Develop Reference

Android studio, if button doesn't have drawable

b4.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (b4.getCompoundDrawables() == null) {
if (turn == 1) {
turn = 2;
b4.setBackgroundResource(R.drawable.iks);
} else if (turn == 2) {
turn = 1;
b4.setBackgroundResource(R.drawable.oks);
}
}
}
});
I have drawable iks (X) and oks (O) (making X-O game), and I wanna use my IF command to check if b4 (button) already have background drawn on it, in order to be able to make only 1 change to button so you can't use button that is already been used again.

You can use getBackground to see whether the background drawable has been set:
if (b4.getBackground() == null)
However, you should really design a "model" for your tic-tac-toe game.
Here's an idea:
Store a 2D int array that can store three possible values: 0, 1 and 2. 0 means nothing in the square. 1 means there is a cross and 2 means there is a nought. You can create constants for these:
public static final int EMPTY = 0;
public static final int CROSS = 1;
public static final int NOUGHT = 2;
Expose a method called updateArray(int x, int y, int value) that updates the value at the specified x and y position.
Each time you call this method, set the drawable of the correct view.
Now to check whether there is nothing in a "square", you can just check the array for EMPTY.

Android scaling/transforming canvas doesn't modify clickable area

I'm having a very similar issue described here, except instead of using ScaleAnimation, I'm allowing pinch zoom/pan in my RelativeLayout.
The zoom/panning works perfectly, but regardless of how my view is panned/zoomed, the clickable area does not change along with the visual representation. Here's what my dispatchTouchEvent looks like:
#Override
public boolean dispatchTouchEvent(MotionEvent ev) {
if (mScaleGestureDetector != null && mGestureDetector != null) {
mScaleGestureDetector.onTouchEvent(ev);
mGestureDetector.onTouchEvent(ev);
}
final int action = ev.getAction();
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN: {
final float x = ev.getX();
final float y = ev.getY();
mLastTouchX = x;
mLastTouchY = y;
mActivePointerId = ev.getPointerId(0);
break;
}
case MotionEvent.ACTION_MOVE: {
final int pointerIndex = ev.findPointerIndex(mActivePointerId);
final float x = ev.getX(pointerIndex);
final float y = ev.getY(pointerIndex);
// Only move if the ScaleGestureDetector isn't processing a gesture.
if (!mScaleGestureDetector.isInProgress() && mScaleFactor > 1f) {
final float dx = x - mLastTouchX;
final float dy = y - mLastTouchY;
float newPosX = mPosX + dx;
float newPosY = mPosY + dy;
if (isCoordinateInBound(newPosX, mScreenSize.x))
mPosX = newPosX;
if (isCoordinateInBound(newPosY, mScreenSize.y))
mPosY = newPosY;
invalidate();
}
mLastTouchX = x;
mLastTouchY = y;
break;
}
case MotionEvent.ACTION_UP: {
mActivePointerId = INVALID_POINTER_ID;
break;
}
case MotionEvent.ACTION_CANCEL: {
mActivePointerId = INVALID_POINTER_ID;
break;
}
case MotionEvent.ACTION_POINTER_UP: {
final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK)
>> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
final int pointerId = ev.getPointerId(pointerIndex);
if (pointerId == mActivePointerId) {
final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
mLastTouchX = ev.getX(newPointerIndex);
mLastTouchY = ev.getY(newPointerIndex);
mActivePointerId = ev.getPointerId(newPointerIndex);
}
break;
}
}
return super.dispatchTouchEvent(ev);
}
and my dispatchDraw:
protected void dispatchDraw(Canvas canvas) {
canvas.save(Canvas.MATRIX_SAVE_FLAG);
canvas.translate(mPosX, mPosY);
canvas.scale(mScaleFactor, mScaleFactor);
super.dispatchDraw(canvas);
canvas.restore();
}
How do you modify the clickable area accordingly to modified scale/transformation of canvas?

