I have to take a small swipe at the touch gesture of swiping on mobile devices. Below is a screenshot of an app I installed this morning called doable. It's good! But they use swiping in an in intuitive way, to complete tasks. Tapping on a task takes you to that task's details, where, to add annoyance, you have no option to complete the task.
What would I do? I would increase the size of the outer and inner circles to the left of each task name and let users tap either circles to indicate completion. I would also indicate completion by fading from an intense color to transparent before moving the task down to its next place in the frequency-based hierarchy.