FastScroll in Relative layout, not a list view - android

I wanted to implement fastScroll like the one that is supported by ListView, but in a Relative Layout which has a large number of views, aligned vertically below each other. There are several different type of views so I can't use a list view.
I'm able to modify the thumb drawable for the scrollbar, but unable to make it work as a fastscrollbar.
is it possible to achieve it?

Do NOT implement list view on relative, linear or any other layout. You will run out of memory very fast.
You can have list view with different types of item views. It's called heterogenous list view.
Take a look here:
https://github.com/codepath/android_guides/wiki/Implementing-a-Heterogenous-ListView
and here:
https://stackoverflow.com/a/4777306/1535436

Related

Is there a way to hold a particular element of a recyclerview on the top?

I am using a recyclerView, with a GridLayoutManager layout.
The recycler view contains 2 types on ViewHolders, one having span size equal to 3 in order to separate different types of grid elements and one of size equal to one.
What i want is to be able to hold always on the top one of the view holders of the size 3 (depending on the horizontal scroll position), like shown in the image below.
Does anyone has any idea how to do it? If it is possible i would want to avoid to create a custom layout, is there an easier way to do it?
grid layout exemple
You can check this github project
StickyHeaders
You can use directly this and import it as a dependency or you can look at the code and try to implement your own "sticky" header.

Recycler View as part of a Scroll View

I'm developing an app that has an UI pretty similar to Play Store. It is organized as a multiple panels one above another. First it has a panel containing a photo. Under that it has another panel containing some text and a custom background color. Under that it has another photo and finally it has a Linear Layout with vertical orientation containing a pretty long list of little views filled dynamically at runtime. I have all this inside a Scroll View, naturally.
The problem? That dynamic fill of the linear layout takes a long processor time and makes my app unresponsive during those inner views inflation. So I thought to replace the linear layout by a Recycler View. And the performance is awesome!
So? Well... Not everything is so awesome. I can't scroll the Recycler View because it's inside the Scroll View. And if I remove the Scroll View then I can't scroll the entire view (some things doesn't fit on the screen).
What's the best approach for fixing this?
It's not recommended to use a RecyclerView or ListView inside of a ScrollView precisely due to the double scrolling issues. RecyclerView is very robust and is prepared to receive headers, footers, etc. I see no reason why the entire layout could not be inside of a RecyclerView instead of a ScrollView
The ViewHolder implementation can include logic to inflate different layouts depending on what section should be next.
Pseudocode:
i.e.
if(currentAdapterItem == sectionA){
useLayoutA();
} else{
useLayoutB();
}
Just use a NestedScrollView instead of a normal ScrollView. It handles the nested scrolling quite well.

Linear layout with nested listview scrolling

I have a LinearLayout with a nested listview which looks like this:
<LinearLayout ... >
<LinearLayout>
</LinearLayout>
<ListView>
</ListView>
</LinearLayout>
The problem is that the listview owns the scrollbar (so only content in the listview is scrollable) but i actually want the parent LinearLayout to own the scrollbar (so making the entire content scrollable).
Wrapping parent ListView in a ScrollView hasn't been successful because the ScrollView doesn't recognize ListView height (which looks like is rendered at running time)
Thanks
Edit: SOLVED My perfect solution was using a MergeAdapter, as advised by Barak
You can use CommonWares MergeAdapter which allows you to define views and list adapters, pour them into the MergeAdapter and get a single list adapter out, containing everything you poured in, and it scrolls as one list.
A previous answer about MergeAdapter I gave with some instructions is here
You could replace the Listview with a Tableview instead, as long as the listview does not have too many items in it. You can still use a childview with the tableview in much the same way as the listview, you just won't be able to databind it in the same way as you can with a listview, and the items won't recycle either.
Since the listview is designed to contain more items than can be displayed the height will never exceed the screen size (best case) which is the intent of the control, though I suppose you could force it to be larger that seems generally like a bad idea for a lot of reasons.
I suspect what you should do is either create a custom listview adapter, and based on position in the list create the view you want, this would allow all items to scroll like you want.
Listview with different view types per row
This may or may not work depending on what exactly you are trying to do, otherwise you might just want to add views to a linear view inside a scroll view san's the listview.
It just depends on the use case (how many items in the list view, memory issues etc) and what the purpose of the other views are.

Is it possible & efficient to put a LinearView and ExpandableListView inside a ScrollView

I'm making a GUI with two different parts. The first part (at the top) is composed of some banners, several fixed buttons. So I think using LinearLayout is the most straightforward way to implement. The second part is composed of several similar items grouped together which can be implemented by using ExpandableListView, I think.
However the problem is that the content exceeds the screen size. So I intend to put two of them into a ScrollView. I checked several sources, it seems that putting "ExpandableListView" inside a ScroolView is NOT possible, or not efficent, so I'm afraid...
Would you help to confirm if this is possible? efficient ?
If no, would you give me some recommendations for this layout design?
I'm indeed looking forward to your supports.
Sincerely.
If you have a fixed header at the top of a list, use ListView's header view feature.
Putting ListViews in ScrollViews fundamentally makes no sense and here is why:
ListView has one purpose: to efficiently display unbounded data sets. Since these can be extremely large (tens of thousands of items and more) you do not want to create a View for each item up front. Instead, ListView asks its Adapter for Views only for the items that currently fit in the ListView's measured space on screen. When an item's View is scrolled out of sight, ListView disconnects that View and hands it back to the adapter to fill out with new data and reuse to show other items. (This is the convertView parameter to an Adapter's getView method.)
ScrollView also has one purpose: to take a single child view and give it "infinite" vertical space to fit within. The user can then scroll up and down to see the full content.
Now given this, how many item Views would a ListView create for a 100,000 item Adapter if it had infinite height available to fill? :)
By putting a ListView inside a ScrollView you defeat ListView's key purpose. The parent ScrollView will give the ListView effectively infinite height to work with, but ListView wants to have a bounded height so that it can provide a limited window into a large data set.
Well Expandable List View itself has scrollable property by placing it in scroll view is really undesirable.As the both scroll would contradict and smooth scrolling can't be obtained in that case..
If we have any data to be shown prior or later to list...
Best way is to use header and footer view to list...
I recommend you use header and footer in your case.

Horizontol Scrolling View in Android

I want to create a Horizontol Scrolling View in Android. The view would be a combination of images and text scrolling horizontally and I should be able to dynamically modify the content(text and images) in the Scroller
Any ideas?
add HorizontalScroolView in the scrollview it will scroll in both directions.
ScrollView
HorizontalScrollView
ImageView
You could perhaps also have a look at the Gallery element.
You'd like something like ListView, but in horizontal orientation.
I'd make this to extend AbsListView, which is made to display dynamic lists.
Ideally if you'd copy ListView source and switch it to horizontal mode, but this is very complicated and long class, so look for easier options.
Try using GridView with just one row, stored in a HorizontalScrollView. Feed it with a ListAdapter, provide Views for your cells and setup content to display.
I didn't try this, but it seems like easy solution. Assuming that number of items will not be large, because there won't be optimizations available in ListView class.

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