Develop Reference

Programmatically animate Android BrokenView

I was going through some of the awesome Android libraries and I found the Android BrokenView. It's quite simple to use and uses the touch events to show the broken animation. Here's the code that we're required to add in order to enable a View to behave as a BrokenView:
brokenView = BrokenView.add2Window(context);
listener = new BrokenTouchListener.Builder(brokenView).build();
view.setOnTouchListener(listener);
The problem that I've is that I want to perform the broken animation programmatically i.e, without any actual touch events. I tried looking at the source code but couldn't figure out how to achieve that as most of the methods are protected.
Any ideas on how can I do that?

I've achieved this using a motion event. It works, but I'd prefer to call createAnimator() directly, as I don't want the user to be able to trigger the smash via a touch event.
long downTime = SystemClock.uptimeMillis();
long eventTime = SystemClock.uptimeMillis()+1000;
int[] coords = new int[2];
targetView.getLocationOnScreen(coords);
float x = coords[0] + targetView.getWidth()/2;
float y = coords[1] + targetView.getHeight()/2;
MotionEvent motionEvent = MotionEvent.obtain(
downTime,
eventTime,
MotionEvent.ACTION_DOWN,
x,
y,
0
);
mBrokenTouchListener = new BrokenTouchListener.Builder(mBrokenView)
.setEnableArea(mRootView)
.build();
mBrokenTouchListener.onTouch(targetView, motionEvent);
What I'd like to do is this:
Point point = new Point((int)x, (int)y);
BrokenConfig config = new BrokenConfig();
brokenView.createAnimator(mFLTargetView, point, config);
brokenView.setEnable(true);
// or
brokenView.start();
but BrokenConfig is package private, and there's no start() method.
HTH

Get the real X/Y position of an onTouch Event

I know there are some similar topics that have been posted, but I couldn’t find a good solution for my problem.
I have a GridView which is filed with a custom ImageAdapter. Everything works fine, but whenever I click on an image contained in the GridView, I would like to move another Imageview at the click's position.
However, the coordinates of the Event, that I take with event.getX() and event.getY(), don’t correspond to the click’s position.
I first thought of a problem of dp/px conversion, and I tried several solutions in this way but none of them worked.
Then I tried to use the getXPrecision(), but I couldn’t make a working solution…
Maybe there is another way?
I would like to make the correct position programmatically, without adding constants int, so my project will work on various phone and tablet, with different dp and resolutions.
EDIT : Here is a screenshot, where i clicked the 3rd cell of the first line, and setted the position of the pencil with getRawX() - getRawY(). As we can see, this is not the correct position, I want the red dot (imageview's center) to be positionned where i clicked.
The code used :
//getting the position of the onTouch event :
GridView centre = (GridView) findViewById(R.id.gridView);
adapter = new ImageAdapter(this, (dim * dim), tailleCell);
centre.setAdapter(adapter);
centre.setOnTouchListener(new View.OnTouchListener() {
public boolean onTouch(View view, MotionEvent event) {
int X = (int)event.getRawX();
int Y = (int)event.getRawY();
animation(X, Y, etat);
return false;
}
});`
//launching the animation (and setting position of the pencil) :
private void animation(int posX, int posY, int etat)
{
final ImageView img;
if(etat == 0)
{
img = (ImageView) findViewById(R.id.imageView);
}
else
{
img = (ImageView) findViewById(R.id.imageView2);
}
img.clearAnimation();
img.setVisibility(View.VISIBLE);
img.setX(posX);
img.setY(posY);
[...]
}
EDIT 2 : ~Solution :
Jesus Molina Rodríguez De Vera's solution wasn't working as expected, but i managed to make a workable solution. I just changed my code in the Event Handler to adjust the image's position :
int[] offset = new int[2];
centre.getLocationOnScreen(offset);
int Xoffset=offset[0];
int Yoffset = offset[1];
int X = (int)event.getRawX();
int Y = (int)event.getRawY();
animation(X-((int)Math.round(Xoffset/1.15)), Y-((int)Math.round(Yoffset/1.5)), etat);
Sorry for my bad English :)
Thanks for your help!

