Develop Reference

String Array in SharedPreferences

I need to work with a persistent String Array (n Rows, 1 column).
* On first running the app, the String Array needs to be created empty.
* On subsequent app executions the Array will be populated from a File and the contents need to be available throughout the rest of the app.
* As the app is executed, the Array needs to be able to 'grow' in row count
* As the app is executed, the Array rows need to be able to grow in length
* The user will have the option to Clear the Array of previous entries.
* At the end, the String Array contents will be written back to a File.
I find a lot of references to Putting and Getting from an existing SharedPreferences String[] but, in the newness of my Android development, I am struggling with how to proceed.
EDIT Follows...
The data itself suggests using an Array
Example:
MAIN ST. F55 63 KY08:57 12142015--------KY11:24 12142015345TMH KY13:57 12142015
MAIN ST. F56 WYE123 IN08:57 12142015--------KY11:24 12142015--------KY13:57 12142015
1ST ST. F57 --------KY08:57 12142015--------KY11:24 12142015789FPF KY13:57 12142015
1ST ST. F58 456FPF KY08:57 12142015998FPF KY11:24 12142015--------KY13:57 12142015
1ST ST. F59 789TTM KY08:57 12142015--------KY11:24 121420151234DG KY13:57 12142015
I first need to have this data in a File
Then in one GUI I check for the existence of the file.
If one exists, fine
If none exists, I create one.
Then, in subsequent GUI's, I must check for the existence of parameters
If they do not already exist, add them to the existing data lines.
If they already exist, notify the user
And so on and on.
Then when all of the current 'pass' data has been collected via multiple, separate GUI's, I have to write out the whole data-set into the file.
My reason for thinking that I need a SharedPreference approach is the need to find and check data from GUI to GUI as the user progresses through the app.
If that 'belief' is wrong, I am open to better approach suggestions.
EDIT 2 follows....
On further study of web references, I am beginning to think that perhaps the best approach for this data and how the data needs to change might be to use a SQLite approach. Any ideas about this?
Any assistance/suggestions you might have would be greatly appreciated.

i would discourage you from using sharedpreferences for anything else than preferences. means things that change rarely - really rarely and are really lightweight. do not put much data in there. less is better. the data structures underlying sharedpreferences are not a database.
another note. it is not a string list, but it would be a string set. sets are not necessarily ordered, nor do they necessarily keep their order. means - it is not rows. its a collection of strings that can come back in any fun order (usually there is some, but that depends on the implementation which i do not know)
now you could go and make your own list, your own data structure, save it into a string and read it out, use json to do exactly that or something similar, or better - use a database, which would exactly do that.
http://developer.android.com/training/basics/data-storage/databases.html
explains it, but as you'll see its something that might take some time.
now dont get me wrong, but i have to warn you about the following approach. it is valid, but has many problems and is far from thread safe. it will not be a problem as long as you only open it from the ui thread and do not keep anything in memory to cache - if you do it will create lots of problems.
your problem of adding a line and clearing can be solved by using a file. just a simple file
look here
http://developer.android.com/training/basics/data-storage/files.html#WriteInternalStorage
the change is to append when writing:
openFileOutput("filename", Context.MODE_APPEND);
see the context mode? now you can basically just write one line and append every time.
if you wanna clear the file, just deleteFile("filename")
this is as said not threadsafe, but can be a viable option if used carefully.

Please follow this step to achieve what you want with sharedPreference
create the class Parent for SharePreference
Create your empty Array
Convert Your empty array to String and put it on SharedPreference
to call your empty array from sharedPreference
Call your sharedPreference using your key
Convert the String to array
You get your array from the sharePreference
Hope it helps, and maybe this link will help you :
http://www.androidhive.info/2012/08/android-session-management-using-shared-preferences/

You can use my open-source library called prefser, which solves this problem and uses SharedPreferences and Gson under the hood. It's basically wrapper for default Android mechanism.
You can use it in the following way:
Prefser prefser = new Prefser(context); // create Prefser object
prefser.put("key", Arrays.asList("one", "two", "three")); // save array of Strings
String[] value = prefser.get("key", String[].class, new String[]{}); // read array of Strings
For more information check repository of the project, tests and README.md file.
Link: https://github.com/pwittchen/prefser
Please note, SharedPreferences have some limitations and shouldn't be used for storing large amount of data. If you expect a lot of data, consider using SQLite database or another type of database (e.g. with NoSQL or similar approach if you strive for simplicity).

OK, based on the data, how it needs to be manipulated and the pros and cons of using a SharedPreferences approach, I have decided to go with a SQLite approach.
With that approach I should be able to readily check:
* if the necessary table exists (if not create it)
* if the necessary Field1 + Field2 exists (if not create a new record)
* and I will be able to modify the record's Field3 contents as needed
Then when the user's actions are complete I can convert the SQLite table 'records' into strings and write them out as a File and then either DROP or PURGE the associated SQLite table (until needed next time).
I sincerely appreciate all of your suggestions.
Thank you.

