I am trying to make the ImageView missile1 to spawn at a random y-coordinate on the right edge of the screen and then move it left across the screen until it is off the screen, and finally move it back to a random y-coordinate on the right edge of the screen to repeat the process in an infinite loop. The code I have spawns the image at a totally random x and y coordinate location whenever the activity is restarted, but it doesn't move. Can anybody see why it doesn't move and give a solution to my problem? Some example code will be appreciated.
The thread that generates x and y coordinate values:
public class Missiles extends Thread {
private int height, width, currentscore;
private ImageView missile1, missile2, missile3, missile4, missile5;
Handler updatemissile = new Handler();
int min = 100;
RelativeLayout layout;
int setx1, sety1, setx2, sety2, setx3, sety3, setx4, sety4, setx5, sety5;
private Random rand = new Random();
TextView x, y;
Missiles(int screenheight, int screenwidth, ImageView missile01, ImageView missile02, ImageView missile03,
ImageView missile04, ImageView missile05, RelativeLayout rl, TextView xtext, TextView ytext) {
missile1 = missile01;
missile2 = missile02;
missile3 = missile03;
missile4 = missile04;
missile5 = missile05;
height = screenheight;
width = screenwidth;
layout = rl;
x = xtext;
y = ytext;
}
public void updatevalue(int value) {
currentscore = value;
}
public void run() {
SetMissilePosition position = new SetMissilePosition(missile1, layout, x, y);
updatemissile.post(position);
//width is the width of the screen as height is the height of the screen
while (true) {
setx1 = width;
position.updateX(setx1);
int randomNum = rand.nextInt((height - min) + 1) + min;
sety1 = randomNum;
position.updateY(sety1);
while (setx1 > -50) {
setx1 = setx1 - 1;
position.updateX(setx1);
}
setx1 = width;
position.updateX(setx1);
}
}
}
The Runnable Class:
public class SetMissilePosition implements Runnable{
int x1,y1, updateindicator;
ImageView missile1;
RelativeLayout layout;
TextView x,y;
SetMissilePosition(ImageView missile01, RelativeLayout relativeLayout, TextView xtext, TextView ytext) {
missile1 = missile01;
layout = relativeLayout;
x = xtext;
y = ytext;
}
public void updateX( int setx1) {
x1 = setx1;
updateindicator = 1;
}
public void updateY(int sety1) {
y1 = sety1;
updateindicator = 1;
}
public void run() {
missile1.setImageResource(R.drawable.missileanim);
layout.addView(missile1);
if(updateindicator == 1) {
missile1.setX(x1);
missile1.setY(y1);
x.setText(Integer.toString(x1));
y.setText(Integer.toString(y1));
updateindicator = 0;
}
}
}
If I am being unclear in any way or you need more code such as my MainActivity, please ask. Thanks in advance!
It sounds like you're trying to update the UI thread from off of the UI thread.
If that's the route you want to go, I'd encourage you to take a look at the 'run on ui thread' operation. Essentially, when you want to update layout positions, you can just call getContext().runOnUiThread([runnable]) and that will update your position. See here for more information: https://developer.android.com/training/multiple-threads/communicate-ui.html Some things to bear in mind:
Android runs at 60fps, so you need to make sure you're updating every 16ms or so in order to match in sync with your framerate. Otherwise your speed will be off.
Instead of doing that, why not use a Translate animation: https://developer.android.com/reference/android/view/animation/TranslateAnimation.html
You can set starting and ending x and y coordinates, you can even use them as percentages of screenwidth and length, and set the animation to repeat infinitely. If repeating infinitely won't work because you want to pick new X (or Y) values each time, you can hook something up on the end of the animation to pick new values and restart.
I found the answer myself through lots of trial end error. What I did was Created an activity that extended surface view, added a bitmap to it, updated the images coordinates in a thread, and finally passed the coordinates into another thread which updated the screen 30 times a second.
Related
I am using a tutorial to understand how sprites work using a draw() method as well as using a gameloop. I adjusted the code as far as I understand it for my own project.
