Android : Activity onviewcreated

Question

My activity have some fragments in a linearLayout (R.id.liste, inside a scrollView) and it takes some time to show. I reduced the size of the array to 50 but it was first 350. Each fragment is independent since I need them to respond to click and to pop a dialog up.

Here is the code :

long start= System.currentTimeMillis();
for (Item item : dao.getList(triKey, start, end)) {
    ItemFragment fragment = ItemFragment.newInstance(item);
    FragmentTransaction fragTransaction = fragMan.beginTransaction();
    fragTransaction.add(R.id.liste, fragment);
    fragTransaction.commit(); 
}
long time = System.currentTimeMillis()-start;

Real question :

I would like to show a circle progressBar and set it Gone when all fragments are shown, but Activity doesn't have a onViewCreated() method, is there any workaround ?

Deeper, theoric question :

If I override Activity.onCreateView() and use the System.currentTimeMillis(), I see that it takes 7.5 seconds to show 50 fragments on my Nexus 4 (and 20s for 350 fragments). Since each fragment only holds 5 TextViews and 1 ProgressBar and takes like 10-15ms to create its view, I'm surprised it takes so long, why does it take nearly 6x more time to add the fragment than to draw it ?

I dont know which piece of code you would need to answer, feel free to ask of course !

Thank you very much for any help !

Do you really need 50-350 Fragments? What functionality, or lack thereof, is preventing you from using Views instead? — Mike M., Aug 26 '14 at 10:56
I would suggest you rethink your approach. Maybe one Fragment would suffice to display various data? If not, have you considered using ViewPager? — Tadej, Aug 26 '14 at 10:58
Actually on a second thought, maybe a custom relativelayout can do the thing... but my real question was about how can I know the activity is finished drawing the UI. And of course if I could understand what takes so long to add fragments if each take 10ms to draw... I edit my first post^^ — Dan Chaltiel, Aug 26 '14 at 12:45

Squonk · Accepted Answer · 2014-08-27T08:08:20.793

3

but Activity doesn't have a onViewCreated() method, is there any workaround ?

No.

am I doing something wrong ?

Yes.

You really need to rethink your design. You could easily do what you're describing by using a ListView either in your Activity (without using ScrollView) or use a ListView in a single ListFragment.

A ListView re-uses its list item views as it scrolls - if you use a custom Adapter it will behave as you want and is very efficient. You may also want to look at the 'view holder' pattern to making scrolling even more efficient.

edited Aug 27 '14 at 08:08

answered Aug 26 '14 at 10:59

Squonk

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1) OK, 2) onCreateView and onViewCreated is 2 separated things, first is when Activity show a view (even if it's inside a fragment) and second is when a view is created (which make more sense in a fragment but would be useful in an activity). 3) I understand, I'll populate my listView with custom relativelayout, would it be better ? – Dan Chaltiel Aug 26 '14 at 12:41
@DanChaltiel : OK, apologies for my mix-up with what you'd posted as far as `onCreateView` and `onViewCreated` - I misread your question. In reality, however, overriding `onCreateView` in the `Activity` isn't going to help you with `Fragments`. In answer to your final point in your comment - yes, I believe you'll see much performance with a `ListView` with list item layouts which use `RelativeLayout`, A `ListView` with a custom `Adapter` is very efficient even for complex list item layouts due to re-using the item views - also look up the 'view holder' pattern for `ListViews`. – Squonk Aug 26 '14 at 14:09

Android : Activity onviewcreated

Real question :

Deeper, theoric question :

1 Answers1