Develop Reference

Android Development: App is lagging when ontouch listener is inactive

I haven't been able to find a question online similar to this, so I thought I would submit the question. In most cases it seems people have the opposite problem were lag may be occurring during a touch event, but I am seeing the exact opposite. I am creating an air hockey game and each frame the pieces are moved based on their current parameters, and the game is redrawn while in the background the override ontouch listener is looking for motion events. The thing is there is noticeable lag when there is no fingers touching the screen and just watching the animated pieces, but as long as there is any form of motion event happening, if ontouch is being called, then the animation is smooth. I really can not figure why this is, my best educated guess is the interrupt that is checking if ontouch should be called is consuming more resources than it should, but I know nothing about how to modify or check the ontouch interrupt behavior at all so hopefully someone might know.
A little more background on how everything is organized. The overall class is located in Main.java, it is created here and requests the Context view, the game class is an extension of ImageView. The game class has a #override OnTouchEvent, which has all the defintions for what to do depending on what state and what motion event. The class also has a draw method, and at the end of the method it calls h.postDelayed(r, FRAME_RATE); where r is a Runnable with #Override public void run() which just calls invalidate();. h is just a handler that is initialized in the class. So each time the game is drawn invalidate will be called after the FRAME_RATE elapse time of 10ms, which tells the game to redraw. All the move functions for the game are also called from the draw method. The OnTouch is happening all along side this process so why would it be smoother if on OnTouch is being called rather than checking if its true, it all seems counter intuitive but I'm sure there is a logical reason. Lastly the lag time was measurable using the system clock and was time dependent based on where exactly it was called. It just showed an increase in passing time between the games move function when a touch event was not occurring.
Sorry for the long response without much actual code context, I hope it is descriptive enough. The code its self is rather long so I didn't think it would help to post that, but if needed I can do better at re posting some pseudo code with the visualized hierarchy. Thank you for any help and suggestions for this problem. It would be great to be able to understand why it is happening.
Here is the code, I was trying to fit it into a comment didn't realize you had to post it by editing the original post.
public class Main extends Activity {
Game game;
private Menus menus; // contains menu info
int menu; //keep track of what menu you are at
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
game = new Game(this);
setContentView(game);
}
#Override
public void onDestroy() {
super.onDestroy();
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
..some code here to process photo files
}
//get the orientation of loaded pictures
public static int getOrientation(Context context, Uri photoUri) {
/* it's on the external media. */
Cursor cursor = context.getContentResolver().query(photoUri,
new String[] { MediaStore.Images.ImageColumns.ORIENTATION }, null, null, null);
if (cursor.getCount() != 1) {
return -1;
}
cursor.moveToFirst();
return cursor.getInt(0);
}
public void Keyboard()
{
use keyboard listener and perform some actions if...
}
public class Game extends ImageView{
private Game game;
//Touch Events
boolean pressed;
private Context mContext;
private Handler h;
private final int FRAME_RATE = 10;
boolean initDimension = false;
//constant for defining the time duration between the click that can be considered as double-tap
static final int MAX_DURATION = 500;
Bitmap background;
int HEIGHT;
int WIDTH;
public Game(Context context) {
super(context);
mContext = context;
h = new Handler();
//ModeInit(); // load up puck game mode
menu = 0; //after tap from ontouch changes to menu = 1 for game
}
private Runnable r = new Runnable() {
#Override
public void run() {
invalidate();
}
};
#Override
public boolean onTouchEvent(MotionEvent e)
{
Switch Statement...
CHECK MOTION EVENT TYPE
CHECK menu state.. perform action
}
public void ModeInit()
{
game = new Game( mContext, WIDTH, HEIGHT );
}
protected void onDraw(Canvas c)
{
if(!initDimension)
{
WIDTH = this.getWidth();
HEIGHT = this.getHeight();
initDimension = true;
}
else
{
//logo screen
if(menu == 0)
{
menu = menus.DisplayIntro(c);
}
//game mode
else if(menu == 1)
{
game.paint_game(c);
long run_test = System.nanoTime()/1000;
game.Move();
Log.d("run time: ",": "+(System.nanoTime()/1000-run_test)); //Ontouch LAG TEST
}
... other menu items here
}
h.postDelayed(r, FRAME_RATE);
}
}
}

