Can someone point me to right direction, how to create an adapter for AutoCompleteTextView, which would be getting data from SQLite DB, using data, which user entered into the text field? I want to use the user-entered data to filter suggestions for autocompletion. I imagine that adapter should always take user-entered data as soon as changes appears and use it for fetching suggestions on-the-fly. Is that possible? So far I've seen many tutorials for autocompletion where static String arrays were used, but never seen them build dynamically. Is it possible to do it automatically or I need always fetch String array myself and pass as ArrayList to adapter on every AutoCompleteTextView change?
You might be looking for CursorAdapter. Use it just like an ArrayAdapter, but instead of feeding it with an ArrayList, provide a database Cursor. Google for CursorAdapter and you should get a lot more example codes.
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I have a ContentProvider implementation in my app which works fine. I have a table called elements where the user can store a bunch of information.
What I am doing is when the user opens the app, I pull this data out of the database, process it using the display options set by the user (Like change the string formats, time formats, date formats, number decimals etc), and then put it in ListFragment which using my own implementation of ArrayAdapter. User can of course change the preferences in the middle of the session, where I reload the data and reformat it and present it to the user. The user can click on an item in the list, and see more details of that item. I accomplish this by overriding ListFragment.onListItemClick().
I have been reading about SimpleCursorAdapter. I am confused if the use of this would be more correct than using an ArrayAdapter for what I am doing. I am confused because I am not directly mapping the database data to the view. So should I be using a SimpleCursorAdapter? Also, the _ID column seems to be a requirement. I don't want to rename my table at this point. After a few articles and tutorials, I am not sure what to do. So any suggestions are appreciated.
I am looking for some help to find a powerfull way to allow selection of different List items.
My case is that i have for exemple a List profiles, List teams ... and i'd like to have an autocomplete input that will show, for exemple if i type Al, all Teams and Profiles objects having there member variable name begining by Al.
The result would be that i could get from the activity, on submit click performed, a List & a List containing all the objects who have been selected through the autocomplete form.
Also i'd like that the list offered to the user that match the chars he typed show the name and a picture (facebook like tag selection).
Obviously i am not asking for some code but at least some guidelines from experienced Android devs who know what to do and not to do to create this kind of thing.
Thanks
Loader are one of the best way to filter list. You init a loader which take the String constraint used for filter, the each time the user type, you update the constraint and restart your Loader.
If I suppose that all your object are cached in a SQLite database you can use a CursorAdapter, Cursor and CursorLoader.
You create the needed CursorLoader by filter the query with the content of the EditText.
If you're not familiar with CursorLoader there is the AsyncTaskLoader, with this you won't have the need of DB and to code a provider which can accept raw query. Your object in ListA, ListB, etc must inherits of common class (hum... DataThing maybe :-)), you concatenate the objects in a list then you can filter the list : What is the best way to filter a Java Collection?
That's for the data filtering. Now in order to display the data the way you want, you can display of list below the EditText field or create a custom component if you want a more advanced look.
is it possible for a Spinner to return multiple values or class object on selected?
For example I have a Spinner of Laptop models. When selected I want it to return LaptopSpecs object that contains size, weight, processor, etc. Then use it to display the information in the view below it.
Thanks
Sorry, there is no multi-select Spinner. You are welcome to use a multi-select list AlertDialog to allow the user to make their selection(s), but you will need to decide for yourself how you want to render those selection(s) when the dialog is not on the screen.
It depends on how you are populating your spinner.
If you are pulling the data from a database in a cursor, what you are trying to do is easy.
As a matter of fact, using a database, there's a couple ways you can do it:
1) You simply pull all the necessary data you need to create the object into your cursor (kinda heavy load on the front end), and when a selection is made (fromthe single bit of data displayed in the spinner), you use the cursor position reference in the onItemSlected method to pull the related data from the cursor and pack it into your object.
2) You pull only the piece of data to display in the spinner and when a selection is made, use the database row id in the onItemSelected method to fetch the rest of the data for your object from the database.
I have two methods which read the same data from database, the first returns Cursor and the second returns List of objects.Now I show my items in activity using SimpleCursorAdapter and the first method, byt I can also use the second method and appropriate adapter.
Which of these two ways is beter to use and in the second way which adapter I should use?
P.S sorry for poor english
Definitely go with SimpleCursorAdapter. If possible, always use Cursor if your data comes from database, you save memory by not creating List of objects. Creating objects in Java is expensive with regards to time and memory consumption and you have to bear in mind you are on mobile platform with limited resources. If you are using List of objects for your ListView than use custom adapter extending from ArrayAdapter.
It's not always straightforward to use Cursor although your data comes from database. Let's say you store places in the database defined by its name and location and you want to display them in a ListView sorted by distance from current location. It makes it difficult to execute a query which returns sorted results unless you don't store relative distance in additional column. But you can get Cursor convert it to List of objects and sort this collection before sending it to your ListView.
The question posted in this thread asks how to update a ListView when the data has changed. It assumes, however, that the data that is modified in a ListView is stored in a database. Therefore, the ListView UI can be updated by simply calling requery() after the changes have been committed to the database.
What should one do when modified data of a ListView is not stored in a database?
For example, if each item in a ListView is showing the distance to a particular landmark based on the user's current GPS coordinates, what is the correct way to update the view with the updated distances as the user moves about? Should the distances simply be stored in the database as a matter of convenience, so that requery() will update the UI? This does not seem like the correct approach if it is not necessary to persist (frequently changing) GPS data.
Edit: To clarify, I'd specifically like to address the situation where some of the data is stored in a database (the coordinates of the landmarks, for example), however, the frequently changing data is computed on the fly (e.g., the distances).
ArrayAdapter can be used instead of CursorAdapter.
The notifyDataSetChanged() method can be used to tell the ListView to refresh itself by requerying the ArrayAdapter assigned to it.
I suggest using ArrayAdapter instead of CursorAdapter (which is used to populate a ListView based on cursor > database query)
ArrayAdapter
You should update the array data storing your coordinate data. When it changes call adapter.notifyDataSetChanged() to have your list updated with the latest array data
Hope that helps