altosui: Handle missing pad distance in descent tab

When the GPS isn't locked, the distance from the pad cannot be
computed and is left missing. Not crashing in this case is more useful.

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/altosui/AltosDescent.java b/altosui/AltosDescent.java
index e9ff590b735e6d79dbec25187ad421426bd9f8f0..a71cdc10c0fc97f2305951365294cc165f1d3580 100644 (file)
--- a/altosui/AltosDescent.java
+++ b/altosui/AltosDescent.java
@@ -309,7 +309,10 @@ public class AltosDescent extends JComponent implements AltosFlightDisplay {
 
        class Distance extends DescentValue {
                void show(AltosState state, int crc_errors) {
-                       show(AltosConvert.distance, state.from_pad.distance);
+                       if (state.from_pad != null)
+                               show(AltosConvert.distance, state.from_pad.distance);
+                       else
+                               show("???");
                }
 
                public Distance (GridBagLayout layout, int x, int y) {