i am trying to do this:
1) user long touches the screen,
2) a circle/ball pops up (centered around the user's finger) and grows in size as long as the user is touching the screen
3) once the user lets go of the finger, the ball (now in its final size) will bounce around.
i think i have the bouncing around figure out from the DivideAndConquer example, but i am not sure how to animate the ball's growth. i looked at various view flipper examples such as this:
http://www.inter-fuser.com/2009/08/android-animations-3d-flip.html
but it seems like view flipper is best for swapping two static pictures. i wasn't able to find a good view animator example other than the flippers. also, i would prefer to use images as opposed to just a circle. can someone point me in the right direction?
thanks.
Here are two simple tutorials to help you get started with drawing basic animations including touch input: balls bouncing randomly around the screen and basic drag and drop.
In brief: You're right, ViewFlipper is really not suited for this. You want to draw on a Canvas by making your own custom View. This is the basic framework for 2D graphics. Canvases let you draw image files, solid colors and other things to the screen, while applying transformations ot them at the same time. Handling the user input (i.e. the finger on the screen) is done via the onTouchEvent(...) method, which lets you do something when the finger touches the screen, moves on the screen or lifts off. Have a play with those two tutorials, they should give you the basics.
If you're using a bitmap on a canvas to draw it
http://developer.android.com/reference/android/graphics/Canvas.html#drawBitmap(android.graphics.Bitmap, android.graphics.Matrix, android.graphics.Paint)
Use a scale matrix, the identity multiplied by the scalar of the size you want the image to be.
Related
Imagine emptying a pouch having 100 stamps on a small area. That would be the starting point for my screen. I should be able to scale individual stamps in and out, animate them on a swiping gesture, overlay them and animate them so they all come towards the place of a former stamp that just got swiped out of screen, filling that space in. Plus zooming and panning over the entire screen.
I have made canvas level zooming, panning, and drawing by hand, but I feel this is going to benefit a lot from some kind of library. What should I be looking for ? Math libraries, physics, game engines ?
I don't suppose making these into ImageViews and all together into a ViewGroup and trying to make it work from there would be a good idea.
Thanks
I have recently completed a simple drag and drop shapes game. It had the user drag a shape (ImageView) to another "empty place holder" ImageView.
I now want to make this a little more advanced, instead of dragging a simple shape, I want to make a puzzle of various non-orthogonal shapes, for example breaking a circle into 5 different pieces. What I'm having a problem with right now is how to design the layout. I do not know how to make a truly "custom" shaped ImageView, as far as I can find from my research it's not possible. So my idea for now is to overlap a number of square ImageViews, each of which will have only a subset of an image and the rest transparent. Thus the final output will look like it's a number of custom shaped ImageViews.
Example:
+ + +
Because only the internal sections are "visible" and the rest of the circle is transparent, when all of these pieces are placed in the same spot on the screen, the final image will look like:
I haven't tried this yet... but I foresee at least one problem. When I go to drag the pieces over to this puzzle, they will all "snap" into place when dragged to the same place. Because in reality all I really have here is a picture of a circle inside a ImageView which has some invisible rectangular boundary around it.
Hopefully this situation is clear. Now my questions:
Is it possible to have truly custom shaped ImageViews instead of my idea of overlapping images?
If what I'm thinking is the best way to handle this puzzle idea, then what property can be changed such that the "drop" action does not happen at the same place for all of these puzzle pieces? If I wanted to "drop" the pizza shaped piece, I'd like it to only snap into place when it go close to the top left of the circle.
Note: I am new to Android programming, and somewhat new to Java/XML as well, it’s very likely I’m overlooking something, so please feel free to suggest other approaches as you see fit.
Not really. Overlapping views is generally the way it's done. You could also use one View and override the drawing action yourself (multiple bitmaps drawn at relative locations within the View), but that would make the drag-drop aspect significantly harder.
