Fix TetherSettings crash issue

- When the user is a guest user, the UI will remove all preferences to restrict setting changes. If the ViewModel updates the UI in this situation, it will cause Settings to crash.
  - Avoid to setup ViewModel when UI is restricted

Bug: 284435378
Test: Manual test
atest -c TetherSettingsTest

Change-Id: I52d4ea717c34eacc9cc2321e3950dc89408049f8

src/com/android/settings/network/tether/TetherSettings.java

@@ -145,19 +145,13 @@ public class TetherSettings extends RestrictedSettingsFragment
         super(UserManager.DISALLOW_CONFIG_TETHERING);
     }
 
-    @Override
-    public void onAttach(Context context) {
-        super.onAttach(context);
-        TetheringManagerModel model = new ViewModelProvider(this).get(TetheringManagerModel.class);
-        mWifiTetherPreferenceController =
-                new WifiTetherPreferenceController(context, getSettingsLifecycle(), model);
-        mTm = model.getTetheringManager();
-        model.getTetheredInterfaces().observe(this, this::onTetheredInterfacesChanged);
-    }
-
     @Override
     public void onCreate(Bundle icicle) {
         super.onCreate(icicle);
+        setIfOnlyAvailableForAdmins(true);
+        if (isUiRestricted()) {
+            return;
+        }
 
         addPreferencesFromResource(R.xml.tether_prefs);
         mContext = getContext();
@@ -165,13 +159,8 @@ public class TetherSettings extends RestrictedSettingsFragment
         mDataSaverEnabled = mDataSaverBackend.isDataSaverEnabled();
         mDataSaverFooter = findPreference(KEY_DATA_SAVER_FOOTER);
 
-        setIfOnlyAvailableForAdmins(true);
-        if (isUiRestricted()) {
-            getPreferenceScreen().removeAll();
-            return;
-        }
-
         setupTetherPreference();
+        setupViewModel();
 
         final Activity activity = getActivity();
         BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();
@@ -223,8 +212,22 @@ public class TetherSettings extends RestrictedSettingsFragment
         onDataSaverChanged(mDataSaverBackend.isDataSaverEnabled());
     }
 
+    @VisibleForTesting
+    void setupViewModel() {
+        TetheringManagerModel model = new ViewModelProvider(this).get(TetheringManagerModel.class);
+        mWifiTetherPreferenceController =
+                new WifiTetherPreferenceController(getContext(), getSettingsLifecycle(), model);
+        mTm = model.getTetheringManager();
+        model.getTetheredInterfaces().observe(this, this::onTetheredInterfacesChanged);
+    }
+
     @Override
     public void onDestroy() {
+        if (isUiRestricted()) {
+            super.onDestroy();
+            return;
+        }
+
         mDataSaverBackend.remListener(this);
 
         BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();

tests/robotests/src/com/android/settings/network/tether/TetherSettingsTest.java

@@ -45,6 +45,7 @@ import android.hardware.usb.UsbManager;
 import android.net.ConnectivityManager;
 import android.net.TetheringManager;
 import android.net.wifi.WifiManager;
+import android.os.Bundle;
 import android.os.UserHandle;
 import android.os.UserManager;
 import android.util.FeatureFlagUtils;
@@ -54,6 +55,7 @@ import androidx.preference.Preference;
 import androidx.preference.SwitchPreference;
 
 import com.android.settings.R;
+import com.android.settings.RestrictedSettingsFragment;
 import com.android.settings.core.FeatureFlags;
 import com.android.settings.wifi.tether.WifiTetherPreferenceController;
 import com.android.settingslib.RestrictedSwitchPreference;
@@ -66,6 +68,9 @@ import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
 import org.robolectric.RobolectricTestRunner;
 import org.robolectric.RuntimeEnvironment;
+import org.robolectric.annotation.Config;
+import org.robolectric.annotation.Implementation;
+import org.robolectric.annotation.Implements;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -92,7 +97,7 @@ public class TetherSettingsTest {
     @Mock
     private Preference mDataSaverFooter;
 
-    TetherSettings mTetherSettings;
+    private MockTetherSettings mTetherSettings;
 
     @Before
     public void setUp() throws Exception {
@@ -114,7 +119,7 @@ public class TetherSettingsTest {
         when(mTetheringManager.getTetherableUsbRegexs()).thenReturn(new String[0]);
         when(mTetheringManager.getTetherableBluetoothRegexs()).thenReturn(new String[0]);
 
-        mTetherSettings = spy(new TetherSettings());
+        mTetherSettings = spy(new MockTetherSettings());
         mTetherSettings.mContext = mContext;
         mTetherSettings.mWifiTetherPreferenceController = mWifiTetherPreferenceController;
         mTetherSettings.mUsbTether = mUsbTether;
@@ -123,6 +128,16 @@ public class TetherSettingsTest {
         mTetherSettings.mDataSaverFooter = mDataSaverFooter;
     }
 
+    @Test
+    @Config(shadows = ShadowRestrictedSettingsFragment.class)
+    public void onCreate_isUiRestricted_doNotSetupViewModel() {
+        when(mTetherSettings.isUiRestricted()).thenReturn(true);
+
+        mTetherSettings.onCreate(null);
+
+        verify(mTetherSettings, never()).setupViewModel();
+    }
+
     @Test
     public void testTetherNonIndexableKeys_tetherAvailable_keysNotReturned() {
         FeatureFlagUtils.setEnabled(mContext, FeatureFlags.TETHER_ALL_IN_ONE, false);
@@ -431,4 +446,19 @@ public class TetherSettingsTest {
         mTetherSettings.registerReceiver();
         updateOnlyBluetoothState(mTetherSettings);
     }
+
+    private static class MockTetherSettings extends TetherSettings {
+        @Override
+        public boolean isUiRestricted() {
+            return false;
+        }
+    }
+
+    @Implements(RestrictedSettingsFragment.class)
+    public static final class ShadowRestrictedSettingsFragment {
+        @Implementation
+        public void onCreate(Bundle icicle) {
+            // do nothing
+        }
+    }
 }