replace unused NFC selection

Instead, tell the user to fix the nfc emulation requirements, e.g.
installing samsung gear plugin or enabling the nfc settings.

ACardEmulator/app/src/main/java/com/vsmartcard/acardemulator/SettingsActivity.java

@@ -201,7 +201,30 @@ public class SettingsActivity extends AppCompatPreferenceActivity {
                 }
             });
 
-            bindPreferenceSummaryToValue(findPreference("nfc"));
+            Preference internal_nfc = findPreference("internal_nfc");
+            internal_nfc.setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {
+                public boolean onPreferenceClick(Preference preference) {
+                    if (android.os.Build.VERSION.SDK_INT >= 16) {
+                        startActivity(new Intent(android.provider.Settings.ACTION_NFC_SETTINGS));
+                    } else {
+                        startActivity(new Intent(android.provider.Settings.ACTION_WIRELESS_SETTINGS));
+                    }
+                    return true;
+                }
+            });
+
+            Preference gear_nfc = findPreference("gear_nfc");
+            gear_nfc.setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {
+                public boolean onPreferenceClick(Preference preference) {
+                    String gearPackage = "com.samsung.android.gearoplugin";
+                    try {
+                        startActivity(new Intent(android.content.Intent.ACTION_VIEW, Uri.parse("market://details?id="+gearPackage)));
+                    } catch (android.content.ActivityNotFoundException e) {
+                        startActivity(new Intent(android.content.Intent.ACTION_VIEW, Uri.parse("https://play.google.com/store/apps/details?id="+gearPackage)));
+                    }
+                    return true;
+                }
+            });
         }
 
         @Override

ACardEmulator/app/src/main/res/values/strings.xml

@@ -45,13 +45,6 @@
     <string name="jcardsim">Builtin Java Card Simulator</string>
     <string name="vicc">Remote Virtual Smart Card</string>
 
-    <string-array name="strNFC">
-        <item>@string/nfc</item>
-        <item>@string/gear</item>
-    </string-array>
-    <string name="nfc">Builtin NFC</string>
-    <string name="gear">Samsung Accessory</string>
-
     <string name="vicc_config_info">If you choose the virtual smart card (VICC) as emulator, you need to start the it on your computer with the `--reversed` flag and configure the connection parameters here accordingly.</string>
     <string name="hint_vicc_port">VICC Port</string>
     <string name="hint_vicc_hostname">VICC Hostname</string>

ACardEmulator/app/src/main/res/xml/settings.xml

@@ -81,11 +81,23 @@
 
     </PreferenceCategory>
 
-    <ListPreference
+    <PreferenceCategory
+        android:title="Near Field Communication"
         android:key="nfc"
-        android:title="NFC communication hardware"
+        >
-        android:defaultValue="@string/nfc"
+
-        android:entries="@array/strNFC"
+        <Preference
-        android:entryValues="@array/strNFC" />
+            android:title="Emulation with Built-in NFC"
+            android:summary="NFC needs to be enabled for smart card emulation. Use the wireless settings to enable NFC."
+            android:key="internal_nfc">
+        </Preference>
+
+        <Preference
+            android:title="Emulation with Gear's NFC"
+            android:summary="Samsung Gear needs to be installed for using the Gear's NFC emulation capabilities."
+            android:key="gear_nfc">
+        </Preference>
+
+    </PreferenceCategory>
 
 </PreferenceScreen>