Since you are already onverriding dispatchTouchEvent, you can try this:
manually evaluate each MotionEvent by considering the current zoom/pan transformation; you can create a new MotionEvent (let's call it FakeMotionEvent) by applying the reverse zoom/pan transformation to the original MotionEvent m.
Check if the FakeMotionEvent intercepts a specific View v; this means the user is touching in a position which represents the user-visibile position of v.
If FakeMotionEvent intercepts v, consume the current MotionEvent and invoke v.dispatchTouchEvent(m);
TIP: You can use the method below to evaluate if a MotionEvent intercepts a View with a certain degree of tolerance:
private boolean intercept(MotionEvent ev, View view, float boundingBoxTolerance){
if (boundingBoxTolerance < 1.0f) {
boundingBoxTolerance = 1.0f;
}
try {
if (ev != null && view != null) {
int coords[] = new int[2];
view.getLocationOnScreen(coords);
if (ev.getRawX() >= ((float)coords[0]) / boundingBoxTolerance && ev.getRawX() <= coords[0] + ((float) view.getWidth()) * boundingBoxTolerance) {
if(ev.getRawY() >= ((float)coords[1]) / boundingBoxTolerance && ev.getRawY() <= coords[1] + ((float) view.getHeight()) * boundingBoxTolerance)
return true;
}
}
}
catch (Exception e) {}
return false;
}

I guess you are using View Animations, i will prefer to use Property animations instead
excerpt from Android documentation (see highlighted)
The view animation system provides the capability to only animate View
objects, so if you wanted to animate non-View objects, you have to
implement your own code to do so. The view animation system is also
constrained in the fact that it only exposes a few aspects of a View
object to animate, such as the scaling and rotation of a View but not
the background color, for instance.
Another disadvantage of the view animation system is that it only
modified where the View was drawn, and not the actual View itself. For
instance, if you animated a button to move across the screen, the
button draws correctly, but the actual location where you can click
the button does not change, so you have to implement your own logic to
handle this.
With the property animation system, these constraints are completely
removed, and you can animate any property of any object (Views and
non-Views) and the object itself is actually modified. The property
animation system is also more robust in the way it carries out
animation. At a high level, you assign animators to the properties
that you want to animate, such as color, position, or size and can
define aspects of the animation such as interpolation and
synchronization of multiple animators.
The view animation system, however, takes less time to setup and
requires less code to write. If view animation accomplishes everything
that you need to do, or if your existing code already works the way
you want, there is no need to use the property animation system. It
also might make sense to use both animation systems for different
situations if the use case arises.

Android OnTouch won't execute return command

this problem is driving me up the wall. I'm sure I'm doing something wrong but I can't figure it out.
I have a static OnTouchListener which I attach to the TextView of a number of identical compound view objects contained within a linearlayout. This listener is in a helper class.
public static View.OnTouchListener getValueTouchListener() {
return new View.OnTouchListener() {
private int lastY;
private int lastX;
#Override
public boolean onTouch(View v, MotionEvent event) {
TextView view = (TextView)v;
int action = event.getActionMasked();
switch (action) {
case MotionEvent.ACTION_DOWN:
view.setBackgroundResource(R.drawable.cog_pressed);
lastY = (int)event.getY();
lastX = (int)event.getX();
return true;
case MotionEvent.ACTION_MOVE:
//calc size of movement
int deltaY = lastY - (int)event.getY();
int deltaX = lastX - (int)event.getX();
// pass gesture up to parent if it's a big x movement - assumes user wishes to scroll parent
if (Math.abs(deltaX) > TOUCH_SLOP *2) {
return false;
}
lastX = (int)event.getX();
//process movement if larger than a touch slop
if (StrictMath.abs(deltaY) > TOUCH_SLOP) {
// reset last touch position
lastY = (int)event.getY();
//get direction of movement
int dir = (deltaY < 0)? -1 : 1;
//change index if within min and max limits
int min = (view.getTag() == Chainring.KEY)? Chainring.MIN_COG : Sprocket.MIN_COG;
int max = (view.getTag() == Chainring.KEY)? Chainring.MAX_COG : Sprocket.MAX_COG;
int value = Integer.valueOf(view.getText().toString());
if ((dir == -1 && value > min) || (dir == 1 && value < max)) {
value = value + dir;
view.setText(String.valueOf(value));
view.playSoundEffect(SoundEffectConstants.CLICK);
}
}
return true;
case MotionEvent.ACTION_UP:
view.setBackgroundResource(R.drawable.cog_unpressed);
return true;
case MotionEvent.ACTION_CANCEL:
view.setBackgroundResource(R.drawable.cog_unpressed);
return false;
default:
return false;
}
}
};
}
I hook up this listener to my TextView in a class that extends linear layout
mValueTextView.setOnTouchListener(CogPickerHelper.getValueTouchListener());
My problem is the method doesn't seem to execute the return command in the ACTION_DOWN, ACTION_UP and ACTION-MOVE cases. For example, with an ACTION_DOWN, the code executes as far as the return command but then steps directly to the default case and returns false - even though Logcat still reports the action as being ACTION-DOWN.
If I try to set a breakpoint on the return commands, IntelliJ says: "No executable code found at line X in class com.amb.GearBuddyV2.views.CogPickerHelper$2"
Does anyone know what I'm doing wrong here?

