我正在开发一个连接到Chromecast的应用程序，当我从一个活动中执行此操作时，一切正常，问题是，我希望该活动是全屏的，没有操作栏，也没有软按钮。我正在实现这一点，当用户连接到Chromecast时隐藏它们，但如果用户从第一个活动（使用操作栏）连接然后转到第二个活动并且那里发生魔术会更好。但我无法在活动之间通过会议。我已经按照this教程与chromecast进行了沟通，但尝试改变一点，以便进行2次活动。
当然，我已对其进行了测试，并返回NullPointerException。
ConnectionFailedListener.java
public class ConnectionFailedListener implements GoogleApiClient.OnConnectionFailedListener {
private String TAG;
private MyConnectionCallbacks myConnectionCB;
public ConnectionFailedListener(String _TAG)
{
this.TAG=_TAG;
}
private void setMyConnectionCallBack(MyConnectionCallbacks _ConnectionCallbacks)
{
this.myConnectionCB = _ConnectionCallbacks;
}
@Override
public void onConnectionFailed(ConnectionResult result)
{
Log.e(TAG, "onConnectionFailed ");
myConnectionCB.teardown();
}
}
Channel.java
public class EventChannel implements Cast.MessageReceivedCallback
{
private Context myContext;
private String TAG;
/**
* @return custom namespace
*/
public EventChannel(Context _context, String _TAG)
{
this.myContext = _context;
this.TAG = _TAG;
}
public String getNamespace()
{
return myContext.getString(R.string.namespace);
}
/*
* Receive message from the receiver app
*/
@Override
public void onMessageReceived(CastDevice castDevice, String namespace,String message)
{
Log.d(TAG, "onMessageReceived: " + message);
}
}
ConnectionCallbacks.java
public class MyConnectionCallbacks implements GoogleApiClient.ConnectionCallbacks
{
private String TAG;
private Context myContext;
public CastDevice mSelectedDevice;
private GoogleApiClient mApiClient;
private boolean mWaitingForReconnect;
private EventChannel mEventChannel;
private String mSessionId;
private boolean mApplicationStarted;
private EventChannel myChannel;
public MyConnectionCallbacks(Context _context, String _TAG)
{
this.myContext=_context;
this.TAG = _TAG;
}
public void setApiClient(GoogleApiClient _newApiClient)
{
this.mApiClient = _newApiClient;
}
@Override
public void onConnected(Bundle connectionHint)
{
Log.d(TAG, "onConnected");
if (mApiClient == null)
{
// We got disconnected while this runnable was pending execution.
return;
}
try
{
if (mWaitingForReconnect)
{
mWaitingForReconnect = false;
// Check if the receiver app is still running
if ((connectionHint != null) && connectionHint.getBoolean(Cast.EXTRA_APP_NO_LONGER_RUNNING))
{
Log.d(TAG, "App is no longer running");
teardown();
}
else
{// Re-create the custom message channel
try
{
Cast.CastApi.setMessageReceivedCallbacks(mApiClient,mEventChannel.getNamespace(),mEventChannel);
}
catch (IOException e)
{
Log.e(TAG, "Exception while creating channel", e);
}
}
}
else
{// Launch the receiver app because is connected
Cast.CastApi.launchApplication(mApiClient,myContext.getString(R.string.app_id), false).setResultCallback(
new ResultCallback<Cast.ApplicationConnectionResult>()
{
@Override
public void onResult(Cast.ApplicationConnectionResult result) {
Status status = result.getStatus();
Log.d(TAG,"ApplicationConnectionResultCallback.onResult: statusCode"+ status.getStatusCode());
if (status.isSuccess())
{
ApplicationMetadata applicationMetadata = result.getApplicationMetadata();
mSessionId = result.getSessionId();
String applicationStatus = result.getApplicationStatus();
boolean wasLaunched = result.getWasLaunched();
Log.d(TAG,"application name: "+ applicationMetadata.getName()
+ ", status: "+ applicationStatus
+ ", sessionId: "+ mSessionId
+ ", wasLaunched: "+ wasLaunched);
mApplicationStarted = true;
// Create the custom message channel
mEventChannel = new EventChannel(myContext,TAG);
try
{
Cast.CastApi.setMessageReceivedCallbacks(mApiClient,mEventChannel.getNamespace(),mEventChannel);
}
catch (IOException e)
{
Log.e(TAG,"Exception while creating channel",e);
}
// set the initial instructions on the receiver
sendMessage("starting from mobile");
}
else
{
Log.e(TAG,"application could not launch");
teardown();
}
}
});
}
}
catch (Exception e)
{
Log.e(TAG, "Failed to launch application", e);
}
}
@Override
public void onConnectionSuspended(int cause)
{
Log.d(TAG, "onConnectionSuspended");
mWaitingForReconnect = true;
}
public void sendMessage(String message)
{
if (mApiClient != null && mEventChannel != null)
{
try
{
Cast.CastApi.sendMessage(mApiClient,mEventChannel.getNamespace(), message)
.setResultCallback(new ResultCallback<Status>() {
@Override
public void onResult(Status result)
{
if (!result.isSuccess())
{
Log.e(TAG, "Sending message failed");
}
}
});
}
catch (Exception e)
{
Log.e(TAG, "Exception while sending message", e);
}
}
else
{
Toast.makeText(myContext, message, Toast.LENGTH_SHORT).show();
}
}
public void teardown()
{
Log.d(TAG, "teardown");
if (mApiClient != null)
{
if (mApplicationStarted)
{
if (mApiClient.isConnected() || mApiClient.isConnecting())
{
try
{
Cast.CastApi.stopApplication(mApiClient, mSessionId);
if (myChannel != null)
{
Cast.CastApi.removeMessageReceivedCallbacks(mApiClient,myChannel.getNamespace());
