Let connect() fail with an I/O exception if tag has left the field.

Because connect() can sometimes be implemented without any I/O,
(usually between transitions to/from the NDEF technology),
it does not always notice when a tag has left the field. Since
we promise in the API docs that it does, fix it by checking
(cached) presence.

Change-Id: Ie6ad1b5dec3621051e395d3be0d0e09615e53ebc

1 files changed, 4 insertions, 0 deletions

diff --git a/src/com/android/nfc/NfcService.java b/src/com/android/nfc/NfcService.java
index dca96b9..560c5aa 100755
--- a/src/com/android/nfc/NfcService.java
+++ b/src/com/android/nfc/NfcService.java
@@ -853,6 +853,10 @@ public class NfcService extends Application implements DeviceHostListener {
                 return ErrorCodes.ERROR_DISCONNECT;
             }
 
+            if (!tag.isPresent()) {
+                return ErrorCodes.ERROR_DISCONNECT;
+            }
+
             if (technology == TagTechnology.NFC_B) {
                 return ErrorCodes.ERROR_NOT_SUPPORTED;
             }