenX;
int i=0;
//context to be used in onTouchEvent to cause the activity transition from GameAvtivity to MainActivity.
Context context;
//the score holder
int score;
//the high Scores Holder
int highScore[] = new int[4];
//Shared Prefernces to store the High Scores
SharedPreferences sharedPreferences;
//to count the number of Misses
int countMisses;
//indicator that the enemy has just entered the game screen
boolean flag ;
//an indicator if the game is Over
private boolean isGameOver ;
private Paint paint;
private Canvas canvas;
private SurfaceHolder surfaceHolder;
private Enemy enemies;
//created a reference of the class Friend
private Friend friend;
//private Bullet bullet;
private ArrayList<Star> stars = new
ArrayList<Star>();
private ArrayList<Bullet> bullet = new
ArrayList<Bullet>();
//defining a boom object to display blast
private Boom boom;
//the mediaplayer objects to configure the background music
static MediaPlayer gameOnsound;
final MediaPlayer killedEnemysound;
final MediaPlayer gameOversound;
public GameView(Context context, int screenX, int screenY) {
super(context);
player = new Player(context, screenX, screenY);
surfaceHolder = getHolder();
paint = new Paint();
//initializing context
this.context = context;
int starNums = 20;
for (int i = 0; i < starNums; i++) {
Star s = new Star(context,screenX, screenY);
stars.add(s);
}
enemies = new Enemy(context,screenX,screenY);
//initializing boom object
boom = new Boom(context);
//initializing the Friend class object
friend = new Friend(context, screenX, screenY);
//setting the score to 0 initially
score = 0;
//setting the countMisses to 0 initially
countMisses = 0;
this.screenX = screenX;
isGameOver = false;
//initializing shared Preferences
sharedPreferences = context.getSharedPreferences("SHAR_PREF_NAME",Context.MODE_PRIVATE);
//initializing the array high scores with the previous values
highScore[0] = sharedPreferences.getInt("score1",0);
highScore[1] = sharedPreferences.getInt("score2",0);
highScore[2] = sharedPreferences.getInt("score3",0);
highScore[3] = sharedPreferences.getInt("score4",0);
//initializing the media players for the game sounds
gameOnsound = MediaPlayer.create(context,R.raw.gameon);
killedEnemysound = MediaPlayer.create(context,R.raw.killedenemy);
gameOversound = MediaPlayer.create(context,R.raw.gameover);
//starting the music to be played across the game
gameOnsound.start();
}
#Override
public void run() {
while (playing) {
long startFrameTime = System.currentTimeMillis();
synchronized (surfaceHolder) {
update();
draw();
control();
}
timeThisFrame = System.currentTimeMillis() - startFrameTime;
if (timeThisFrame >= 1) {
fps = 1000 / timeThisFrame;
}
}
}
private void update() {
//incrementing score as time passes
score++;
player.update();
//setting boom outside the screen
boom.setX(-250);
boom.setY(-250);
for (Star s : stars) {
s.update(player.getSpeed());
}
for (Bullet b : bullet) {
b.update();
}
//setting the flag true when the enemy just enters the screen
if(enemies.getX()==screenX){
flag = true;
}
enemies.update(player.getSpeed(),getFps());
}
private void draw() {
if (surfaceHolder.getSurface().isValid()) {
canvas = surfaceHolder.lockCanvas();
canvas.drawColor(Color.argb(500,135,206,250));
paint.setColor(Color.WHITE);
paint.setTextSize(20);
for (Star s : stars) {
canvas.drawBitmap(
s.getBitmap(),
s.getX(),
s.getY(),
paint);
}
for (Bullet b : bullet) {
canvas.drawBitmap(
b.getBitmap(),
b.getX(),
b.getY(),
paint);
}
canvas.drawBitmap(
player.getBitmap(),
player.getX(),
player.getY(),
paint);
canvas.drawBitmap( enemies.getBitmap(), enemies.getframeToDraw(), enemies.getwhereToDraw(), null);
//drawing the score on the game screen
paint.setTextSize(30);
canvas.drawText("Score:"+score,100,50,paint);
//drawing boom image
canvas.drawBitmap(
boom.getBitmap(),
boom.getX(),
boom.getY(),
paint
);
//draw game Over when the game is over
if(isGameOver){
paint.setTextSize(150);
paint.setTextAlign(Paint.Align.CENTER);
int yPos=(int) ((canvas.getHeight() / 2) - ((paint.descent() + paint.ascent()) / 2));
canvas.drawText("Game Over",canvas.getWidth()/2,yPos,paint);
}
surfaceHolder.unlockCanvasAndPost(canvas);
}
}
private void control() {
try {
gameThread.sleep(17);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
