Make getSystemService(NFC_SERVICE) the NFC entry point.

This gives NFC service a handle to the application context.

Deprecate NfcAdapter.getDefaultAdapter(), it does not provide a context.
Using this method will print a warning, and will later throw an exception
if a method that requires a context is called. No 2.3 API's will fail, but
new API's that do require a context might fail.

Also add helper NfcAdapter.getDefaultAdapter(Context).

Change-Id: I9a6378de4ef4b61ad922f8d53e64e2a1a1d5d60c

Author: Nick Pelly

api/current.xml

@@ -35673,6 +35673,17 @@
  visibility="public"
 >
 </field>
+<field name="NFC_SERVICE"
+ type="java.lang.String"
+ transient="false"
+ volatile="false"
+ value="&quot;nfc&quot;"
+ static="true"
+ final="true"
+ deprecated="not deprecated"
+ visibility="public"
+>
+</field>
 <field name="NOTIFICATION_SERVICE"
  type="java.lang.String"
  transient="false"
@@ -100183,6 +100194,19 @@
  deprecated="not deprecated"
  visibility="public"
 >
+<parameter name="context" type="android.content.Context">
+</parameter>
+</method>
+<method name="getDefaultAdapter"
+ return="android.nfc.NfcAdapter"
+ abstract="false"
+ native="false"
+ synchronized="false"
+ static="true"
+ final="false"
+ deprecated="deprecated"
+ visibility="public"
+>
 </method>
 <method name="isEnabled"
  return="boolean"
@@ -100229,6 +100253,26 @@
 >
 </field>
 </class>
+<class name="NfcManager"
+ extends="java.lang.Object"
+ abstract="false"
+ static="false"
+ final="true"
+ deprecated="not deprecated"
+ visibility="public"
+>
+<method name="getDefaultAdapter"
+ return="android.nfc.NfcAdapter"
+ abstract="false"
+ native="false"
+ synchronized="false"
+ static="false"
+ final="false"
+ deprecated="not deprecated"
+ visibility="public"
+>
+</method>
+</class>
 </package>
 <package name="android.opengl"
 >

core/java/android/app/ContextImpl.java

@@ -72,6 +72,7 @@
 import android.net.Uri;
 import android.net.wifi.IWifiManager;
 import android.net.wifi.WifiManager;
+import android.nfc.NfcManager;
 import android.os.Binder;
 import android.os.Bundle;
 import android.os.DropBoxManager;
@@ -201,6 +202,7 @@ class ContextImpl extends Context {
     private DevicePolicyManager mDevicePolicyManager = null;
     private UiModeManager mUiModeManager = null;
     private DownloadManager mDownloadManager = null;
+    private NfcManager mNfcManager = null;
 
     private final Object mSync = new Object();
 
@@ -977,6 +979,8 @@ public Object getSystemService(String name) {
             return getUiModeManager();
         } else if (DOWNLOAD_SERVICE.equals(name)) {
             return getDownloadManager();
+        } else if (NFC_SERVICE.equals(name)) {
+            return getNfcManager();
         }
 
         return null;
@@ -1204,6 +1208,15 @@ private DownloadManager getDownloadManager() {
         return mDownloadManager;
     }
 
+    private NfcManager getNfcManager() {
+        synchronized (mSync) {
+            if (mNfcManager == null) {
+                mNfcManager = new NfcManager(this);
+            }
+        }
+        return mNfcManager;
+    }
+
     @Override
     public int checkPermission(String permission, int pid, int uid) {
         if (permission == null) {

core/java/android/content/Context.java

@@ -1549,6 +1549,14 @@ public abstract boolean startInstrumentation(ComponentName className,
      */
     public static final String DOWNLOAD_SERVICE = "download";
 
+    /**
+     * Use with {@link #getSystemService} to retrieve a
+     * {@link android.nfc.NfcManager} for using NFC.
+     *
+     * @see #getSystemService
+     */
+    public static final String NFC_SERVICE = "nfc";
+
     /**
      * Use with {@link #getSystemService} to retrieve a
      * {@link android.net.sip.SipManager} for accessing the SIP related service.

