太长了；跳至步骤 3 - 选项 1 (SessionManager.startSession) or 步骤 3 - 选项 2 (MediaRouter.selectRoute)
第 1 步 - 设置
像平常一样设置 CastOptionsProvider。
以下是我们将使用的主要对象：
MediaRouter mediaRouter = MediaRouter.getInstance(activity);
CastContext context = CastContext.getSharedInstance(activity);
SessionManager sessionManager = context.getSessionManager();
第 2 步 - 检索路由（设备）以保存/使用
获取路由/设备 ID
步骤 2 - 选项 1 - 当前缓存的路由
只需获取当前缓存的路由：
for (RouteInfo route : mediaRouter.getRoutes()) {
// Save route.getId(); however you want (it's a string)
}
缺点：返回的路线可能已经过时。 MediaRouter 的路由缓存仅在触发扫描时更新（由您手动或由转换库触发）。
步骤 2 - 选项 2 - 主动扫描
主动扫描最准确的路线列表：
MediaRouter.Callback callback = new MediaRouter.Callback() {
private void updateMyRouteList() {
for (RouteInfo route : mediaRouter.getRoutes()) {
// Save route.getId() however you want (it's a string)
}
}
@Override
public void onRouteAdded(MediaRouter router, RouteInfo route) {
updateMyRouteList();
}
@Override
public void onRouteRemoved(MediaRouter router, RouteInfo route) {
updateMyRouteList();
}
@Override
public void onRouteChanged(MediaRouter router, RouteInfo route) {
updateMyRouteList();
}
};
mediaRouter.addCallback(new MediaRouteSelector.Builder()
.addControlCategory(CastMediaControlIntent.categoryForCast(appId))
.build(),
callback,
MediaRouter.CALLBACK_FLAG_PERFORM_ACTIVE_SCAN);
NOTE!停止主动扫描非常重要，否则电池会很快耗尽！您可以使用以下命令停止扫描
mediaRouter.removeCallback(callback);
步骤 2 - 选项 3 - 被动扫描
Same as Option 2但是，省略flags的论证mediaRouter.addCallback.
This should（我认为）被动地监听路线变化。 （虽然你的结果可能不会比Option 1）。例如：
mediaRouter.addCallback(new MediaRouteSelector.Builder()
.addControlCategory(CastMediaControlIntent.categoryForCast(appId))
.build(),
callback);
步骤 3 - 加入路线（设备）
如何以编程方式加入路线（设备）。
有两个主要选项。
这两个选项都会创建一个新会话，或者加入您尝试加入的设备上的现有会话（如果 appId 相同）。
首先，prep:
// Optional - if your app changes receiverApplicationId on the fly you should change that here
context.setReceiverApplicationId(appId);
// Most people would just set this as a constant in their CastOptionsProvider
// Listen for a successful join
sessionManager.addSessionManagerListener(new SessionManagerListener<Session>() {
@Override
public void onSessionStarted(CastSession castSession, String sessionId) {
// We successfully joined a route(device)!
}
});
现在，如何实际加入一条路线，给定一个routeId我们从Step 2
步骤 3 - 选项 1 - SessionManager.startSession
注意：我发现此方法在我的 Android 4.4 设备上不起作用。我正在得到SessionManagerListener.onSessionStartFailed错误 15（超时）。
不过它确实可以在我的 Android 7.0 设备上运行。
// Create the intent
Intent castIntent = new Intent();
// Mandatory, if null, nothing will happen
castIntent.putExtra("CAST_INTENT_TO_CAST_ROUTE_ID_KEY", routeId);
// (Optional) Uses this name in the toast
castIntent.putExtra("CAST_INTENT_TO_CAST_DEVICE_NAME_KEY", route.getName());
// Optional - false = displays "Connecting to <devicename>..."
castIntent.putExtra("CAST_INTENT_TO_CAST_NO_TOAST_KEY", true);
sessionManager.startSession(castIntent);
步骤 3 - 选项 2 - MediaRouter.selectRoute
要使用此选项，您必须拥有完整的Route对象，而不仅仅是 id 字符串。
如果您已经拥有该对象，那就太好了！
如果没有的话，你可以使用下面的方法步骤 2 - 选项 2 - 主动扫描得到Route通过查找匹配的 id 来获取对象。
mediaRouter.selectRoute(routeObject);
第 4 步 - 流式传输内容
一旦您获得了会话步骤3准备，艰苦的工作完成了。
您可以使用远程媒体客户端 https://developers.google.com/android/reference/com/google/android/gms/cast/framework/media/RemoteMediaClient控制投射的内容。
RemoteMediaClient remoteMediaClient = castSession.getRemoteMediaClient();
remoteMediaClient.load(...);
完整代码
我之所以将其包括在内，是因为我花了大量的时间来解决会话问题，希望它可以使其他人受益。 （包括 Android 4.4/慢速设备上的间歇性计时和崩溃问题 [不确定哪一个是问题根源]）。
那里可能有一些额外的东西（特别是如果你使用常量 appId，initialize无关紧要），所以请使用您需要的。
最相关的方法是selectRoute它接受一个routeId字符串，并会主动扫描匹配最多15秒。它还可以处理一些重试可能有效的错误。
您可以看到真正的完整代码在这里 https://github.com/miloproductionsinc/cordova-plugin-chromecast/blob/master/src/android/ChromecastConnection.java.
