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Session state of ListView

I am new to Android App development, working on an android app which populate a list of numbers, in a listview dynamically, depending on the choice of the user, but, the moment user closes the App, the items in the listview are lost. How can I maintain the state of the listview?
Examples with code would be highly appreciated.
When I open Activity A, it allows users to add friends, and this friend list is shown in the form of items of listview in the same Activity, however, when I move to Activity B, and then come back to Activity A, this friend list disappears. I need to make sure that this friend list should not be lost while moving between activities. Please help.

I think that for your purpose there are 3 main methods, i'll explain them from the easier to the most difficult (in my opinion).
Text File
A way to do this is to create two methods in a class:
one has to create the text file in the storage if it isn't created before and read that, the other has to append a String to a StringBuilder and write it on the previous text file.
For this method you need the uses-permission of reading and writing to storage.
This link can help you: http://developer.android.com/training/basics/data-storage/files.html
JSON (also XML)
With JSON file you can create a list of objects with your data that you can serialize when you update the list and deserialize when you want to read it. For this purpose you have to study JavaScript syntax or, at least, JSON one.
SQLite Database
Android SDK incorporate a class named SQLiteOpenHelper that you can extend to create a database inside your app.
This link can help you: http://developer.android.com/training/basics/data-storage/databases.html
There are also references saving methods but i think that aren't right for your purpose, they work betters to save something like preferences or single data like last login informations.

I went through your comment. I would personally suggest using SQLiteOpenHelper
You might need to understand the use of SQLite, hence the tutorial
Simple Flow. On your Activity 1 where person Add Friends save it to DB
Then refresh the List from the DB. So when you move to Activity 2 and come back again to Activity 1 your List will refresh from DB. Hence no loss of data as you want.
EDIT
As user wanted to know how to use the ListView with DB.
Following are my suggestion
Sai Geetha
Youtube

Save highscore on corona sdk?

I want to save the highscore created in the game and can be seen in the main menu when the player hits the highscore button, can someone help me?

you can use SQLITE to save the highscore to database another way is make a file that write the score to a Text File and save it to the directory of the system

You can solve your problem in a easier way..
Just declare a Variable for the Score like this..
local score=0
Then Increment the score variable by 1 whenever it hits the paddle. So Insert the coding in Collision Function as given below:
local function onCollision(event)
{
score=score+1
}
ball.collision=onCollision
ball:addEventListener("collision",ball)
Finally When you need to save your highscore (after gameover), You can use Preference instead of json which makes the larger coding.
local preference= require "preference"
local highscore=0
preference.save{highscore=score}
If you want to display the Highscore, then use the following:
highscore_value=preference.getValue("highscore")
display.newText(highscore_value,0,0,nil,30)
This might be useful for your problem !!

Multiple libraries exist for this purpose.
GGScore is an open source library built by GlitchGames which can easily allow you to do this: GlitchGames/GGScore
All the documentation you need is in the main page (README.md) so there isn't really a need for me to explain the code. But it's really easy to use.

Android txt files v's database

My music app is referencing persistently stored data. All are currently stored as text files:
Favorites - single text file array. App starts, reads the text file, stores in memory. Array is checked when ListView is expanded. If array changes text file is rewritten.
Last Played - single text file array list. Updated every 5 seconds. Retains the history of the played songs to allow the user to return to any album and resume position.
Playlists - currently individual text files, one for each list. List of playlists generated from file names when required. Each playlist text file has array list inside it. Read Write when required.
Most Played - single text file array list. Updated once per song played.
I am wondering whether this data would warrant the need to change to a database, or whether I have taken the right approach. I don't foresee the need for adding additional data so this should be the most I would need.
Advice please!

You can store the text files in SharedPreference and it should work well.
Database if preferable if a lot of data needs to be stored. Using a database is more optimal than parsing a string.

The correct approach is to create a class for each of the things you want to represent, e.g. favourites. Each class has a save() and reload() method. The point is that you can change the underlying storage mechanism in the save() and reload() methods without having to change the rest of your code. Imagine in the future, you want to enable saving to Dropbox. You would simply change these methods and your app would just work (OK, you'd need to add stuff to get Dropbox account details but you get the idea).
You could go further and define Interfaces for loading and saving. That interface can use a single class responsible for nothing except saving and loading. As long as any consumer and provider classes adhere to the interface, you can mix and match, and even implement storage approaches yet to be invented, without recoding your app. You only have one class to work with if, and whenever, you change your storage approach.
class StorageManager(){
enum DataType {Favourites, MostPlayed, PlayList };
...
public save(DataType dataType){
if (dataType == DataType.Favourites){
saveFavouritesToDB();
...
...
}
This approach gives you maximum flexibility, maximum future proofing and better maintainability.

I think it would be better to go with Database.
The database should provide you with some optimizations, performance improvements and basically you don't have to reinvent the wheel (doing read / write operations on the disk, use some buffers before rewriting, and the like).
Plus, I think you will love the way all code will be organized and split into its own layers once you start using this way.

Android save state before ondestroy() [duplicate]

This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
Android: Saving a state during Android lifecycle
i want to save some values in a file before the user terminates the activity.In which method should i implement this?
Apart from using a file , or sql lite is there a way of storing complex data such as a layout (that has dynamically changed ) ?
"onDestroy() Note: do not count on this method being called as a place for saving data!"

Layouts are bound to the context of the Activity that holds it, so you do no want to save full View objects to files because the Activity that it's attached to is void.
The easiest method (depending on the amount and type of data you want to save) is using the SharedPreferences library. It's a file I/O wrapper that makes saving and retrieving data pretty simple. You can save the specific layout data in the onPause() method, the rebuild the layout with the specifications in onResume().
If the data you need is too complex for SharedPreferences, you'll have to save it to use other methods for saving (found in that link). The process for rebuilding the layouts will be the same.

I would call all the stuff you want to pass to the bundle in your onPause method. Here is some stuff on the android lifecycle and why not try storing stuff in csv if you want to load from file. (comma seperated values) (althoughthat is mainly used for tile based games)

you can use SharedPreferences , refer the doc , and this tutorial to understand how to do it :)

Why not save the data using a SharedPreference? Here are the android docs: http://developer.android.com/guide/topics/data/data-storage.html#pref

How to save parsed data in android?

I am creating an android application in which I am parsing so much XML data (XML data comes from a server) which contains Strings and image url's also.I need to use this data in many part of application. So for saving all these data I have used ArrayList and HashMap.I have declared ArrayList's and HashMap's variables in a single class as public static variables so I can access this data through a single class whenever I need.
And for images I have created ArrayList and placed in same single class same as other data(public static).Once I download a image through image url's I save those image drawables to these ArrayList variables so whenever I need any image again so I use these variables to get it.
Now my doubt is whether this approach is right or not. Please suggest me the right way.
Thank you

You should actually take a look at: http://developer.android.com/guide/topics/data/data-storage.html
It all depends on how you use the data, does it need to be updated all the time when the user opens the app you could take a look at this answer: How to declare global variables in Android? where you declare a global application and have the variables there.
Otherwise I would actually advice to use an sqlite database. http://developer.android.com/guide/topics/data/data-storage.html#db One good example is here: http://www.vogella.de/articles/AndroidSQLite/article.html