Answered

Is it possible to alternate background colors on tableviews?

12 year бұрын • updated by 12 year бұрын • 3

Ok, tricky one for you (maybe). Look at the iOS 6 Music app. Navigate into an artist, then an album. All the songs are listed, and the backgrounds alternate by row. I want to do that on a tableview. Here's what I tried:





<class name="itemsclass">


      <panel name="[param:index]" width="100%" height="70" align="left" _index="[param:index]" background="666666" padding="5" onclickup="showdetails" lhs="[eval:Math.pow(-1,[param:index])]" operator="e" rhs="1">


        <text name="title" text="[param:title]" width="80%" align="center" valign="center" alignment="left" height="fit" font="Avenir" size="24" color="#333333" decode="yes" maxlength="65" endcap="..."></text>


      </panel>


      <panel name="[param:index]" width="100%" height="70" align="left" _index="[param:index]" background="333333" padding="5" onclickup="showdetails" lhs="[eval:Math.pow(-1,[param:index])]" operator="e" rhs="-1">


        <text name="title" text="[param:title]" width="80%" align="center" valign="center" alignment="left" height="fit" font="Avenir" size="24" color="#333333" decode="yes" maxlength="65" endcap="..."></text>


      </panel>


    </class>

The key parts (I think) are the lhs/operator/rhs attributes. It's my understanding that using those attributes is basically and if statement that will create the panel (if true) or not (if false). The logic goes like this: if -1 to the Xth power (where X is the index) is equal to 1, it's an even numbered row and should be #666666 in color. If it is equal to -1, it's an odd numbered row and should be #333333 in color.

In theory, I think this makes sense. In reality, it's only showing one background color (though it shows all the items from the datasource). Any glaring mistakes or helpful tips?

Vote

12 year бұрын

Tyler,

Here is a solution for you. If you use this example in your class for the list items.
On your class background you can add this to the alpha attribute:

alpha="[eval: [datasource:myDatasourceName.dataSourceIndex] % 2 == 0 ? 0 : 1 ]"

Modulus (%) is just about the remainder. If you want to know if a number is even or odd, modulus it by 2 and if there is a remainder the number is odd.

12 year бұрын

This means you only need one class.

12 year бұрын

If you put it directly in the class, you don't have to use the datasource:, you can just do something like this:




<panel name="background" background="#00ff00" height="100%" width="100%" alpha="[eval: [param:dataSourceIndex] % 2 == 0 ? 0 : 1 ]" />

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