I have to implement a ListView or GridView where every item will have non-uniform height/width. Also a particular item could span multiple columns. A GridView is perhaps a better candidate, but again each row has a different schematic. The attached image best describes what I want to achieve.
I am looking for ideas on how best to implement this. I am not looking for code samples, but just some guidelines.
Right now, I'm thinking of implementing a custom ListAdapter where each row is laid out in the scheme I want. Of course then I'd have to do some tricks to map list indexes to actually items in array of items (if I use and array adapter). For example, in the mockup below, the penguins will have an index of 1 in my array, but 0 in the ListView.
in these kind of structure you should use a layout in xml and add dynamic view in that layout from java file.
May be a relative Layout with ImageViews is good. It may get a bit messy for the .xml though! This seems quite interesting. Do keep us updated on which of the solutions you finally chose.
Thanks!
Related
I'm creating a detail view for a Dictionary entry. The basic structure is as follows: A dictionary item can have 1 or many 'Meanings'. Each of these 'Meanings' can further have 0 or many 'Field of Applications', 'Part of Speech', and 'Dialect' values. There are other similar sections for a dictionary item as well such as example sentences.
Due to the size and structure varying based on a query result, it seems to me like the best way to do this would be to have multiple ListViews as follows:
I realise that putting ListViews inside ScrollViews is a bad idea, and Google themselves say you shouldn't do it, so what is the 'best practice' way to accomplish something like this?
I've thought of the following solutions, none of which seem ideal:
Use a single TextView instead of a ListView, and use new line characters to separate data rows. This feels very hacky and makes formatting specific parts of a row difficult.
Replace the ListViews with LinearLayouts, then programmatically insert TextViews within them as needed.
Create a custom ListView which is not scrollable.
This seems like a very common use case for a detail view, yet I can't find any concrete answer on how to deal with this.
You can replace your ListView with RecyclerView (and adapter as well= and call
recyclerView.setNestedScrollingEnabled(false);
which will enable smooth nested scrolling.
When you are working with a long, big list, certainly one should use ListView because it handles cell recycling.
Notice here, for example Can i use nested linearlayouts instead of list view, for a big list? the OP is asking about ListView verses a dynamic LinearList -- the answer is "have to use a ListView, because of recycling"
Now, say you are making a short list -- imagine say a popup with only 10 or 20 items. It may even fit all on the one screen, so there's no recycling.
In fact, is there any difference between using a ListView and just using a LinearLayout, and dynamically populating the little views inside it?
It seems to me that the latter is in many cases much simpler, more elegant, and easier to work with. But I could well be missing something that seasoned Android engineers know about.
Should I just use an ordinary LinearList (populate it dynamically) for lists where recycling is not relevant? What's the usual, and why? Cheers!
{Incidentally, for popup cases, is there some better, lightweight method for "choose one from a popup-list" that I'm too silly to know about?! :) )
ListView(and other lists) supports very useful idea: splitting data and view. These parts could be changed at any time so it's important to support flexibility. And it could be solved by special mediator object: Adapter. Adapter roughly speaking says how to fill your view with particular data item.
So I'm sure that if you decide to use LinearLayout sooner or later you will implement you own Adapter.
If you used dynamic linear view then rendering the view will take more time as compare to listview. In listview we are rendering views which are visible only but if you used dynamic linear view then its problem.
I'm looking to create a music app and I'd like to make a GridView similar to what Google Play uses where they inject elements that will span rows and columns like the Soilwork album does in this screenshot:
I've thought about using a ListView and populating rows with custom elements, but I couldn't think of a good way to use that with ViewHolder pattern, or really a way to make that reusable and account for differing number of items in width based on screen size (for example, the grid is only two items wide on phones, and "large" items span both columns and only one row).
I've also thought about using a ScrollView filled with custom ViewGroups, but that seems to run into the same issues I previously mentioned.
