1 files changed, 101 insertions, 0 deletions
diff --git a/java/src/com/android/inputmethod/latin/utils/NetworkConnectivityUtils.java b/java/src/com/android/inputmethod/latin/utils/NetworkConnectivityUtils.java
new file mode 100644
index 000000000..101c55067
--- /dev/null
+++ b/java/src/com/android/inputmethod/latin/utils/NetworkConnectivityUtils.java
@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.inputmethod.latin.utils;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.net.ConnectivityManager;
+import android.net.NetworkInfo;
+
+import javax.annotation.Nonnull;
+
+/**
+ * This class keeps track of the network connectivity state by receiving the system intent
+ * {@link ConnectivityManager#CONNECTIVITY_ACTION}, and invokes an registered call back to notify
+ * changes of the network connectivity state.
+ */
+public final class NetworkConnectivityUtils {
+    private static NetworkConnectivityReceiver sNetworkConnectivityReceiver;
+
+    public interface NetworkStateChangeListener {
+        /**
+         * Called when the network connectivity state has changed.
+         */
+        public void onNetworkStateChanged();
+    }
+
+    private static class NetworkConnectivityReceiver extends BroadcastReceiver {
+        @Nonnull
+        private final NetworkStateChangeListener mListener;
+        private boolean mIsNetworkConnected;
+
+        public NetworkConnectivityReceiver(@Nonnull final NetworkStateChangeListener listener,
+                final boolean isNetworkConnected) {
+            mListener = listener;
+            mIsNetworkConnected = isNetworkConnected;
+        }
+
+        public synchronized boolean isNetworkConnected() {
+            return mIsNetworkConnected;
+        }
+
+        @Override
+        public void onReceive(final Context context, final Intent intent) {
+            final String action = intent.getAction();
+            if (action.equals(ConnectivityManager.CONNECTIVITY_ACTION)) {
+                final boolean noConnection = intent.getBooleanExtra(
+                        ConnectivityManager.EXTRA_NO_CONNECTIVITY, false);
+                synchronized (this) {
+                    mIsNetworkConnected = !noConnection;
+                }
+                mListener.onNetworkStateChanged();
+            }
+        }
+    }
+
+    private NetworkConnectivityUtils() {
+        // This utility class is not publicly instantiable.
+    }
+
+    public static void onCreate(@Nonnull final Context context,
+            @Nonnull final NetworkStateChangeListener listener) {
+        final ConnectivityManager connectivityManager =
+                (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
+        final NetworkInfo info = connectivityManager.getActiveNetworkInfo();
+        final boolean isNetworkConnected = (info != null && info.isConnected());
+
+        // Register {@link BroadcastReceiver} for the network connectivity state change.
+        final NetworkConnectivityReceiver receiver = new NetworkConnectivityReceiver(
+                listener, isNetworkConnected);
+        final IntentFilter filter = new IntentFilter();
+        filter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
+        context.registerReceiver(receiver, filter);
+
+        sNetworkConnectivityReceiver = receiver;
+    }
+
+    public static void onDestroy(final Context context) {
+        context.unregisterReceiver(sNetworkConnectivityReceiver);
+    }
+
+    public static boolean isNetworkConnected() {
+        final NetworkConnectivityReceiver receiver = sNetworkConnectivityReceiver;
+        return receiver != null && receiver.isNetworkConnected();
+    }
+}