Android use thread to draw every 4 seconds

I am quite new to Android and want to create a simple game.
Therefor i need a thread which is drawing a transparent Rectangle on different positions every 4 seconds with a 2 second break (without drawing).
I got it working with a "recursive" thread calling a new instance of itself with handler.postdelayed.
My feeling about threads tells me, that this isn't a very nice way...
While searching here for similar topics, i found out about the Timer construct. Can i use this for my problem?
Is there a better way to do this?
(edit) The thread is meant for highlighting part of the gameboard, but only for 4 seconds. After that there should be 2 seconds without highlighting. Then 4 seconds highlighting the next part of the board etc.
(edit2) I couldn't use sleep, because it froze my UI. If anyone has a similar situation, here is how i solved it:
public class myRunnable implements Runnable {
private int duration;
private int counter;
private boolean highlight;
public myRunnable(int duration, boolean highlight) {
this.duration = duration;
this.highlight = !highlight;
}
#Override
public void run() {
if (highlight) {
// highlight 4s long
highlight();
invalidate();
myThread = new myRunnable(duration, highlight);
postDelayed(myThread, duration);
} else {
// pause (2s)
resetHighlight();
invalidate();
myThread = new myRunnable(duration, highlight);
postDelayed(myThread, noHighlightDuration);
}
}
}

The Best way to do this is use to use invalidate() to call the onDraw() function and a method to update the position. Something like this-
int x,y;
protected void onDraw(Canvas canvas) {
x=10;
y=10;
canvas.drawRect(___);
update();
invalidate();
}
private void update()
{/*Change the x and y/*}
Here everytime inavlidate() is called from anywhere the onDraw() is called again with the new x and y.

AndEngine move two objects simultaneously

I am creating a game using Andengine and in this I want an object flying in the sky to drop bombs below. Currently I am using a timehandler to create both the flying object and the bombs. But its not working properly. The problems I am facing are:
1) Sometimes instead of a single bomb 2 or 3 bombs are dropped.
2) And the bomb objects are also not getting recycled. The code for recycling the object is getting called, but it doesn't seem to work.
I have noticed one thing i.e. suppose, initially I have one flying object that drops a bomb. When the bomb leaves the screen, the recycling code for bomb object gets called once. And after sometime as the flying object leaves the screen it also gets recycled. Now when another flying object is created and it drops the bomb, the code for recycling the bomb is getting called twice. Then for third flying object, the code for recycling the single bomb is getting called thrice and so on.
The code to add flying object is as follows
private void createDragonHandler() {
TimerHandler spriteTimerHandler;
float mEffectSpawnDelay = 10f;
spriteTimerHandler = new TimerHandler(mEffectSpawnDelay, true,
new ITimerCallback() {
#Override
public void onTimePassed(TimerHandler pTimerHandler) {
addDragon();
}
});
getEngine().registerUpdateHandler(spriteTimerHandler);
}
public void addDragon() {
Dragon dragon = (Dragon) dragonSpritePool.obtainPoolItem();
if (dragon.getParent() != mainScene)
mainScene.attachChild(dragon);
}
public synchronized Dragon obtainPoolItem() {
dragon = super.obtainPoolItem();
Random rand = new Random();
final int x = (int) (CAMERA_WIDTH + resourceManager.dragonTextureRegion
.getWidth());
int minY = (int) resourceManager.dragonTextureRegion.getHeight();
int maxY = (int) (CAMERA_HEIGHT / 2 - resourceManager.dragonTextureRegion
.getHeight());
int rangeY = maxY - minY;
final int y = rand.nextInt(rangeY) + minY;
dragon.reset();
dragon.setVisible(true);
dragon.setIgnoreUpdate(false);
dragon.animate(150);
dragon.setPosition(x, y);
MoveXModifier mod = new MoveXModifier(15, dragon.getX(),
-dragon.getWidth());
float mEffectSpawnDelay = 5f;
TimerHandler spriteTimerHandler = new TimerHandler(mEffectSpawnDelay,
true, new ITimerCallback() {
#Override
public void onTimePassed(TimerHandler pTimerHandler) {
DragonFire dragonFire = BirdShoot.dragonFireSpritePool
.obtainPoolItem(dragon.getX(), dragon.getY());
BirdShoot.mainScene.attachChild(dragonFire);
}
});
dragon.registerEntityModifier(mod.deepCopy());
dragon.setNoHit(0);
PhysicsHandler mPhysicsHandler;
mPhysicsHandler = new PhysicsHandler(dragon);
dragon.setPhysicsHandler(mPhysicsHandler);
dragon.registerUpdateHandler(dragon.getmPhysicsHandler());
BirdShoot.engine.registerUpdateHandler(spriteTimerHandler);
return dragon;
}
`

Where are you writing the code for recycling the sprite objects? According to your problem, I see something fishy there. It might be possible that the code is not getting executed. The code to recycle the sprites must be something like this:-
public void onHandleRecycleItem(Sprite sprite){
super.onHandleRecycleItem(sprite);
// Your code to recycle the object
}
Also it should be called using the following line :
yourPool.recyclePoolItem(spriteObject);

Without seeing your code, it will be hard to help with this. But, this has the smell of things not being done on the updateThread.
Any time you do something that affects AndEngine, be sure you call it via
runOnUpdateThread(new Runnable() {
#Override
public void run() {
/* Do your AndEngine changes in here*/
}
});`