The question I have is how can I access a different row of my sprite sheet besides the second row. My sprite sheet has 9 columns and 20 rows.
public class Sprite implements Drawable {
private static final int BMP_COLUMNS = 9;
private static final int BMP_ROWS = 20;
private int x = 0;
private int y = 0;
private int xSpeed = 5;
private Bitmap bmp;
float fracsect = 30;
private GameContent gameContent;
private int currentFrame = 0;
private int width;
private int height;
public Sprite(GameContent gameContent, Bitmap bmp) {
this.gameContent = gameContent;
this.bmp = bmp;
this.width = bmp.getWidth() / BMP_COLUMNS;
this.height = bmp.getHeight() / BMP_ROWS;
}
#Override
public void update(float fracsec) {
if (x > gameContent.getGameWidth() - width - xSpeed) {
xSpeed = -5;
}
if (x + xSpeed < 0) {
xSpeed = 5;
}
x = x + xSpeed;
currentFrame = ++currentFrame % BMP_COLUMNS;
}
#Override
public void draw(Canvas canvas) {
update(fracsect);
int srcX = currentFrame * width;
int srcY = 1*height - 41;
Rect src = new Rect(srcX +20 , srcY,srcX + width,srcY + height-38); // Generates
Rect dst = new Rect(x,y,x+width -30, y+height-30); // Scales
canvas.drawBitmap(bmp, src, dst, null);
}
}
How do I gain access to the second row and how can I change it for instance to the third or 4th row ?
What I understand so far is that using a sprite as an object as a bitmap instead via imageview the code implementation of the code works differently. Is there any advice on how to access a different row for the sprite sheet ? I used the android documentation as well as the tutorial to understand this process as far as I can.
Here is the tutorial also:
http://www.edu4java.com/en/androidgame/androidgame4.html
From what I can see you are iterating through the first row, drawing each sprite in turn, perhaps to create an animation.
If you want to draw the animation for the second row, you can simply add 'height' to 'srcY'. It looks like you had this idea but you substracted instead of adding. Remember that Y-coordinates on computers go from top to bottom (i.e. (0,0) is top-left, (0, 10) is 10 pixels lower).
Likewise for the third and fourth rows, just add 'height' to 'srcY' again.
This is my first question and I'll try to make it as clear as possible. Please forgive me if someone asked a similar question before (I checked but found nothing).
I'm trying to create my first android application in java. It's a small game with a character on the left side of the screen (landscape mode) and a background which goes from right to left giving the impression of movement. The speed of the background is meant to be constant.
I used a Background class which looks like this:
public class Background {
int x=0, y=0;
Bitmap background;
Background(int screenX, int screenY, Resources res){
background = BitmapFactory.decodeResource(res, R.drawable.background);
background = Bitmap.createScaledBitmap(background, screenX, screenY, false);
}
}
then in the GameView Class I create 2 background objects
private Background background1, background2;
and in the constructor:
background1 = new Background(screenX, screenY, getResources());
background2 = new Background(screenX, screenY, getResources());
//both backgrounds are the same picture
background2.x = screenX;
paint= new Paint();
finally:
private void update(){
background1.x -=2 * screenRatioX;
background2.x -=2 * screenRatioX;
//both have the same speed
if (background1.x + background1.background.getWidth()<0){
background1.x = screenX;
// to make it reappear on the right side when it vanishes on the left side
}
if (background2.x + background2.background.getWidth()<0){
background2.x = screenX;
}
}
I hope it's clear and that someone will be able to help me.
Edit: I actually solved it by giving background2 a x position relative to the position of background1
private void update(){
background1.x =(int)(background1.x - (2 * screenRatioX));
if(background1.x < background2.x) {
background2.x = background1.x + background1.background.getWidth();}
//(int)(background2.x - (2 * screenRatioX));
else {background2.x =background1.x-background1.background.getWidth();
}
if (background1.x + background1.background.getWidth()<0){
background1.x = background2.x + background2.background.getWidth();
}
if (background2.x + background2.background.getWidth()<0){
background2.x = background1.x+background1.background.getWidth();
}
I'm still interested in understanding why this happened before. Thank you all
I am trying to make a multiple enemy array, where every 30 secods a new bullet comes from a random point. And if the bullet is clicked it should disapear and a pop like an explosion should appear. And if the bullet hits the ball then the ball pops.
so the bullet should change to a different sprite or texture. same with the ball pop.
But all that happens is the bullet if touched pops and nothing else happens. And if modified then the bullet keeps flashing as the update is way too much.
I have added COMMENTS in the code to explain more on the issues.
below is the code.
if more code is needed i will provide.
