diff --git a/packages/SystemUI/res/values/strings.xml b/packages/SystemUI/res/values/strings.xml
index e1c71fa..42e19aa 100644
--- a/packages/SystemUI/res/values/strings.xml
+++ b/packages/SystemUI/res/values/strings.xml
@@ -761,6 +761,8 @@
     <string name="quick_settings_cast_device_default_description">Ready to cast</string>
     <!-- QuickSettings: Cast detail panel, text when there are no items [CHAR LIMIT=NONE] -->
     <string name="quick_settings_cast_detail_empty_text">No devices available</string>
+    <!-- QuickSettings: Cast unavailable, text when not connected to WiFi [CHAR LIMIT=NONE] -->
+    <string name="quick_settings_cast_no_wifi">Wi\u2011Fi not connected</string>
     <!-- QuickSettings: Brightness dialog title [CHAR LIMIT=NONE] -->
     <string name="quick_settings_brightness_dialog_title">Brightness</string>
     <!-- QuickSettings: Brightness dialog auto brightness button [CHAR LIMIT=NONE] -->
@@ -1999,6 +2001,9 @@
     <!-- accessibility label for quick settings items that open a details page [CHAR LIMIT=NONE] -->
     <string name="accessibility_quick_settings_open_details">Open details.</string>
 
+    <!-- accessibility label for quick settings items that are currently disabled. Must have a reason [CHAR LIMIT=NONE] -->
+    <string name="accessibility_quick_settings_not_available">Unvailable due to <xliff:g name="reason" id="reason" example="Wifi not available">%s</xliff:g></string>
+
     <!-- accessibility label for quick settings items that open a details page [CHAR LIMIT=NONE] -->
     <string name="accessibility_quick_settings_open_settings">Open <xliff:g name="page" example="Bluetooth">%s</xliff:g> settings.</string>
 
diff --git a/packages/SystemUI/src/com/android/systemui/qs/tiles/CastTile.java b/packages/SystemUI/src/com/android/systemui/qs/tiles/CastTile.java
index ed78048..921db69 100644
--- a/packages/SystemUI/src/com/android/systemui/qs/tiles/CastTile.java
+++ b/packages/SystemUI/src/com/android/systemui/qs/tiles/CastTile.java
@@ -46,6 +46,7 @@
 import com.android.systemui.statusbar.policy.CastController;
 import com.android.systemui.statusbar.policy.CastController.CastDevice;
 import com.android.systemui.statusbar.policy.KeyguardMonitor;
+import com.android.systemui.statusbar.policy.NetworkController;
 
 import java.util.LinkedHashMap;
 import java.util.Set;
@@ -58,16 +59,18 @@
     private final CastController mController;
     private final CastDetailAdapter mDetailAdapter;
     private final KeyguardMonitor mKeyguard;
+    private final NetworkController mNetworkController;
     private final Callback mCallback = new Callback();
     private final ActivityStarter mActivityStarter;
     private Dialog mDialog;
-    private boolean mRegistered;
+    private boolean mWifiConnected;
 
     public CastTile(QSHost host) {
         super(host);
         mController = Dependency.get(CastController.class);
         mDetailAdapter = new CastDetailAdapter();
         mKeyguard = Dependency.get(KeyguardMonitor.class);
+        mNetworkController = Dependency.get(NetworkController.class);
         mActivityStarter = Dependency.get(ActivityStarter.class);
     }
 
@@ -87,10 +90,12 @@
         if (listening) {
             mController.addCallback(mCallback);
             mKeyguard.addCallback(mCallback);
+            mNetworkController.addCallback(mSignalCallback);
         } else {
             mController.setDiscovering(false);
             mController.removeCallback(mCallback);
             mKeyguard.removeCallback(mCallback);
+            mNetworkController.removeCallback(mSignalCallback);
         }
     }
 