public void pause() {
playing = false;
try {
gameThread.join();
} catch (InterruptedException e) {
gameThread.interrupt();
}
}
public void resume() {
playing = true;
gameThread = new Thread(this);
gameThread.start();
}
//stop the music on exit
public static void stopMusic(){
gameOnsound.stop();
}
#Override
public boolean onTouchEvent(MotionEvent motionEvent) {
switch (motionEvent.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_UP:
player.stopBoosting();
break;
case MotionEvent.ACTION_DOWN:
player.setBoosting();
break;
}
//if touch the player
if (player.getDetectCollision().contains((int)motionEvent.getX(), (int)motionEvent.getY())) {
Bullet b = new Bullet(context,player.getX()+player.getDetectCollision().width()
,player.getY()-(player.getDetectCollision().height()/2));
bullet.add(b);
Log.d("test", "touch not inside myEditText");
}
//if the game's over, tappin on game Over screen sends you to MainActivity
if(isGameOver){
if(motionEvent.getAction()==MotionEvent.ACTION_DOWN){
context.startActivity(new Intent(context,MainActivity.class));
}
}
return true;
}
public long getFps(){
return fps;
}
}
I want to connect several classes which are functioning separately but are related.
Lets say I am writing an app in which you can swipe to draw a chart. There are lots of classes in the app which are related and should be connected.
For example three of the classes are:
Swiper - responsible for interpreting the gesture of the user
Points - responsible for handling the points on the chart
ChartDrawer - responsible for drawing the chart on the screen
I want to know is there any design pattern such as a connector which can handle the relation and communication of these classes? Any way i can redesign in a better way or make mind more object oriented?
This is my ChartDraw class which extends a view:
public class ChartDraw extends View implements GestureReceiver {
int chartYPosition;
private int circleColor;
private int circleRadius;
int height;
private float lastPointOnChart;
private int lineColor;
private int lineWidth;
private Paint paint;
private float tempPoint;
int width;
public ChartDraw(Context context) {
super(context);
init();
}
public ChartDraw(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public ChartDraw(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
this.lineWidth = 15;
this.circleRadius = 20;
this.lineColor = Color.parseColor("#1976D2");
this.circleColor = Color.parseColor("#536DFE");
this.lastPointOnChart = 0.0f;
this.tempPoint = 0.0f;
this.paint = new Paint();
this.height = getHeight();
this.width = getWidth();
this.chartYPosition = this.height / 2;
}
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
this.chartYPosition = canvas.getHeight() / 2;
this.paint.setStrokeWidth((float) this.lineWidth);
this.paint.setColor(this.lineColor);
canvas.drawLine(0.0f, (float) this.chartYPosition, this.tempPoint, (float) this.chartYPosition, this.paint);
if (this.tempPoint > 20.0f) {
this.paint.setColor(this.circleColor);
canvas.drawCircle(20.0f, (float) this.chartYPosition, 20.0f, this.paint);
drawTriangle(canvas, this.paint, this.tempPoint, this.chartYPosition);
}
}
private void drawTriangle(Canvas canvas, Paint paint, float startX, int startY) {
Path path = new Path();
path.moveTo(startX, (float) (startY - 20));
path.lineTo(startX, (float) (startY + 20));
path.lineTo(30.0f + startX, (float) startY);
path.lineTo(startX, (float) (startY - 20));
path.close();
canvas.drawPath(path, paint);
}
public void onMoveHorizontal(float dx) {
this.tempPoint = this.lastPointOnChart + dx;
invalidate();
}
public void onMoveVertical(float dy) {
}
public void onMovementStop() {
this.lastPointOnChart = this.tempPoint;
}
}
And this is My SwipeManager which is handling user gesture:
public class SwipeManager implements View.OnTouchListener {
GestureReceiver receiver;
private int activePointer;
private float initX,
initY;
private long startTime,
stopTime;
private boolean resolving = false;
private boolean resolved = false;
private Direction direction;
#Override
public boolean onTouch(View view, MotionEvent motionEvent) {
if (receiver == null) throw new AssertionError("You must register a receiver");
switch (motionEvent.getActionMasked()) {
case ACTION_DOWN:
activePointer = motionEvent.getPointerId(0);