Thank you
public class GameRenderer {
private GameWorld myWorld;
private OrthographicCamera cam;
private ShapeRenderer shapeRenderer;
private SpriteBatch batcher;
// Game Objects
private Ball ball;
private ScrollHandler scroller;
private Background background;
private Bullet bullet1;
private BulletPop bPop;
private Array<Bullet> bullets;
// This is for the delay of the bullet coming one by one every 30 seconds.
/** The time of the last shot fired, we set it to the current time in nano when the object is first created */
double lastShot = TimeUtils.nanoTime();
/** Convert 30 seconds into nano seconds, so 30,000 milli = 30 seconds */
double shotFreq = TimeUtils.millisToNanos(30000);
// Game Assets
private TextureRegion bg, bPop;
private Animation bulletAnimation, ballAnimation;
private Animation ballPopAnimation;
public GameRenderer(GameWorld world) {
myWorld = world;
cam = new OrthographicCamera();
cam.setToOrtho(true, 480, 320);
batcher = new SpriteBatch();
// Attach batcher to camera
batcher.setProjectionMatrix(cam.combined);
shapeRenderer = new ShapeRenderer();
shapeRenderer.setProjectionMatrix(cam.combined);
// This is suppose to produce 10 bullets at random places on the background.
bullets = new Array<Bullet>();
Bullet bullet = null;
float bulletX = 00.0f;
float bulletY = 00.0f;
for (int i = 0; i < 10; i++) {
bulletX = MathUtils.random(-10, 10);
bulletY = MathUtils.random(-10, 10);
bullet = new Bullet(bulletX, bulletY);
AssetLoader.bullet1.flip(true, false);
AssetLoader.bullet2.flip(true, false);
bullets.add(bullet);
}
// Call helper methods to initialize instance variables
initGameObjects();
initAssets();
}
private void initGameObjects() {
ball = GameWorld.getBall();
bullet1 = myWorld.getBullet1();
bPop = myWorld.getBulletPop();
scroller = myWorld.getScroller();
}
private void initAssets() {
bg = AssetLoader.bg;
ballAnimation = AssetLoader.ballAnimation;
bullet1Animation = AssetLoader.bullet1Animation;
ballPopAnimation = AssetLoader.ballPopAnimation;
}
// This is to take the bullet away when clicked or touched.
public void onClick() {
for (int i = 0; i < bullets.size; i++) {
if (bullets.get(i).getBounds().contains(0, 0))
bullets.removeIndex(i);
}
}
private void drawBackground() {
batcher.draw(bg1, background.getX(), background.getY(), background.getWidth(), backgroundMove.getHeight());
}
public void render(float runTime) {
Gdx.gl.glClearColor(0, 0, 0, 1);
Gdx.gl.glClear(GL30.GL_COLOR_BUFFER_BIT);
batcher.begin();
// Disable transparency
// This is good for performance when drawing images that do not require
// transparency.
batcher.disableBlending();
drawBackground();
batcher.enableBlending();
// when the bullet hits the ball, it should be disposed or taken away and a ball pop sprite/texture should be put in its place
if (bullet1.collides(ball)) {
// draws the bPop texture but the bullet does not go just keeps going around, and the bPop texture goes.
batcher.draw(AssetLoader.bPop, 195, 273);
}
batcher.draw(AssetLoader.ballAnimation.getKeyFrame(runTime), ball.getX(), ball.getY(), ball.getWidth(), ball.getHeight());
// this is where i am trying to make the bullets come one by one, and if removed via the onClick() then bPop animation
// should play but does not???
if(TimeUtils.nanoTime() - lastShot > shotFreq){
// Create your stuff
for (int i = 0; i < bullets.size; i++) {
bullets.get(i);
batcher.draw(AssetLoader.bullet1Animation.getKeyFrame(runTime), bullet1.getX(), bullet1.getY(), bullet1.getOriginX(), bullet1.getOriginY(), bullet1.getWidth(), bullet1.getHeight(), 1.0f, 1.0f, bullet1.getRotation());
if (bullets.removeValue(bullet1, false)) {
batcher.draw(AssetLoader.ballPopAnimation.getKeyFrame(runTime), bPop1.getX(), bPop1.getY(), bPop1.getWidth(), bPop1.getHeight());
}
}
/* Very important to set the last shot to now, or it will mess up and go full auto */
lastShot = TimeUtils.nanoTime();
}
// End SpriteBatch
batcher.end();
}
}
Thank you
Hmm...why are you drawing graphics from inside of the if where you are adding new bullets? This way all you draw will be drown only one frame per 30 seconds. Inside that if you should only add/remove objects and draw them outside, all the time. No drawing inside that if!