@@ -112,6 +117,9 @@
 
     @Override
     protected void handleClick() {
+        if (getState().state == Tile.STATE_UNAVAILABLE) {
+            return;
+        }
         if (mKeyguard.isSecure() && !mKeyguard.canSkipBouncer()) {
             mActivityStarter.postQSRunnableDismissingKeyguard(() -> {
                 showDetail(true);
@@ -164,13 +172,22 @@
         if (!state.value && connecting) {
             state.label = mContext.getString(R.string.quick_settings_connecting);
         }
-        state.state = state.value ? Tile.STATE_ACTIVE : Tile.STATE_INACTIVE;
         state.icon = ResourceIcon.get(state.value ? R.drawable.ic_qs_cast_on
                 : R.drawable.ic_qs_cast_off);
+        if (mWifiConnected) {
+            state.state = state.value ? Tile.STATE_ACTIVE : Tile.STATE_INACTIVE;
+            state.secondaryLabel = "";
+            state.contentDescription = state.contentDescription + ","
+                    + mContext.getString(R.string.accessibility_quick_settings_open_details);
+            state.expandedAccessibilityClassName = Button.class.getName();
+        } else {
+            state.state = Tile.STATE_UNAVAILABLE;
+            String noWifi = mContext.getString(R.string.quick_settings_cast_no_wifi);
+            state.secondaryLabel = noWifi;
+            state.contentDescription = state.contentDescription + ", " + mContext.getString(
+                    R.string.accessibility_quick_settings_not_available, noWifi);
+        }
         mDetailAdapter.updateItems(devices);
-        state.expandedAccessibilityClassName = Button.class.getName();
-        state.contentDescription = state.contentDescription + ","
-                + mContext.getString(R.string.accessibility_quick_settings_open_details);
     }
 
     @Override
@@ -192,6 +209,22 @@
                 : mContext.getString(R.string.quick_settings_cast_device_default_name);
     }
 
