Improve the sample code, add empty parameter callback.

Author: codezjx

sample/src/main/java/com/example/andlinker/BindingActivity.java

@@ -133,6 +133,12 @@ protected void onDestroy() {
     }
 
     private final IRemoteCallback mRemoteCallback = new IRemoteCallback() {
+        
+        @Override
+        public void onStart() {
+            Log.d(TAG, "Server callback onStart!");
+        }
+
         @Override
         public void onValueChange(int value) {
             // Invoke when server side callback

sample/src/main/java/com/example/andlinker/IRemoteCallback.java

@@ -8,5 +8,7 @@
 @RemoteInterface
 public interface IRemoteCallback {
 
+    void onStart();
+
     void onValueChange(int value);
 }

sample/src/main/java/com/example/andlinker/RemoteService.java

@@ -61,6 +61,7 @@ public void basicTypes(int anInt, long aLong, boolean aBoolean,
 
         @Override
         public void registerCallback(IRemoteCallback callback) {
+            callback.onStart();
             callback.onValueChange(1234);
         }