Merge "Update sample NSD app to work reliably with current Android"

samples/training/NsdChat/src/com/example/android/nsdchat/ChatConnection.java

@@ -52,7 +52,9 @@ public class ChatConnection {
 
     public void tearDown() {
         mChatServer.tearDown();
-        mChatClient.tearDown();
+        if (mChatClient != null) {
+          mChatClient.tearDown();
+        }
     }
 
     public void connectToServer(InetAddress address, int port) {

samples/training/NsdChat/src/com/example/android/nsdchat/NsdChatActivity.java

@@ -43,6 +43,7 @@ public class NsdChatActivity extends Activity {
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
+        Log.d(TAG, "Creating chat activity");
         setContentView(R.layout.main);
         mStatusView = (TextView) findViewById(R.id.status);
 
@@ -54,11 +55,6 @@ public class NsdChatActivity extends Activity {
             }
         };
 
-        mConnection = new ChatConnection(mUpdateHandler);
-
-        mNsdHelper = new NsdHelper(this);
-        mNsdHelper.initializeNsd();
-
     }
 
     public void clickAdvertise(View v) {
@@ -100,8 +96,20 @@ public class NsdChatActivity extends Activity {
         mStatusView.append("\n" + line);
     }
 
+    @Override
+    protected void onStart() {
+        Log.d(TAG, "Starting.");
+        mConnection = new ChatConnection(mUpdateHandler);
+
+        mNsdHelper = new NsdHelper(this);
+        mNsdHelper.initializeNsd();
+        super.onStart();
+    }
+
+
     @Override
     protected void onPause() {
+        Log.d(TAG, "Pausing.");
         if (mNsdHelper != null) {
             mNsdHelper.stopDiscovery();
         }
@@ -110,16 +118,37 @@ public class NsdChatActivity extends Activity {
 
     @Override
     protected void onResume() {
+        Log.d(TAG, "Resuming.");
         super.onResume();
         if (mNsdHelper != null) {
             mNsdHelper.discoverServices();
         }
     }
 
+
+    // For KitKat and earlier releases, it is necessary to remove the
+    // service registration when the application is stopped.  There's
+    // no guarantee that the onDestroy() method will be called (we're
+    // killable after onStop() returns) and the NSD service won't remove
+    // the registration for us if we're killed.
+
+    // In L and later, NsdService will automatically unregister us when
+    // our connection goes away when we're killed, so this step is
+    // optional (but recommended).
+
     @Override
-    protected void onDestroy() {
+    protected void onStop() {
+        Log.d(TAG, "Being stopped.");
         mNsdHelper.tearDown();
         mConnection.tearDown();
+        mNsdHelper = null;
+        mConnection = null;
+        super.onStop();
+    }
+
+    @Override
+    protected void onDestroy() {
+        Log.d(TAG, "Being destroyed.");
         super.onDestroy();
     }
 }

samples/training/NsdChat/src/com/example/android/nsdchat/NsdHelper.java

@@ -44,8 +44,6 @@ public class NsdHelper {
 
     public void initializeNsd() {
         initializeResolveListener();
-        initializeDiscoveryListener();
-        initializeRegistrationListener();
 
         //mNsdManager.init(mContext.getMainLooper(), this);
 
@@ -87,13 +85,11 @@ public class NsdHelper {
             @Override
             public void onStartDiscoveryFailed(String serviceType, int errorCode) {
                 Log.e(TAG, "Discovery failed: Error code:" + errorCode);
-                mNsdManager.stopServiceDiscovery(this);
             }
 
             @Override
             public void onStopDiscoveryFailed(String serviceType, int errorCode) {
                 Log.e(TAG, "Discovery failed: Error code:" + errorCode);
-                mNsdManager.stopServiceDiscovery(this);
             }
         };
     }
@@ -125,24 +121,30 @@ public class NsdHelper {
             @Override
             public void onServiceRegistered(NsdServiceInfo NsdServiceInfo) {
                 mServiceName = NsdServiceInfo.getServiceName();
+                Log.d(TAG, "Service registered: " + mServiceName);
             }
 
             @Override
             public void onRegistrationFailed(NsdServiceInfo arg0, int arg1) {
+                Log.d(TAG, "Service registration failed: " + arg1);
             }
 
             @Override
             public void onServiceUnregistered(NsdServiceInfo arg0) {
+                Log.d(TAG, "Service unregistered: " + arg0.getServiceName());
             }
 
             @Override
             public void onUnregistrationFailed(NsdServiceInfo serviceInfo, int errorCode) {
+                Log.d(TAG, "Service unregistration failed: " + errorCode);
             }
 
         };
     }
 
     public void registerService(int port) {
+        tearDown();  // Cancel any previous registration request
+        initializeRegistrationListener();
         NsdServiceInfo serviceInfo  = new NsdServiceInfo();
         serviceInfo.setPort(port);
         serviceInfo.setServiceName(mServiceName);
@@ -154,12 +156,20 @@ public class NsdHelper {
     }
 
     public void discoverServices() {
+        stopDiscovery();  // Cancel any existing discovery request
+        initializeDiscoveryListener();
         mNsdManager.discoverServices(
                 SERVICE_TYPE, NsdManager.PROTOCOL_DNS_SD, mDiscoveryListener);
     }
 
     public void stopDiscovery() {
-        mNsdManager.stopServiceDiscovery(mDiscoveryListener);
+        if (mDiscoveryListener != null) {
+            try {
+                mNsdManager.stopServiceDiscovery(mDiscoveryListener);
+            } finally {
+            }
+            mDiscoveryListener = null;
+        }
     }
 
     public NsdServiceInfo getChosenServiceInfo() {
@@ -167,6 +177,12 @@ public class NsdHelper {
     }
 
     public void tearDown() {
-        mNsdManager.unregisterService(mRegistrationListener);
+        if (mRegistrationListener != null) {
+            try {
+                mNsdManager.unregisterService(mRegistrationListener);
+            } finally {
+            }
+            mRegistrationListener = null;
+        }
     }
 }