iOS Question Different behavior of map in b4i and b4a

schimanski

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In b4a, each time, I add one key to a map, the new key will add at the end of the map. In b4i, it is another behavior: New keys are added sometimes to the first position, then to the last or in the middle, without any logic (...for me). I have tested the chronological order with
B4X: 
For Each key As String In Map1.keys   
    Log(key)
Next

For example, when I add the following keys in series to the map:
11155, 211534, 211560, 211533,

in b4a it is: 11155, 211534, 211560, 211533.
in b4i it is: 211560, 211534, 11155, 211533

Is it possible to define the map to add the new keys always at the end of the map?
 
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sorex

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do you have a reason to have it in the right order there? you could add an order value to sort on later.
 
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schimanski

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Yes, I need the right order and I hoped, that it should be possible to get a solution for 'last in, last out'. So it is possible to hold the same code in b4a and b4i....
 
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Erel

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That is correct the order is not kept: https://www.b4x.com/b4i/help/collections.html#map

There are technical reasons for this.

You can use the attached class to implement an ordered map:
B4X: 
Dim map1 As OrderedMap
map1.Initialize
map1.Put("1", "a")
map1.Put("2", "b")
map1.Put("3", "c")
map1.Put("4", "d")
map1.Put("5", "e")
map1.Put("1", "f")
For Each key As String In map1.keys   
   Log(key & ": " & map1.Get(key))
Next
 

Attachments

  • OrderedMap.bas
    716 bytes · Views: 283
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fbritop

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Erel,
Is it possible in B4I to attach an imageview to a map key?

I have done it in Android but in iOS there is no chance to retrieve this image after from the map.

Is there any special treament to attach an imageview to a map?. Same thing happends when I put a label. After putting any of these items, if I log the map it outputs only numeric or string values:

B4X: 
(read only map) {
    idProducto = 1302;
    isActive = 1;
    isDelete = 0;
    isDiferido = 0;
    isNew = 0;
    isOffer = 0;
    precio = 36900;
    precioFormat = "$ 36.900";
    producto = "Nutra Nuggets Large Breed Puppy";
    unidad = "SACO 15 KG";
}

Thanks
FBP
 
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LucaMs

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Hi, Erel,

do you think I could use this your class also with B4J "thread safe maps" without problems?
(I know, this could not be the right place for this question, but your class is here )

P.S. from doc.:
Unlike B4J / B4A Maps, B4i Map does not retain the original order of items.

So in B4J the order should be kept, but I remember some post in which I read the opposite. Well, it's early (2:13 AM), I can search and test



If: "The order in B4A and B4J maps is preserved."
why: You shouldn't use these methods (GetValueAt and GetKeyAt)?
 
Last edited:
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