How can you get the Manifest Version number from the App's (Layout) XML variables?

I believe that was already answered here.

String versionName = getPackageManager().getPackageInfo(getPackageName(), 0).versionName;

OR

int versionCode = getPackageManager().getPackageInfo(getPackageName(), 0).versionCode;

There is not a way to directly get the version out, but there are two work-arounds that could be done.

1. The version could be stored in a resource string, and placed into the manifest by:

   <manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="com.somepackage"
        android:versionName="@string/version" android:versionCode="20">
   

2. One could create a custom view, and place it into the XML. The view would use this to assign the name:

   context.getPackageManager().getPackageInfo(context.getPackageName(), 0).versionName;
   

Either of these solutions would allow for placing the version name in XML. Unfortunately there isn't a nice simple solution, like android.R.string.version or something like that.

You can use the versionName in XML resources, such as activity layouts. First create a string resource in the app/build.gradle with the following snippet in the android node:

applicationVariants.all { variant ->
    variant.resValue "string", "versionName", variant.versionName
}

So the whole build.gradle file contents may look like this:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion '24.0.0 rc3'
    defaultConfig {
        applicationId 'com.example.myapplication'
        minSdkVersion 15
        targetSdkVersion 23
        versionCode 17
        versionName '0.2.3'
        jackOptions {
            enabled true
        }
    }
    applicationVariants.all { variant ->
        variant.resValue "string", "versionName", variant.versionName
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    productFlavors {
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
} 

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.3.0'
    compile 'com.android.support:design:23.3.0'
    compile 'com.android.support:support-v4:23.3.0'
}

Then you can use @string/versionName in the XML. Android Studio will mark it red, but the app will compile without issues. For example, this may be used like this in app/src/main/res/xml/preferences.xml:

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">

    <PreferenceCategory
        android:title="About"
        android:key="pref_key_about">

        <Preference
            android:key="pref_about_build"
            android:title="Build version"
            android:summary="@string/versionName" />

    </PreferenceCategory>


</PreferenceScreen>