Develop Reference

Unity3d - Touch Input issue

I develop a game that need user to have a single touch to draw over to link multiple objects. Currently using mouse button as touch input with this code:
if(Input.GetButton("Fire1"))
{
mouseIsDown = true;
...//other codes
}
It works fine with mouse but it will give me problem when I compile it for multi touch device. In multitouch device, if you have 2 fingers down, the middle point will be taken as the input. But if I already touch an object then with second finger down to screen, it will mess up my game input and give me havoc design.
What I want is to limit it to 1 touch only. If the second finger come touching, ignore it. How can I achieve that?

Below is all you need:
if ((Input.touchCount == 1) && (Input.GetTouch (0).phase == TouchPhase.Began)) {
mouseIsDown = true;
...//other codes
}
It will only fire when one finger is on the screen because of Input.touchCount == 1

You are using Input.GetButton. A button is not a touch. You probably want to look at Input.GetTouch
If you need to support multiple input-type devices, you may want to consider scripting your own manager to abstract this out somewhat.

I would roll with a bit of polling!
so in your Update() I typically do something like this:
foreach (Touch touch in Input.touches)
{
// Get the touch id of the current touch if you're doing multi-touch.
int pointerID = touch.fingerId;
if (touch.phase == TouchPhase.Began)
{
// Do something off of a touch.
}
}
If you're looking for more info check this out:
TouchPhases in Unity

Android onTouch multi-touch not receiving all touch events

I am using an Android SurfaceView and listening for multi-touch events. I am able to detect multiple touches but it seems that the ACTION_POINTER_UP touch event is not getting fired. Here is a quick snip of my code.
public class GameView extends SurfaceView implements Runnable {
...
#Override
public boolean onTouchEvent(MotionEvent motionEvent) {
Log.i("pointer count", Integer.toString(motionEvent.getPointerCount()));
return true;
}
...
}
When I put 2 fingers on the screen the pointer count log out is 2. If I remove one of my fingers the pointer count log out is not 1 and stays at 2. It only goes to 1 if I move my finger that is still on the screen. Why is this and how to I firkin fix it? thanks!
EDIT
This problem occurs on my One Plus One and my friends Samsung Galaxy Note 2. It is interesting that when I put it on my Samsung Galaxy s4 the problem did not occur.

Do not use getAction() == MotionEvent.ACTION_POINTER_UP as the action will also contain the pointer index.
getActionMasked() will strip out this information, and could be used for comparison.
See http://developer.android.com/reference/android/view/MotionEvent.html#getActionMasked()

Is there a offset between onTouchEvent and onTouchListener?

I have developed a game that shoots when player touches the screen by using onTouchListener for my custom SurfaceView and Thread.
But now I want to change the approach and instead of onTouchListener I added onTouchEvent to the SurfaceView o my Activity.
The problem is that I get some kind of offset when I click on the emulator.
Everything is working great, except that offset keeps appearing and I don't understand why.
Also let me mention that my app is running in landscape mode, maybe this is relevant.
I suspect that it isn't working properly because onTouchListener was added to the view and depended on it, but onTouchEvent doesn't depend on the view.
Also my view doesn't have any padding or margin properties, it is full-screen view (fill_parent).
Does anyone have any ideas on this?

I have done my application, and everything works correctly now, but i still do not know what the problem was.
After lots of debugging of my application the onTouchEvent returned random Y values that were always higher than the ones that the onTouchListener returned. And i am not sure why this is hapening since my view that recognizes the onTouchListener is a full-screen view.
So i figured out a way to get passed this by doing some math.
The first function that the android calls is the onTouch method which gives the correct values but just for one touch. I needed it to give right values even on the MotionEvent.ACTION_MOVE so i noticed that MotionEvent.ACTION_MOVE is actually doing correctly depending on the first touch recognized by the onTouchEvent.
So i just got the coordinate Y from the onTouch and the different coordinate with the offset from onTouchEvent calculated the difference and in every onTouchEvent from there, until the user lifts up their finger, i just subtract that difference and that gives me the correct value.
If anyone else has this problem, and doesn't know how to fix it, here is my code, maybe it will be helpful.
#Override
public boolean onTouchEvent(MotionEvent arg1) {
/*you can only touch when the thread is running*/
if(game.state() != STATE_PAUSE){
if(arg1.getAction() == MotionEvent.ACTION_DOWN){
coordinateX = arg1.getX();
coordinateY = arg1.getY();
differenceY = Math.abs(coordinateY - touchedY);
coordinateY = coordinateY - differenceY;
shootingIsOkay = true;
game.setDrawCircle(coordinateX,coordinateY);
}
if(arg1.getAction() == MotionEvent.ACTION_MOVE){
coordinateX = arg1.getX();
coordinateY = arg1.getY();
coordinateY = coordinateY - differenceY;
shootingIsOkay = true;
game.setDrawCircle(coordinateX,coordinateY);
}
if(arg1.getAction() == MotionEvent.ACTION_UP){
shootingIsOkay = false;
}
}
return false;
}
And the onTouch method that is called from the onTouchListener that depends on the view is just simple, here:
#Override
public boolean onTouch(View arg0, MotionEvent arg1) {
touchedY = arg1.getY();
return false;
}
If anyone knows how to fix this problem, please post your answer, i am very curious why this is happening

