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.
Related
I want to handle a press In react native app, so that :
When I touch the screen and move my finger across the screen,
I want to show the coordinates X and Y in real time, so by moving my finger the coordinates changes.
You can use react-native-gesture-handler and react-native-gesture-detector to detect custom gestures which allow you to create gestures on the fly. Yep, just plug it in, paint the gesture and you will receive the coordinate data for your super-complex, custom gesture. You can use it to just use the data points as a predefined gesture in your app, or you can even let your app users create their own custom gestures
I am an amateur (desktop) programmer but I want to get into phones. I have some ideas for apps but the touchscreen and it's inputs confuse me....
I know that touchscreens can accept multiple points of touch. For instance zooming in you take two fingers and you bring them closer.. and for zooming out you do the opposite.
Here is my problem though... I've never seen functionality with any phone app on any phone (I use windows phones and android phones) where.... the input on touch is multiple points but it doesn't begin at the same time.
For the sake of illustration I'll make an example. Suppose you have a mini browser on a phone... and it has a vertical scroll bar... and a horizontal one. What I want to do is be able to scroll down... and WHILE i am scrolling down also scroll the horizontal one so i can move the page left or right. So a few seconds after I touch the screen and begin moving the vertical scrollbar downwards or upwards... i want to use a different finger and touch the horizontal scrollbar and move it as well (at the same time).
Is this even possible? Are there certain hardware or software limitations preventing something like this?
You are mixing up gestures and touches. Gestures are touch behaviors, such as...
Two fingers placed at the same time that grow apart from each other means zoom-in.
Tap and hold means context popup.
Tap and drag equals scroll.
You can cancel these gestures when your app doesn't follow these conventions. For example, Angry birds doesn't scroll if you tap and drag on a bird, but it does if you do it elsewhere on the scene.
The default state of gestures is to not detect additional touches while you are performing a gesture. if you scroll and introduce a second finger to click on a button while still holding the scroll finger, nothing will happen. I'm not sure if you can override this behavior (and I don't think it's a good idea either).
Touches, on the other hand, allow a certain amount of simultaneous touches depending on the device. When a touch is not a gesture you can start a second or n number of touches after the first one starts.
You can try this out yourself at http://raphaeljs.com/touches.html.
Now, going back to your example: it depends on how it's implemented. If you are using the OS gestures (tap and drag anywhere) then no, you can't introduce a second finger to drag horizontally, you'd use the same finger used to scroll vertically (panning with a single finger). But, if you have actual scrollbars (like those in mouse interfaces) then yes, you can implement the kind of interface you are describing.
Yes its possible and it depends on the phone but since most android devices and all WP7 devices got multi touch it shouldn't be a problem
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 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.
I am recently getting into Android programming and want to make a simple game using 2D canvas drawing. I have checked out the Lunar Lander example and read up on some gestures, but it looks like I can only detect if a gesture occurred. I am looking to do a little more complicated detection on a swipe:
I want to make a simple game where a user can drag their finger through one or more objects on the screen and I want to be able to detect the objects that they went over in their path. They may start going vertically, then horizontally, then vertically again, such that at the end of a contiguous swipe they have selected 4 elements.
1) Are there APIs that expose the functionality of getting the full path of a swipe like this?
2) Since I am drawing on a Canvas, I don't think I will be able to access things like "onMouseOver" for the items in my game. I will have to instead detect if the swipe was within the bounding box of my sprites. Am I thinking about this correctly?
If I have overlooked an obvious post, I apologize. Thank you in advance!
I decided to implement the
public boolean onTouchEvent(MotionEvent event)
handler in my code for my game. Instead of getting the full path, I do a check to see which tile the user is over each time the onTouchEvent fires. I previously thought this event fired only once on the first touch, but it fires as long as you are moving along the surface of the screen, even if you haven't retouched.