Resetting game trouble in AndEngine

I'm making a brick breaking game. I coded that when I pressed back button in-game, the game turns back to the main menu. And when I touch the Start button, I want to re-create the game. But my ball isn't moving after timer_StartCompletely is passed. In other words, my timer_ball isn't working. I have this code in my onBackPressed:
#Override
public void onBackPressed()
{
if(status == INGAME) {
scene.detachChildren();
moveBall = false;
status = MENU;
ballX = (kamera.getWidth()/2)-(32/2);
ballY = (kamera.getHeight()/2)-(32/2);
ballSpeed = 3.5f;
cx = (kamera.getWidth()/2)-(cubukTex.getWidth()/2);
cy = kamera.getHeight()-25;
this.mEngine.unregisterUpdateHandler(timer_ball);
this.mEngine.unregisterUpdateHandler(timer_club);
timer_ball.reset();
musicBackground.play();
}
}
My timer declaration:
timer_StartCompletely = new TimerHandler(0.5f, new ITimerCallback() {
#Override
public void onTimePassed(final TimerHandler pTimerHandler) {
mEngine.unregisterUpdateHandler(pTimerHandler);
mEngine.registerUpdateHandler(timer_ball);
}
});
In my timer_ball, I coded movement of ball (the ball must move certainly, if timer_ball is called).
I have also a touch event that I control the touching buttons and registering timer_StartCompletely.

When instantiating your TimerHandler, you can pass a parameter called pAutoReset (You didn't pass it, so false is passed:
public TimerHandler(final float pTimerSeconds, final ITimerCallback pTimerCallback) {
this(pTimerSeconds, false /*pAutoReset*/, pTimerCallback);
}
This parameter decides whether the TimerHandler should automatically reset itself after the time has passed (Which means that if you pass true, the callbacks are repeated).
The problem here: You didn't pass true, neither called the reset method of the TimerHandler. So if we look at the relevant code in TimeHandler.java:
if(!this.mTimerCallbackTriggered) {
this.mTimerSecondsElapsed += pSecondsElapsed;
if(this.mTimerSecondsElapsed >= this.mTimerSeconds) {
this.mTimerCallbackTriggered = true;
this.mTimerCallback.onTimePassed(this);
}
}
Your callback executes once, and now mTimerCallbackTriggered is true, so it won't execute anymore.
Solution: Either call the reset method each time before registering the TimerHandler, or create it with pAutoReset = true.

Physics with Box2d and Andengine tutorial

Hello everyone I'm trying to develop a game like Jetpack so i want to set a gravity that normally push down and when the user tap the screen the gravity change it push up. I searched for a week a tutorial that explain how to do that but I didn't find what I search. Someone can explain me how to do that or post a link to a tutorial ?
Thank you !!
main = new Sprite(sX, sY, mainTextureRegion);
main.setScale(1);
main.setFlippedHorizontal(true);
scene.attachChild(main);
mPhysicsWorld = new PhysicsWorld(new Vector2(0, SensorManager.GRAVITY_EARTH), false);
final FixtureDef objectFixtureDef = PhysicsFactory.createFixtureDef(1, 0.5f, 0.5f);
final Body body = PhysicsFactory.createBoxBody(mPhysicsWorld, main, BodyType.DynamicBody, objectFixtureDef);
mPhysicsWorld.registerPhysicsConnector(new PhysicsConnector(main, body, true, true));
final Vector2 gravity = new Vector2(0, 5f);
mPhysicsWorld.setGravity(gravity);
scene.registerUpdateHandler(new IUpdateHandler() {
#Override
public void onUpdate(float pSecondsElapsed) {
}
#Override
public void reset() {
// TODO Auto-generated method stub
}});

When the user touches the screen, you shouldn't change the gravity because it is not suppose to be done like that.
When he touches the screen, just apply a LinearImpulse (check if it not already at maximum speed) or something like that to make it go upper. The gravity shouldn't change as it should always attract all of your physics objects down. If your change the gravity you change the behavior of all your objects, not only the player one.
EDIT
To have the physics engine to work you have to call the step() method of the PhysicsWorld class at each render. The problem with Andengine is that you don't directly access the render() method as Andengine handle it at all.
So what you have to do is to register a IUpdateHandler on the Engine object that you return in your onLoadEngine() method.
This way the onUpdate() method of the interface will be called at each render and here you can call the step() method to get the physics part to work. The float value tells you about how many seconds elapsed since last render but you don't have to take care of that. The method is called multiple times per second.
Hope it helps.
EDIT 2
I think this should work :
//on the Scene object or on the Engine one
scene.registerUpdateHandler(new IUpdateHandler() {
#Override
public void onUpdate(float pSecondsElapsed) {
mPhysicsWorld.onUpdate(pSecondsElapsed);
}
#Override
public void reset() {}
});