initX = motionEvent.getX(activePointer);
initY = motionEvent.getY(activePointer);
startTime = new Date().getTime();
break;
case ACTION_MOVE:
if (!resolving && !resolved) {
resolving = true;
float x = motionEvent.getX(activePointer);
float y = motionEvent.getY(activePointer);
direction = resolveDirection(x, y);
if (direction != Direction.STILL) {
resolved = true;
resolving = false;
} else {
resolving = false;
resolved = false;
}
break;
}
if (resolved) {
if (direction == Direction.HORIZONTAL)
receiver.onMoveHorizontal(motionEvent.getX(activePointer) - initX);
else receiver.onMoveVertical(motionEvent.getX(activePointer) - initY);
}
break;
case ACTION_UP:
resolved = false;
receiver.onMovementStop();
break;
}
return true;
}
private Direction resolveDirection(float x, float y) {
float dx = x - initX;
float dy = y - initY;
float absDx = Math.abs(dx);
float absDy = Math.abs(dy);
if (absDx > absDy + 10) {
return Direction.HORIZONTAL;
} else if (absDy > absDx + 10) {
return Direction.VERTICAL;
}
return Direction.STILL;
}
public void setReceiver(GestureReceiver receiver) {
this.receiver = receiver;
}
private enum Direction {HORIZONTAL, VERTICAL, STILL;}
}
And i didn't start the Points class because i was not sure about the architecture.
I want this Connector to register all the listeners for the classes and wait for a change and inform the corresponding class of the change, like new point added or swipe started and finished or any other event in the app.
Chain of Responsibility might be what you are looking for.
It is a pattern to tie a series of 'processing objects' in a 'chain' that can handle 'command objects'.
I could see you making command objects that encapsulate the touch events and then get passed through several processors and finally get 'processed' by the 'processing objects' which handle input detection/output generation for that particular 'command object'.
I don't know if this is -ideal-, but it is potentially valid.
Other related patterns to look into might be:
https://en.wikipedia.org/wiki/Command_pattern
https://en.wikipedia.org/wiki/Observer_pattern
https://en.wikipedia.org/wiki/Bridge_pattern
Really what you're looking for here is an MVC-style architecture. Your application should (broadly speaking) be separated into 3 different areas:
the Model, which is completely divorced from your presentation or communication concerns. It provides an API for interaction and can be tested entirely independently with a simple framework such as JUnit.
the View, which is responsible for displaying the Model. It may be that a model can be displayed in different ways - in which case you get a single model and a few different views.
the Controller, which is responsible for making changes to the Model in response to user (or other) input.
The important thing is that the three sets of components are loosely-coupled and that responsibilities are clearly separated. All three should communicated via well defined interfaces (perhaps using the Observer, Command and ChainOfResponsibility patterns). In particular, the Model classes should have no direct knowledge of any of the View or Controller classes.
So, you might have some Model/View classes like this...
public interface ChartListener {
void notifyUpdate();
}
public interface Chart {
void newPoint(Point p);
Collection<Point> thePoints();
void addListener(ChartListener listener);
}
public class ChartModel implements Chart {
private final Collection<Point> points;
private final Collection<ChartListener> listeners;
public Collection<Point> thePoints() {
return Collections.unmodifiableCollection(points);
}
public void newPoint(Point p) {
thePoints.add(p);
listeners.stream().forEach(ChartListener::notifyUpdate);
}
public void addListener(ChartListener cl) {
listeners.append(cl);
}
}
public PieChartViewer implements ChartListener {
// All you colour management or appearance-related concerns is in this class.
private final Chart chart;
public PieChartView(Chart chart) {
this.chart = chart;
// set up all the visuals...
}
public void notifyUpdate() {
for (final Point p:chart.thePoints()) {
// draw a point somehow, lines, dots, etc,
}
}
}
Then you might have multiple different implementations of your View classes, utilising the ChartListener interface.
