B4J Question How to filter objects ?

FrenchDeveloper

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Hello,
I have a set of objects. Each object is an imageview + properties.
This set will grow without limit.
What is the best solution to filter these objects upon one property ?

For example :

Object1 Imageview1 Group1
Object2 Imageview2 Group1
Object3 Imageview3 Group1
Object4 Imageview4 Group2
Object5 Imageview5 Group2

I need to do something on all imageviews of group2.
I could scan each object with a For Each loop but it may be quite long with a lot of objects.
I could copy all properties in a database, a table or in a map and filter the database, the table or the map. Is it possible to filter a table or a map ?
What is the most efficient solution ?
 

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  • Map filter.zip
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stevel05

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You could keep an index (as a Map) of the objects that contain each group keyed on the group with a list of objects as the Value.
 
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Daestrum

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You could store the info you want using setUserData in each Imageview, then retrieve it with getUserData. It takes a java object so you could store almost anything in there.
You would probably need to use RunMethod to access the field as I don't think B4J exposes it.
 
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FrenchDeveloper

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stevel05 said:
You could keep an index (as a Map) of the objects that contain each group keyed on the group with a list of objects as the Value.
Click to expand...
Thank you for your answer!
As I am a newbie, I don't imagine how the code would be and how to filter a map upon this index. May be you know a thread where I can find example ?
 
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FrenchDeveloper

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Thanks for this advice ! I didn't think it would be possible to store informations in java objects.
How to filter upon one of these informations ?
 
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stevel05

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If you can give me an example of how you are coding the structure, I'll give you an example of indexing it using Map.
 
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FrenchDeveloper

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stevel05 said:
If you can give me an example of how you are coding the structure, I'll give you an example of indexing it using Map.
Click to expand...

Thank you very much Stevel ! I added a project in the first post.
May be you know where I can find further informations on maps purpose and coding ?
 
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stevel05

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No Problem, attached is an example.

You can get info on maps from the internet, there are many examlples. One is: http://www.javamex.com/tutorials/collections/using_4.shtml.

Although the examples will be in java, it should be easy to change for B4a/j. If you get any questions just post then in the forums and someone will help.

Steve
 

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  • MapFilter1.zip
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