Initial work towards output on serial port

GPSTest/build.gradle

@@ -117,6 +117,9 @@ dependencies {
     // Graphs for sliding drawer
     implementation 'com.github.PhilJay:MPAndroidChart:v3.1.0-alpha'
 
+    // Serial-over-USB output
+    implementation 'com.github.felHR85:UsbSerial:6.0.6'
+
     // Map (Google flavor only)
     googleImplementation 'com.google.android.gms:play-services-maps:16.1.0'
     // Calculating offset for camera target in map view (Google flavor only)

GPSTest/src/main/java/com/android/gpstest/GpsTestActivity.java

@@ -35,6 +35,8 @@ import android.hardware.Sensor;
 import android.hardware.SensorEvent;
 import android.hardware.SensorEventListener;
 import android.hardware.SensorManager;
+import android.hardware.usb.UsbDevice;
+import android.hardware.usb.UsbDeviceConnection;
 import android.location.GnssMeasurement;
 import android.location.GnssMeasurementsEvent;
 import android.location.GnssNavigationMessage;
@@ -80,6 +82,7 @@ import com.android.gpstest.util.MathUtils;
 import com.android.gpstest.util.PermissionUtils;
 import com.android.gpstest.util.PreferenceUtils;
 import com.android.gpstest.util.UIUtils;
+import com.felhr.usbserial.UsbSerialDevice;
 
 import java.util.ArrayList;
 
@@ -223,6 +226,10 @@ public class GpsTestActivity extends AppCompatActivity
 
     private String mInitialLanguage;
 
+    UsbDevice mUsbDevice;
+    UsbDeviceConnection mUsbConnection;
+    UsbSerialDevice mSerial;
+
     /** Called when the activity is first created. */
     @Override
     public void onCreate(Bundle savedInstanceState) {
@@ -293,6 +300,13 @@ public class GpsTestActivity extends AppCompatActivity
                 (DrawerLayout) findViewById(R.id.nav_drawer_left_pane));
     }
 
+    private void setupSerialOverUsb() {
+        mSerial = UsbSerialDevice.createUsbSerialDevice(mUsbDevice, mUsbConnection);
+        if (mSerial != null) {
+            mSerial.open();
+        }
+    }
+
      @Override
     public void onSaveInstanceState(Bundle outState) {
         // Save current GPS started state
@@ -320,6 +334,8 @@ public class GpsTestActivity extends AppCompatActivity
             }
         }
         mBenchmarkController.onResume();
+
+        setupSerialOverUsb();
     }
 
     /**
@@ -441,6 +457,10 @@ public class GpsTestActivity extends AppCompatActivity
             gpsStop();
         }
 
+        if (mSerial != null) {
+            mSerial.close();
+        }
+
         super.onPause();
     }
 
@@ -1047,6 +1067,7 @@ public class GpsTestActivity extends AppCompatActivity
                     if (mLogNmea) {
                         writeNmeaToLog(message,
                                 mWriteNmeaTimestampToLog ? timestamp : Long.MIN_VALUE);
+                        mSerial.write(message.getBytes());
                     }
                     PreferenceUtils.saveInt(Application.get().getString(R.string.capability_key_nmea), PreferenceUtils.CAPABILITY_SUPPORTED);
                 }

build.gradle

@@ -4,13 +4,10 @@ buildscript {
     repositories {
         google()
         jcenter()
-        maven {
-            url 'https://maven.google.com/'
-            name 'Google'
-        }
+        maven { url "https://jitpack.io" }
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.4.1'
+        classpath 'com.android.tools.build:gradle:3.4.2'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }