Application accepts null intents causing a crash

Change-Id: Ia7f98f43567f25ae7abc6e5ac7e07323e75d9047
Fixes: 116869239
Test: adb shell am start -n com.android.settings/com.android.settings.Settings\\\$ApnEditorActivity
Test: make RunSettingsRoboTests ROBOTEST_FILTER="com.android.settings.network"

src/com/android/settings/network/ApnEditor.java

@@ -231,9 +231,13 @@ public class ApnEditor extends SettingsPreferenceFragment
 
         final Intent intent = getIntent();
         final String action = intent.getAction();
+        if (TextUtils.isEmpty(action)) {
+            finish();
+            return;
+        }
+
         mSubId = intent.getIntExtra(ApnSettings.SUB_ID,
                 SubscriptionManager.INVALID_SUBSCRIPTION_ID);
-
         mReadOnlyApn = false;
         mReadOnlyApnTypes = null;
         mReadOnlyApnFields = null;

tests/robotests/src/com/android/settings/network/ApnEditorTest.java

@@ -19,11 +19,13 @@ package com.android.settings.network;
 import static com.google.common.truth.Truth.assertThat;
 
 import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.Mockito.doNothing;
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
 
 import android.content.ContentResolver;
 import android.content.ContentValues;
@@ -450,6 +452,15 @@ public class ApnEditorTest {
         assertThat(ApnEditor.formatInteger("not an int")).isEqualTo("not an int");
     }
 
+    @Test
+    public void onCreate_noAction_shouldFinishAndNoCrash() {
+        doNothing().when(mApnEditorUT).addPreferencesFromResource(anyInt());
+
+        mApnEditorUT.onCreate(null);
+
+        verify(mApnEditorUT).finish();
+    }
+
     private void initCursor() {
         doReturn(2).when(mCursor).getColumnCount();
         doReturn(Integer.valueOf(2)).when(mCursor).getInt(CURSOR_INTEGER_INDEX);