Random number generator with no duplicate - android

I am having a hard time trying to ensure no duplicates numbers appear in the following code below. I tried to create an ArrayList to add all the possible index of the array and then gradually remove the values of the array from the List as more elements are generated by the number generator. This; however, didnt work as I expected. I've been trying to think about it but Haven't been able to come up with a viable solution.
Random randGen = new Random();
public boolean onTouchEvent(MotionEvent touchevent) {
switch (touchevent.getAction()) {
case MotionEvent.ACTION_DOWN: {
x1 = touchevent.getX();
y1 = touchevent.getY();
break;
}
case MotionEvent.ACTION_UP: {
x2 = touchevent.getX();
y2 = touchevent.getY();
int maxLength=exampleArray.length;
List<Integer>indices=new ArrayList<Integer>(maxLength);
for(int i=0;i<maxLength;i++){
indices.add(i);
}
int randomApple = randGen.nextInt(exampleArray.length);
int randomNum=indices.get(randomApple) ;
indices.remove(randomApple);
textView.setText(exampleArray[randomNum]);
if (x1 < x2) {
}
if (x1 > x2) {
//textView.setText(exampleArray[randomNum]);
}
}
}
return false;
}

I think you are missing some steps and adding extraneous ones....
One simple way (if you don't care whether the numbers keep going up) is to keep adding a random positive value to a counter. That way the new counter will always be different.
If you do:
Another way to do this is to creating a list of numbers beforehand (either sequentially [1, 2, 3...] or you randomly add some amount to each new index [rnd1, rnd1 + rnd2, rnd1 + rnd2 + rnd3...]), randomizing the ordering by shuffling the numbers (click this!), and then simply iterating through the created array.