Your code seems to be working fine, the OnTouch return value is being returned correctly.
And yes, adding a break at a return statement will lead the debugger to complain about missing executable code.

ACTION_DOWN or only ACTION_MOVE in onTouch()

onTouch method of my View:
public boolean onTouch(View view, MotionEvent event) {
Log.d("Touch", "Touch");
int mNewX = (int) Math.floor(event.getX());
int mNewY = (int) Math.floor(event.getY());
boolean isPositionFree = isPositionFree(mNewX, mNewY);
if (!isPositionFree) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
int i = 0;
for (Point point : points) {
if (point.spotted) {
points.remove(i);
invalidate();
break;
}
i++;
}
} else if (event.getAction() == MotionEvent.ACTION_MOVE) {
int i = 0;
for (Point point : points) {
if (point.spotted) {
points.remove(i);
Point p = new Point(mNewX, mNewY, point.TYPE);
points.add(i, p);
invalidate();
break;
}
i++;
}
}
}
}
There are multiple items in the canvas. Their positions are saved in "points". They get drawn to the canvas in a onDraw method via the position of those "points", means Point point.x and point.y.
Now, when I click an item (a point on the canvas), it should disappear.
Then, when the MotionEvent.ACTION_MOVE is true, I want to move the point, depending on the event.getX() and event.getY().
the method "isPositionFree(newX,newY)" checks if the point.x and point.y equals newX and newY (the position I just touched on the screen).
if the position is taken (means, there is an item where I just clicked), I'll get to the motionevent-IFs.
Here comes the problem:
my code removes the point before I can actually move it. I didnt find any way I could fix this problem for hours. :/ I find it difficult, since the onTouch is always called from the beginning, means ACTION_DOWN and ACTION_MOVE never take place at the same time.
Do you know any fix for this?
thanks in advance, Sebastian

