Hiding views declaratively based on screen size in Android

Question

In android xml:ish

Is there any way to change a visibility attribute based on the layout size/orientation in the xml directly?

I have a button in a fragment that should be visible for small screens sizes only. On larger sizes, let's say layout-large, I want it to be hidden.

Sure, I can write code for this without any problem but for academic reasons I would like to know it it's possible to do something like this.

<Button
     android:id="@+id/btn_check_availability"
     style="@style/product_info_footer_button"
     android:layout_width="fill_parent"
     android:layout_height="35dp"
     android:text="@string/check_availability"
     android:visibility="<magic expression here>" />

Thanks

// Johan

score 6 · Accepted Answer · edited May 23 '17 at 12:22

6

This answer is based off the explanation provided here by Flávio Faria.

The visible, gone, etc can be values mapped to their corresponding enum values in a string resource - which means you can create a visibilty.xml with string resources for each layout you want, and Android will automatically resolve the one you want for each screen type.

I'd recommend the following:

/res/values/visibilty.xml:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <!-- Enum values pulled from Android source -->
    <string name="visibility_visible">0</string>
    <string name="visibility_invisible">1</string>
    <string name="visibility_gone">2</string>

    <string name="product_info_footer_button_visibility">@string/visibility_visible</string>
</resources>

/res/values-large/visibilty.xml:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="product_info_footer_button_visibility">@string/visibility_invisible</string>
</resources>

And then you can reference the visibility as follows for your button:

<Button
     android:id="@+id/btn_check_availability"
     style="@style/product_info_footer_button"
     android:layout_width="fill_parent"
     android:layout_height="35dp"
     android:text="@string/check_availability"
     android:visibility="@string/product_info_footer_button_visibility" />

Warning: This depends on the device having the same enum values for visibility (0/1/2) as defined in the AOSP source. Device manufacturers and custom ROM creators can change these values, in which case this code will likely not work as desired.

edited May 23 '17 at 12:22

Community

1
1

answered Jun 12 '14 at 15:38

Adam S

16,144
6
54
81

After some experimentation, @ben75's answer also works (using `@integer` references rather than `@string`) for me in Android Studio 0.5.8. Unfortunately the layout editor fails to correctly parse either solution and complains that `@string/some_string` is not a valid value for the visibility attribute. – Adam S Jun 12 '14 at 15:58
Maybe specific to AS-0.5.8 ? I'm using AS-0.5.2 and both solutions works fine in preview. (preview is fine, no warnings in the editor) – ben75 Jun 12 '14 at 16:04
It's almost like we're using beta software ;) – Adam S Jun 12 '14 at 16:06
1

While this works technically, it is a rather hacky solution. It's interesting but I wouldn't want to release that to a wide range of devices. You better hope some version of Android or random custom ROM doesn't change the values of the visibility enum. Android has well-documented ways to better handle differences in layouts that are orientation or resolution dependent. – Robert Nekic Jun 12 '14 at 16:09
I agree about the problem with Android ROMs changing the values of the visibility enum, I'll add a disclaimer to the answer. As far as I'm aware, the ways of doing this _without_ taking the enum values would be to either use an `` and reproduce the entire button code in each layout file, or to use a ` – Adam S Jun 12 '14 at 16:16
AFAIK the values of the enum are part of the public API so I don't think they can be changed without breaking the contract. – ben75 Jun 13 '14 at 08:46

ben75 · Answer 2 · 2014-06-12T15:49:35.457

2

The android:visibility attribute is an int (like many attributes) so you can do the following :

Define a resource file named visibility.xml in values-port and values-land resource directories. The content of this file is like this :

values-port/visibility.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <integer name="buttonvisibility">0</integer> <!-- 0 is the value for android:visible -->
</resources>

values-land/visibility.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <integer name="buttonvisibility">1</integer> <!-- 1 is the value for android:invisible -->
</resources>

and in your layout.xml :

<Button
 android:id="@+id/btn_check_availability"
 style="@style/product_info_footer_button"
 android:layout_width="fill_parent"
 android:layout_height="35dp"
 android:text="@string/check_availability"
 android:visibility="@integer/buttonvisibility" />

It works : btn_check_availability is visible in portrait and invisible in landscape.

Note : this example use layout orientation as discriminator, but you can of course do it with any resource qualifier (like dimension, density, ...)

edited Jun 12 '14 at 15:49

answered Jun 12 '14 at 15:31

ben75

29,217
10
88
134

I don't think this will work. Attributes which can be references to resources are explicitly marked so in the documentation (_This may also be a reference to a resource in the form..._). The visibility attribute says _Must be one of the following constant values..._ – matiash Jun 12 '14 at 15:39
I experimented with this for my answer, and it seems that when you reference an _integer_ resource for the visiblity, it resolves the id of that resource, rather than the value. So for my example where I have 0/1/2 in String resources, the 0/1/2 gets swapped in, but when I have 0/1/2 in integer resources, I get: `Caused by: java.lang.NumberFormatException: Invalid int: "@2131361851"` – Adam S Jun 12 '14 at 15:41
@AdamS there must be something wrong in your code. I tried this solution exactly with the code posted here and it works fine. – ben75 Jun 12 '14 at 15:45
@ben75 You're right, I must've done something wrong - it worked fine this time. I'd recommend putting the visibility values in separate constants though, so you can do `@integer/visibility_invisible` instead so you don't have to remember what 0/1/2 means. – Adam S Jun 12 '14 at 15:54

score 1 · Answer 3 · answered Jun 12 '14 at 16:51

There is no magic expressions available in XML. If only.

There are two approaches to this problem:

a/ use the drawable folder system. Drawable folders can be copied and named to be DPI aware following the conventions dictated here: Supporting Multiple Screens.

b/ Do it programmatically. On runtime check for screen DPI and show/hide view accordingly.

score 0 · Answer 4 · answered Jun 12 '14 at 15:14

0

Have you looked at using includes and multiple layouts organized into the appropriate size/orientation layout folders? Some layouts could either simply not have the button or have it hidden by default.

Re-using Layouts with include

Providing Alternative Resources

answered Jun 12 '14 at 15:14

Robert Nekic

3,087
3
24
36

the question is about one attribute in one layout file – ben75 Jun 12 '14 at 15:32
The question is about how to display a control for some resolutions and orientations but not others. By the docs, that should be handled with resolution and/or orientation-specific layouts and possibly the include to streamline it a bit. – Robert Nekic Jun 12 '14 at 15:59

Hiding views declaratively based on screen size in Android

4 Answers4