I am trying to develop a game with Android where I need to move a tile in all directions. My question is how can I get the motion of the finger on the screen(right,left,top) using getX() and getY()?
Thanks.
Take a look at getHistoricalSize, getHistoricalX(int) and getHistoricalY(int).
When the finger is touching the screen, Android records the move positions and saves them. You can then call getHistorySize to get the number of motions recorded, and then call getHistoricalX and getHistoricalY with a parameter less that the history size to get the x/y at that history position.
So, for example, you can call getHistoricalY with a parameter that indicates that previous motion event, and then compare it to the current one. If the current one is bigger, then the finger is swiping down.
Note: Motion events recording applies only to ACTION_MOVE.
Related
I want to be able to decompose a long gestures (the touch finger remains on the screen until the gesture ends) into multiple main points in order to measure and store the pressure and velocity between each one of them as shown in an example gesture in Example.
I am also open to other approaches that would allow me to get a similar result.
I'm making simple app where user can move squares with finger on screen. First I'm checking if touch coords are on square to allow the move. Then square is moving along GLSurfaceView#onTouchEvent event coordinates.
It works OK. But when finger is moving too quick (like swipe) square looses the focus and stays still. It seems that OpenGL renders square after the move event occurs, so coordinates check fail.
Please point some keywords to figure out the question (googling gives same links again and again) or some docs. Thanks.
You need hold focus on sprite. If sprite got event "down" it holds focus until doesn't get "up" or "cancel" event. So, while sprite holds focus all touch events send to it.
I am creating an Android game that uses touch input. I noticed that, when I put down a finger and move it, there is a threshold of a couple of pixels until the first MotionEvent.ACTION_MOVE is generated. What is the correct way of disabling this threshold filter?
It's called touch slop. And here's the same question already answered: Android ACTION_MOVE Threshold
Is it possible to detect every pixel being touched? More specifically, when the user touches the screen, is it possible to track all the x-y coordinates of the cluster of points touched by the user? How can I tell the difference between when users are drawing with their thumb and when they are drawing with the tip of a finger? I would like to reflect the brush difference depending on how users touch the screen, and would also like to track x-y coordinates of all the pixels being touched over time. Thanks so much in advance for any help.
This would be very tricky primarily because every android phone is going to behave differently. There are some touch screen devices that are very, very sensitive and some that are basically "dull" by comparison.
It also sounds more like you are wanting to track pressure - how hard is the user pushing on the screen - which is actually supported on android devices.
I think some of your answer may be found by monitoring all of the touch events - in practice, most applications ignore a great number of events or perform some kind of "smoothing" of the events since there is literally a deluge of touch events when the user is manipulating the screen. Doing this may negatively impact your applications performance though.
I would recommend that you look into pressure sensitivity and calculate a circular region around the primary touch point based on pressure, then build your brush around that.
Another idea would be to incorporate more of a gesture approach to what you are trying to do - for example, visualize touching the screen with the tip of two fingers together (index and middle) and rolling the middle finger around the index finger or simply moving the middle finger up and down in relation to the index finger. Both fingers would be moved together for painting. This could be used to manipulate drawing angle on the fly or perhaps even toggle between a set of pre-selected brushes or could change brush size on the fly as you are painting.
Some of the above ideas I would love to see implemented - let me know when you have your app ready.
Good luck!
Rodney
If you have a listener on your image it will respond that there was a touch within that bounding box, basically.
So, to get what you want, you could, but, I would never do this, create a box around every pixel, or small group of pixels, and listen for a touch.
Wherever you get a touch, it may fire off an event, then you can react accordingly.
I can't think of any other solution that will give you each pixel that a person touched, at one time.
You may want to read up on multitouch though, as there are some suggestions in here that my help you:
http://android-developers.blogspot.com/2010/06/making-sense-of-multitouch.html
If you're looking for a way to get your content view as a View after Activity#setContentView(int), then you can set an id on the outer-most element of your layout:
android:id="#+id/entire_view" and reference it in your onCreate() method after setContentView:
View view = getViewById(R.id.entire_view);
view.setOnTouchListener( ... );
I want to move an image around the screen according to the trackball movement. I am able to capture the movements using the onTrackballEvent method. But this is being called for very small float values (I believe for each rotation?) of the trackball.
Now as X and Y positions of views should be integers when specifying with LayoutParams, it makes no sense to move the view with every rotation. Instead I want to move the view only after the user stops rotating the trackball.
Is there any method by which we can get whether the user stopped using the trackball or not?
If there isn't (I don't know Android), the classic approach is to start a timer in each event, and keep track of the deltas reported in it (by adding them to a running sum, one for X and one for Y). On any subsequent event, before the timer has triggered, just re-start the same timer, pushing its triggering further into the future.
When the user stops generating events, the timer will eventually trigger, and then you can apply the sum of all the movements, and clear the sums.
A suitable timeout must be chosen so that the user interaction is not perceived as being too sluggish. Perhaps something on the order of 200-300 milliseconds, or more. This is easy to tweak until it feels "right".
I've also gotten a lot of value out of setting a threshold. So if the total movement in a specific direction adds up to a given amount, then trigger a navigational event.