ActiveAndroid: Date columns not created

I am trying to store a Person object with ActiveAndroid. I set the birthdate like this: person.setBirthdate(new java.sql.Date((new Date()).getTime()));. After assigning all data i am calling person.save();.
I get a list of all persons from the database with this command: new Select().from(Person.class).execute();
If I do not close the app everything works fine (birthdate is always returned correctly from the database). However, when I close the app completely and then restart it, the birthdate is always null. All other fields (first name, last name etc.) are correct.
I really don't know why this is happening and would appreciate some help!
EDIT: After taking a closer look at my database I found out that the birthdate-column is not created. I am still not sure why the data is available when not closing the app though.
Second EDIT: I added a new column (a string) which is saved to the database and works just fine. So the problem is not an outdated database. All columns but the date column get created.
I also changed the date datatype to a string. The birthdate was then saved. Changing it back to a Date datatype resulted in the original problem again. Really weird... Does anyone know whats going on?

It should be some caching problem.
for saving Date try to use type serializer. it is so easy just read this page.

Number of Data in a row checking

I am building a monopoly game and from what I'm doing I'm almost done, but I want the game to end after 30dice rolls. But the way I want to do it is weird. I need a way to store data and check if the data is upto 30 or not, I mean check the amount of data is a row, I've been looking if sqlite or shared preferences would do, but can't get anything. Any idea would be welcomed and if you can help review my code too, I wouldn't mind. Thank You.

If you realy want to persist it in the Database, you want to have a key-value table current_game_progress with an item dice_rolls and update this each dice roll.
UPDATE current_game_progress SET content = content + 1 WHERE keyname = "dice_rolls"
But its a bit overhead. Maybe you want to store it local in a variable and transfer it on "save" action to the database.

Implementing OR Condition using Parse Android SDK?

I am new to Parse and i am working on a Project that uses Android PARSE Sdk so i was wondering on how can i make a where query with or condition using the android sdk.
I want to make a query like this [Psuedo code]
Select * from employ where employId is ("1","2","3")
I found this on parse documentation, i don't know if it helps or not.
Edit:
This is what i found on PARSE but its not working
String[] id= {"1","2","3"};
query.whereContainedIn("employId ", Arrays.asList(id));
It returns me an empty list but if i query them one by one i get result... Can anyone tell me whats wrong ?

You can use whereContainedIn to select specific rows. See this post you can get more ideas. https://www.parse.com/questions/different-arrays-and-wherecontainedin-for-android.
List<String> employId = new ArrayList<String>();
employId.add("1"); employId.add("2"); employId.add("2");
query.whereContainedIn("employId", employId);
If you are still not clear. check this https://www.parse.com/docs/android_guide#queries

I have found the solution and i must say its pretty lame of PARSE to not mention this anywhere in there documentation.
The problem was that the values that i was using inwhereContainedIn method were of type String but in reality they were pointers to another table's row.
I was trying to get the values using only there ids[as it is displayed on parse] but instead i had to pass the whole object in order to retrieve them. That was the reason on why it was returning empty list.
The thing is Even though it displays IDs [pointer to object in a table] we cant search using only ID's instead we have to use complete Parse objects if we want to search a table based on Specific Object.

Geofencing in Android

I am getting a kmz-file from a webservice, which I use for geofencing.
The app is responsible to check whether the gps-location of the phone is within the geofence, or not.
I don't really know how the kmz-file will be structured (I am not creating it), but I think the coordinates might look like this:
<coordinates>
-112.2550785337791,36.07954952145647,2357
-112.2549277039738,36.08117083492122,2357
-112.2552505069063,36.08260761307279,2357
-112.2564540158376,36.08395660588506,2357
-112.2644963846444,36.08627897945274,2357
-112.2656969554589,36.08649599090644,2357
</coordinates>
How can I check if the gps-coordinates of my phone are within the geofence (the example above is only a line, it should be a closed area, for example a rectangle)? Right now I can't really think of how to do that.
And what library should be used to access the kmz-files?

First, for geofencing, download the sample from here and read the documentation. And I don;t know about kmz file. But if you can get the string from it(using file reading) and know its structure, then you can easily parse it. If the format is like you mentioned, then you can get the values by following method:
Split the string on coordinates (including <>). You will get a string array. Take the string at index 1.
Split this string on /coordinates (including <>). You will get another string array. Take the string at index 0.
Now split this string on ",". You will get an array of strings again! Now at indexes 0,3,6... are latitudes and at indexes 1,4,7... are longitudes and at indexes 2,5,8... are the third number in the data you mentioned.