Your Swipe class seems like a Controller class, which would take a ChartModel implementation and then modify it in response to some input from the user.
I currently have (among others) these classes:
public class Main extends Activity {
Panel p;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
p = new Panel(this);
setContentView(p);
}
#Override
public boolean onTouchEvent(MotionEvent event) {
p.onTouchEvent(event);
// Make your UI thread sleep.
try {
Thread.sleep(30);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return true;
}
and
public class Panel extends SurfaceView implements SurfaceHolder.Callback {
private ViewThread mThread;
private ArrayList<GraphicsElement> mElements = new ArrayList<GraphicsElement>();
public static int panelHeight;
public static int panelWidth;
private int numberOfElements = 0;
private Paint mPaint;
public Panel(Context context) {
super(context);
getHolder().addCallback(this);
mThread = new ViewThread(this);
mPaint = new Paint();
mPaint.setColor(Color.CYAN);
mPaint.setTextSize(20);
}
public void doDraw(long elapsed, Canvas canvas) {
canvas.drawColor(Color.parseColor("#003045"));
if (!(mElements.size() > 15)) {
synchronized (mElements) {
for (GraphicsElement element : mElements) {
element.doDraw(canvas);
}
canvas.drawText("FPS: " + Math.round(1000f / elapsed) + " Elements: " + numberOfElements, 10, 30, mPaint);
}
} else {
mElements.clear();
numberOfElements = 0;
}
}
public void animate(long elapsedTime) {
synchronized (mElements) {
for (GraphicsElement element : mElements) {
element.animate(elapsedTime);
}
}
}
#Override
public boolean onTouchEvent(MotionEvent event) {
int action = event.getAction();
int xspeed = 0;
int yspeed = 0;
if (action == MotionEvent.ACTION_DOWN || action == MotionEvent.ACTION_MOVE) {
if (event.getX() > panelWidth / 2) {
xspeed = 5;
} else if (event.getX() < panelWidth / 2) {
xspeed = -5;
}
synchronized (mElements) {
for (GraphicsElement element : mElements) {
element.changeSpeed(xspeed, yspeed);
}
}
}
return true;
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
#Override
public void surfaceCreated(SurfaceHolder holder) {
if (!mThread.isAlive()) {
mThread = new ViewThread(this);
mThread.setRunning(true);
mThread.start();
}
mElements.add(new GraphicsElement(getResources(), 80, 300));
numberOfElements += 1;
}
public void surfaceDestroyed(SurfaceHolder holder) {
I also have ViewThread, just my animation thread, and GraphicsElement, which defines the moving object. My animation is going very slow(on touch), and I think it has something to do with my .sleep() method. Could anyone please help me ?
Edit: I'm using .sleep() because I don't want to flood TouchEvents.
i'm trying to get it like: Check for TouchEvent, Sleep, Check for TouchEvent, Sleep.. etc...
I've had the same issues with touch slowing things down and ended up with a similar approach to yours (sleeping the UI thread on touch events, as recommended by a Google game developer). The thing that seemed to help me was playing with the length of the sleep time. Try increasing it to 70 ms or even more and see if that helps. Most apps don't need a super high sample rate for touch input.
Firstly, you should initialize your Panel inside your onCreate() method.
Panel p = null;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
p = new Panel(this);
setContentView(p);
}
Secondly, I do not understand why you are doing a sleep in your onTouchEvent() handler. Try taking that out, and things should speed up, especially if you think that may be the cause!
