[FM] FM default name of recording file is not correct

    Launch FM, play a channel without a name or PS info ->
    Select "Start Recording" in options menu -> Tap "STOP
    RECORDINGS" and check the default name, It is
    "FM__MMddyyyy_hhmmss".

    The fix is to change recordingName according to different
    condition.

    Bug 18780825

    Review: https://partner-android-review.git.corp.google.com/#/c/189540

Signed-off-by: Benson Huang <benson.huang@mediatek.com>

Change-Id: I75a3565f689f552e4965ede900f07f68749ed736

src/com/android/fmradio/FmRecordActivity.java

@@ -454,8 +454,12 @@ public class FmRecordActivity extends Activity implements
         }
         String sdcard = FmService.getRecordingSdcard();
         String recordingName = mService.getRecordingName();
-        recordingName = FmRecorder.RECORDING_FILE_PREFIX + "_" + mStationName.getText() + "_"
-                + recordingName;
+        if (TextUtils.isEmpty(mStationName.getText())) {
+            recordingName = FmRecorder.RECORDING_FILE_PREFIX +  "_" + recordingName;
+        } else {
+            recordingName = FmRecorder.RECORDING_FILE_PREFIX + "_" + mStationName.getText() + "_"
+                    + recordingName;
+        }
         FmSaveDialog newFragment = new FmSaveDialog(sdcard, recordingName, recordingName);
         newFragment.show(mFragmentManager, TAG_SAVE_RECORDINGD);
         mFragmentManager.executePendingTransactions();