Setting Permissions for Android System Apps: A Quick and Easy Guide

Chapter 1: Introduction to Android System Apps and Permission Settings

Android system apps provide and manage the core functions of a device. These apps are differentiated from regular user apps and often require specific permissions. Therefore, understanding permission settings is necessary for developing and managing Android system apps.

In this chapter, we introduce the basic concepts of Android system apps and permission settings, and briefly explain how to request permissions for system apps.

What is a System App?

System apps are built-in apps on Android devices, commonly referred to as default apps. These apps are installed and provided by the device manufacturer and are developed by the open-source Android Open Source Project (AOSP). Examples include the Camera, Contacts, Calendar, and more.

Why System App Permission Settings are Necessary

System apps require more permissions than general apps since they perform core functions. For example, the Camera app needs permission settings because it directly controls the camera hardware. System apps need to acquire and manage these permissions through settings in the manifest file.

Chapter 2: Requesting Permissions for System Apps

Just like regular apps, Android system apps need to request permissions as well. To do this, you need to set permissions in the app's manifest file. In this chapter, we explain how to request permissions in Android system apps.

Modifying the AndroidManifest.xml

Android system apps need to request permissions through permission settings in the AndroidManifest.xml file. The permission request process for Android apps is as follows:

1. Open the manifest file 2. Add code including permission settings 3. Save, then build and run

Below is an example code containing permission settings:

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

    <uses-permission android:name="android.permission.CAMERA"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.RECORD_AUDIO"/>
    ...
    ...
</manifest>

In the example above, the code includes requests for camera, external storage write, and audio recording permissions. You can add multiple <uses-permission> tags depending on the required permissions.

Chapter 3: Setting Permissions in the Manifest

In this chapter, we explain in detail how to set permissions for system apps in the manifest file.

Setting Protected System Permissions

Some Android system permissions are classified as protected system permissions. These permissions are restricted to prevent regular application developers from using them. For example, the "android.permission.INTERACT_ACROSS_USERS" permission is required for system apps to implement interactions between users.

To use protected system permissions, add a <uses-permission> tag in the AndroidManifest.xml file and set the 'android:protectionLevel' attribute to either 'signature' or 'signatureOrSystem'.

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

    <permission
        android:name="your.package.name.permission.INTERACT_ACROSS_USERS"
        android:protectionLevel="signature"/>
    ...
    ...
</manifest>

Defining Custom Permissions

Android system app developers can also define custom permissions as needed. To do this, you need to define the permission using the <permission> tag in the manifest file.

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

    <permission
        android:name="your.package.name.permission.MY_CUSTOM_PERMISSION"
        android:description="@string/my_custom_permission_description"
        android:label="@string/my_custom_permission_label"
        android:protectionLevel="normal"/>
    ...
    ...
</manifest>

In the example above, we defined a custom permission and specified a description and label. To help understand the custom permission you've implemented, please set appropriate values for the description and label.

Chapter 4: Checking Permissions and Handling Request Results

In this chapter, we explain how to check permissions and handle request results in Android system apps. Before using permissions in a system app, it is essential to ensure that the needed permissions have been granted.

Checking Permissions

To check the status of permissions in Android system apps, use the checkSelfPermission() method. This method takes the permission name as a parameter and returns the current permission status.

int permissionCheck = ContextCompat.checkSelfPermission(context, Manifest.permission.READ_CONTACTS);
if (permissionCheck == PackageManager.PERMISSION_GRANTED) {
    // Code to execute when the permission is granted
} else {
    // Code to execute when the permission is denied
}

Handling Request Results

To handle the results after requesting permissions, override the onRequestPermissionsResult() method. This method receives the request code, an array of permission names, and an array containing the permission request results as parameters.

The code below is an example of a method to handle runtime permission request results.

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    if (requestCode == MY_PERMISSION_REQUEST_CODE) {
        if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            // Code to execute when the permission is granted
        } else {
            // Code to execute when the permission is denied
        }
    } else {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    }
}

By checking permissions and handling request results, you can ensure usability and stability for permissions in Android system apps. This allows developers to effectively manage the necessary permissions in their Android system apps.