Try using getRawX() and getRawY() instead of getX and getY.
Edit
I think that i have found the problem.
You are obtaining X and Y relative to the GridView top-left corner, not to the absolute screen coordinetes.
What you can do is the following:
int[] offset = new int[2];
center.getLocationOnScreen(offset);
int Xoffset=offset[0];
int Yoffset = offset[1];
private void animation(int posX, int posY, int etat){
//...
img.setX(posX+Xoffset);
img.setY(posY+Yoffset);
[...]
}
This is supposed to set the the top-left corner of the ImageView in the selected point. In order to set the center in that point:
int ivWidth = img.getWidth();
int ivHeight = img.getHeight();
private void animation(int posX, int posY, int etat){
//...
int[] finalPosition=new int[2];
finalPosition[0] = posX+Xoffset-(ivWidth/2);
finalPosition[1] = posY+Yoffset-(ivHeight/2);
img.setX(finalPosition[0]);
img.setY(finalPosition[1]);
[...]
}
I haven't try it but it should work.
Edit 2
Xoffset and Yoffset are only needed if you use getX()/getY() instead of getRawX()/getRawY()

view.getHitRect(rect) not working

I am overriding onInterceptTouch(MotionEvent) for the purpose of allowing horizontal scrolling. What I am finding however is that I cannot detect when the user has touched the embedded v. The x,y on the view are like 2000, 2400 while the MotionEvent.getX(),getY() are like 400,500
View v = findViewById(R.id.myView);
Rect r = new Rect();
v.getHitRect(r);
int[] loc = new int[2];
v.gtLocationOnScreen(loc);
int x = loc[0];
int y = loc[1];
// Result x,y are huge numbers 2400, etc
// event.getX() is 30, event.getY() == 500 nothing close to 2400.
if (r.contains((int)event.getX(), (int)event.getY())
{
return false; // this is never true even when I click right on View v.
}

I know this is an old question and is mostly answered in the linked post, but I just came across this problem so I thought I'd fill in my solution.
private boolean isTouchInView(View view, MotionEvent event) {
Rect hitBox = new Rect();
view.getGlobalVisibleRect(hitBox);
return hitBox.contains((int) event.getRawX(), (int) event.getRawY());
}

Try using getRawX() and getRawY(). These will give you the absolute positions you need.
See:
How do I know if a MotionEvent is relative or absolute?
You also have to adjust the location of your destination view to account for any displacement by other views like so:
int[] screenLocation = new int[2];
view.getLocationOnScreen(screenLocation);
hitRect.offset(screenLocation[0] - view.getLeft(), screenLocation[1] - view.getTop());
//Then check if source view is contained in target view
x=event.getRawX();
y=event.getRawY();
if (hitRect.contains(x, y)) {
//do your stuff
}

Get MotionEvent.getRawX/getRawY of other pointers

Can I get the value of MotionEvent.getRawX()/getRawY() of other pointers ?
MotionEvent.getRawX() api reference
The api says that uses getRawX/getRawY to get original raw X/Y coordinate, but it only for 1 pointer(the last touched pointer), is it possible to get other pointer's raw X/Y coordinate ?

Indeed, the API doesn't allow to do this, but you can compute it. Try that :
public boolean onTouch(final View v, final MotionEvent event) {
int rawX, rawY;
final int actionIndex = event.getAction() >> MotionEvent.ACTION_POINTER_ID_SHIFT;
final int location[] = { 0, 0 };
v.getLocationOnScreen(location);
rawX = (int) event.getX(actionIndex) + location[0];
rawY = (int) event.getY(actionIndex) + location[1];
}

A solution worth trying for most use cases is to add this to the first line of the onTouchEvent it simply finds the difference between the raw and processed, and shifts the location of the MotionEvent event, by that amount. So that all the getX(int) values are now the raw values. Then you can actually use the getX() getY() stuff as the Raw values.
event.offsetLocation(event.getRawX()-event.getX(),event.getRawY()-event.getY());
While Ivan's point is valid, it's simply the case that applying a matrix directly to the view itself sucks so bad you likely shouldn't do it. It's weird and inconsistent between devices, cause the touch events to fall out of view and get declined, etc. If you are moving a view around like that you are better off simply overloading the onDraw() and applying that matrix to the canvas, then applying the inverse matrix to the MotionEvent so everything meshes up right. Then you can properly react to the events with proper and fine grain control. And, if you do that, my solution here wouldn't be subject to Ivan's objection.

