hampei / android.arabicwheel Goto Github PK

Currently it's just a simple image rotating and scaling within it's view. But you could build up that image dynamically or even apply the same logic to the draw function of a container, but then I'm not sure if clicks would register correctly.

Features:

• follow finger
• fling wheel
• come to standstill at center of a segment.
• pinch to zoom zooms in on cut-off to a maximum of 2.5 times the window-height.
• The wheel is always centered horizontally.
• The wheel is centered vertically if smaller than the screen, otherwise the top is the top of the screen.

Method:

• On finger-down the angle on the wheel is registered
• On finger-move the new angle is determined and the wheel rotated the same amount of degrees.
• On finger-up the angular speed between the last 2 events is determined and given to a runnable
  • the runnable calls itself every 14ms, moves the wheel based on elapsed time and velocity and then decreases the velocity.
  • As the speed drop below a certain value, the speed is adapted to the distance to the closest segment-center so it moves there.
  • If the distance to the closest segment-center is small enough it stops.
• Touch events are also passed to a ScaleGestureDetector which recognises pinching and saves the new scale.

The showWheel creates a matrix that first does in order:

• The scaling according to the scale factor.
• The rotation around the center of the scaled image.
• The translation to get the scaled image in the right position.