Related

Android Multitouch Strange Behavior

After a lot of tinkering, I think I've finally come up with a good multitouch handling system for my android game. It makes use of Robert Greene's Input Pipeline, modified for use with multitouch. Right now, the code has a simple system that records which pointer ID is currently doing which action (right now just shooting and moving). Each pointer's state is kept in a Pointer class, which is just a simple encapsulation of whether it is down, and it's coordinates. The ID acts as the pointer array index.
This seems like it should work well in practice, but in game it behaves very erratic. When recording the pointer actions in LogCat, oftentimes Android will send an "UP" action when the pointer remains down, or just before a number of "MOVE" actions by the pointer. Because my code believes the pointer is up, the game doesn't respond to it.
This also happens with button presses like the shooting button. When the pointer comes down on the area (which right now is just simply the lower left region), Android will send multiple "UP" and "DOWN" actions even though the pointer remains down the whole time. I had a single touch movement system before and none of these problems happened.
Is this just an issue with how I am reacting to the events? Should I handle POINTER_DOWN and DOWN separately? Or should I detect which pointers are moving after the "UP" action to see which ones really are down despite what Android says?
Here's my current code in my thread which receives the input events from Android. Because it is a pipeline system, I have the events encapsulated in the InputObject which is somewhat similar to Robert Greene's. Maybe a new set of eyes can help me tell what's wrong? Thanks for any help!
private int inx, iny;
private int shootID;
public boolean shooting = false;
private int moveID;
public boolean moveDown = false;
private static final int MAX_POINTERS = 10;
private Pointer[] pointers = new Pointer[MAX_POINTERS];
public void inputTouch(InputObject in) {
switch(in.action) {
case MotionEvent.ACTION_DOWN:
case MotionEvent.ACTION_POINTER_DOWN:
pointers[in.pID].press(in.pX[in.actionIndex], in.pY[in.actionIndex]);
//Log.i("D", "DOWN");
break;
case MotionEvent.ACTION_MOVE:
for(int p = 0; p < in.pointCount; p++) {
int id = in.pointerIDs[p];
pointers[id].setCoord(in.pX[id], in.pY[id]);
}
//Log.i("D", "MOVE");
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_POINTER_UP:
pointers[in.pID].release();
if(shootID == in.pID) {
shooting = false;
}
if(moveID == in.pID) {
moveDown = false;
}
//Log.i("D", "UP");
break;
case MotionEvent.ACTION_CANCEL:
default:
break;
}
for(int ap = 0; ap < MAX_POINTERS; ap++) {
if(pointers[ap].down) {
if(pointers[ap].x < world.cam.pixelWidth / 4 &&
pointers[ap].y > world.cam.pixelHeight - (world.cam.pixelHeight / 4)) {
shootID = ap;
shooting = true;
} else {
inx = pointers[ap].x;
iny = pointers[ap].y;
moveID = ap;
moveDown = true;
}
}
}
StringBuilder sb = new StringBuilder();
for(int j = 0; j < 3; j++) {
sb.append("ID " + (j+1) + ": " + pointers[j].down + "[" + pointers[j].x + ", " + pointers[j].y + "]" + " | ");
}
//Log.i("D", sb.toString());
}
Hope you got the answer by now, but here''s my solution:
First of all, there's a couple of things to add in the InputHolder class:
-internal public fields for mPointerIndex = event.getPointerIndex and mPointerID = event.getPointerID(mPointerIndex) (these get assigned in the useEvent/useHistory)
-if you only need to track 2 touchpoints, you need to add mPointerIndex2, x2 and y2 aswell. Add more as you need to track more points.
-add definitions for the case where MotionEvent.ACTION_POINTER_2_UP/DOWN gets passed. Turns out, POINTER_1 is the same as POINTER_UP/DOWN! This really tripped me up because I was falling through the switch case to the default. I only caught this because I changed my default to -1 and saw it logged.
Depending on how you process the actions in your processInput(obj), you map these to different ints. In my case I used the obj.y to see if they where left/right touches and I only needed two points, so I mapped these to ACTION_TOUCH_POINTER_UP/DOWN instead of giving each touch it's own action int identifier.
-now, if you want to track multiple touch points, you would have to do the above and the below in a for loop over all entries in event.getPointerCount(). In my case I was only interested in the x/y of one other touchpoint, so I could get away with only doing a check after I had filled the first point and the other pointerindex was easy to deduce:
public void useEvent(MotionEvent event) {
eventType = EVENT_TYPE_TOUCH;
int a = event.getAction();
switch (a) {
case MotionEvent.ACTION_DOWN:
action = ACTION_TOUCH_DOWN;
break;
case MotionEvent.ACTION_POINTER_DOWN:
action = ACTION_TOUCH_POINTER_DOWN;
break;
case MotionEvent.ACTION_POINTER_2_DOWN:
action = ACTION_TOUCH_POINTER_DOWN;
break;
case MotionEvent.ACTION_MOVE:
action = ACTION_TOUCH_MOVE;
break;
case MotionEvent.ACTION_UP:
action = ACTION_TOUCH_UP;
break;
case MotionEvent.ACTION_POINTER_UP:
action = ACTION_TOUCH_POINTER_UP;
break;
case MotionEvent.ACTION_POINTER_2_UP:
action = ACTION_TOUCH_POINTER_UP;
break;
default:
action = -1;
}
time = event.getEventTime();
pointerIndex = (event.getAction() & MotionEvent.ACTION_POINTER_ID_MASK) >> MotionEvent.ACTION_POINTER_ID_SHIFT;
pointerID = event.getPointerId(pointerIndex);
x = (int) event.getX(pointerIndex);
y = (int) event.getY(pointerIndex);
if (event.getPointerCount() > 1)
{
pointerIndex2 = pointerIndex== 0 ? 1 : 0;
x2 = (int)event.getX(pointerIndex2);
y2 = (int)event.getY(pointerIndex2);
}
}
If you''re tracking more points, or need more information about each touchevent, you have to extend the for loop up over the action switch case.
Anyway, now you need two variables in your thread so you can keep track of your two touches: call 'em touchOneID and touchTwoID (or index). On an ACTION_POINTER_2_UP, the obj.mPointerID refers to the obj which is going UP! This means that the other touch will change it's ID! Keep track of this change, and you're sorted. The internal obj's mPointerID/Index will always be correct, you just have to track them correctly in your surfaceview's thread so you can act accordingly to when you get a POINTER_DOWN. In my case, I did a simple x position check to determine what to do in my ACTION_MOVE event which told me enough to correctly determine which x/y or x2/y2 I should use and how to use it. This meant less code to run and limits to the things I had to keep in memory, but it all depends on what and how much information you need.
Finally:
To be honest, if you handled the definitions correctly and assigned every MotionEvent and held them in the InputObject, you'd probably be fine. Hell, I think you can ignore and lose the whole switch case and just say obj.mAction = event.getAction() and handle these in your processInput(obj)!
Meaning, all those static ints he's remapping to in the InputHolder seem unnecessary, unless you really only need one or two touch definitions (which explains his mysterious standalone comment of "this app is only interested in down touches"). Getting rid of those statically defined ints also means you can just test against MotionEvent.ACTION_CODE instead of doing a lookup against InputHolder.TOUCH_ACTION_CODE.