Got it to work!
For everbody having the same issue, feel free to take this sample code as a help :)
Stuff I declared in the beginning
Vector<Point> points = new Vector<Point>();
Bitmap[] monsterTypes = new Bitmap[3];
Vector<Integer> distanceMovedX = new Vector<Integer>();
Vector<Integer> distanceMovedY = new Vector<Integer>();
int mNewX = -1;
int mNewY = -1;
OnTouch-Method
public boolean onTouch(View view, MotionEvent event) {
mNewX = (int) FloatMath.floor(event.getX());
mNewY = (int) FloatMath.floor(event.getY());
boolean touchedPoint = touchedPoint(mNewX, mNewY);
switch (event.getAction()) {
case MotionEvent.ACTION_MOVE:
distanceMovedX.add(mNewX);
distanceMovedY.add(mNewY);
break;
case MotionEvent.ACTION_UP:
isMoveEvent = isMoveEvent();
if (isMoveEvent) {
for (Point point : points) {
if (point.spotted) {
// Your code
}
i++;
}
} else {
if (touchedPoint) {
for (Point point : points) {
if (point.spotted) {
// Your code
}
}
}
}
distanceMovedX.clear();
distanceMovedY.clear();
return true;
}
return true;
}
touchedPoint-Method
public boolean touchedPoint(int mNewX, int mNewY) {
boolean touchedPoint = false;
int height = 0;
int width = 0;
for (Point point : points) {
height = monsterTypes[point.TYPE - 1].getHeight();
width = monsterTypes[point.TYPE - 1].getWidth();
if (point.x + width < mNewX || point.x > mNewX + width
|| point.y + height < mNewY || point.y > mNewY + height) {
touchedPoint = false;
point.spotted = false;
} else {
touchedPoint = true;
point.spotted = true;
return touchedPoint;
}
}
return touchedPoint;
}
isMoveEvent-Method
public boolean isMoveEvent() {
boolean isMoveEvent = false;
boolean isMoveEventX = false;
boolean isMoveEventY = false;
for (int i = 0; i <= (points.size() -1); i++) {
Log.d("point", "for loop entered");
if (!distanceMovedY.isEmpty()) {
Log.d("point.x", "distanceMovedY is not empty");
int dMY = distanceMovedY.get(distanceMovedY.size() - 1) - distanceMovedY.get(0);
if ((dMY > 50 || dMY <= 0) && dMY != 0) {
Log.d("point.y", "is move event");
Log.d("point.y", "dMY: " + dMY);
isMoveEventY = true;
} else {
Log.d("point.x", "is no move event");
Log.d("point.x", "dMY: " + dMY);
isMoveEvent = false;
return isMoveEvent;
}
}
if (!distanceMovedX.isEmpty()) {
Log.d("point.x", "distanceMovedX is not empty");
int dMX = distanceMovedX.get(distanceMovedX.size() - 1) - distanceMovedX.get(0);
if (dMX <= 50 && dMX >= -50 && dMX != 0) {
Log.d("point.x", "is move event");
Log.d("point.x", "dMX: " + dMX);
isMoveEventX = true;
} else {
Log.d("point.x", "is no move event");
Log.d("point.x", "dMX: " + dMX);
isMoveEvent = false;
return isMoveEvent;
}
}
if (isMoveEventX && isMoveEventY) {
Log.d("point", "is move event");
isMoveEvent = true;
return isMoveEvent;
}
}
Log.d("point", "is no move event");
return isMoveEvent;
}
Point Class
class Point {
int x, y;
int TYPE;
boolean spotted;
boolean halfSpotted;
public Point() {
}
public Point(int x, int y, int t) {
this.x = x;
this.y = y;
this.TYPE = t;
}
#Override
public String toString() {
return x + ", " + y;
}
}
EXPLANATION:
Point:
we got a class Point. All those points declared in the Vector are x- and y-coordinates on your canvas. They help us to check the position we clicked.
monsterTypes:
its the different graphics I use. If you only use one graphic that you draw onto the canvas, change it to your needs
distanceMovedX & Y:
saves all the X and Y Coordinates of your "ACTION_MOVE". From pos 0 (the first touched point) to pos Z (the last touched point, where ACTION_UP occurs). Though its not the original X and Y position. Its the result of posZ - pos0.
With these values you can determine, after what distance travelled you wanna invoke "onMove" and BELOW which distance "onClick" should be invoked.
mNewX & Y:
the currently position of your onTouch-Method. Everytime you move your finger, newX & Y become overwritten.
Methods:
onTouch():
First, we'll overwrite mNewX and Y to the current position touched. Then we check if we clicked on an existing spot (in my case some 48px*48px area)
Next we record the taken distance in ACTION_MOVE.
After that we continue with ACTION_UP, where we check if we just performed some moveEvent or clickEvent.
touchedPoint():
calculates if we touched some existing point on the canvas, or not. returns true or false
isMoveEvent():
checks if we moved the certain distance. in my case i wanna move down, 50px or more. though im not allowed to move sidewards -50px or +50px. If its NOT a move event, the last spot touched still has to be on the in the giving distance (in my case in the 48px*48px range of the point).
Thats it. took me days to only figure out that option ;/ ashamed of that ... though I coded it pretty fast, what makes me feeling better again :D

I'm just suggesting some walk-around :
Instead of removing the point when clicking it,
make a privata Point in your class, where you currently remove the point, just set your new Variable Point to the Point you would remove...
Then, after using it in action or action move, the last place you would use it,
check if your private variable is not null, if so, remove it, then, set it to null.

try using a switch case statement:
switch finger_action:
case(ACTION_MOVE)
{
//move code
return false;
}
case(ACTION_TOUCH)
{
//dissappear code
return false;
}
note the up above code is pseudo code, but what it does it checks to see if you are moving the dot before just touching it. this way the dot will attempt a move first instead of being removed first.
thanks,
Alex

Android Sprite Animation Move To position X (should be simple but, I'm stuck)

