Add media session wrappers to support library.

This is an initial check-in which just wraps the API 21+ media session
features for use in the support library.  It does not provide any
backwards compatibility.

Change-Id: Ife5f8ddeefa8c6920517fc6704cc19e22767b7d6

1 files changed, 176 insertions, 0 deletions

diff --git a/v4/jellybean-mr1/android/support/v4/media/routing/MediaRouterJellybeanMr1.java b/v4/jellybean-mr1/android/support/v4/media/routing/MediaRouterJellybeanMr1.java
new file mode 100644
index 0000000000..6e5cfd5d1a
--- /dev/null
+++ b/v4/jellybean-mr1/android/support/v4/media/routing/MediaRouterJellybeanMr1.java
@@ -0,0 +1,176 @@
+/*
+ * Copyright (C) 2013 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 android.support.v4.media.routing;
+
+import android.content.Context;
+import android.hardware.display.DisplayManager;
+import android.os.Build;
+import android.os.Handler;
+import android.util.Log;
+import android.view.Display;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+class MediaRouterJellybeanMr1 extends MediaRouterJellybean {
+    private static final String TAG = "MediaRouterJellybeanMr1";
+
+    public static Object createCallback(Callback callback) {
+        return new CallbackProxy<Callback>(callback);
+    }
+
+    public static final class RouteInfo {
+        public static boolean isEnabled(Object routeObj) {
+            return ((android.media.MediaRouter.RouteInfo)routeObj).isEnabled();
+        }
+
+        public static Display getPresentationDisplay(Object routeObj) {
+            return ((android.media.MediaRouter.RouteInfo)routeObj).getPresentationDisplay();
+        }
+    }
+
+    public static interface Callback extends MediaRouterJellybean.Callback {
+        public void onRoutePresentationDisplayChanged(Object routeObj);
+    }
+
+    /**
+     * Workaround the fact that the version of MediaRouter.addCallback() that accepts a
+     * flag to perform an active scan does not exist in JB MR1 so we need to force
+     * wifi display scans directly through the DisplayManager.
+     * Do not use on JB MR2 and above.
+     */
+    public static final class ActiveScanWorkaround implements Runnable {
+        // Time between wifi display scans when actively scanning in milliseconds.
+        private static final int WIFI_DISPLAY_SCAN_INTERVAL = 15000;
+
+        private final DisplayManager mDisplayManager;
+        private final Handler mHandler;
+        private Method mScanWifiDisplaysMethod;
+
+        private boolean mActivelyScanningWifiDisplays;
+
+        public ActiveScanWorkaround(Context context, Handler handler) {
+            if (Build.VERSION.SDK_INT != 17) {
+                throw new UnsupportedOperationException();
+            }
+
+            mDisplayManager = (DisplayManager) context.getSystemService(Context.DISPLAY_SERVICE);
+            mHandler = handler;
+            try {
+                mScanWifiDisplaysMethod = DisplayManager.class.getMethod("scanWifiDisplays");
+            } catch (NoSuchMethodException ex) {
+            }
+        }
+
+        public void setActiveScanRouteTypes(int routeTypes) {
+            // On JB MR1, there is no API to scan wifi display routes.
+            // Instead we must make a direct call into the DisplayManager to scan
+            // wifi displays on this version but only when live video routes are requested.
+            // See also the JellybeanMr2Impl implementation of this method.
+            // This was fixed in JB MR2 by adding a new overload of addCallback() to
+            // enable active scanning on request.
+            if ((routeTypes & MediaRouterJellybean.ROUTE_TYPE_LIVE_VIDEO) != 0) {
+                if (!mActivelyScanningWifiDisplays) {
+                    if (mScanWifiDisplaysMethod != null) {
+                        mActivelyScanningWifiDisplays = true;
+                        mHandler.post(this);
+                    } else {
+                        Log.w(TAG, "Cannot scan for wifi displays because the "
+                                + "DisplayManager.scanWifiDisplays() method is "
+                                + "not available on this device.");
+                    }
+                }
+            } else {
+                if (mActivelyScanningWifiDisplays) {
+                    mActivelyScanningWifiDisplays = false;
+                    mHandler.removeCallbacks(this);
+                }
+            }
+        }
+
+        @Override
+        public void run() {
+            if (mActivelyScanningWifiDisplays) {
+                try {
+                    mScanWifiDisplaysMethod.invoke(mDisplayManager);
+                } catch (IllegalAccessException ex) {
+                    Log.w(TAG, "Cannot scan for wifi displays.", ex);
+                } catch (InvocationTargetException ex) {
+                    Log.w(TAG, "Cannot scan for wifi displays.", ex);
+                }
+                mHandler.postDelayed(this, WIFI_DISPLAY_SCAN_INTERVAL);
+            }
+        }
+    }
+
+    /**
+     * Workaround the fact that the isConnecting() method does not exist in JB MR1.
+     * Do not use on JB MR2 and above.
+     */
+    public static final class IsConnectingWorkaround {
+        private Method mGetStatusCodeMethod;
+        private int mStatusConnecting;
+
+        public IsConnectingWorkaround() {
+            if (Build.VERSION.SDK_INT != 17) {
+                throw new UnsupportedOperationException();
+            }
+
+            try {
+                Field statusConnectingField =
+                        android.media.MediaRouter.RouteInfo.class.getField("STATUS_CONNECTING");
+                mStatusConnecting = statusConnectingField.getInt(null);
+                mGetStatusCodeMethod =
+                        android.media.MediaRouter.RouteInfo.class.getMethod("getStatusCode");
+            } catch (NoSuchFieldException ex) {
+            } catch (NoSuchMethodException ex) {
+            } catch (IllegalAccessException ex) {
+            }
+        }
+
+        public boolean isConnecting(Object routeObj) {
+            android.media.MediaRouter.RouteInfo route =
+                    (android.media.MediaRouter.RouteInfo)routeObj;
+
+            if (mGetStatusCodeMethod != null) {
+                try {
+                    int statusCode = (Integer)mGetStatusCodeMethod.invoke(route);
+                    return statusCode == mStatusConnecting;
+                } catch (IllegalAccessException ex) {
+                } catch (InvocationTargetException ex) {
+                }
+            }
+
+            // Assume not connecting.
+            return false;
+        }
+    }
+
+    static class CallbackProxy<T extends Callback>
+            extends MediaRouterJellybean.CallbackProxy<T> {
+        public CallbackProxy(T callback) {
+            super(callback);
+        }
+
+        @Override
+        public void onRoutePresentationDisplayChanged(android.media.MediaRouter router,
+                android.media.MediaRouter.RouteInfo route) {
+            mCallback.onRoutePresentationDisplayChanged(route);
+        }
+    }
+}