I have a custom ViewPager in which I have 4 fragments, each fragment has different listviews, and its on the start screen of the application. The listview's are taking time to load as soon as the application starts. I'm not pulling any data into the listview, its just the implementation. Implemented OnPageChangeListener to change the listview as I swipe through the fragments
Why does this happen?
changed the implementation, instead of fragments I used PagerAdapter.
Related
I am having this problem with nested viewpagers.
I have two levels of viewpager. Lets call it levelOneViewPager inside which I have one more viewpager, let's call this levelTwoViewPager.
The Activity loads the data for levelOneViewPager and sets the adapter.
The levelOneViewPager loads data for levelTwoViewPager in onViewCreated and sets the adapter.
Everything works fine when the levelOneViewPager loads data for first time.
Now here is the problem.
First page of levelOneViewPager is loaded, I move to 4th page and come back to first page and the app crashes.
Reason, now first page of levelOneViewPager is recreated and is loading the data, even before it sets adapter, the fragments of levelTwoViewPager are created and is accessing some data in the parent fragment which is not available yet.
How is this happening? I haven't set the adapter to levelTwoViewPager yet but fragments are created for it.
(I tried using both FragmentPagerAdapter and FragmentStatePagerAdapter, it's the same behaviour)
add offscreenpage limit to parent viewpager this should fix the issue
android View pager load two pages at a time into memory.i want to load one page at a time and call when page scrolled is it possible?
how can i load one page at a time when user scrolled then call second fragment?
actually it is 3. view pager always load 3 pages or to be exact 3 fragments into memory. this insures user doesn't encounter a frame drop. but there is a catch:
we have two kind of view pager adapter: FragmentPagerAdapter and FragmentStatePagerAdapter .
if you have fragments with heavily content i suggest FragmentStatePagerAdapter because it doesn't load all 3 fragments together. it loads the first one and the save only the states of the other two. its better in case you want to manage memory for heavily content Fragments
I have an Activity with ViewPager and three Fragments with-in. One Fragment contains ListView with custom CursorAdapter which loads data from database.
I've noticed that my cursor adapter loads data every time I switch Fragments in ViewPager. I think that it's normal and is due to the fact that every Fragment has its own lifecycle.
Regarding this it will be great pleasure for me if the users of the stackoverflow explain about their experience or best practices at all.
Thanks!
ViewPagers maintain the state of only certain number of fragments, which defaults to 1 for both sides of the current selected fragment. For example, if you have 3 fragments, when the first is selected, only first two fragments will be instantiated and have the listview data loaded. Alternatively, if you have the second fragment selected, the first and the third will be instantiated. If you switch to the third fragment, the second fragment will be retained, but the first one will be lost. However, you can set the number of fragments to be retained with calling setOffscreenPageLimit method on viewPager with any number of fragments to retain you need. Though you should remember, that setting the number too high may cause your app to consume too much memory.
For example, if you want your fragment to not reload listview content from db while switching fragments and you have 3 framents in your viewPager, you may write the following code:
ViewPager mViewPager;
mViewPager.setOffscreenPageLimit(2);
once again, I am following this tutorial: androidhive - tab layout with swipe able views . All 3 fragment tabs are loaded with different information and logic and layouts. I would like to refresh each fragment when their tabs have been clicked as it auto loads the fragments from start as it uses the view pager. Is there any simplest way out that I could load only a/1 fragment using view pager? Or to reload the fragments? Thanks for your help!
Try to add this to your viewpager:
MY_VIEWPAGER.setOffscreenPageLimit(0);
Check out the documentation.
Pages beyond this limit will be recreated from the adapter when needed.
The limit of 0 will cause a recreation of the fragment when you open a tab.
I have seen lots of examples of how to use a ViewPager to scan through multiple instances of the same Fragment. I don't want to do that. I want to have a single instance of a Fragment that runs off the edge of a screen and use a ViewPager (or at least the nice clean ViewPager swiping effect) to scan through the different sections of the single fragment. Is this possible?
Is this possible?
You can:
Use nested fragments for the pages in ViewPager, or
Use views for the pages in ViewPager, such as in this sample app, or
Use HorizontalScrollView instead of ViewPager to wrap around a single wide view