Steps to introduce VirtualApk:

I. Introduction of virtual APK to host application

1. Add dependency in the build.gradle file of the project:

dependencies {
    classpath 'com.didi.virtualapk:gradle:0.9.8.6'
}

The complete gradle file is as follows:

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {

    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.1.4'
        classpath 'com.didi.virtualapk:gradle:0.9.8.6'
        

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

2. Add dependency in the build.gradle file of app:

apply plugin: 'com.didi.virtualapk.host'

dependencies {
    implementation 'com.didi.virtualapk:core:0.9.8'
}

The complete gradle file is as follows:

    apply plugin: 'com.android.application'
    apply plugin: 'com.didi.virtualapk.host'
    
    android {
        compileSdkVersion 28
        defaultConfig {
            applicationId "com.wangyz.virtualapk.host"
            minSdkVersion 21
            targetSdkVersion 28
            versionCode 1
            versionName "1.0"
            testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        }
        buildTypes {
            release {
                minifyEnabled false
                proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
            }
        }
    }

    dependencies {
        implementation fileTree(dir: 'libs', include: ['*.jar'])
        implementation 'com.android.support:appcompat-v7:28.+'
        implementation 'com.android.support.constraint:constraint-layout:1.0.2'
        testImplementation 'junit:junit:4.12'
        androidTestImplementation 'com.android.support.test:runner:1.0.1'
        androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
    
        implementation 'com.didi.virtualapk:core:0.9.8'
    }

3. The Application of the new project is inherited from Application and initialized in attachBaseContext method

public class App extends Application{

    @Override
    protected void attachBaseContext(Context base) {
        super.attachBaseContext(base);
        PluginManager.getInstance(base).init();
    }
}

4. Introduce custom Application in Android manifest.xml

<application
    android:name=".App"
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

5. Declaration of authority

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

II. Introducing VirtualApk into Plugin

1. Add dependency in the build.gradle file of the project:

dependencies {
    classpath 'com.didi.virtualapk:gradle:0.9.8.6'
}

The complete gradle file is as follows:

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.1.4'
        classpath 'com.didi.virtualapk:gradle:0.9.8.6'
        

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

2. Add dependency in the build.gradle file of app:

apply plugin: 'com.didi.virtualapk.plugin'

virtualApk{
    packageId = 0x6f
    targetHost = '../../VirtualAPKHost/app'//app module path of host application
    applyHostMapping = true
}

3. Add signature configuration to build.gradle file of app

signingConfigs{
        release{
            storeFile file('../../android.keystore')
            storePassword "android"
            keyAlias "android"
            keyPassword "android"
        }
    }

    buildTypes {
    release {
        minifyEnabled false
        signingConfig signingConfigs.release
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}

The complete gradle file is as follows:

apply plugin: 'com.android.application'
apply plugin: 'com.didi.virtualapk.plugin'

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.wangyz.virtualapk.plugin"
        minSdkVersion 21
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    signingConfigs{
        release{
            storeFile file('../../android.keystore')
            storePassword "android"
            keyAlias "android"
            keyPassword "android"
        }
    }
    buildTypes {
        release {
            minifyEnabled false
            signingConfig signingConfigs.release
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:28.+'
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.1'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
}

virtualApk{
    packageId = 0x6f
    targetHost = '../../VirtualAPKHost/app'
    applyHostMapping = true
}

Note: the resource file of Plugin application cannot have the same name as the resource file of host, otherwise an error will be reported when generating plug-in APK:

It is recommended that module resource names begin with module names.

4. Generate plug-in APK

Open gradle window, double-click assemblyplugin to generate APK

File generation Directory: app/build/outputs/plugin/release/

3. Load the plug-in APK in the host application

1. Push the generated plug-in APK (through the network or adb, etc.) to the specified path of the mobile phone, such as / sdcard/Plugin.apk.

2. Load APK in the host application

private static final String PLUGIN_PACKAGE_NAME = "com.wangyz.virtualapk.plugin";
private static final String PLUGIN_NAME = "com.wangyz.virtualapk.plugin.MainActivity";

private void loadPlugin() {
    try {
        String pluginPath = Environment.getExternalStorageDirectory().getAbsolutePath().concat("/Plugin.apk");
        File plugin = new File(pluginPath);
        PluginManager.getInstance(this).loadPlugin(plugin);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

3. Call the Activity in APK

public void loadPlugin(View view) {
    if (PluginManager.getInstance(this).getLoadedPlugin(PLUGIN_PACKAGE_NAME) == null) {
        Toast.makeText(getApplicationContext(), "Plug in not loaded", Toast.LENGTH_SHORT).show();
        return;
    }
    Intent intent = new Intent();
    intent.setComponent(new ComponentName(PLUGIN_PACKAGE_NAME, PLUGIN_NAME));
    startActivity(intent);
}

Source address: https://github.com/miloveting/samples/tree/master/virtuaapk