Question

I have an Android application, and i want to store some generic view attributes (primarily width and height) in a separate XML file (values.xml). An example:

<Button
    android:id="@+id/button1"
    android:layout_width="@strings/genericbuttonwidth"
    android:layout_height="wrap_content"
    android:text="Button" />

with the res/values/strings.xml looking like:

<resources>
    <string name="genericbuttonwidth">50dp</string>
</resources>

The Eclipse graphical layout viewer makes the width 50dp, as given in strings.xml, but when ran on an Android (physical) device, it throws an exception:

Caused by: java.lang.RuntimeException: Binary XML file line #174: You must supply a layout_width attribute.

So what I am trying to do doesn’t really work (when I replace the the reference with 50dp, it works nicely). Any way or workaround to load the attributes from a separate XML file?

Answer 1

XML file saved at res/values/dimens.xml:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <dimen name="textview_height">25dp</dimen>
    <dimen name="textview_width">150dp</dimen>
    <dimen name="ball_radius">30dp</dimen>
    <dimen name="font_size">16sp</dimen>
</resources>

This application code retrieves a dimension:
Resources res = getResources();
float fontSize = res.getDimension(R.dimen.font_size);
This layout XML applies dimensions to attributes:

<TextView
    android:layout_height="@dimen/textview_height"
    android:layout_width="@dimen/textview_width"
    android:textSize="@dimen/font_size"/>