Is it possible in android to define constants in XML that vary with configuration

问题

I am interested in having an XML layouts in Android change size depending on landscape or portrait viewing (and maybe other configurations later).

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_alignParentBottom="true"
android:background="@drawable/stream_bg_1px_wide"
android:layout_height="150dip" >

In this example I just want to vary the 150dip size depending on landscape or portrait, not change anything else.

I am using layout and layout-land, and I know I could repeat the layout in each of those folders, but that makes maintaining changes in it a bit of a pain. When I introduce more variants based on screen density and size it just gets worse.

So, I wondered if it's possible to define a value (constant) in an XML file, and reference it from my layout, similar to how colors can be defined

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="shopper_background"> #FFFFFF</color>
</resources>

along the lines of......

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <value name="footer_size" >150</value>
</resources>

Then I could just replicate that file, with different values, in each config.

thanks for any help

回答1:

Yes. A dimension is an accepted item in a resource file. So create e.g. res/values/dimension.xml and put

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <dimen name="footer_size" >150dp</dimen>
</resources>

回答2:

Yes you can do this, we do it all over the place in Android itself :) Just define your constants in res/values/, res/values-land/ etc. For dimensions, use the tag and refer to them using @dimen/my_value in the layout.

来源：https://stackoverflow.com/questions/5285429/is-it-possible-in-android-to-define-constants-in-xml-that-vary-with-configuratio

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