It might be not enough to just shift local coordinates by a view's location if the view is rotated. In this case you need something like this:
void getRowPoint(MotionEvent ev, int index, PointF point){
final int location[] = { 0, 0 };
getLocationOnScreen(location);
float x=ev.getX(index);
float y=ev.getY(index);
double angle=Math.toDegrees(Math.atan2(y, x));
angle+=getRotation();
final float length=PointF.length(x,y);
x=(float)(length*Math.cos(Math.toRadians(angle)))+location[0];
y=(float)(length*Math.sin(Math.toRadians(angle)))+location[1];
point.set(x,y);
}

The getLocationOnScreen answer works most of the time, but I was seeing it return incorrect values sometimes (when I was repositioning and re-parenting the view while the touch event was taking place), so I found an alternate approach that works more reliably.
If you look at the implementation of getRawX, it calls a private native function that accepts a pointerIndex, but the MotionEvent class only ever calls it with index 0:
public final float getRawX() {
return nativeGetRawAxisValue(mNativePtr, AXIS_X, 0, HISTORY_CURRENT);
}
Unfortunately, nativeGetRawAxisValue is private, but you can hack around that by using reflection to give yourself access to everything you need. Here's what the code looks like:
private Point getRawCoords(MotionEvent event, int pointerIndex) {
try {
Method getRawAxisValueMethod = MotionEvent.class.getDeclaredMethod(
"nativeGetRawAxisValue", long.class, int.class, int.class, int.class);
Field nativePtrField = MotionEvent.class.getDeclaredField("mNativePtr");
Field historyCurrentField = MotionEvent.class.getDeclaredField("HISTORY_CURRENT");
getRawAxisValueMethod.setAccessible(true);
nativePtrField.setAccessible(true);
historyCurrentField.setAccessible(true);
float x = (float) getRawAxisValueMethod.invoke(null, nativePtrField.get(event),
MotionEvent.AXIS_X, pointerIndex, historyCurrentField.get(null));
float y = (float) getRawAxisValueMethod.invoke(null, nativePtrField.get(event),
MotionEvent.AXIS_Y, pointerIndex, historyCurrentField.get(null));
return new Point((int)x, (int)y);
} catch (NoSuchMethodException|IllegalAccessException|InvocationTargetException|
NoSuchFieldException e) {
throw new RuntimeException(e);
}
}
Of course, the MotionEvent internals aren't documented, so this approach might crash on past or future versions of the SDK, but it seems to be working for me.
Edit: It looks like the type of mNativePtr and the nativePtr param changed from int to long in API level 20, so if you're targeting API level 19 or earlier, the above code will crash because getDeclaredMethod won't find anything. To fix this in my code, I just fetched the method by name instead of full type signature, which happens to work in this case. There isn't a way to directly look up methods with a given name, so I looped through the declared methods at static init time and saved the matching one to a static field. Here's the code:
private static final Method NATIVE_GET_RAW_AXIS_VALUE = getNativeGetRawAxisValue();
private static Method getNativeGetRawAxisValue() {
for (Method method : MotionEvent.class.getDeclaredMethods()) {
if (method.getName().equals("nativeGetRawAxisValue")) {
method.setAccessible(true);
return method;
}
}
throw new RuntimeException("nativeGetRawAxisValue method not found.");
}
Then I used NATIVE_GET_RAW_AXIS_VALUE in place of the getRawAxisValueMethod in the above code.

