walt: app: fix ping while WALT hardware is disconnected

WALT app crashed if WALT equipment was disconnected and click Ping in
the menu Diagnostics.

Bug: 149721303
Test: disconnect WALT hardware and click Ping
Signed-off-by: Tai Kuo <taikuo@google.com>
Change-Id: Ib5c72d402eaa5ef8d0facea2aeb420ac729edc9a

2 files changed, 14 insertions, 6 deletions

diff --git a/android/WALT/app/src/main/java/org/chromium/latency/walt/MainActivity.java b/android/WALT/app/src/main/java/org/chromium/latency/walt/MainActivity.java
index 2c35411..81a637b 100644
--- a/android/WALT/app/src/main/java/org/chromium/latency/walt/MainActivity.java
+++ b/android/WALT/app/src/main/java/org/chromium/latency/walt/MainActivity.java
@@ -355,13 +355,8 @@ public class MainActivity extends AppCompatActivity {
     }
 
     public void onClickPing(View view) {
-        long t1 = waltDevice.clock.micros();
         try {
-            waltDevice.command(WaltDevice.CMD_PING);
-            long dt = waltDevice.clock.micros() - t1;
-            logger.log(String.format(Locale.US,
-                    "Ping reply in %.1fms", dt / 1000.
-            ));
+            waltDevice.ping();
         } catch (IOException e) {
             logger.log("Error sending ping: " + e.getMessage());
         }
diff --git a/android/WALT/app/src/main/java/org/chromium/latency/walt/WaltDevice.java b/android/WALT/app/src/main/java/org/chromium/latency/walt/WaltDevice.java
index 90d75ea..631afb8 100644
--- a/android/WALT/app/src/main/java/org/chromium/latency/walt/WaltDevice.java
+++ b/android/WALT/app/src/main/java/org/chromium/latency/walt/WaltDevice.java
@@ -223,6 +223,19 @@ public class WaltDevice implements WaltConnection.ConnectionStateListener {
         }
     }
 
+    public void ping() throws IOException {
+        if (!isConnected() || clock == null) {
+            throw new IOException("Not connected to WALT");
+        }
+
+        long t1 = clock.micros();
+        command(CMD_PING);
+        long dt = clock.micros() - t1;
+        logger.log(String.format(Locale.US,
+                "Ping reply in %.1fms", dt / 1000.
+        ));
+    }
+
     public void syncClock() throws IOException {
         clock = connection.syncClock();
     }