何时加载UITableView的数据？ 什么时候tableview调用其委托方法。 查看后会出现吗？

Question

I am wondering when UITableview 's data is loaded.

I mean, when I create a UITableView , then normally I will set its datasource and delegate. After that, this tableview will be added as a subview.

However, If I don't call reload method, I don't know when the tableview know it needs to ask its delegates and show the data. In another word, since a view has no viewWillAppear methods, what's the exact time that a tableview ask its delegate and show the data?

I've tried some what:

In viewDidLoad , I create a tableview, added it as subview, but not setting its delegates. Obviously, the data is not loaded.

Then I set its delegate once I tap a button, its data is not loaded.

But when the tableview's controller's viewWillAppear is called again (when the controller disappears and appears again), the data is loaded.

Answer 1

There is no universal set time, because a UITableView's display data is in cells, and the cells are dynamically loaded. (also probably reused) You can call reload, but that just instructs the table to refetch the data on visible cells. The question remains: why do you need to know? If you need to intercept the data before it's loaded into a cell, do it in cellForRowAtIndexPath, where you're supposed to stuff the data into the cell.