In addition to MilanG's answer
The bullets.get(i); line does nothing.. You'll want to store the returned Bullet into a variable, for which it seems you created the bullet1 var.
Also, you really shouldn't add elements to or remove elements from an array while looping through it. Consider using a second array for elements to be added/removed and use that to alter the main array or use an iterator.
[edit]
In this particular case you could also do something like this, though it would only work for one bullet per click
int index = -1;
for (int i = 0; i < bullets.size; i++) {
if (bullets.get(i).getBounds().contains(0, 0)) {
index = i;
break;
}
}
if(index > -1) bullets.removeIndex(index);
It also seems your .contains() should be passed the clicked position instead of 0,0?
I want to set margin of Imageview. What I wanted to achieve is to move one image up to some distance. The content of screen is RelativeLayout, in that there is ImageView at left and button at right aligned. Now I want to move image from left to right within the gap between Image and Button in 100 click of button. The code I am following is as below:
private static int count= 1 ;
public void onClick(View view) {
RelativeLayout lay = (RelativeLayout)findViewById(R.id.layout1);
ImageView i1= (ImageView)findViewById(R.id.img1);
ImageButton btn= (ImageButton)findViewById(R.id.iBtn);
int i1Width = i1.getWidth();
int btnWidth = btn.getWidth();
int totalMragine = lay.getWidth() - i1Width - btnWidth ; //the total margine image will move.
int stepSize = (lay.getWidth() - i1Width - btnWidth ) / 100;
int step = stepSize * count++;
Log.i("i1Width ", ""+i1Width );
Log.i("btnWidth ", ""+btnWidth );
Log.i("lay.getWidth()", ""+lay.getWidth());
Log.i("stepSize", ""+stepSize);
Log.i("count", ""+count);
LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
lp.setMargins(step, 0, 0, 0);
i1.setLayoutParams(lp);
LinearLayout.LayoutParams lp1 = (LinearLayout.LayoutParams) horse.getLayoutParams();
Log.i("currentMargine", ""+lp1.leftMargin);
if(lp1.leftMargin >= totalMragine ){
Log.i("Result", "maringe over");
}
}
What I wanted to know that the margin I am setting is in Integer but the value for the step is in float. So How to set margin float in LayoutParams? or is there any other way to do this?
you can do one thing calculate distance to move every time as when going to move
distance to move = the rest of length/rest of clicks
of in final step (100th step) it will reach to end with error < . 5px and . 5px is too small )
like in
1st click distance_to_move = 370/100; as round off come 4
2nd click distance_to_move = 366/99; as round off come 4
3rd click distance_to_move = 362/98; as round off come 4
so movemnt will be as in px 44444...3444...3444..3444...
Wonder if anyone could point me in the right direction.
I want to be able to animate an object like a bullet from a static position to any area on the screen.
I have no problem with simple horizontal and vertical movements. I.e. x +/- 1 or y +/- 1.
But when it comes to an object like a bullet could move/animate at any degree I'm not quite sure how to do this by making the animation look smooth. For example at 18, 45, or 33 degree angle an algorithm like y+1, x+1, y+1..... Is not going to make the animation very smooth.
Thanks in advance
P.s maybe there is some documentation out there already?
Update
Thanks to everyone who has replied.
This is the code I have so far based on your comments.
