Android - INSTALL_FAILD_SHARED_USER_INCOMPATIBLE

Question

My original question is here: Android - How to programmatically switch users by user name? and it still unanswered, but I got some progress and now I'm completely stuck.

Now I've followed these steps:

1. Added a DeviceAdmin class as shown in the code samples, I don't know if it is good or am I supposed to implement something there:

   import android.app.admin.DeviceAdminReceiver;
   import android.content.Context;
   import android.content.Intent;
   import android.widget.Toast;
   
   public class DeviceAdmin extends DeviceAdminReceiver {
   
   void showToast(Context context, String msg) {
       Toast.makeText(context, msg, Toast.LENGTH_SHORT).show();
   }
   
   @Override
   public void onEnabled(Context context, Intent intent) {
       showToast(context, "admin_receiver_status_enabled");
   }
   
   @Override
   public CharSequence onDisableRequested(Context context, Intent intent) {
       return ""; //context.getString(R.string.admin_receiver_status_disable_warning);
   }
   
   @Override
   public void onDisabled(Context context, Intent intent) {
       showToast(context, "admin_receiver_status_disabled");
   }
   
   @Override
   public void onPasswordChanged(Context context, Intent intent) {
       showToast(context, "admin_receiver_status_pw_changed");
   }
   }
   

2. Added the DeviceAdmin in the manifest:

   <receiver android:name=".DeviceAdmin"
           android:label="@string/device_admin"
           android:description="@string/device_admin_description"
           android:permission="android.permission.BIND_DEVICE_ADMIN">
           <meta-data android:name="android.app.device_admin"
               android:resource="@xml/security_policies" />
           <intent-filter>
               <action android:name="android.app.action.DEVICE_ADMIN_ENABLED" />
           </intent-filter>
       </receiver>
   

3. In my MainActivity class I've added this code to get admin permissions:

   DevicePolicyManager mDPM;
   ComponentName mDeviceAdmin;
   final int REQUEST_CODE_ENABLE_ADMIN = 1;
   
   
   mDPM = (DevicePolicyManager)getSystemService(Context.DEVICE_POLICY_SERVICE);
   mDeviceAdmin = new ComponentName(this, DeviceAdmin.class);
   if (!mDPM.isAdminActive(mDeviceAdmin)) {
       // try to become active – must happen here in this activity, to get result
       Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);
       intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, mDeviceAdmin);
       intent.putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION, mContext.getString(R.string.device_admin_description));
       startActivityForResult(intent, REQUEST_CODE_ENABLE_ADMIN);
   } else {
       UserManager um = (UserManager) mContext.getSystemService(Context.USER_SERVICE);
       // always return 1
       List<UserHandle> h = um.getUserProfiles();
       // crashes !!! saying I need MANAGE_USERS persmission
       mDPM.switchUser(mDeviceAdmin, h.get(0)); 
   }
   

   I can see my app in the settings menu as device administrator.

4. So I went to the manifest and added these 2 permissions:

   <permission android:name="android.permission.INTERACT_ACROSS_USERS_FULL"
       android:permissionGroup="android.permission-group.SYSTEM_TOOLS"
       android:protectionLevel="signature"
       android:label="@string/manage_users_permission"
       android:description="@string/manage_users_permission_description" />
   
   <permission android:name="android.permission.MANAGE_USERS"
       android:permissionGroup="android.permission-group.SYSTEM_TOOLS"
       android:protectionLevel="signature"
       android:label="@string/manage_users_permission"
       android:description="@string/manage_users_permission_description" />
   

5. This also didn't work, so I found out that I need to sign my app and I have no idea how to even start doing that. I found posts saying I need these 2 files: platform.x509.pem, platform.pk8 so I went and got them from our source code team who worked on the ROM we have installed. I asked a Linux guy to run keytool-importkeypair as shown here: Apk with system privileges, this got me a file: debug.keystore which I placed in the app folder of my application.

6. Then I've added this to the build.gradle file in the project:

   signingConfigs {
       release {
           storeFile file("debug.keystore")
           storePassword "test123"
           keyAlias "platform"
           keyPassword "test123"
       }
   }
   

7. None of these solved my problem and I still can't get MANAGE_USERS permission and I still can't switch users and then I saw a post saying add this: android:sharedUserId="android.uid.system" to the <manifest> tag and this got me this error INSTALL_FAILD_SHARED_USER_INCOMPATIBLE

I'm very new to android, and this is very advanced for me to understand but I have to do this at work and there are no other Android developers here...

Answer 1

You can only use "android.uid.system" when your app is signed with platform key.