There is no API to get pointer's specific RawX and RawY.
But you can calculate similar values with regards to View's position to the parent and its rotation.
In case if parent view occupies the entire touch area you are trying to handle, using Matrix will help you to solve your problem:
private float[] calcRawCoords(MotionEvent event, int pointerIndex) {
Matrix screenMatrix = new Matrix();
screenMatrix.postRotate(getRotation(), mPivotX, mPivotY);
screenMatrix.postTranslate(getLeft(), getTop());
float viewToScreenCoords[] = {event.getX(pointerIndex), event.getY(pointerIndex)};
screenMatrix.mapPoints(viewToScreenCoords);
return viewToScreenCoords;
}

How can you detect which view you are passing over when performing a touch event?

I want to know how I can detect child views if I move a view from one ViewGroup to another ViewGroup, particularly when doing a touch event. Is there a method I can call that will let me know which views i'm "hovering" over?
What I'm doing right now is when I detect an ACTION_MOVE event on my view i'm raising it to the top level parent so that it can move and be drawn within the entire window ( and not just inside it's original parent bounds ), then I want to move the view across to a different ViewGroup and on ACTION_UP attach the view to that ViewGroup.

Inspired by Ami's response, but discovering that MotionEvent#getX()/getY() along with View#getTop()/etc return coordinates wrt the parent View, I ended up doing the following below to operate in screen coordinates, allowing me to work across ViewGroups:
private boolean inRegion(float x, float y, View v) {
v.getLocationOnScreen(mCoordBuffer);
return mCoordBuffer[0] + v.getWidth() > x && // right edge
mCoordBuffer[1] + v.getHeight() > y && // bottom edge
mCoordBuffer[0] < x && // left edge
mCoordBuffer[1] < y; // top edge
}
whose usage inside an OnTouchListener is e.g.:
boolean inside = inRegion(event.getRawX(), event.getRawY(), targetView);

I think I found a simpler way to do this.
Create an ArrayList of possible targets
Call this method from your touch event, supplying your targets list and the coords
private View findView(float x, float y, ArrayList<View> targets)
{
final int count = targets.size();
for (int i = 0; i < count; i++) {
final View target = targets.get(i);
if (target.getRight() > x && target.getTop() < y
&& target.getBottom() > y && target.getLeft() < x) {
return target;
}
}
return null;
}

I found Sebastian Roth's answer very helpful with resources, but since it wasn't really an answer to my question, I thought I'd share what I came up with.
Here is the code I use to detect views ( only views that will accept a drop that is ) given a coordinate on the screen.
private DropView findDropTarget( int x, int y, int[] dropCoordinates ){
final Rect r = mRectTemp;
final ArrayList<DropView> dropTargets = ((main) context).getBoardDropTargets();
final int count = dropTargets.size();
for (int i=count-1; i>=0; i--) {
final DropView target = dropTargets.get(i);
target.getHitRect(r);
target.getLocationOnScreen(dropCoordinates);
r.offset(dropCoordinates[0] - target.getLeft(), dropCoordinates[1] - target.getTop());
if (r.contains(x, y)) {
dropCoordinates[0] = x - dropCoordinates[0];
dropCoordinates[1] = y - dropCoordinates[1];
return target;
}
}
}
Ok, first off mRectTemp is just an allocated Rectangle so you don't have to keep creating new ones ( I.E. final Rect r = new Rect() )
The next line dropTargets is a list of views that will accept a drop in my app.
Next I loop through each view.
I then use getHitRect(r) to return the screen coordiantes of the view.
I then offset the coordiantes to account for the notification bar or any other view that could displace the coordiantes.
finally I see if x and y are inside the coordinates of the given rectangle r ( x and y are the event.rawX() and event.rawY() ).
It actually turned out to be simpler then expected and works very well.

Read this:
http://developer.android.com/reference/android/view/ViewGroup.html#onInterceptTouchEvent(android.view.MotionEvent)
http://developer.android.com/reference/android/view/View.html#onTouchEvent(android.view.MotionEvent)
I had implemented a Drag and Drop using that method.
I also highly recommend a read of the HomeScreen sourcecode, which contains this thing (kind of):
https://android.googlesource.com/platform/packages/apps/Launcher2