[下面的代码可能已过时。真正的完整代码是为在 Cordova 插件中使用而编写的。如果您想在应用程序中使用代码，那么删除 Cordova 依赖项很简单。]
public class ChromecastConnection {
/** Lifetime variable. */
private Activity activity;
/** settings object. */
private SharedPreferences settings;
/** Lifetime variable. */
private SessionListener newConnectionListener;
/** The Listener callback. */
private Listener listener;
/** Initialize lifetime variable. */
private String appId;
/**
* Constructor. Call this in activity start.
* @param act the current context
* @param connectionListener client callbacks for specific events
*/
ChromecastConnection(Activity act, Listener connectionListener) {
this.activity = act;
this.settings = activity.getSharedPreferences("CORDOVA-PLUGIN-CHROMECAST_ChromecastConnection", 0);
this.appId = settings.getString("appId", CastMediaControlIntent.DEFAULT_MEDIA_RECEIVER_APPLICATION_ID);
this.listener = connectionListener;
// Set the initial appId
CastOptionsProvider.setAppId(appId);
// This is the first call to getContext which will start up the
// CastContext and prep it for searching for a session to rejoin
// Also adds the receiver update callback
getContext().addCastStateListener(listener);
}
/**
* Must be called each time the appId changes and at least once before any other method is called.
* @param applicationId the app id to use
* @param callback called when initialization is complete
*/
public void initialize(String applicationId, CallbackContext callback) {
activity.runOnUiThread(new Runnable() {
public void run() {
// If the app Id changed, set it again
if (!applicationId.equals(appId)) {
setAppId(applicationId);
}
// Tell the client that initialization was a success
callback.success();
// Check if there is any available receivers for 5 seconds
startRouteScan(5000L, new ScanCallback() {
@Override
void onRouteUpdate(List<RouteInfo> routes) {
// if the routes have changed, we may have an available device
// If there is at least one device available
if (getContext().getCastState() != CastState.NO_DEVICES_AVAILABLE) {
// Stop the scan
stopRouteScan(this);
// Let the client know a receiver is available
listener.onReceiverAvailableUpdate(true);
// Since we have a receiver we may also have an active session
CastSession session = getSessionManager().getCurrentCastSession();
// If we do have a session
if (session != null) {
// Let the client know
listener.onSessionRejoin(session);
}
}
}
}, null);
}
});
}
private MediaRouter getMediaRouter() {
return MediaRouter.getInstance(activity);
}
private CastContext getContext() {
return CastContext.getSharedInstance(activity);
}
private SessionManager getSessionManager() {
return getContext().getSessionManager();
}
private CastSession getSession() {
return getSessionManager().getCurrentCastSession();
}
private void setAppId(String applicationId) {
this.appId = applicationId;
this.settings.edit().putString("appId", appId).apply();
getContext().setReceiverApplicationId(appId);
}
/**
* This will create a new session or seamlessly selectRoute an existing one if we created it.
* @param routeId the id of the route to selectRoute
* @param callback calls callback.onJoin when we have joined a session,
* or callback.onError if an error occurred
*/
public void selectRoute(final String routeId, SelectRouteCallback callback) {
activity.runOnUiThread(new Runnable() {
public void run() {
if (getSession() != null && getSession().isConnected()) {
callback.onError(ChromecastUtilities.createError("session_error",
"Leave or stop current session before attempting to join new session."));
}
// We need this hack so that we can access these values in callbacks without having
// to store it as a global variable, just always access first element
final boolean[] foundRoute = {false};
final boolean[] sentResult = {false};
final int[] retries = {0};
// We need to start an active scan because getMediaRouter().getRoutes() may be out
// of date. Also, maintaining a list of known routes doesn't work. It is possible
// to have a route in your "known" routes list, but is not in
// getMediaRouter().getRoutes() which will result in "Ignoring attempt to select
// removed route: ", even if that route *should* be available. This state could
// happen because routes are periodically "removed" and "added", and if the last
// time media router was scanning ended when the route was temporarily removed the
// getRoutes() fn will have no record of the route. We need the active scan to
// avoid this situation as well. PS. Just running the scan non-stop is a poor idea
// since it will drain battery power quickly.