I next thought about using GridLayout, but that doesn't accept ListAdapters, and doesn't seem tuned to the kind of usage I'm looking at (nor does it seem to scroll)
I'd greatly appreciate if anyone could give me somewhere to start on this, or could point me to a library that does this. I've already checked out StaggeredGridView but it doesn't seem to accomplish what I'd like. My ideal solution would be a view which lays out items on an even grid like GridView and accepts view from a ListAdapter, also like GridView, but allow for elements to span, using the single cell constraint of GridView as the default behaviour.
Cheers.
EDIT
I have a perfectly functioning GridView as shown below, but I'd like to make items at regular intervals (every nth item) span more than one column and/or row, as shown in the previous screenshot.
Check out Parchment. GridDefinitionView may help you achieve the UI you are looking to build.
I have created a custom adapter to display a list, there is an image that is displayed in each row ( the image is the same for all rows, except using an array i am assigning it different values depending on the position). An xml file defines the relative layout that i am using. My problem is that i can either get the entire row to be clickable or nothing at all, I only want this image to be clickable, instead of the entire row. How would i be able to do this ? i am new to android and am pretty much following different tutorials trying to create my list. Any help would be appreciated.
layout is like this :
TEXT:
[Image]
TEXT:
thats wat a row looks like...getting two texts from two different arrays and shows it, a third array is used to link to the image. I just want this image to be clickable instead of the entire row.
Thanks
Android's list component manages clicks per row. This makes it very difficult to achieve what you want to do. Two solutions come into mind:
1) If your list is never very long you could simply use linear layout and scroll view to build the list. This approach won't work if you fill in the list dynamically and you can't be sure that there won't be a very large number of rows as it would use too much memory in that case.
2) Other option is to use ListView but make your text components and images different view types in list ie. break you row into three.
That can be achieved overriding list adapter's getItemViewType(int)
http://developer.android.com/reference/android/widget/Adapter.html#getItemViewType(int)
In this approach you can make the image rows clickable but the text rows not.
I have a RelativeLayout with different elements. I was planning to have two ListViews on it, but I have noticed there are some problems with scrolling. Since each ListView only shows a maximum of 5 rows should I try to make some kind of custom adapter to merge those ListViews? Or is it better to replace the ListView with a LinearLayout/RelativeLayout and add the rows as I get them manually? (like the first answer in here: android listview display all available items without scroll with static header ).
Which should be the proper way on doing this? or is there another way? Also, each row will have an OnClickListener.
There's two solutions if you'd like to keep your list... list-y, without having to prerender all the row Views like the above solution suggests (which can be slow to render, eats RAM and doesn't scale nicely to more than a screen or two of Views, but is a fine quick solution for smaller lists, though I'd just use a bunch of Views in a LinearLayout in a ScrollView rather than a ListView in that case).
Write a custom ListAdapter, overriding getItemViewType, getViewTypeCount and GetView to inflate the proper kind of view and recycle appropriately for your two types of views. You'll also either need to override getItem to contain custom logic for figuring out which set of source data to look in and to map the data accordingly, or mush the data down into one list of Objects (if you're using an arrayadapter) and cast in the getView method (probably a bit slower than handling it in the getItem without casting).
Just use cwac-merge, a view-and-adapter wrapping adapter. You can put two ListAdapters into a MergeAdapter and set that as your single ListView's adapter.
I had problems with scrolling. I never figured out how to have the ListView share vertical space with a different View, and have a single scrollbar for them both.
I worked around it by having everything that needs to scroll on the layout a row in the ListView.
Adding views as rows to a LinearLayout may have problems scaling up, but I think you'll be OK if you only have 10 rows in total. On 1st gen Android devices it'll probably start to get sluggish around 20 items (depends on Layout complexity obviously). ListView scales up by only inflating views as they come on screen.
So in answer to your question either of the two alternatives you suggest will be OK, but the LinearLayout option will be the easiest to code.