I think I have hit a coders block here. I am writing a game where multiples images will fall from the top of the screen and you have to catch them at the bottom. There will be an indeterminate number of images, so you don't know how many there will be upon start time. For the life of me I CANNOT figure out the way to implement this. I understand the logic, but am having trouble trucking through Android's classes. I tried to create my own "blossom" object, but every time I try to write anything having to do with a bitmap inside of it, it freaks out. Maybe I'm just writing the class wrong, I don't know. All of this is being performed on a SurfaceView. Is there anybody who has any ideas on how to accomplish this? Here is my code thus far:
public class BoardView extends SurfaceView implements SurfaceHolder.Callback{
Context mContext;
Bitmap box =
(BitmapFactory.decodeResource
(getResources(), R.drawable.box));
Bitmap blossom =
(BitmapFactory.decodeResource
(getResources(), R.drawable.blossom));
private BoardThread thread;
private float box_x = 140;
private float box_y = 378;
private float blossom_x = 0;
private float blossom_y = 0;
private float boxWidth = box.getWidth();
private float boxHeight = box.getHeight();
private float blossomWidth = blossom.getWidth();
private float blossomHeight = blossom.getHeight();
private Random generator = new Random();
boolean mode = false;
RectF boxRect = new RectF(box_x,box_y, box_x + boxWidth, box_y + boxHeight);
//ImageView box_view;
public BoardView(Context context){
super(context);
//surfaceHolder provides canvas that we draw on
getHolder().addCallback(this);
// controls drawings
thread = new BoardThread(getHolder(),this);
//draws the blossom at a random starting point
blossom_x = generator.nextInt(300);
//box_view = (ImageView)findViewById(R.id.box_view);
//box_view.setVisibility(ImageView.VISIBLE);
//TranslateAnimation anim = new TranslateAnimation(0,0,300,0);
//anim.setDuration(500);
//box_view.startAnimation(anim);
//intercepts touch events
setFocusable(true);
}
#Override
public void onDraw(Canvas canvas){
canvas.drawColor(Color.WHITE);
//draw box and set start location
canvas.drawBitmap(box, box_x - (boxWidth/2),
box_y - (boxHeight/2), null);
canvas.drawBitmap(blossom, blossom_x,
blossom_y = blossom_y+3 , null);
//collision detection, currently not working after
//implementing random draw
if(blossom_y + blossomHeight == box_y)
{
canvas.drawBitmap(blossom, 40,100, null);
}
}
#Override
public boolean onTouchEvent(MotionEvent event){
if(event.getAction() == MotionEvent.ACTION_DOWN){
if(boxRect.contains(event.getX(),event.getY())){
mode = true;
}
}
if(event.getAction() == MotionEvent.ACTION_MOVE) {
if(boxRect.contains(event.getX(),event.getY())){
mode = true;
}
if(mode == true){
box_x = (int)event.getX();
boxRect.set(box_x,box_y, box_x + boxWidth, box_y + boxHeight);
}
}
if(event.getAction() == MotionEvent.ACTION_UP){
mode = false;
}
invalidate();
return true;
}
#Override
public void surfaceChanged(SurfaceHolder holder,
int format, int width, int height ){
}
#Override
public void surfaceCreated(SurfaceHolder holder){
thread.startRunning(true);
thread.start();
}
#Override
public void surfaceDestroyed(SurfaceHolder holder){
thread.startRunning(false);
thread.stop();
}
}
I am currently using a bitmap to draw the falling flower. I started making a class for the flower object instead, which so far looks like this
public class Blossom{
private Bitmap blossom;
public Blossom()
{
Bitmap blossom =
(BitmapFactory.decodeResource
(getResources(), R.drawable.blossom));
}
public void setImage(Bitmap bitmap)
{
//sets the image for the blossom;
Bitmap blossom = bitmap;
}
}
It keeps giving me an error saying getResources is undefined for the Blossom class. When I try to write a method called setImage, and do the setting of the Image in the BoardView class, it won't let me at all :( It looked something like this
public class Blossom{
private Bitmap blossom;
public void setImage(Bitmap bitmap)
{
//sets the image for the blossom;
Bitmap blossom = bitmap;
}
}
Can anybody see what is going wrong here?
Since your class extends SurfaceView, you should be doing getContext().getResources()
Edit - if you want to use getResources in your other class, then you need to pass in a Context as well. You might instead just pass in your Bitmap instead of trying to fetch it from that data class.
Is it possible to pass arguments to an Android Handler?? I have two pieces of code.
new Thread(){
public void run(){
for(;;){
uiCallback.sendEmptyMessage(0);
Thread.sleep(2000); //sleep for 2 seconds
}
}
}.start();
private Handler uiCallback = new Handler(){
public void handleMessage(Message msg){
//add a new blossom to the blossom ArrayList!!
blossomArrayList.add(new Blossom(context, R.drawable.blossom));
}
};
I of course get an error because the Handler method cannot see my context. This is probably because of this piece of code
public BoardView(Context context){
super(context);
Context is not visible elsewhere, and I'm wondering if I can pass it as an argument to my Handler.
