Android best practices for fragment animations - android

I have activity with two tabs. Both tab uses different fragments. When a particular event occur like user click on item, I am opening another fragment in same activity.
I know how to add fragment dynamically and I also know how to animate it.
Here, how I added fragment to frameLayout in my activity:
transaction.setCustomAnimations(R.animator.object_slide_in_up, R.animator.activity_hold)
transaction.add(R.id.flSellerHome, fragment)
transaction.commit()
Everything works fine in emulator and newer phones. I have tested with emulator with api 25, it works fine now flickering occur, When I am testing it with real device with api 23 it flicker little, so it doesn't affect, after then when I tested it with api 19, it flickers too much.
So my question is any best practise for doing animation.
Notes
My third fragment which is dynamically added contains recylerview with around 20 items from local db, and I also done db fatching in background thread.
No loads on main thread. recyclerview is also simple with one Image and three texts.
Image is also loaded using Glide and also I have override function of glide**
any help is appreciated..

I found problem is with recyclerview data updation.
I am loading data in background thread, but when notifying recyclerview, it stucks for small amout of time.
So what I have done is. I have delayed data load for same amount of time which is for animation.
I don't know it is good idea or bad idea. But it is too late for my project so I used this workaround.

I wanted to write comment to your answer, but I dont have enough rep, but I want try to advice you something, so sorry for this.
I am loading data in background thread, but when notifying recyclerview, it stucks for small amout of time.
Try to start loading, which you did, after click and show simple ProgressBar, and when data is loaded, hide progress bar, set info to your fragment and then show fragment. Then you will have all data wich you need in fragment when it is attached and can put it (data) to your adapter.
It have to look good.

If it occurs only for API 19 and lower, it may be a lack of performance from the device.
Maybe the problem do not come from Fragments and Animations, but from another functionality which slow down the UI thread. By functionality, I mean the way your fragments communicate together. Do they share a huge amount of data ? Or heavyweight datas ? If so, you should use Async Tasks or Threads.
Good luck !

Related

Android RecyclerView items empty when being swiped after switching apps

First of all, I have looked at similar questions (for example, this one: Android RecyclerView ItemTouchHelper revert swipe and restore view holder). This already helped a great deal, until I - more or less, accidentally - noticed my current (and hopefully, final) issue with this screen of mine.
Let's start with the setup:
I have a fragment with a RecyclerView filled with some CardView items (it's a little fancier, but that's what is important right now). I also created an ItemTouchHelper with the implementation of SimpleCallback (nothing in onMove()) to make swiping the items (right) possible. For the record: I am using API 27 right now.
So far, so good.
What I want to achieve:
I want to be able to swipe the items to be notified through the onSwiped() method of my SimpleCallback implementation. Also, I do NOT want the items to disappear, be removed, or otherwise taken out of my list of items in the RecyclerView. I just want to swipe them and have them return to their original position afterward (and yes, I know that it is sort of assumed that swiped items get removed). I am using the notifyItemChanged() method of my adapter in the onSwiped() method (also tried using notifyDataSetChanged()).
The problem:
Funnily enough, that works (mostly thanks to the aforementioned question) - until I hit that "app switch" button (don't know if there's actually one official name for it) and send the app to the background. Once I put it in the foreground again and start swiping, the items will not (visually) return. They are still on the list, and if I scroll or click the "app switch" button again, they will be displayed properly again (but won't return on swiping). Same if I navigate back one screen and come back to the list.
That makes me think something happens when I send the app to the background and recover it. Something different than navigating to that screen (in which case everything works as intended) - which I thought would more or less produce the same results. Any ideas what I might be overlooking here?
After some testing, I finally found the source of the issue:
I had both the RecyclerView and its Adapter initialised through onStart() of the Fragment and not onViewCreated(). After changing that, I got the proper results I wanted.
Lesson learned: Set your RecyclerView's Adapter as early as possible, unless you want to deal with sometimes strange issues.

PagerAdapter prevent destroying already loaded views

I'm trying to prevent my ViewPager's PagerAdapter from destroying Views it already loaded once.
If I understood it correctly, the method ViewPager.setOffscreenPageLimit(1) will create and cache a page on each side of the selected view.
This is okay for me, except for the part that if I for example jump to page 5, pages 4 and 5 will be created and cached, but pages 0 and 1 will be destroyed.
I've tried commenting out everything in my pager's destroyItem() method, and caching in a HashMap the views created in instantiateItem(), and returning them as-is if they are found on the HashMap.
This seems to be working OK, but I'm not sure if there are any downsides to doing that this way, apart from the higher memory usage, which is hopefully not a problem here.
My app is actually an application framework and I'm going to leave that decision to the final developer, leaving ViewPager's default behavior in case he/she doesn't want to apply this caching behaviour. Some clients are pretty unreasonable and they have a huge number of views in everypage. I've tried to convince them to work their way around in different pages since Android's View creation is costly, but as I said, they're unreasonable.
Do you guys know of any good way to do this?

Advice on developing a timeline view for Android?

I want to develop a timeline view for Android, which is like a infinite scrolling Google Calendar day view.
Now I use a fixed length RelativeLayout in a ScrollView, and I think I should use AsyncTask to dynamically load the data.
I do not know if it is necessary to use AsynTask to load the data, because I just want to load some texts now.
My idea is to set two points near the upper and lower borders of the RelativeLayout and load data when scroll across the points. Should I prepare the child views in AsyncTask and attach them to the RelativeLayout in onPostExecute() or create a new RelativeLayout and then replace the old one in onPostExecute()?
What is the common practice? Thanks.
If you're loading the data from a static array or some other data source that is already in memory, you may be able to get away with doing it on the UI thread. If you're going to be loading the data from disk or network, you should (and in the case of network must) load it from a background thread (i.e. not the UI thread), and AsyncTask<> is a great way to do that.
Your approach seems reasonable. You may be able to memoize and reuse layouts as the user scrolls.

Android load listviews at end of scrolling

I want to implement functionality where a listview loads a set number of views, but at the end of the scrolling it has a spinner in that view, while it loads more views
the official android twitter app has something like this, where it shows you old messages from your timeline but at the bottom of the list it will load more after running a spinner. you can still scroll up and down while this thread is happening without breaking anything
how would this be done? insight appreciated
i think by spinner u mean blocking screen ?
anyways what u need is pretty common, just search for listview implementation in android
here is one of the link i still had:
http://blog.zjor.ru/2010/12/loading-list-data-asynchronously-in.html
also check this if u really want to go to that extent ;)
https://github.com/commonsguy/cwac-endless
basically, it would probably be something like:
Load some data (use a limit)
When you enter the bindView of your last element, change your limit (may be by joining the cursor to another one)

Any way to animate new elements in a GridView being added?

My app polls a server every 15 seconds to see if there are any new items to display, then downloads the new items and disposes of the old items so that there are always exactly 100 items in the GridView. Unfortunately, this process can be confusing to the user if they see a page of images change without knowing where the items went.
My idea is that there could be some kind of animation (such as the new items being inserted at the top and pushing the older ones down the list) to show what action is happening. Unfortunately, I have no clue how to make this animation happen.
Is my idea even possible? How would I accomplish this?
Ben,
I know it's been almost a year since you posted this question. But I thought this might help you out.
http://developer.android.com/reference/android/view/animation/GridLayoutAnimationController.html
I think you will have to extend this layout and somehow pass in the position of the changes.
There are like 10 animations examples in the sdk (you will have to download them using the updates manager); the example is called "API demos". First, you can take a look of the Views -> animations examples... though, in your case the more interesting ones can be found in Views -> LayoutAnimatons.

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