core/java/android/nfc/NfcAdapter.java

@@ -19,6 +19,7 @@
 import android.annotation.SdkConstant;
 import android.annotation.SdkConstant.SdkConstantType;
 import android.app.ActivityThread;
+import android.content.Context;
 import android.content.pm.IPackageManager;
 import android.content.pm.PackageManager;
 import android.os.IBinder;
@@ -29,11 +30,12 @@
 /**
  * Represents the device's local NFC adapter.
  * <p>
- * Use the static {@link #getDefaultAdapter} method to get the default NFC
- * Adapter for this Android device. Most Android devices will have only one NFC
- * Adapter, and {@link #getDefaultAdapter} returns the singleton object.
+ * Use the helper {@link #getDefaultAdapter(Context)} to get the default NFC
+ * adapter for this Android device.
  */
 public final class NfcAdapter {
+    private static final String TAG = "NFC";
+
     /**
      * Intent to start an activity when a tag is discovered.
      */
@@ -161,29 +163,17 @@ public final class NfcAdapter {
      */
     private static final int DISCOVERY_MODE_CARD_EMULATION = 2;
 
-    private static final String TAG = "NFC";
 
-    // Both guarded by NfcAdapter.class:
+    // Guarded by NfcAdapter.class
     private static boolean sIsInitialized = false;
-    private static NfcAdapter sAdapter;
 
-    // Final after construction, except for attemptDeadServiceRecovery()
-    // when NFC crashes.
-    // Not locked - we accept a best effort attempt when NFC crashes.
-    /*package*/ INfcAdapter mService;
+    // Final after first constructor, except for
+    // attemptDeadServiceRecovery() when NFC crashes - we accept a best effort
+    // recovery
+    private static INfcAdapter sService;
 
-    private NfcAdapter(INfcAdapter service) {
-        mService = service;
-    }
+    private final Context mContext;
 
-    /**
-     * Returns the binder interface to the service.
-     * @hide
-     */
-    public INfcAdapter getService() {
-        return mService;
-    }
-    
     /**
      * Helper to check if this device has FEATURE_NFC, but without using
      * a context.
@@ -204,8 +194,27 @@ private static boolean hasNfcFeature() {
         }
     }
 
+    private static synchronized INfcAdapter setupService() {
+        if (!sIsInitialized) {
+            sIsInitialized = true;
+
+            /* is this device meant to have NFC */
+            if (!hasNfcFeature()) {
+                Log.v(TAG, "this device does not have NFC support");
+                return null;
+            }
+
+            sService = getServiceInterface();
+            if (sService == null) {
+                Log.e(TAG, "could not retrieve NFC service");
+                return null;
+            }
+        }
+        return sService;
+    }
+
     /** get handle to NFC service interface */
-    private static synchronized INfcAdapter getServiceInterface() {
+    private static INfcAdapter getServiceInterface() {
         /* get a handle to NFC service */
         IBinder b = ServiceManager.getService("nfc");
         if (b == null) {
@@ -214,35 +223,55 @@ private static synchronized INfcAdapter getServiceInterface() {
         return INfcAdapter.Stub.asInterface(b);
     }
 