ScanCallback scan = new ScanCallback() {
@Override
void onRouteUpdate(List<RouteInfo> routes) {
// Look for the matching route
for (RouteInfo route : routes) {
if (!foundRoute[0] && route.getId().equals(routeId)) {
// Found the route!
foundRoute[0] = true;
// try-catch for issue:
// https://github.com/jellyfin/cordova-plugin-chromecast/issues/48
try {
// Try selecting the route!
getMediaRouter().selectRoute(route);
} catch (NullPointerException e) {
// Let it try to find the route again
foundRoute[0] = false;
}
}
}
}
};
Runnable retry = new Runnable() {
@Override
public void run() {
// Reset foundRoute
foundRoute[0] = false;
// Feed current routes into scan so that it can retry.
// If route is there, it will try to join,
// if not, it should wait for the scan to find the route
scan.onRouteUpdate(getMediaRouter().getRoutes());
}
};
Function<JSONObject, Void> sendErrorResult = new Function<JSONObject, Void>() {
@Override
public Void apply(JSONObject message) {
if (!sentResult[0]) {
sentResult[0] = true;
stopRouteScan(scan);
callback.onError(message);
}
return null;
}
};
listenForConnection(new ConnectionCallback() {
@Override
public void onJoin(CastSession session) {
sentResult[0] = true;
stopRouteScan(scan);
callback.onJoin(session);
}
@Override
public boolean onSessionStartFailed(int errorCode) {
if (errorCode == 7 || errorCode == 15) {
// It network or timeout error retry
retry.run();
return false;
} else {
sendErrorResult.apply(ChromecastUtilities.createError("session_error",
"Failed to start session with error code: " + errorCode));
return true;
}
}
@Override
public boolean onSessionEndedBeforeStart(int errorCode) {
if (retries[0] < 10) {
retries[0]++;
retry.run();
return false;
} else {
sendErrorResult.apply(ChromecastUtilities.createError("session_error",
"Failed to to join existing route (" + routeId + ") " + retries[0] + 1 + " times before giving up."));
return true;
}
}
});
startRouteScan(15000L, scan, new Runnable() {
@Override
public void run() {
sendErrorResult.apply(ChromecastUtilities.createError("timeout",
"Failed to to join route (" + routeId + ") after 15s and " + retries[0] + 1 + " trys."));
}
});
}
});
}
/**
* Must be called from the main thread.
* @param callback calls callback.success when we have joined, or callback.error if an error occurred
*/
private void listenForConnection(ConnectionCallback callback) {
// We should only ever have one of these listeners active at a time, so remove previous
getSessionManager().removeSessionManagerListener(newConnectionListener, CastSession.class);
newConnectionListener = new SessionListener() {
@Override
public void onSessionStarted(CastSession castSession, String sessionId) {
getSessionManager().removeSessionManagerListener(this, CastSession.class);
callback.onJoin(castSession);
}
@Override
public void onSessionStartFailed(CastSession castSession, int errCode) {
if (callback.onSessionStartFailed(errCode)) {
getSessionManager().removeSessionManagerListener(this, CastSession.class);
}
}
@Override
public void onSessionEnded(CastSession castSession, int errCode) {
if (callback.onSessionEndedBeforeStart(errCode)) {
getSessionManager().removeSessionManagerListener(this, CastSession.class);
}
}
};
getSessionManager().addSessionManagerListener(newConnectionListener, CastSession.class);
}
/**
* Starts listening for receiver updates.
* Must call stopRouteScan(callback) or the battery will drain with non-stop active scanning.
* @param timeout ms until the scan automatically stops,
* if 0 only calls callback.onRouteUpdate once with the currently known routes
* if null, will scan until stopRouteScan is called
* @param callback the callback to receive route updates on
* @param onTimeout called when the timeout hits
*/
public void startRouteScan(Long timeout, ScanCallback callback, Runnable onTimeout) {
// Add the callback in active scan mode
activity.runOnUiThread(new Runnable() {
public void run() {
callback.setMediaRouter(getMediaRouter());
if (timeout != null && timeout == 0) {
// Send out the one time routes
callback.onFilteredRouteUpdate();
return;
}
// Add the callback in active scan mode
getMediaRouter().addCallback(new MediaRouteSelector.Builder()
.addControlCategory(CastMediaControlIntent.categoryForCast(appId))
.build(),
callback,
MediaRouter.CALLBACK_FLAG_PERFORM_ACTIVE_SCAN);
// Send out the initial routes after the callback has been added.
