Controlling view visibility from a resources

Question

I have a layout that contains two ImageViews. I want one of them to be visible in portrait and the other in landscape. How do I achieve it using resources? (I know how to set it programmatically for but this specific use I need to achieve it using resources).

I tried something like

in res/layout/may_layout.xml:

...
<ImageView
      android:id="@+id/image1"
      android:visibility="@integer/visible_in_portrait"   <<-- is this allowed?
      ...
/>
<ImageView
      android:id="@+id/image2"
      android:visibility="@integer/visible_in_landscape"   
      ...
/>

in res/values/integers.xml:

...
<!-- NOTE: 0 and 8 are VISIBLE and GONE respectively -->
<integer name="visibile_in_portrait">0</integer>
<integer name="visibile_in_landscape">8</integer>

in res/values-land/integers.xml:

...
<integer name="visibile_in_portrait">8</integer>
<integer name="visibile_in_landscape">0</integer>

But I get a runtime error (index out of bound) when trying to inflate the images. When I remove the android:visibility statements, the program runs but I see both images.

Q: What is the way to use a resource as a value for the android:visibility attribute?

(if you wonder why setting it programmatically will not help me, it has to do with automatic landspace/portrait switch of app widgets with file uri bitmaps).

Answer 1

This is an old question that has already been accepted, but the following solution may help someone else:

If you check res/values/attrs.xml in Android source code, you'll see the definition of visibility property like this:

 <!-- Controls the initial visibility of the view.  -->
    <attr name="visibility">
        <!-- Visible on screen; the default value. -->
        <enum name="visible" value="0" />
        <!-- Not displayed, but taken into account during layout (space is left for it). -->
        <enum name="invisible" value="1" />
        <!-- Completely hidden, as if the view had not been added. -->
        <enum name="gone" value="2" />
    </attr>

This attribute expects a string value (visible, invisible, gone) that will be converted to (0, 1, 2) respectively. So, you can declare integer resources containing these values like this:

values/integers.xml

<integer name="visible_in_portrait">2</integer> <!-- This is GONE -->

values-land/integers.xml

<integer name="visible_in_landscape">0</integer> <!-- This is VISIBLE -->

However, if you want to make it even better in order to stop guessing these numeric constants every time, you could do like this:

values/integers.xml

<!-- These are alias for the constants we'll reference below -->
<integer name="view_visible">0</integer> <!-- This is VISIBLE -->
<integer name="view_invisible">1</integer> <!-- This is INVISIBLE -->
<integer name="view_gone">2</integer> <!-- This is GONE -->

<integer name="visible_in_portrait">@integer/view_gone</integer> <!-- We're referencing the visibility alias we declared above -->

values-land/integers.xml

<integer name="visible_in_landscape">@integer/view_visible</integer>

You can use this approach or the one suggested by Keyhan. Choose the one that fits you better.

Answer 2

it will be possible when you use this trick, add your visibility line to a style and put two instances of that file in -land and normal mode.

I mean in file styles.xml in folder values put a style with name s1, and put android:visibility=visible in that, and in styles.xml in folder values-land put a style with name s1, and put android:visibility=gone.

also, in file styles.xml in folder values put a style with name s2, and put android:visibility=gone in that, and in styles.xml in folder values-land put a style with name s2, and put android:visibility=visible.

and then, set s1 to first imageview and s2 to second.

solution given by dear Calvin is also correct, but when you have a complex layout that may change during time, having one layout file would be better, and will have less need to change.

Answer 3

It is not possible. (I tried define fill_parent as string and use it for layout_width and it fails too.)

Why don't you use 2 layouts?

1. res/layout/may_layout.xml
2. res/layout-land/may_layout.xml

Which each define the correct imageview to show.

In addition, having values-land may cause you problem when you needs to support multi-languages. (You will need to have value-xx-land for each language)