Radial Gradient for different dpi

Question

I'm creating a radial gradient like:

 <?xml version="1.0" encoding="utf-8"?>
 <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
 <gradient
      android:startColor="#7faacaFF"
      android:endColor="#cfe1edFF"
      android:gradientRadius="326"
      android:type="radial"/>
 </shape>

But in the gradientRadius field using values like sp and dip return an error. Is there a way to specify the radius and scale for mdpi and scale it automatically in the rest of screen densities, or is necessary to create multiple drawable files?

Answer 1

Old question, but this answer shows highly ranked in Google and I belief an alternative approach is more scaleable. Instead of having to supply the dimension for every density, create a density-independent dimension from XML:

<dimen name="gradient_radius">25dp</dimen>

Since we cannot apply this directly to the radial gradient XML drawable, we have to apply in from code:

((GradientDrawable) someView.getBackground())
        .setGradientRadius(getResources().getDimension(
            R.dimen.yellowbadge_largeradius));

This overrides the android:gradientRadius field, so you can leave that to 0. You can still not use a (screen based or otherwise) % dimension, though. I apply this to the background of my view (to which the gradient drawable is already set!) but it applies to an ImageView's src element as well, of course.

Answer 2

So what if you do this:

res/drawable/foo.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
                                android:shape="rectangle">
 <gradient
      android:startColor="#7faacaFF"
      android:endColor="#cfe1edFF"
      android:gradientRadius="@dimen/radius"
      android:type="radial"/>
 </shape>

res/values-mdpi/dimens.xml

<resources ...>
...
<item name="radius" format="float" type="dimen">326</item>
....

</resources>

res/values-hdpi/dimens.xml

<resources ...>
...
<item name="radius" format="float" type="dimen">200.34</item>
....

</resources>

What do you think?