Watch zero cell towers

2 files changed, 16 insertions, 11 deletions

diff --git a/src/main/java/org/traccar/protocol/WatchProtocolDecoder.java b/src/main/java/org/traccar/protocol/WatchProtocolDecoder.java
index 4ab7875b7..b25a15f93 100644
--- a/src/main/java/org/traccar/protocol/WatchProtocolDecoder.java
+++ b/src/main/java/org/traccar/protocol/WatchProtocolDecoder.java
@@ -145,17 +145,19 @@ public class WatchProtocolDecoder extends BaseProtocolDecoder {
 
         int cellCount = Integer.parseInt(values[index++]);
         index += 1; // timing advance
-        int mcc = !values[index].isEmpty() ? Integer.parseInt(values[index++]) : 0;
-        int mnc = !values[index].isEmpty() ? Integer.parseInt(values[index++]) : 0;
-
-        for (int i = 0; i < cellCount; i++) {
-            int lac = Integer.parseInt(values[index++]);
-            int cid = Integer.parseInt(values[index++]);
-            String rssi = values[index++];
-            if (!rssi.isEmpty()) {
-                network.addCellTower(CellTower.from(mcc, mnc, lac, cid, Integer.parseInt(rssi)));
-            } else {
-                network.addCellTower(CellTower.from(mcc, mnc, lac, cid));
+        if (cellCount > 0) {
+            int mcc = !values[index].isEmpty() ? Integer.parseInt(values[index++]) : 0;
+            int mnc = !values[index].isEmpty() ? Integer.parseInt(values[index++]) : 0;
+
+            for (int i = 0; i < cellCount; i++) {
+                int lac = Integer.parseInt(values[index++]);
+                int cid = Integer.parseInt(values[index++]);
+                String rssi = values[index++];
+                if (!rssi.isEmpty()) {
+                    network.addCellTower(CellTower.from(mcc, mnc, lac, cid, Integer.parseInt(rssi)));
+                } else {
+                    network.addCellTower(CellTower.from(mcc, mnc, lac, cid));
+                }
             }
         }
 
diff --git a/src/test/java/org/traccar/protocol/WatchProtocolDecoderTest.java b/src/test/java/org/traccar/protocol/WatchProtocolDecoderTest.java
index 4fab19f26..34ef7839b 100644
--- a/src/test/java/org/traccar/protocol/WatchProtocolDecoderTest.java
+++ b/src/test/java/org/traccar/protocol/WatchProtocolDecoderTest.java
@@ -15,6 +15,9 @@ public class WatchProtocolDecoderTest extends ProtocolTest {
 
         var decoder = new WatchProtocolDecoder(null);
 
+        verifyPosition(decoder, buffer(
+                "[3G*9031853319*004E*UD2,220322,055105,A,22.761162,N,114.360192,E,0,0,47,14,100,64,0,0,00000008,0,0]"));
+
         verifyAttribute(decoder, buffer(
                 "[3G*2104326058*000E*btemp2,1,35.29]"),
                 Position.PREFIX_TEMP + 1, 35.29);