+    /**
+     * Helper to get the default NFC Adapter.
+     * <p>
+     * Most Android devices will only have one NFC Adapter (NFC Controller).
+     * <p>
+     * This helper is the equivalent of:
+     * <pre>{@code
+     * NfcManager manager = (NfcManager) context.getSystemService(Context.NFC_SERVICE);
+     * NfcAdapter adapter = manager.getDefaultAdapter();
+     * }</pre>
+     * @param context the calling application's context
+     *
+     * @return the default NFC adapter, or null if no NFC adapter exists
+     */
+    public static NfcAdapter getDefaultAdapter(Context context) {
+        /* use getSystemService() instead of just instantiating to take
+         * advantage of the context's cached NfcManager & NfcAdapter */
+        NfcManager manager = (NfcManager) context.getSystemService(Context.NFC_SERVICE);
+        return manager.getDefaultAdapter();
+    }
+
     /**
      * Get a handle to the default NFC Adapter on this Android device.
      * <p>
      * Most Android devices will only have one NFC Adapter (NFC Controller).
      *
      * @return the default NFC adapter, or null if no NFC adapter exists
+     * @deprecated use {@link #getDefaultAdapter(Context)}
      */
+    @Deprecated
     public static NfcAdapter getDefaultAdapter() {
-        synchronized (NfcAdapter.class) {
-            if (sIsInitialized) {
-                return sAdapter;
-            }
-            sIsInitialized = true;
-
-            /* is this device meant to have NFC */
-            if (!hasNfcFeature()) {
-                Log.v(TAG, "this device does not have NFC support");
-                return null;
-            }
-
-            INfcAdapter service = getServiceInterface();
-            if (service == null) {
-                Log.e(TAG, "could not retrieve NFC service");
-                return null;
-            }
+        Log.w(TAG, "WARNING: NfcAdapter.getDefaultAdapter() is deprecated, use " +
+                "NfcAdapter.getDefaultAdapter(Context) instead", new Exception());
+        return new NfcAdapter(null);
+    }
 
-            sAdapter = new NfcAdapter(service);
-            return sAdapter;
+    /*package*/ NfcAdapter(Context context) {
+        if (setupService() == null) {
+            throw new UnsupportedOperationException();
         }
+        mContext = context;
+    }
+
+    /**
+     * Returns the binder interface to the service.
+     * @hide
+     */
+    public INfcAdapter getService() {
+        return sService;
     }
 
     /**
@@ -256,9 +285,9 @@ public void attemptDeadServiceRecovery(Exception e) {
             Log.e(TAG, "could not retrieve NFC service during service recovery");
             return;
         }
-        /* assigning to mService is not thread-safe, but this is best-effort code
+        /* assigning to sService is not thread-safe, but this is best-effort code
          * and on a well-behaved system should never happen */
-        mService = service;
+        sService = service;
         return;
     }
 
@@ -275,7 +304,7 @@ public void attemptDeadServiceRecovery(Exception e) {
      */
     public boolean isEnabled() {
         try {
-            return mService.isEnabled();
+            return sService.isEnabled();
         } catch (RemoteException e) {
             attemptDeadServiceRecovery(e);
             return false;
@@ -292,7 +321,7 @@ public boolean isEnabled() {
      */
     public boolean enable() {
         try {
-            return mService.enable();
+            return sService.enable();
         } catch (RemoteException e) {
             attemptDeadServiceRecovery(e);
             return false;
@@ -311,7 +340,7 @@ public boolean enable() {
      */
     public boolean disable() {
         try {
-            return mService.disable();
+            return sService.disable();
         } catch (RemoteException e) {
             attemptDeadServiceRecovery(e);
             return false;
@@ -338,7 +367,7 @@ public boolean disable() {
      */
     public void setLocalNdefMessage(NdefMessage message) {
         try {
-            mService.localSet(message);
+            sService.localSet(message);
         } catch (RemoteException e) {
             attemptDeadServiceRecovery(e);
         }
@@ -353,7 +382,7 @@ public void setLocalNdefMessage(NdefMessage message) {
      */
     public NdefMessage getLocalNdefMessage() {
         try {
-            return mService.localGet();
+            return sService.localGet();
         } catch (RemoteException e) {
             attemptDeadServiceRecovery(e);
             return null;
@@ -366,7 +395,7 @@ public NdefMessage getLocalNdefMessage() {
      */
     public NfcSecureElement createNfcSecureElementConnection() {
         try {
-            return new NfcSecureElement(mService.getNfcSecureElementInterface());
+            return new NfcSecureElement(sService.getNfcSecureElementInterface());
         } catch (RemoteException e) {
             Log.e(TAG, "createNfcSecureElementConnection failed", e);
             return null;