attributes for multiple resources in attrs.xml

Vlemmix · by **Vlemmix** » Fri Apr 17, 2009 3:44 pm

Hello all,

I'm introducing multiple custom widgets for my application, extending View. These widgets (LineGraph and DotMatrix) include various attributes that can be set via the layout-xml. How can I have multiple widgets using attributes with the same name. For instance, 2 attributes both having color as an attribute that can be set via the layout XML?

main.xml snippet:

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xmlns:app="http://schemas.android.com/apk/res/net.vlemmix.android.widgetdemos"
<net.vlemmix.android.widget.DotMatrix
                android:id="@+id/dotmatrix1"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                app:color="0xFFF" />
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attrs.xml snippet:

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<?xml version="1.0" encoding="UTF-8"?>
<resources>
<declare-styleable
                name="DotMatrix">
                <attr
                        name="color"
                        format="integer" />
        </declare-styleable>
</resources>
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When I want to add the info for my LineGraph in attrs.xml, Eclipse starts to whine: "ERROR Attribute "color" has already been defined"

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<?xml version="1.0" encoding="UTF-8"?>
<resources>
<declare-styleable
                name="DotMatrix">
                <attr
                        name="color"
                        format="integer" />
        </declare-styleable>
<declare-styleable
                name="LineGraph">
                <attr
                        name="color"
                        format="integer" />
        </declare-styleable>
</resources>
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Is it not possible to have a DotMatix resource with a color attribute, and a LineGraph resource with a color attribute?

Vlemmix · by **Vlemmix** » Mon Apr 20, 2009 12:51 pm

Got some help from Dianne Hackborn:
> Just don't re-declare the format in the second one. Also, if this is a
> color, don't you want the format to be "color"? As it is now, when you
> write a color of the form "0xfff" you will not get the right integer value
> for an aarrggbb color.
>
> Oh and I am almost positive the framework already has a color attribute
> defines, so you could just use that.

So, once declared for a resource, you can declare the attribute names to resources, but do not include the format. So, once you declare "color" to be an int, "color" will be an int for all your resources (custom widgets). This forces that an attribute-name always refers to the same type, even between different resources.

And indeed, try to use the pre-defined attributes names/types when possible, no need to define my own color attribute...

attributes for multiple resources in attrs.xml

attributes for multiple resources in attrs.xml

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