Android Activity

• Android Activity - Intent
• Android Activity - Lifecycle

• Activities are a fundamental application component
  • representing a single screen with a user interface and able to be presented in several modes:
    • full-screen
      - floating
      - embedded - multi-window`
• An Activity is the main component that allows the interaction between the user and the app
• can be started by:
  • other Activities
  • apps
  • system events
• Apart from managing and handling the application's user interface and interaction
  • Activities are also responsible for managing the app's lifecycle.
• Activities are Interactive

Declaring activities in AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.myapp">

    <application
        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">

        <!-- Declare your Activity here -->
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

        <!-- Declare other Activities if needed -->
        <!-- <activity android:name=".AnotherActivity" /> -->

    </application>

</manifest>

• In the above snippet
  • the android.intent.action.MAIN action indicates that the MainActivity is the entry point of the app
• This means it is the first Activity launched when the app starts
• This action is typically used for the home screen of an app
• While the activity name MainActivity is usually used as an entry point in Android applications
  • this name can be changed
• Identifying the entry point of an application is very important during penetration testing since testers can better understand the application's:
  • flow
  • functionality
  • overall structure
  • discovery of possible attack surfaces
  • eventually identification of potential vulnerabilities and weaknesses
• The second property
  - android.intent.category.LAUNCHER tells the Android system that this Activity should be listed in the system's app launcher
• So when the user taps on the application's icon in the launcher
  • this Activity should be started.