// This is important because if the callback calls stopRouteScan only once, and it
// happens during this call of "onFilterRouteUpdate", there must actually be an
// added callback to remove to stop the scan.
callback.onFilteredRouteUpdate();
if (timeout != null) {
// remove the callback after timeout ms, and notify caller
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
// And stop the scan for routes
getMediaRouter().removeCallback(callback);
// Notify
if (onTimeout != null) {
onTimeout.run();
}
}
}, timeout);
}
}
});
}
/**
* Call to stop the active scan if any exist.
* @param callback the callback to stop and remove
*/
public void stopRouteScan(ScanCallback callback) {
activity.runOnUiThread(new Runnable() {
public void run() {
callback.stop();
getMediaRouter().removeCallback(callback);
}
});
}
/**
* Create this empty class so that we don't have to override every function
* each time we need a SessionManagerListener.
*/
private class SessionListener implements SessionManagerListener<CastSession> {
@Override
public void onSessionStarting(CastSession castSession) { }
@Override
public void onSessionStarted(CastSession castSession, String sessionId) { }
@Override
public void onSessionStartFailed(CastSession castSession, int error) { }
@Override
public void onSessionEnding(CastSession castSession) { }
@Override
public void onSessionEnded(CastSession castSession, int error) { }
@Override
public void onSessionResuming(CastSession castSession, String sessionId) { }
@Override
public void onSessionResumed(CastSession castSession, boolean wasSuspended) { }
@Override
public void onSessionResumeFailed(CastSession castSession, int error) { }
@Override
public void onSessionSuspended(CastSession castSession, int reason) { }
}
interface SelectRouteCallback {
void onJoin(CastSession session);
void onError(JSONObject message);
}
interface ConnectionCallback {
/**
* Successfully joined a session on a route.
* @param session the session we joined
*/
void onJoin(CastSession session);
/**
* Called if we received an error.
* @param errorCode You can find the error meaning here:
* https://developers.google.com/android/reference/com/google/android/gms/cast/CastStatusCodes
* @return true if we are done listening for join, false, if we to keep listening
*/
boolean onSessionStartFailed(int errorCode);
/**
* Called when we detect a session ended event before session started.
* See issues:
* https://github.com/jellyfin/cordova-plugin-chromecast/issues/49
* https://github.com/jellyfin/cordova-plugin-chromecast/issues/48
* @param errorCode error to output
* @return true if we are done listening for join, false, if we to keep listening
*/
boolean onSessionEndedBeforeStart(int errorCode);
}
public abstract static class ScanCallback extends MediaRouter.Callback {
/**
* Called whenever a route is updated.
* @param routes the currently available routes
*/
abstract void onRouteUpdate(List<RouteInfo> routes);
/** records whether we have been stopped or not. */
private boolean stopped = false;
/** Global mediaRouter object. */
private MediaRouter mediaRouter;
/**
* Sets the mediaRouter object.
* @param router mediaRouter object
*/
void setMediaRouter(MediaRouter router) {
this.mediaRouter = router;
}
/**
* Call this method when you wish to stop scanning.
* It is important that it is called, otherwise battery
* life will drain more quickly.
*/
void stop() {
stopped = true;
}
private void onFilteredRouteUpdate() {
if (stopped || mediaRouter == null) {
return;
}
List<RouteInfo> outRoutes = new ArrayList<>();
// Filter the routes
for (RouteInfo route : mediaRouter.getRoutes()) {
// We don't want default routes, or duplicate active routes
// or multizone duplicates https://github.com/jellyfin/cordova-plugin-chromecast/issues/32
Bundle extras = route.getExtras();
if (extras != null) {
CastDevice.getFromBundle(extras);
if (extras.getString("com.google.android.gms.cast.EXTRA_SESSION_ID") != null) {
continue;
}
}
if (!route.isDefault()
&& !route.getDescription().equals("Google Cast Multizone Member")
&& route.getPlaybackType() == RouteInfo.PLAYBACK_TYPE_REMOTE
) {
outRoutes.add(route);
}
}
onRouteUpdate(outRoutes);
}
@Override
public final void onRouteAdded(MediaRouter router, RouteInfo route) {
onFilteredRouteUpdate();
}
@Override
public final void onRouteChanged(MediaRouter router, RouteInfo route) {
onFilteredRouteUpdate();
}
@Override
public final void onRouteRemoved(MediaRouter router, RouteInfo route) {
onFilteredRouteUpdate();
}
}
abstract static class Listener implements CastStateListener {
abstract void onReceiverAvailableUpdate(boolean available);
abstract void onSessionRejoin(CastSession session);
/** CastStateListener functions. */
@Override
public void onCastStateChanged(int state) {
onReceiverAvailableUpdate(state != CastState.NO_DEVICES_AVAILABLE);
}
}
}
使用 chromecast 非常有趣...
