Checkboxes in UITableView State Persistence

问题:

So I have a table which contains option cells, each of which has a bound label and check box provided by the BEMCheckbox library. Everything works fine, however, when I select let's say the first three options and scroll down, I find three other adjacent cells selected even though I have yet to encounter them.

I understand this has something to do with the inner workings of UITableView and how cells are basically reused and re-rendered as they are scrolled, but no attempt I make to persist state seems to be working. At the moment I'm trying to store selected IndexPath objects in an array, and in the cellForRowAt I will draw the checkbox as on if the path appears in the array. However, even this doesn't seem to work. Any ideas how to fix it?

回答1:

Think of a table view cell as the patient info form you get in the waiting room at a doctor's office. The catch is that the doctor's office reuses the forms, and doesn't erase the old info from them.

In your cellForRowAt method, it's up to you to completely restore the cell to its default state before using it again. You have to reset everything to it's default state.

As an alternative to doing that resetting in cellForRowAt, you can use a custom cell and implement the prepareForReuse() method.

The key thing is that you need to force every view in the cell to it's default state before you begin configuring it.