Fix APN cannot save after ApnEditor is paused.

When ApnEditor is paused and user does not enter name or APN,
the new APN URI will be deleted in validateAndSave() method.
After the activity is resumed, the APN will not able to be
saved because the database record has been deleted.

Change-Id: I19f5246020e4a52239a7fc0ac86a281372e34b90

src/com/android/settings/ApnEditor.java

@@ -249,6 +249,21 @@ public class ApnEditor extends InstrumentedPreferenceActivity
     @Override
     public void onResume() {
         super.onResume();
+
+        if (mUri == null && mNewApn) {
+            // The URI could have been deleted when activity is paused,
+            // therefore, it needs to be restored.
+            mUri = getContentResolver().insert(getIntent().getData(), new ContentValues());
+            if (mUri == null) {
+                Log.w(TAG, "Failed to insert new telephony provider into "
+                        + getIntent().getData());
+                finish();
+                return;
+            }
+            mCursor = managedQuery(mUri, sProjection, null, null);
+            mCursor.moveToFirst();
+        }
+
         getPreferenceScreen().getSharedPreferences()
                 .registerOnSharedPreferenceChangeListener(this);
     }
@@ -596,6 +611,7 @@ public class ApnEditor extends InstrumentedPreferenceActivity
         // If it's a new APN and a name or apn haven't been entered, then erase the entry
         if (force && mNewApn && name.length() < 1 && apn.length() < 1) {
             getContentResolver().delete(mUri, null, null);
+            mUri = null;
             return false;
         }