Android使用哪个ViewGroup

Question

This is a very specific case so I'll try my best to organize this question appropriately. I have a custom ViewGroup that is working for my purpose but it's initializing is causing skipped frames.

My app contains a ViewPager of Fragment 's where the parent container to each is a ScrollView . Within these, I have many different views, one being a LinearLayout containing vertical rows of custom views (to manipulate a data set). See in picture 'Foreground, Visible, Secondary apps'

For this layout, I've extended LinearLayout and each one is populated at runtime, inflating each child from xml.

It's working fine, the issue is that inflating all these child views at runtime is causing skipped frames. I've used method tracing to find that each call to LayoutInflater.inflate() is taking avg 4-6 ms. Between all my fragments each containing 1 or more of these lists, it's adding up to a significant amount (40-50) skipped frames on startup.

Manually creating child views instead of inflating improved it a little, but not enough. Still very noticeable frame skipping.

It needs some form of view re-using, similarly to what a ListView does.

I see one solution although it doesn't seem ideal at all. That is to replace the fragment container ScrollView with a ListView with multiple view types.

Some problems I see with this are

• It would require up to 5-6 different view types between the views above, below, and between these lists. Seems very messy to write.
• Each child view needs the ability to expand size vertically with a simple expand/collapse animation. Not sure if this is even possible to do with ListView rows.
• It involves rewritting almost the entire app. Which I am willing to do but would like to avoid if possible.

I wondered is it at all possible to do:

• Instead of using LinearLayout for these lists, use a ListView and have its size be expanded to show all items. It would be nested in the parent ScrollView . Would it even reuse any views if its size was expanded to all items?

Is there any other type of container I can use in this circumstance? I have not used the new RecyclerView yet but from what I've read it seems essentially the same as a ListView .

Basically what I'm trying to create is a LinearLayout that recycles views.

Would appreciate any suggestions. Please let me know if this question doesn't read well I can add more information or post code if needed. I realize what I'm trying to do here is a bit unconventional and may be inherently flawed by design. But i'm very pleased with how it's presented currently and would like to keep it this way.

Answer 1

From what I understand you have clickable title views that when clicked an inner layout is shown/hidden.

So you could have your view inflate without the inner layouts.Just the clickable titles. Then when the titles are clicked, if the corresponding inner layout hasn't been inflated yet then you inflate it. Otherwise you show/hide it. That should save up a lot of time from the initial inflation. Also building your layout programmatically on runtime instead of inflating an xml saves a lot of time too because you don't have to use findViewById() method that is quite costly.