I'm trying to move sprites to stop the frames in center(or move them to certain x position) when right or left pressed on screen. There are 3 sprites created using box.java in the view, placed one after another with padding, stored in arraylist.
The problem: No smooth movement and doesn't stop in the center of each frames after movement has begun, sometimes all boxes are moving on top of each others, padding is totally lost. Please let me know what I'm doing wrong, thanks a lot!
//BEGINING OF BOX.JAVA >> The problem is in this class!
//This goes in Update();
private void boxMove()
{
int get_moved_pos = getMovedPos(); //get moved pos
int sprite_size = view.getSpriteSize(); //get sprite arraylist size
currentDirection = view.getDirection(); //get direction "left" or "right" from view
if(currentDirection == "right" && isMoving == false)
{
setSpriteMovedNext();
}else
if(currentDirection == "left" && isMoving == false)
{
setSpriteMovedPrev();
}
if(currentDirection != lastDirection)
{
lastDirection = currentDirection;
//MOVE RIGHT
if(currentDirection == "right" && get_moved_pos > 0) //move left and make sure that moved pos isn't overlapping / or moving to empty space
{
//Animate left until it reaches the new x position
if(x > get_new_pos_left)
{
x -= pSpeedX;
}
Log.d("RIGHT","POS: " + get_moved_pos);
}else
//MOVE LEFT
if(currentDirection == "left" && get_moved_pos < sprite_size-1) //move left and make sure that moved pos isn't overlapping / or moving to empty space
{
//Animate right until it reaches the new x position
if(x < get_new_pos_right)
{
x += pSpeedX;
}
}
}
}
//Call when screen is touched (in View.java), to set a new position to move to.
public void resetMoving()
{
isMoving = false;
this.lastDirection = "";
Log.d("RESET", "MOVING RESET");
}
public int getMovedPos()
{
return this.smoved_pos;
}
private void setSpriteMovedNext()
{
int get_max_moved = getMovedPos();
int s_size = view.getSpriteSize();
if (isMoving == false) //take a break between movements
{
if(get_max_moved < s_size-1)
{
Log.d("NEXT", "CALLED");
this.get_new_pos_right = x + view.getNextPosX(); //current x and next stop position
this.smoved_pos += 1;
this.isMoving = true; //set to avoid double touch
Log.d("NEXT", "X POS SET: " + get_max_moved);
}
}
}
private void setSpriteMovedPrev()
{
int get_max_moved = getMovedPos();
if (isMoving == false) //take a break between movements
{
if(get_max_moved > 0)
{
Log.d("PREV", "CALLED");
this.get_new_pos_left = x - view.getNextPosX(); //get current x pos and prev stop position
this.smoved_pos -= 1; //to limit the movements
this.isMoving = true; //set to avoid double touch
Log.d("PREV", "X POS SET: " + get_max_moved);
}
}
}
//END OF BOX.JAVA
//VIEW
//Add boxes
public void addBox()
{
int TOTAL_BOXES = 3;
int padding_left = 200;
int padding_tmp = this.getWidth()/2;
box.clear(); //clear old
//Box 1
box.add(new Boxes(box, this, "box1",
padding_tmp,
this.getHeight()/2,
boxSpriteImage, 1, 2, 0, 0));
padding_tmp += boxSpriteImage.getWidth()/TOTAL_BOXES + padding_left;
//Box 2
box.add(new Boxes(box, this, "box2",
padding_tmp,
this.getHeight()/2,
boxSpriteImage, 1, 2, 1, 1));
padding_tmp += boxSpriteImage.getWidth()/TOTAL_BOXES + padding_left;
//Box 3
box.add(new Boxes(box, this, "box3",
padding_tmp,
this.getHeight()/2,
boxSpriteImage, 1, 2, 2, 1));
}
public boolean onTouchEvent(MotionEvent event){
if (System.currentTimeMillis() - lastClick > 100){
lastClick = System.currentTimeMillis();
float x = event.getX();
float y = event.getY();
synchronized (getHolder())
{
if(isBoxWindow() == true)
{
if(x >= this.getWidth()/2)
{
Direction = "right";
}else
{
Direction = "left";
}
}
}
}
//called in box.java to get next x pos to move
public float getNextPosX()
{
int PADDING = 200; //padding between frames
next_pos_x = boxSprite.getWidth()/TOTAL_COLUMNS + PADDING;
return next_pos_x;
}

I think your error is in the if statements, where you compare currentDirection and lastDirection (I'm assuming that lastDirection is a String) with other Strings using the == operator. The == almost operator never works when you want to compare Objects for equality. You should use the equals() method.
For eg.
if(currentDirection != lastDirection)
should be written as:
if(!currentDirection.equals(lastDirection)
Make such changes in your code(They are needed at many places!) and I think your problem should be solved.
A good debugging practice would be logging data about your app, from each of the if blocks, to see if each of them is executed. You could have found out if your if statements are being executed.
EDIT: Why have you put this code?
if (System.currentTimeMillis() - lastClick > 100)
This means onTouchEvents are only interpreted after 100ms. remove it and check, probably that's what is causing the problem.

Alrite, decided to use onFling() method and call via View instead of adding the animations separately into the class itself, works really well when called box.get(i).update() in a loop of all added boxes, all of them animated equally. Thanks udiboy.