Fix NPE in UltraSoundSpeaker test.

The function LineAndPointFormatter#configure will use invoke function to get the object/variable
which defined in xml resource. aosp/758566 defined new object pointLabelFormatter on
R.xml.ultrasound_line_formatter_trials, it's the reason to get NPE here.


Bug: 110259506
Test: local build & run CtsVerifier.
Change-Id: I7f401a19c03bd2911e47631c68e87187aca74547
diff --git a/apps/CtsVerifier/src/com/android/cts/verifier/audio/HifiUltrasoundSpeakerTestActivity.java b/apps/CtsVerifier/src/com/android/cts/verifier/audio/HifiUltrasoundSpeakerTestActivity.java
index 87618b1..01802a4 100644
--- a/apps/CtsVerifier/src/com/android/cts/verifier/audio/HifiUltrasoundSpeakerTestActivity.java
+++ b/apps/CtsVerifier/src/com/android/cts/verifier/audio/HifiUltrasoundSpeakerTestActivity.java
@@ -280,9 +280,9 @@
             Arrays.asList(powerWrap),
             "");
         LineAndPointFormatter seriesFormat = new LineAndPointFormatter();
+        seriesFormat.setPointLabelFormatter(new PointLabelFormatter());
         seriesFormat.configure(getApplicationContext(),
             R.xml.ultrasound_line_formatter_trials);
-        seriesFormat.setPointLabelFormatter(new PointLabelFormatter());
         plot.addSeries(series, seriesFormat);
       }
 
@@ -297,9 +297,9 @@
           Arrays.asList(noiseDBWrap),
           "background noise");
       LineAndPointFormatter noiseSeriesFormat = new LineAndPointFormatter();
+      noiseSeriesFormat.setPointLabelFormatter(new PointLabelFormatter());
       noiseSeriesFormat.configure(getApplicationContext(),
           R.xml.ultrasound_line_formatter_noise);
-      noiseSeriesFormat.setPointLabelFormatter(new PointLabelFormatter());
       plot.addSeries(noiseSeries, noiseSeriesFormat);
 
       double[] dB = wavAnalyzerTask.getDB();
@@ -313,9 +313,9 @@
           Arrays.asList(dBWrap),
           "median");
       LineAndPointFormatter seriesFormat = new LineAndPointFormatter();
+      seriesFormat.setPointLabelFormatter(new PointLabelFormatter());
       seriesFormat.configure(getApplicationContext(),
           R.xml.ultrasound_line_formatter_median);
-      seriesFormat.setPointLabelFormatter(new PointLabelFormatter());
       plot.addSeries(series, seriesFormat);
 
       Double[] passX = new Double[] {Common.MIN_FREQUENCY_HZ, Common.MAX_FREQUENCY_HZ};
@@ -323,9 +323,9 @@
       XYSeries passSeries = new SimpleXYSeries(
           Arrays.asList(passX), Arrays.asList(passY), "passing");
       LineAndPointFormatter passSeriesFormat = new LineAndPointFormatter();
+      passSeriesFormat.setPointLabelFormatter(new PointLabelFormatter());
       passSeriesFormat.configure(getApplicationContext(),
           R.xml.ultrasound_line_formatter_pass);
-      passSeriesFormat.setPointLabelFormatter(new PointLabelFormatter());
       plot.addSeries(passSeries, passSeriesFormat);
     }
   }