EDIT: I am posting the two main pieces of code to answer a question about why my Blossom object needs context. I myself am not 100% sure >.> Maybe you could have a look and see what's going on.
public class Blossom{
private Bitmap blossom;
private float blossomX = 0;
private float blossomY = 0;
private Random generator = new Random();
public Blossom(Context context, int drawable)
{
blossom = BitmapFactory.decodeResource(context.getResources(), drawable);
blossomX = generator.nextInt(300);
}
public Bitmap getBitmap()
{
return blossom;
}
public float getBlossomX()
{
return blossomX;
}
public float getBlossomY()
{
return blossomY;
}
public void Fall(Canvas canvas, float boxY)
{
//draws the flower falling
canvas.drawBitmap(blossom, blossomX,
blossomY = blossomY+3 , null);
//collision detection, currently not working after
//implementing random start location
//if(blossomY + 29 == boxY)
//{
//canvas.drawBitmap(blossom,0,0,null);
//}
}
}
public class BoardView extends SurfaceView implements SurfaceHolder.Callback{
Context mContext;
Bitmap box =
(BitmapFactory.decodeResource
(getResources(), R.drawable.box));
private BoardThread thread;
private float box_x = 140;
private float box_y = 378;
private float boxWidth = box.getWidth();
private float boxHeight = box.getHeight();
private ArrayList<Blossom> blossomArrayList = new ArrayList<Blossom>();;
boolean mode = false;
RectF boxRect = new RectF(box_x,box_y, box_x + boxWidth, box_y + boxHeight);
public BoardView(Context context){
super(context);
//surfaceHolder provides canvas that we draw on
getHolder().addCallback(this);
// controls drawings
thread = new BoardThread(getHolder(),this);
//pass variables to instance of Blossom
//for(int i = 0; i <= 3; i++)
//{
//blossomArrayList.add(new Blossom(context, R.drawable.blossom));
//}
new Thread(){
public void run(){
for(;;){
uiCallback.sendEmptyMessage(0);
Thread.sleep(2000); //sleep for 2 seconds
}
}
}.start();
//intercepts touch events
setFocusable(true);
}
#Override
public void onDraw(Canvas canvas){
canvas.drawColor(Color.WHITE);
//draw box and set start location
canvas.drawBitmap(box, box_x - (boxWidth/2),
box_y - (boxHeight/2), null);
for(int i = 0; i<= 3; i++)
{
blossomArrayList.get(i).Fall(canvas, box_y);
}
}
#Override
public boolean onTouchEvent(MotionEvent event){
if(event.getAction() == MotionEvent.ACTION_DOWN){
if(boxRect.contains(event.getX(),event.getY())){
mode = true;
}
}
if(event.getAction() == MotionEvent.ACTION_MOVE) {
if(boxRect.contains(event.getX(),event.getY())){
mode = true;
}
if(mode == true){
box_x = (int)event.getX();
boxRect.set(box_x,box_y, box_x + boxWidth, box_y + boxHeight);
}
}
if(event.getAction() == MotionEvent.ACTION_UP){
mode = false;
}
invalidate();
return true;
}
#Override
public void surfaceChanged(SurfaceHolder holder,
int format, int width, int height ){
}
#Override
public void surfaceCreated(SurfaceHolder holder){
thread.startRunning(true);
thread.start();
}
#Override
public void surfaceDestroyed(SurfaceHolder holder){
thread.startRunning(false);
thread.stop();
}
private Handler uiCallback = new Handler(){
public void handleMessage(Message msg){
//add a new blossom to the blossom ArrayList!!
blossomArrayList.add(new Blossom(context, R.drawable.blossom));
}
};
}
Create a class that extends Handler, and store a weak reference to the context. This will help prevent some memory issues.
public class SomeHandler extends Handler {
// A weak reference to the enclosing context
private WeakReference<Context> mContext;
public SomeHandler (Context context) {
mContext = new WeakReference<Context>(context);
}
public void handleMessage(Message msg) {
// Get an actual reference to the DownloadActivity
// from the WeakReference.
Context context=mContext.get();
...
}
}
What if you create a subclass which extends Handler? That way you could pass any parameters you want.
But just out of curiosity, why does the Blossom object require the context object? It's usually best to separate your logic from GUI dependencies.