Android - Transforming widgets within transformed widgets and the resulting usability issues.

Question

Hello. I'm new to Android application development and I'm currently experimenting with various UI ideas. In the image below, you can see a vertically scrolling list of horizontally scrolling galleries (and also textviews as you can see). I'm also doing some matrix and camera transformations which I will come to in a minute.

For the background of the list elements, I use green. Blue is the background of the galleries, and red is the background for the images. These are just for my benefit of learning.

The galleries being used are extended classes where I overrode the drawChild method to perform a canvas scale operation in order for the image closest to the center (width) to be larger than the others.

The list view going vertically, I overrode the drawChild method and used the camera rotations from lack of depth dimension in the canvas functionality. The items in the list are scaled down and rotated relative to their position's proximity to the center (height).

I understood that scrolling and clicking would not necessarily follow along with the image transforms, but it appears as though the parent Gallery class's drawing is constrained to the original coordinates as well (see photo below).

I would love to hear any insight any of you have regarding how I can change the coordinates of the galleries in what is rendered via gallery scroll and the touch responsiveness of said gallery.

Images in the gallery are not same dimensions, so don't let that throw you in looking at the image below

Thanks in advance!

Ben

link to image (could not embed)

-- Update: I was using my test application UI and noticed that when I got the UI to the point of the linked image and then I touched the top portion of the next row in the list, the gallery updated to display the proper representation. So, I added a call to clearFocus() in the drawChild method and that resulted in more accurate drawing. It does seem a tad slower, and since I'm on the Incredible, I'm worried it is a bloated solution.

In any event, I would still appreciate any thoughts you have regarding the best way to have the views display properly and how to translate the touch events in the gallery's new displayed area to its touchable coordinates so that scrolling on the actual images works when the gallery has moved.

Thanks!

Answer 1

As I updated earlier, the issue of the graphics of the gallery not fully refreshing was resolved by calling clearFocus in drawChild method for the ListView extending class.

The problem with registering the touch events turned out to be where I had used an example for the basis of my experimental program which called a pre-translation on the matrix used for painting. Once I removed that call and adjusted the post-translate call to compensate not having the pre-translate call any longer, I was able to scroll through the galleries regardless of their position, size or rotation (around x axis).