getPressure always returning 1.0

Does anyone have any idea why getPressure() returns always 1.0?
Here is my code:
#Override
public boolean onTouchEvent(MotionEvent event) {
super.onTouchEvent(event);
System.out.println(event.getPressure());
return true;
}

Does anyone have any idea why getPressure() returns always 1.0?
The typical touchscreen / input device has no way to measure pressure. You either don't press and get no touch event or you press and get a touch event with value 1.

https://groups.google.com/forum/#!topic/android-developers/10pF8EUEuy0
Here's an answer about how getPressure and getSize() work in Android, I think this would help

Android will treat fast single touch as move?

I write a very simple android application, that I can draw something on the pad. Touch the screen with a finger, you will see a green ball, move your finger, you will see a red line.
But I found a very strange thing: If I touch the screen with two fingers one by one very fast, it will draw a line between them! (Imaging you are pressing two keys jkjkjkjkjkjjkjkjkjkjkjkj on the keyboard)
The key code is pretty simple:
public boolean onTouch(View v, MotionEvent event) {
int action = event.getAction();
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
multiTouch = false;
id = event.getPointerId(0);
PointF p = getPoint(event, 0);
path = new Path();
path.moveTo(p.x, p.y);
paths.add(path);
points.add(copy(p));
break;
case MotionEvent.ACTION_POINTER_DOWN:
multiTouch = true;
for (int i = 0; i < event.getPointerCount(); i++) {
int tId = event.getPointerId(i);
if (tId != id) {
points.add(getPoint(event, i));
}
}
break;
case MotionEvent.ACTION_MOVE:
if (!multiTouch) {
p = getPoint(event, 0);
path.lineTo(p.x, p.y);
}
break;
}
invalidate();
return true;
}
The full source is here: https://github.com/freewind/TouchTest/blob/master/src/com/example/MyImageView.java
And it's a working demo: https://github.com/freewind/TouchTest
Or you can just download the signed apk on your android device, and test it yourself: https://github.com/freewind/TouchTest/blob/master/TouchTest.apk?raw=true
You can see in my code, I have checked if it's multi touch and disabled drawing on that case.
My android version is 4.0, and my code target is 2.3.3
There is a picture on my android pad:
You can see there are some lines but it should not be, there should be a green ball on the left of the red line instead.
I'm not sure why android treat fast single touch as moving, I considered 3 reasons:
My code has something wrong
Android sdk has something wrong
My android pad has something wrong, e.g. missing a ACTION_DOWN event
How to find out the real reason?
UPDATE
One of my friend used his android mobile(android 2.1) to test this app and found there is no red line, another used android 2.3.5 and found there are red lines.
Please review my code, I have checked multi-touch by ACTION_POINTER_DOWN, and will do nothing on ACTION_MOVE if there are more than 1 points. So the id of point is not needed. (Actually, in my first version of this code, I used id but have the same issue).
And I don't think this is an expected behavior, because it made the development of touching programs hard. I found this issue because in my another application(user can drag/zoom/rotate an image by fingers), the image sometimes "jump" on screen.
I even tried a popular game (Fruit Ninja) on my android pad and iTouch, and found android version has the issue but iTouch doesn't.
Now I'm sure there is something wrong (missing an ACTION_UP event when the first finger ups), but I still don't know what causes it. My android pad? Or Android sdk?

That is way it works for multitouch. When you press fast android handle it as gesture, and you will have 2 pressed pointers. To avoid it try to handle action_up, or use action_pointer_down instead

you can check the id of the touch , so that you will handle only the first touch alone.
alternatively , you can monitor all touches and handle them together .