Question

I’ve been using custom attributes for some custom layout components without problem. So far, I’ve only used simple attributes (string, int, etc). These are defined like so in values/attrs.xml:

<declare-styleable name="StaticListView">
    <attr name="border_size" format="dimension" />
</declare-styleable>

and in my layout:

<de.example.androidapp.StaticListView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        namespace:border_size="1px"
   />

and used like so:

int borderSize = (int) a.getDimension(R.styleable.StaticListView_border_size, 0);

Now, I’m trying to specify a layout as a custom attribute and am not able to use the R.styleable method used above.

Here’s how I’m defining the attribute:

<declare-styleable name="StaticListView">
    <attr name="emptyLayout" format="reference" />
</declare-styleable>

and using it:

<de.example.androidapp.StaticListView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        namespace:emptyLayout="@layout/empty"
   />

And this is how I would like to use it, but I always get the default value (-1):

int emptyLayoutInt = attrs.getAttributeResourceValue(R.styleable.StaticListView_emptyLayout, -1);

This, however, works:

int emptyLayoutInt = attrs.getAttributeResourceValue("http://schemas.android.com/apk/res/de.example.androidapp", "emptyLayout", -1);

I dislike having to hardcode the XML namespace. Using the R.styleable attribute avoids this in a nice way.

Am I doing something wrong or is this a bug/expected behavior?

Answer 1

Instead of using the line :

int emptyLayoutInt = attrs.getAttributeResourceValue(R.styleable.StaticListView_emptyLayout, -1);

Use this –

TypedArray a = context.obtainStyledAttributes(attrs,
            R.styleable.MyLayout);
    int layoutId = a.getResourceId(R.styleable.MyLayout_text,-1);

The -1 is getting returned because the value is not available in the attr set.