Add dynamic path to sprite

I have to move the sprite along the path that is drawn onTouch.For that I'm using Path and PathModifier
case MotionEvent.ACTION_UP:
int historySize = pSceneTouchEvent.getMotionEvent().getHistorySize();
pointX = new float[historySize];
pointY = new float[historySize];
for (int i = 1; i < historySize; i++) {
pointX[i] = pSceneTouchEvent.getMotionEvent().getHistoricalX(i);
pointY[i] = pSceneTouchEvent.getMotionEvent().getHistoricalY(i);
}
path = new path(pointX,pointY);
PathModifier pathModifier = new PathModifier(2.5f, path);
pathModifier.setRemoveWhenFinished(true);
sprite1.clearEntityModifiers();
sprite1.registerEntityModifier(pathModifier);
break;
Its giving me error as path needs at least 2 way points.
Any idea why so?
Normally this shouldn't happen, since a motion event is very often more than just one coordinate. Maybe you should test if the historySize is really bigger than 2. In addition you can add the sprites starting coordinates, otherwise the sprite would "jump" towards the first touch point (but that wasn't your question).
This isn't actually different – just another possibility:
path= new Path(historySize);
for (int i = 0; i < historySize; i++) {
float x = pSceneTouchEvent.getMotionEvent().getHistoricalX(i);
float y = pSceneTouchEvent.getMotionEvent().getHistoricalY(i);
path.to(x,y);
}
In addition I noticed you start your for-loop with int i=1 so if your historySizeis 2, the loop iterates only one times!
EDIT
I couldn't find the problem, but I found a solution:
Instead of using the motionEvent history, save the coordinates of the toucheEvent on the go as the touchEventoccurs:
ArrayList<Float> xCoordinates; // this is where you store all x coordinates of the touchEvents
ArrayList<Float> yCoordinates; // and here will be the y coordinates.
onSceneTouchEvent(TouchEvent sceneTouchEvent){
switch(sceneTouchEvent.getAction()){
case (TouchEvent.ACTION_DOWN):{
// init the list every time a new touchDown is registered
xCoordinates = new ArrayList<Float>();
yCoordinates = new ArrayList<Float>();
break;
}
case (TouchEvent.ACTION_MOVE): {
// while moving, store all touch points in the lists
xCoordinates.add(sceneTouchEvent.getX());
yCoordinates.add(sceneTouchEvent.getY());
break;
}
case (TouchEvent.ACTION_UP): {
// when the event is finished, create the path and make the sprite move
// instead of the history size use the size of your own lists
Path path = new Path(xCoordinates.size());
for (int i = 0; i < xCoordinates.size(); i++) {
path.to(xCoordinates.get(i), yCoordinates.get(i)); // add the coordinates to the path one by one
}
// do the rest and make the sprite move
PathModifier pathModifier = new PathModifier(2.5f, path);
pathModifier.setAutoUnregisterWhenFinished(true);
sprite1.clearEntityModifiers();
sprite1.registerEntityModifier(pathModifier);
break;
}
}
I tested this on my phone (which does not run in debug mode) and it works fine. But to make sure that no Exception will be thrown, you should always test if the xCoordinates list is bigger than 1. Although it is very probable that it is.
Well I hope it helps at least to go around your original problem. I noticed that some methods are named differently (e.g. setAutoUnregisterWhenFinished(true);) I guess you are using AndEngine GLES1 ? I use GLES2, so when a method has another name in my code, don't worry and just look for the equivalent in GLES1 (I didn't rename them because, the code works as it is)
Christoph

Can i use motionEvent .getRawY() with View . getTop()?

