Throw a nicer error message when using an invalid context to create Nfc

This can happen when using getContext() instead of getTargetContext()
in an InstrumentationTestCase.

Bug: 5644274
Change-Id: I020a637c271e25bcf25ae2927fd878001d5fea0a

2 files changed, 9 insertions, 2 deletions

diff --git a/core/java/android/nfc/NfcAdapter.java b/core/java/android/nfc/NfcAdapter.java
index dec262b..b6af0f2 100644
--- a/core/java/android/nfc/NfcAdapter.java
+++ b/core/java/android/nfc/NfcAdapter.java
@@ -357,8 +357,11 @@ public final class NfcAdapter {
             throw new IllegalArgumentException("context cannot be null");
         }
         context = context.getApplicationContext();
-        /* use getSystemService() instead of just instantiating to take
-         * advantage of the context's cached NfcManager & NfcAdapter */
+        if (context == null) {
+            throw new IllegalArgumentException(
+                    "context not associated with any application (using a mock context?)");
+        }
+        /* use getSystemService() for consistency */
         NfcManager manager = (NfcManager) context.getSystemService(Context.NFC_SERVICE);
         return manager.getDefaultAdapter();
     }
diff --git a/core/java/android/nfc/NfcManager.java b/core/java/android/nfc/NfcManager.java
index 6ec2e21..2bbed57 100644
--- a/core/java/android/nfc/NfcManager.java
+++ b/core/java/android/nfc/NfcManager.java
@@ -40,6 +40,10 @@ public final class NfcManager {
     public NfcManager(Context context) {
         NfcAdapter adapter;
         context = context.getApplicationContext();
+        if (context == null) {
+            throw new IllegalArgumentException(
+                    "context not associated with any application (using a mock context?)");
+        }
         try {
             adapter = NfcAdapter.getNfcAdapter(context);
         } catch (UnsupportedOperationException e) {