+    private final NetworkController.SignalCallback mSignalCallback =
+            new NetworkController.SignalCallback() {
+                @Override
+                public void setWifiIndicators(boolean enabled,
+                        NetworkController.IconState statusIcon,
+                        NetworkController.IconState qsIcon, boolean activityIn, boolean activityOut,
+                        String description, boolean isTransient, String statusLabel) {
+                    // statusIcon.visible has the connected status information
+                    boolean enabledAndConnected = enabled && qsIcon.visible;
+                    if (enabledAndConnected != mWifiConnected) {
+                        mWifiConnected = enabledAndConnected;
+                        refreshState();
+                    }
+                }
+            };
+
     private final class Callback implements CastController.Callback, KeyguardMonitor.Callback {
         @Override
         public void onCastDevicesChanged() {
diff --git a/packages/SystemUI/tests/src/com/android/systemui/qs/tiles/CastTileTest.java b/packages/SystemUI/tests/src/com/android/systemui/qs/tiles/CastTileTest.java
new file mode 100644
index 0000000..d9412ec
--- /dev/null
+++ b/packages/SystemUI/tests/src/com/android/systemui/qs/tiles/CastTileTest.java
@@ -0,0 +1,149 @@
+/*
+ * Copyright (C) 2018 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.systemui.qs.tiles;
+
+import static junit.framework.TestCase.assertEquals;
+import static junit.framework.TestCase.assertTrue;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.service.quicksettings.Tile;
+import android.support.test.filters.SmallTest;
+import android.testing.AndroidTestingRunner;
+import android.testing.TestableLooper;
+
+import com.android.systemui.Dependency;
+import com.android.systemui.SysuiTestCase;
+import com.android.systemui.plugins.ActivityStarter;
+import com.android.systemui.qs.QSTileHost;
+import com.android.systemui.statusbar.policy.CastController;
+import com.android.systemui.statusbar.policy.KeyguardMonitor;
+import com.android.systemui.statusbar.policy.NetworkController;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import java.util.HashSet;
+import java.util.Set;
+
+
+@RunWith(AndroidTestingRunner.class)
+@TestableLooper.RunWithLooper
+@SmallTest
+public class CastTileTest extends SysuiTestCase {
+
+    @Mock
+    private CastController mController;
+    @Mock
+    private ActivityStarter mActivityStarter;
+    @Mock
+    private KeyguardMonitor mKeyguard;
+    @Mock
+    private NetworkController mNetworkController;
+    @Mock
+    private QSTileHost mHost;
+    @Mock
+    NetworkController.SignalCallback mCallback;
+
+    private TestableLooper mTestableLooper;
+    private CastTile mCastTile;
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+        mTestableLooper = TestableLooper.get(this);
+
+        mDependency.injectTestDependency(Dependency.BG_LOOPER, mTestableLooper.getLooper());
+        mController = mDependency.injectMockDependency(CastController.class);
+        mActivityStarter = mDependency.injectMockDependency(ActivityStarter.class);
+        mKeyguard = mDependency.injectMockDependency(KeyguardMonitor.class);
+        mNetworkController = mDependency.injectMockDependency(NetworkController.class);
+
+        when(mHost.getContext()).thenReturn(mContext);
+
+        mCastTile = new CastTile(mHost);
+
+        // We are not setting the mocks to listening, so we trigger a first refresh state to
+        // set the initial state
+        mCastTile.refreshState();
+
+        mCastTile.handleSetListening(true);
+        ArgumentCaptor<NetworkController.SignalCallback> signalCallbackArgumentCaptor =
+                ArgumentCaptor.forClass(NetworkController.SignalCallback.class);
+        verify(mNetworkController).addCallback(signalCallbackArgumentCaptor.capture());
+        mCallback = signalCallbackArgumentCaptor.getValue();
+
+    }
+
+    @Test
+    public void testStateUnavailable_wifiDisabled() {
+        NetworkController.IconState qsIcon =
+                new NetworkController.IconState(false, 0, "");
+        mCallback.setWifiIndicators(false, mock(NetworkController.IconState.class),
+                qsIcon, false,false, "",
+                false, "");
+        mTestableLooper.processAllMessages();
+
+        assertEquals(Tile.STATE_UNAVAILABLE, mCastTile.getState().state);
+    }
+
+    @Test
+    public void testStateUnavailable_wifiNotConnected() {
+        NetworkController.IconState qsIcon =
+                new NetworkController.IconState(false, 0, "");
+        mCallback.setWifiIndicators(true, mock(NetworkController.IconState.class),
+                qsIcon, false,false, "",
+                false, "");
+        mTestableLooper.processAllMessages();
+
+        assertEquals(Tile.STATE_UNAVAILABLE, mCastTile.getState().state);
+    }
+
+    @Test
+    public void testStateActive_wifiEnabledAndCasting() {
+        CastController.CastDevice device = mock(CastController.CastDevice.class);
+        device.state = CastController.CastDevice.STATE_CONNECTED;
+        Set<CastController.CastDevice> devices = new HashSet<>();
+        devices.add(device);
+        when(mController.getCastDevices()).thenReturn(devices);
+
+        NetworkController.IconState qsIcon =
+                new NetworkController.IconState(true, 0, "");
+        mCallback.setWifiIndicators(true, mock(NetworkController.IconState.class),
+                qsIcon, false,false, "",
+                false, "");
+        mTestableLooper.processAllMessages();
+
+        assertEquals(Tile.STATE_ACTIVE, mCastTile.getState().state);
+    }
+
+    @Test
+    public void testStateInactive_wifiEnabledNotCasting() {
+        NetworkController.IconState qsIcon =
+                new NetworkController.IconState(true, 0, "");
+        mCallback.setWifiIndicators(true, mock(NetworkController.IconState.class),
+                qsIcon, false,false, "",
+                false, "");
+        mTestableLooper.processAllMessages();
+
+        assertEquals(Tile.STATE_INACTIVE, mCastTile.getState().state);
+    }
+}