Android Question Large lists

scarr · Nov 13, 2019

Hi All,

I have a program that I wrote a couple of years ago, it compiled and worked OK at the time, the other day I wanted to make a change, so I loaded up the code and compiled it, it failed! saying the code was too large. There are 4143 integers in each list

So after playing around I found that removing two large lists in Process_Globals allowed it to compile, so here are my questions.

1) has something changed in that stops you using large lists
2) Any idea how to fix this.

Thanks

Steve

P.S. In the altered code (one without the two large lists) I create another activity with just one of the large lists and nothing else to see if I could separate them out, this failed to compile.

Erel · Nov 13, 2019

Did it fail to compile in release mode?

DonManfred · Nov 13, 2019

scarr said:
saying the code was too large. There are 4143 integers in each list

are you using 4143 codelines to fill the list? Why not loading the List directly?

B4X:

Dim List1 As List
List1 = File.ReadList(File.DirDefaultExternal, "1.txt") ' List with 50000 Lines...
For i = 0 to List1.Size - 1
    Log(List1.Get(i))
Next

5 Lines of code.

How did you structure your code?

Erel · Nov 13, 2019

(Don't use File.DirDefaultExternal. It should be File.DirAssets).

DonManfred · Nov 13, 2019

Erel said:
(Don't use File.DirDefaultExternal. It should be File.DirAssets)

To be honest; i just copied the example-code the IDE Onlinehelp suggests for File.ReadList ....

scarr · Nov 13, 2019

Extra Info:

I was creating the list this way as I was trying to avoid a separate file with the INT's in them

B4X:

Sub Process_Globals
    'These global variables will be declared once when the application starts.
    'These variables can be accessed from all modules.

    Dim List3 As List

    List3.Initialize

List3.AddAll(Array As Int(475,275,700,675,625,375,700,850,50,325,675,525,275,575,250,725, _
    875,200,875,475,875,25,100,700,50,350,850,375,150,575,375,300, _
    200,525,425,250,350,825,550,100,625,750,500,400,450,425,375,50, _

DonManfred · Nov 13, 2019

Put them in a File or a Database (if you have 1000 lists it is better to use ONE Database instead of 1000 files).

Erel · Nov 13, 2019

DonManfred said:
To be honest; i just copied the example-code the IDE Onlinehelp suggests for File.ReadList ....

Will be fixed. File.DirDefaultExternal should not be used anymore. It was replaced with RuntimePermissions.GetSafeDirDefaultExternal.

scarr said:
I was creating the list this way as I was trying to avoid a separate file with the INT's in them

There are several mistakes here:
1. It is better to put them in a file and load them at runtime. It is a mistake to put data inside the code.
2. You shouldn't initialize or call AddAll in Process_Globals.
3. Unless you plan to modify the list in the future then it is better to initialize it like this:

B4X:

Private List3 As List = Array (475, 275, ...)

scarr · Nov 13, 2019

Erel said:
Will be fixed. File.DirDefaultExternal should not be used anymore. It was replaced with RuntimePermissions.GetSafeDirDefaultExternal.

There are several mistakes here:
1. It is better to put them in a file and load them at runtime. It is a mistake to put data inside the code.
2. You shouldn't initialize or call AddAll in Process_Globals.
3. Unless you plan to modify the list in the future then it is better to initialize it like this:

B4X:

Private List3 As List = Array (475, 275, ...)

Hi Erel, Where would you put your example? also Erel are you saying it is possible to have a large list within the code?

B4X:

Private List3 As List = Array (475, 275, ...)

DonManfred · Nov 13, 2019

scarr said:
also Erel are you saying it is possible to have a large list within the code?

No. This is just the way to initialize a List effectively. He mentioned that it is a mistake to put data in Code. This has not changed.

scarr · Nov 13, 2019

DonManfred said:
No. This is just the way to initialize a List effectively. He mentioned that it is a mistake to put data in Code. This has not changed.

Thanks Don, the reason I put it in the code is I don't want the user to see the list or access it. any suggestions? also any good simple examples of using external files for lists?

Thanks Steve

DonManfred · Nov 13, 2019

scarr said:
I don't want the user to see the list or access it

Use encrypted files. Decrypt them at runtime. Or directly use an Encrypted Database.

Erel · Nov 13, 2019

The user will not see the internal file.

You can create a text file with this content:
475
275
...

And load it as suggested above:

B4X:

List3 = File.ReadList(File.DirAssets, "data.txt")

Note that each element will be a string. In most cases it doesn't matter however if it does matter then you can do something like this:

B4X:

List3.Initialize
For Each s As String In File.ReadList(File.DirAssets, "data.txt")
 Dim n As Int = s
 List3.Add(n)
Next

Don't do it in Process_Globals. You should do it in Activity_Create when FirstTime is true (or better in the starter service).

scarr · Nov 13, 2019

Erel said:
The user will not see the internal file.

You can create a text file with this content:
475
275
...

And load it as suggested above:

B4X:

List3 = File.ReadList(File.DirAssets, "data.txt")

Note that each element will be a string. In most cases it doesn't matter however if it does matter then you can do something like this:

B4X:

List3.Initialize For Each s As String In File.ReadList(File.DirAssets, "data.txt") Dim n As Int = s List3.Add(n) Next

Don't do it in Process_Globals. You should do it in Activity_Create when FirstTime is true (or better in the starter service).

OK, so I will use an external file but firstly I have not used B4A for about two years so totally rusty (not that I was well oiled before ) so I have a few newbie questions.

1) Can the list (data.txt) be created within B4A so it installs as part of the application or is it created in a simple text editor and I place it somewhere?
2) if I create and place it, where do I place it on the device?

Thanks for everyone's patience and help

Steve

Erel · Nov 13, 2019

Create the text file with a text editor and put it in the Files folder in the IDE. Files folder = File.DirAssets.

scarr · Nov 13, 2019

Well that was easy

This is what a forum / software community should be, OK I'm no coding guru anymore, I used to love coding and was into assembly and C and all the other ones at the time, now my life occasionally meets code but I'm a lot older and have not got the time to understand 80% of modern IDE's / development languages or platforms but with a community like this and the help it provides, especially Erel you personify the word "community" thanks for everything, I am sure I will be back in the future to make you all go but then help out as you do. thanks for helping an old man

Steve

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