Android Question Storing Activity State in External Class

[DawningTruth]

I need to create an external class for storing activity data during the activity lifecycle.

Here is the envisioned Sequence:

The Activity is quite complex. Having sophisticated custom elements.

So I need to be able to carry the state across from activity destruction to activity recreation. I understand that UI elements cannot be serialised so it is not possible to save the activities in a datastore. So, I will have to save them in a persistent class.

Now to the question. How is this done?

I have tried declaring the class in my Main Activity, and then using it in the above activity (Working Activity), but it keeps giving me an error. If I declare the class in the Working Activity, then it is destroyed when the activity is destroyed during the pause event.

By declared I am using code like:

'In Working Activity
Private StorageClass1 As StorageClass

'When I tried Main Activity Declaration
Public StorageClass1 As StorageClass

Any suggestions?

 

[agraham]

Anything declared in Process_Globals should survive while the app process exists. You can't put Activity objects there but you can save state such as Strings and Ints etc.

 

[MarkusR]

there is something ready that save/load the ui state
i believe it was this StateManager
https://www.b4x.com/android/forum/t...applications-settings-and-state.9777/#content

its also possible that android not destroy the activity.

if you put the declaration in Process_Globals
Public StorageClass1 As StorageClass
and it was initialized
StorageClass1.Initialize once
you can access it via Main.StorageClass1. ...
in StorageClass use a public sub or properties set/get

 

[DawningTruth]

Anything declared in Process_Globals should survive while the app process exists. You can't put Activity objects there but you can save state such as Strings and Ints etc.

Thx Agraham

 

[DawningTruth]

there is something ready that save/load the ui state
i believe it was this StateManager
https://www.b4x.com/android/forum/t...applications-settings-and-state.9777/#content

its also possible that android not destroy the activity.

if you put the declaration in Process_Globals
Public StorageClass1 As StorageClass
and it was initialized
StorageClass1.Initialize once
you can access it via Main.StorageClass1. ...
in StorageClass use a public sub or properties set/get

Thx Markus.

I managed to get the second option working

 

[DawningTruth]

Ok, have tried the suggested approach. It is retaining the state of the elements, however when I try to recreate the view in Landscape, none of the elements are transferring across.

So for instance I have a label value. I copy the lbl_MyLabel UI element to Main.StorageClass1.MyLabel at pause. However when I copy the value back into lbl_MyLabel during the resume process. Nothing is copied back into the label value.

Any suggestions?

 

[Erel]

It is retaining the state of the elements, however when I try to recreate the view in Landscape, none of the elements are transferring across.

I'm not sure what you mean here however you cannot reuse the same views after the activity was destroyed.

Check the suggested state manager module. It saves the user related state and sets it again when the activity is created.

 

[DawningTruth]

I'm not sure what you mean here however you cannot reuse the same views after the activity was destroyed.

Check the suggested state manager module. It saves the user related state and sets it again when the activity is created.

Thx Erel, I will look at it. Does it support all the B4A views?

 

[Erel]

The question is not accurate enough for me to give a full answer. It only saves user related state. It supports all native views. In some cases you will need to do some work to get the state of all views (see the code, it is quite simple).

 

[DawningTruth]

The question is not accurate enough for me to give a full answer. It only saves user related state. It supports all native views. In some cases you will need to do some work to get the state of all views (see the code, it is quite simple).

Thx Erel, I will investigate further...

 

[MarkusR]

It is retaining the state of the elements, however when I try to recreate the view in Landscape, none of the elements are transferring across.

if android not recreate the activity / ui then u need handle the new orientation by yourself.

 

[DawningTruth]

if android not recreate the activity / ui then u need handle the new orientation by yourself.

Thx Markus, it appears like that is the root I will have to take as the required UI Elements are not supported.