Add Link Capacity Estimation (LCE) demo app.

Change-Id: I42f6a4fa5c989559db75d6d658081b44f7850b7a

samples/LceDemo/src/com/example/android/lce/LceDemoActivity.java

@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2016 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.example.android.lce;
+
+import android.annotation.TargetApi;
+import android.app.Activity;
+import android.net.ConnectivityManager;
+import android.net.Network;
+import android.net.NetworkCapabilities;
+import android.net.NetworkRequest;
+import android.os.Bundle;
+import android.os.Handler;
+import android.os.Message;
+import android.text.method.ScrollingMovementMethod;
+import android.view.View;
+import android.view.Menu;
+import android.view.MenuItem;
+import android.widget.Button;
+import android.widget.TextView;
+
+public class LceDemoActivity extends Activity {
+    private ConnectivityManager connectityManager;
+
+    @Override
+    @TargetApi(23)
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        // Default toolbar action handler.
+        setContentView(R.layout.activity_lce_demo);
+        final TextView text = (TextView) findViewById(R.id.lceText);
+        text.setMovementMethod(new ScrollingMovementMethod());
+
+        // Get an instance of ConnectivityManager.
+        connectityManager = (ConnectivityManager)getSystemService(
+            getApplicationContext().CONNECTIVITY_SERVICE);
+
+        // Create a handler to update text on the screen.
+        final Handler handler = new Handler() {
+            @Override
+            public void handleMessage(Message msg) {
+                text.append((String)msg.obj);
+                super.handleMessage(msg);
+            }
+        };
+
+        // Now register the network call back function.
+        NetworkRequest.Builder builder = new NetworkRequest.Builder();
+        connectityManager.registerNetworkCallback(builder.build(),
+            new ConnectivityManager.NetworkCallback() {
+            @Override
+            public void onCapabilitiesChanged(Network network, NetworkCapabilities cap) {
+                Message message = handler.obtainMessage();
+                message.obj = "New downlink capacity received: " +
+                    cap.getLinkDownstreamBandwidthKbps() + " kbps on network: "
+                    + network.toString() + "\n";
+                handler.sendMessage(message);
+            }
+        });
+
+        // Regsiter button action callback function, which pulls the LCE service
+        // for bandwidth update.
+        final Button button = (Button) findViewById(R.id.lceButton);
+        button.setOnClickListener(new View.OnClickListener() {
+            public void onClick(View v) {
+                for(Network network : connectityManager.getAllNetworks()) {
+                    // No-op for network interface not supporting LCE.
+                    connectityManager.requestBandwidthUpdate(network);
+                }
+            }
+        });
+    }
+}