[Network Connection] Implement Unavailable callback when the user cancels

UI should invoke NetworkRequestUserSelectionCallback.reject() callback when the user clicks cancel.

Bug: 128876386
Test: atest NetworkRequestDialogFragment
Change-Id: Ia5faedf8cc7113a602a4cda10b3252d02c3c8876

src/com/android/settings/wifi/NetworkRequestDialogFragment.java

@@ -124,7 +124,7 @@ public class NetworkRequestDialogFragment extends InstrumentedDialogFragment imp
         final AlertDialog.Builder builder = new AlertDialog.Builder(context)
                 .setCustomTitle(customTitle)
                 .setAdapter(mDialogAdapter, this)
-                .setNegativeButton(R.string.cancel, (dialog, which) -> getActivity().finish())
+                .setNegativeButton(R.string.cancel, (dialog, which) -> onCancel(dialog))
                 // Do nothings, will replace the onClickListener to avoid auto closing dialog.
                 .setNeutralButton(R.string.network_connection_request_dialog_showall,
                         null /* OnClickListener */);
@@ -221,6 +221,9 @@ public class NetworkRequestDialogFragment extends InstrumentedDialogFragment imp
         if (getActivity() != null) {
             getActivity().finish();
         }
+        if (mUserSelectionCallback != null) {
+            mUserSelectionCallback.reject();
+        }
     }
 
     @Override

tests/robotests/src/com/android/settings/wifi/NetworkRequestDialogFragmentTest.java

@@ -330,4 +330,21 @@ public class NetworkRequestDialogFragmentTest {
         // Check
         assertThat(button.getVisibility()).isEqualTo(View.GONE);
     }
+
+    @Test
+    public void cancelDialog_callsReject() {
+        // Assert
+        networkRequestDialogFragment.show(mActivity.getSupportFragmentManager(), /* tag */ null);
+        final AlertDialog alertDialog = ShadowAlertDialogCompat.getLatestAlertDialog();
+        final NetworkRequestUserSelectionCallback selectionCallback = mock(
+                NetworkRequestUserSelectionCallback.class);
+        networkRequestDialogFragment.onUserSelectionCallbackRegistration(selectionCallback);
+
+        // Action
+        final Button button = alertDialog.getButton(AlertDialog.BUTTON_NEGATIVE);
+        button.performClick();
+
+        // Check
+        verify(selectionCallback, times(1)).reject();
+    }
 }