If the Views are all the same size, with the visible portions in the correct relative placement in each, they should snap together correctly. This is because the snap is (I believe) based on the position of the upper-left corner of the View. If the pizza-shaped piece's visible portion is correct with regards to that, it should snap in at exactly the right spot.
So you have certain places you want to accept the drops, and I'm assuming you know their coordinates, say (d_x,d_y).
Then why not simply monitor the coordinate of the center (p_x,p_y) of image view of the piece you are dragging, say the "pizza" piece, and when the distance between the the piece and drop point is within an acceptable amount accept the drop.
But if you are asking if there is some way to make non-rectangular image views I don't believe that is possible.
However I don't think it is necessary in your case, because I believe even if you want them to drag the piece precisely into place you can calculate the coordinates where the draggable rectangle needs to go with knowledge of the shape of the piece and the assumption that the rectangle wraps the piece.
I am trying to learn some more about gestures and graphics in Android, so I am trying to make a sort of game where you start with a ball (just a red circle) in the middle of the screen, and if you swipe in a direction, the ball will be launched in that direction, bouncing of the screen etc. Now, I have succeeded in detecting when somebody swipes in a certain direction, and currently I just display the direction on the screen. My question is: how do I continue? How can I draw the ball, make the user able to move it and make it bounce off the sides of the screen? I think I need to use onDraw somehow, but I'm not sure.
There's a guy with similar problem, he has managed to get circles going around the screen and bouncing from the edges, you may use his code as a basis for your drawing and animation routines: Moving circles in android
I am interested in implementing a user interface navigation control mechanism based on a wheel shaped device (or pie chart shaped or circle shaped) in my Android app.
I would like only half of the wheel to be visible at any time. That is, only the top half of the wheel should be visible since the bottom half should be below the border of the screen. The user can then turn the 'half wheel' to show options hidden by the screen border. The visible top half should then be divided into three parts like a pie chart, so the user can press either one of them to invoke some action. The following pic should explain (it is an example with seven (A-G) options).
http://imgur.com/lNu1F
The rotation itself should not be hard, but I am having a hard time understanding how to position the wheel so that half of it is outside the actual screen. I am thinking that loading the entire wheel (but hiding half of it) is best, since that is that graphics I have and it will also allow a smooth animation when the user swipes to show some other options. How can I make Android show the wheel in this way?
Also. Any comment on how to implement the 'swipe along the wheel shape' would be appreciated.
Thank you.
So for the wheel - you are hving trouble knowing how to position the wheel because you are using XML to align you objects and would like to use something like "Align Object Center To Bottom" which does not exist.
Here is one approach that might work fine: Mask the wheel view.
Is it possible to mask a View in android?
As for swipe the wheel along, I would register the wheel to take touche events, and use only the horizontal componenet of move events to apply to the rotation of the wheel. This setup is common in audio software that uses knobs.
However if you want to have it stick to the users finger in a more realistic fashion, you will need to do the following:
When the user first touches the wheel, calculate the angle from the wheel center to the finger.
Every time the finger moves, check the angle from the wheel center to the finger - and rotate the wheel the amount that the angle has changed from the last touch event.
The formula for getting the angle between two points is this:
Float angleInRadians = Math.atan2(point1.y-point2.y, point1.x-point2.x);
Hey I was wondering if there is any way to do this without going insane with lil buttons built up to make it but basically what I want to do is make two curved buttons around a circle one, is there any way of doing this?
Hers an example of what I kinda want, sorry for how crude the drawing is.
There are two parts in answering this question : how to have buttons looking like this, and getting the touch on the areas you draw.
For the first part, you can use a FrameLayout or a Relative Layout to draw your buttons exactly where you want, and custom images as background (maybe for the circle you can make a ShapeDrawable).
For the second part, it can be very simple : if the Circle (biggest button) is on top of the other two, then this can be ok. But I guess the touchable area on each button will be a rectangle.
Another way to do this is create a custom view, handle the Touch events yourself and based on the X and Y, detect which part has been touched