package com.bullet;
//imports go here
public class canvas extends SurfaceView implements OnTouchListener, SurfaceHolder.Callback{
private Bitmap bullet;
private int bulletStartX, bulletStartY;
private int bulletX, bulletY;
private int bulletEndX = -1;
private int bulletEndY = -1;
private int incX = 0;
private int incY = 0;
private SurfaceHolder holder;
private Thread t;
public canvas(Context context) {
super(context);
this.setBackgroundColor(Color.WHITE);
setFocusable(true);
setFocusableInTouchMode(true);
setOnTouchListener(this);
bulletStartX = 0;
bulletStartY = 0;
bulletX = bulletStartX;
bulletY = bulletStartY;
bullet = BitmapFactory.decodeResource(getResources(), R.drawable.bullet);
holder = getHolder();
holder.addCallback(this);
}
public void onDraw(Canvas canvas){
if(bulletEndX != -1 && bulletEndY != -1){
Log.e("here", "drawing bullet");
Log.e("here", "x: " + bulletX + ", y: " + bulletY);
canvas.drawBitmap(bullet, bulletX, bulletY, null);
}
}
public void updateBullet(){
Log.e("here", "inc bullet");
bulletX += incX;
bulletY += incY;
if(bulletX > bulletEndX){
bulletEndX = -1;
}
if(bulletY > bulletEndY){
bulletEndY = -1;
}
}
#Override
public boolean onTouch(View v, MotionEvent event) {
int[] coordinates = {(int) event.getX(), (int) event.getY()};
int motion = event.getAction();
switch(motion){
case MotionEvent.ACTION_DOWN:
break;
case MotionEvent.ACTION_MOVE:
break;
case MotionEvent.ACTION_UP:
bulletX = bulletStartX;
bulletY = bulletStartY;
bulletEndX = (int) event.getX();
bulletEndY = (int) event.getY();
incX = (int) bulletEndX / 50;
incY = (int) bulletEndY / 50;
Log.e("here", "touch up");
break;
}
return true;
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO Auto-generated method stub
}
#Override
public void surfaceCreated(SurfaceHolder holder) {
t = new GameThread(this, holder);
t.start();
}
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
//Thread class
class GameThread extends Thread{
private canvas canvas;
private SurfaceHolder holder;
private boolean run = false;
long delay = 70;
public GameThread(canvas canvas, SurfaceHolder holder){
this.holder = holder;
this.canvas = canvas;
startThread(true);
}
public boolean isRunning(){
return this.run;
}
private void startThread(boolean run){
this.run = run;
}
public void stopThread(){
this.run = false;
}
#Override
public void run(){
while(run){
Canvas c = null;
try {
//lock canvas so nothing else can use it
c = holder.lockCanvas(null);
synchronized (holder) {
//clear the screen with the black painter.
//This is where we draw the game engine.
//Log.e("drawthread", "running");
if(bulletEndX != -1 && bulletEndY != -1){
updateBullet();
canvas.postInvalidate();
}
canvas.onDraw(c);
//Log.e("drawthread", "ran");
try {
sleep(32);
//Log.e("slept", "sleeping");
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
} finally {
// do this in a finally so that if an exception is thrown
// during the above, we don't leave the Surface in an
// inconsistent state
if (c != null) {
holder.unlockCanvasAndPost(c);
}
}
}
}
}
}
The drawing works pretty well, however there are two problems.
1. the drawing is fairly slow and jumpy... compared to something like this java example http://www.youtube.com/watch?v=-g5CyPQlIo4
2. If the click is on a position to close to Y = 0 then due to the value of ENDY / FRAME being less that 1, means that the round up is to 0 and the bullet travels across the top of the screen, rather than the ocassionaly increment in Y.
#SyntaxT3rr0r your right, that is prob the best way to go about it. But do you know of any documentation for implementing something like this?
Thanks again to everyone who replied
My understanding is that you're asking how to determine how many x&y pixels to move the bullet per frame, as opposed to asking about implementation details specific to animating on Android.
The short answer: Attack it with Math :P
With the example of the bullet:
-You can either chop up the animation as "divide up the animation into 100 frames, play them as fast as we can" or "Play the animation in about 2 seconds, smash as many frames in those 2 seconds as you can." I'm going to explain the former, because that sounds like what you're trying to do.
Start out with a starting X & Y, and an ending X & Y: Let's pretend you want to move from 0,0 to 200,400, and you want to do it in about 100 frames of animation.
Divide up the total distance travelled along the X axis by the number of frames. Do the same with total distance along Y axis. Now you have the distance to travel x & y for each frame. For this example, you want the bullet to move 2 pixels per frame (200 pixels / 100 frames) sideways, and 4 pixels per frame (400 pixels / 100 frames) vertically. So every frame, add x +=2, y+=4.
I suggest you to read the following articles:
View Animation and Property Animation
I don't think this can be answered in it's current form. First how are you animating? are you using the graphics API? GL? AndEngine?
If is graphics API I would rotate the canvas the appropriate degree and move the bullet up the y axis.
For GL you can do the same thing.
For and engine, refer to the tutorials.