Android Question List not initializing

[DrownedBat]

Did we ever get an answer for this?
In the old version 5.5 it worked. In version 8.8 does not work. "(List) Not initialized". Why?

https://www.b4x.com/android/forum/threads/list-folders-or-listfiles.55263/#post-654507

 

[Erel]

There is nothing that works in B4A v5.50 and doesn't work in v9.80.
There are many new requirements that are applied when you increase targetSdkVersion.

You should post more information. My guess is that you are trying to access File.DirRootExternal without requesting the permission.

Must see tutorial: Runtime Permissions (Android 6.0+ Permissions)
And: android.jar / targetSdkVersion / minSdkVersion

 

[DrownedBat]

Quite correct Erel, as usual. I am running into a "List not initialized" error when I try to populate that list with files that are in a specific folder, as per:

Dim FilesFound As List
FilesFound.Initialize
FilesFound=File.ListFiles(File.DirRootExternal & "/My Folder")

My manifest editor for permissions reads as follows:

AddManifestText(
<uses-sdk android:minSdkVersion="5" android:targetSdkVersion="26"/>
<supports-screens android:largeScreens="true"
    android:normalScreens="true"
    android:smallScreens="true"
    android:anyDensity="true"/>)
SetApplicationAttribute(android:icon, "@drawable/icon")
SetApplicationAttribute(android:label, "$LABEL$")
SetApplicationAttribute(android:theme, "@android:style/Theme.Holo")
SetApplicationAttribute(android:largeHeap, "true")
AddPermission(android.permission.WRITE_EXTERNAL_STORAGE)
AddPermission(android.permission.READ_EXTERNAL_STORAGE)
SetApplicationAttribute(android:hardwareAccelerated, "true")

It would seem I have the external read/write permissions in place but something is causing the list not to be understood as "initialized". If, for example, I were to add

FilesFound.SortCaseInsensitive(True)

I would trigger the same error.

 

[Erel]

SetApplicationAttribute(android:theme, "@android:style/Theme.Holo")

This is a mistake.

My manifest editor for permissions reads as follows:

This is not related.

Must see tutorial: Runtime Permissions (Android 6.0+ Permissions)
And: android.jar / targetSdkVersion / minSdkVersion

 

[DrownedBat]

That's it! Thank you so much Erel; I am so out of touch on Android that I had no knowledge at all of Runtime Permissions as a THING. The last version of B4A I used was v4.0 so I'm catching up. I've got some reading to do but until then, I'll drop the targetSdkVersion down to 22 (for the time being). Thanks again!
P.S. Mistake removed.

 

[Computersmith64]

I've got some reading to do but until then, I'll drop the targetSdkVersion down to 22 (for the time being).

Just be aware that you cannot submit a new app or update to Play Store if the targetSdkVersion is lower than 28.

- Colin.

 

[DrownedBat]

Oh, I know Colin. I was just trying to get it working again before I had to head off to an appointment. I'll bring it up into the future soon but it's still a few years out.

 

[OliverA]

Please note, just because you initialized your list, does not mean that File.ListFiles returns an initialized list. Actually, the list you initialized is being replaced by the list that is returned by File.ListFiles and that list may be uninitialized.

 

[Erel]

Please note, just because you initialized your list, does not mean that File.ListFiles returns an initialized list. Actually, the list you initialized is being replaced by the list that is returned by File.ListFiles and that list may be uninitialized.

Very true. This is a programming bug:

Dim FilesFound As List
FilesFound.Initialize
FilesFound=File.ListFiles(File.DirRootExternal & "/My Folder")

Correct code:

Dim FilesFound As List = File.ListFiles(File.DirRootExternal & "/My Folder")