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A problem arises when a key stroke for changing the slider does not match what happens visually. For example, it's possible that the user presses the down arrow to decrease the value of the slider, but visually the arm rotates upward. This is can be unexpected behaviour.
Example:
A slider is configured to go from -180 0 to 18060, with 0 value being at the doorknob. Positive values are positions "above the doorknob", and negative positions are "below the doorknob". The user would use the native slider control to move along this continuum. So when the user moves up and down (or left and right) on the slider, the arm would rotate around.
Problems appear when the arm is in the following locations along the rotation arc:
- left half of the rotation arc: up arrow key presses causes the arm to move down, and down arrow key presses causes the arm to move up.
- top half of the rotation arc: left arrow presses appears to move the arm right, and right arrow presses appears to move the arm left.
Notes
This problem exists regardless of:
top of the circle. From the 0 to 30 positions, pressing down makes the arm move upward, and pressing up makes the arm move downward. Similarly from 15 to 45, pressing left makes the arm rotate right, and pressing right makes the arm move left.
This issue exists regardless of the orientation of the slider (horizontal or vertical slider doesn't matter)
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, and the number
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scale used.
Issues
- Is the inverted controls in these areas acceptable to the target audience?If you .
- You can restrict rotation to just the right side of the rotation arc , you can eliminate the UP / DOWN key press confusion(i.e. 0 to 30).
- Is the restricted arm movement acceptable?
- The problem of LEFT / RIGHT key press confusion remains: is this okay?
- Issue persists.
- Is 0 to 60 (clock scale) acceptable? are there alternatives?
Approach #2: Number Spinner Implementation
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