Im making a program about the game Go and im trying to write some code to allow a person to place a bead, which really just shows an invisible bead. But after an hour of going back and forth with it i just cant seem to figure out why the Y coordinate of my motionevent always seems 2 rows down from where it needs to be.
My code for filling my array
for(int y=0; y< 9;y++)
{
for(int x=0;x<9;x++)
{
String name="Whitebead" + ((9*y)+x+2); //The +2 is because of a naming problem
WhitePieces[x][y]=(ImageView) findViewById(getResources().getIdentifier(name, "id", getPackageName()));
}
}
My code for handling motion events
#Override
public boolean onTouchEvent(MotionEvent e)
{
if(e.getAction() == MotionEvent.ACTION_DOWN)
{
float X=e.getRawX();
float Y=e.getRawY();
if(X>Board.getLeft() && X<Board.getRight())
if(Y< Board.getTop() && Y>Board.getBottom());
player1.placepiece(X, Y);
}
return super.onTouchEvent(e);
}
And finally my code that resolves which bead to what coordinate
public void placepiece(float X, float Y)
{
int[] pieceindex=resolvePiece(X,Y);
pieces[pieceindex[0]][pieceindex[1]].setVisibility(ImageView.VISIBLE);
}
private int[] resolvePiece(float x, float y) {
int Xindex=0;
int[] oldcoords= new int[2]; //cordinates are like so {xCoord, Ycoord}
int[] newcoords= new int[2];
oldcoords[0]=pieces[0][0].getLeft(); //set the oldcoordinates to the first index
oldcoords[1]=pieces[0][0].getTop();
for(int i=1; i<9;i++) //go through the 9 indexs to find the closest X value
{
newcoords[0]=pieces[i][0].getLeft();
newcoords[1]=pieces[i][0].getTop();
if(Math.abs((int)x-newcoords[0])<Math.abs((int)x-oldcoords[0]))
{
Xindex=i;
oldcoords[0]=newcoords[0];
}
}
int Yindex=0;
oldcoords[0]=pieces[0][0].getLeft(); //Reset oldcoords again
oldcoords[1]=pieces[0][0].getTop();
for(int n=1; n<9;n++) //Go through the 9 indexes for the closest Y value
{
newcoords[0]=pieces[0][n].getLeft();
newcoords[1]=pieces[0][n].getTop();
if(Math.abs((int)y-newcoords[1])<Math.abs((int)y-oldcoords[1]))
{
Yindex=n;
oldcoords[1]=newcoords[1];
}
}
int[] rInt= new int[]{Xindex,Yindex};
return rInt;
}
//////EDIT: Fixed
I figured it out, at the top of the android window is about and inch of space where the title and battery life and stuff go, when you get motion coordinates it takes in the whole screen, where .getTop() only gets from where linear layout Starts. SO instead of using .getTop or.getLeft i used .getLocationInWindow(oldcoord[]) and it places the info i needed into my oldcoord array.
//////EDIT: Fixed I figured it out, at the top of the android window is about and inch of space where the title and battery life and stuff go, when you get motion coordinates it takes in the whole screen, where .getTop() only gets from where linear layout Starts. SO instead of using .getTop or.getLeft i used .getLocationInWindow(oldcoord[]) and it places the info i needed into my oldcoord array.

Iteration error when started from 1st one to last one i.e in normal way

#Override
public boolean onTouchEvent(MotionEvent event)
{
if (System.currentTimeMillis() - lastClick > 300)
{
lastClick = System.currentTimeMillis();
synchronized (getHolder()) {
for (int i = sprites.size() - 1; i >= 0; i--) <-------why in reverse?
{
Sprite sprite = sprites.get(i);
if (sprite.isCollition(event.getX(), event.getY()))
{
sprites.remove(sprite);
break;
}
}
}
But when i iterate from lastone to firstone i.e in reverse order it gives the result.why ..? Need help
It's because you are removing the sprites while inside the for loop. When you alter the number of objects in the loop when moving forward, you stuff up the iteration. When you remove the current element, all elements found in the list after this element (and still to be enumerated through) are now shifted down an index, i.e. the element that was at index i+1 is now at index i.
If you are removing from the loop you are iterating through, the correct way is to iterate in reverse, like you have found out. That way when you remove the current element, all other elements to still be enumerated through are still at the same index.

Multiple finger input for android development

After getting the calculator application to work I decided to try to create pong. There is a box in the center and two paddles on both ends. The phone is horizontal. I have the box bouncing off the walls and the paddle moves with me moving my finger down. My problem is i want to make it two player and i want to have multiple finger input for the game. I want one finger to move paddle 1 and the other to move paddle 2. So far this is my input code
#Override
public boolean onTouchEvent(MotionEvent ev) {
final int action = ev.getAction();
switch (action) {
case MotionEvent.ACTION_MOVE: {
// Find the index of the active pointer and fetch its position
float p1y = ev.getY();
if(ev.getX()<300)
{
player1y = p1y;
}
if(ev.getX()>300)
{
player2y = p1y;
}
//player1y = p1y;
invalidate();
break;
}
}
return true;
}
it resides in my surfaceview class. How can i modify the input method or completely get rid of it and change it to accomplish my goal? Also sorry about my variables. Eclipse crashes a lot on me and my laptops touch panel tends to move my cursor so shorter variables seemed viable. p1y is the y of the touch. and player1y and player2y is the y positions of the player1 and player2 paddle.
A MotionEvent can hold multiple pointers. Use getPointerCount() to see how many pointers are touching the screen in the current event. There are alternate versions of getX and getY that take an index from 0-getPointerCount() - 1.
In a more complex app you would want to track fingers by pointer ID, but for something this simple where you are using a cutoff point on the screen you could do something like this in your ACTION_MOVE case:
int pointerCount = ev.getPointerCount();
for (int i = 0; i < pointerCount; i++) {
float x = ev.getX(i);
float y = ev.getY(i);
if (x < 300) {
player1y = y;
} else if (x > 300) {
player2y = y;
}
}
This post from the Android Developers Blog might help if you'd like more information: http://android-developers.blogspot.com/2010/06/making-sense-of-multitouch.html

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