myChannel = null;
}
}
catch (IOException e)
{
Log.e(TAG, "Exception while removing channel", e);
}
mApiClient.disconnect();
}
mApplicationStarted = false;
}
mApiClient = null;
}
mSelectedDevice = null;
mWaitingForReconnect = false;
mSessionId = null;
}
}
MediaRouterCallback.java
public class MyMediaRouterCallback extends MediaRouter.Callback {
private GoogleApiClient mApiClient;
private Cast.Listener mCastListener;
private Context myContext;
private ConnectionFailedListener mConnectionFailedListener;
public MyConnectionCallbacks mConnectionCallbacks;
public String TAG;
//private String mSessionId;
public MyMediaRouterCallback(Context _context, String _TAG)
{
this.myContext = _context;
this.TAG = _TAG;
mConnectionCallbacks = new MyConnectionCallbacks(myContext,TAG);
}
@Override
public void onRouteSelected(MediaRouter router, MediaRouter.RouteInfo info) {
Log.d(TAG, "onRouteSelected");
mConnectionCallbacks.mSelectedDevice = CastDevice.getFromBundle(info.getExtras());
launchReceiver();
}
@Override
public void onRouteUnselected(MediaRouter router, MediaRouter.RouteInfo info) {
Log.d(TAG, "onRouteUnselected: info=" + info);
mConnectionCallbacks.teardown();
mConnectionCallbacks.mSelectedDevice = null;
}
private void launchReceiver()
{
try
{
mCastListener = new Cast.Listener() {
@Override
public void onApplicationDisconnected(int errorCode) {
Log.d(TAG, "application has stopped");
mConnectionCallbacks.teardown();
}
};
//Constructors for Google Play Services Connection
//mConnectionCallbacks = new MyConnectionCallbacks(myContext,TAG);
mConnectionFailedListener = new ConnectionFailedListener(TAG);
Cast.CastOptions.Builder apiOptionsBuilder =
Cast.CastOptions.builder(mConnectionCallbacks.mSelectedDevice, mCastListener);
// ApiClient to Connect to Google Play services
mApiClient = new GoogleApiClient.Builder(myContext)
.addApi(Cast.API, apiOptionsBuilder.build())
.addConnectionCallbacks(mConnectionCallbacks)
.addOnConnectionFailedListener(mConnectionFailedListener)
.build();
mConnectionCallbacks.setApiClient(mApiClient);//setting ApiClient to achieve sendMessage
//Connect to Google Play services
mApiClient.connect();
}
catch (Exception e)
{
Log.e(TAG, "Failed launchReceiver", e);
}
}
}
FirstActivity （连接chromecast的地方）
public class ConnectCastActivity extends ActionBarActivity {
private static final String TAG = ConnectCastActivity.class.getSimpleName();
private MediaRouter mMediaRouter;
private MediaRouteSelector mMediaRouteSelector;
private MediaRouter.Callback mMediaRouterCallback;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ActionBar actionBar = getSupportActionBar();
actionBar.setBackgroundDrawable(new ColorDrawable(android.R.color.transparent));
setContentView(R.layout.activity_connect_cast);
// Configure Cast device discovery
mMediaRouter = MediaRouter.getInstance(getApplicationContext());
mMediaRouteSelector = new MediaRouteSelector.Builder().addControlCategory(CastMediaControlIntent.categoryForCast(getResources().getString(R.string.app_id))).build();
mMediaRouterCallback = new MyMediaRouterCallback(getApplicationContext(),TAG);
TextView myTextView = (TextView)findViewById(R.id.txt_helloworld);
myTextView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent i = new Intent(getApplicationContext(),MainActivity.class);
startActivity(i);
}
});
}
@Override
protected void onStart() {
super.onStart();
// Start media router discovery
mMediaRouter.addCallback(mMediaRouteSelector, mMediaRouterCallback, MediaRouter.CALLBACK_FLAG_REQUEST_DISCOVERY);
}
@Override
protected void onStop() {
// End media router discovery
Log.w(TAG, "onStop");
//mMediaRouter.removeCallback(mMediaRouterCallback);
super.onStop();
}
@Override
public void onDestroy() {
Log.w(TAG, "onDestroy");
// mMediaRouterCallback.onRouteUnselected(mMediaRouter,null);
super.onDestroy();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
getMenuInflater().inflate(R.menu.menu_connect_cast, menu);
MenuItem mediaRouteMenuItem = menu.findItem(R.id.media_route_menu_item);
MediaRouteActionProvider mediaRouteActionProvider = (MediaRouteActionProvider) MenuItemCompat.getActionProvider(mediaRouteMenuItem);
// Set the MediaRouteActionProvider selector for device discovery.
mediaRouteActionProvider.setRouteSelector(mMediaRouteSelector);
return true;
}
}
SecondActivity （将发送消息的那个）
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
MediaRouter mMediaRouter = MediaRouter.getInstance(getApplicationContext());
mConnectionCallbacks = new MyConnectionCallbacks(getApplicationContext(),TAG);
setContentView(R.layout.activity_main);
//What should I put here?
}
答案 0 :(得分：0)
如果您的应用程序具有多个活动，那么如果您不将强制转换连接和相关状态与任何这些活动联系起来，那么您最好使用单例，或者使用您的Application实例或使用后台服务或...维护连接并访问在该全局位置维护的所需部分。如果它符合您的要求，您可能希望使用已经完成大部分常规工作的CastCompanionLibrary;如果没有，您可以查看它，看看CastVideos示例应用程序如何使用它并尝试为您的应用程序执行类似操作。