我想将音频路由到蓝牙耳机，或类似的输出（如果已连接）。我使用mediarouter是为了这个目的，因为我知道我打算做什么。但我不能让它工作，因为它没有发现我的蓝牙耳机，虽然它配对。
我将发布我用于活动的代码。
我想问，为了这个目的，我必须使用蓝牙框架吗？因为我只想路由音频，而不是处理连接或配对蓝牙设备。

import android.content.Context;
import android.content.DialogInterface;
import android.os.Bundle;
import android.util.Log;
import android.view.Display;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import androidx.appcompat.widget.Toolbar;
import androidx.core.view.MenuItemCompat;
import androidx.mediarouter.app.MediaRouteActionProvider;
import androidx.mediarouter.app.MediaRouteControllerDialog;
import androidx.mediarouter.app.MediaRouteControllerDialogFragment;
import androidx.mediarouter.app.MediaRouteDialogFactory;
import androidx.mediarouter.media.MediaControlIntent;
import androidx.mediarouter.media.MediaRouteSelector;
import androidx.mediarouter.media.MediaRouter;

public class MediaRouterPlaybackActivity extends AppCompatActivity {
    private MediaRouter mMediaRouter;

    // Active Presentation, set to null if no secondary screen is enabled
    private SamplePresentation mPresentation;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.media_route);
        mTextStatus = findViewById(R.id.textStatus);

        Toolbar myToolbar = findViewById(R.id.my_toolbar);
        setSupportActionBar(myToolbar);

        Log.d("tag", "on create");

        // Enable clicks on the 'change color' button
        mButton = findViewById(R.id.button1);
        mButton.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                showNextColor();
            }
        });

        // BEGIN_INCLUDE(getMediaRouter)
        // Get the MediaRouter service
        mMediaRouter = MediaRouter.getInstance(this);
        // END_INCLUDE(getMediaRouter)
    }

    /**
     * Implementing a {@link android.media.MediaRouter.Callback} to update the displayed
     * {@link android.app.Presentation} when a route is selected, unselected or the
     * presentation display has changed. The provided stub implementation
     * {@link android.media.MediaRouter.SimpleCallback} is extended and only
     * {@link android.media.MediaRouter.SimpleCallback#onRouteSelected(android.media.MediaRouter, int, android.media.MediaRouter.RouteInfo)}
     * ,
     * {@link android.media.MediaRouter.SimpleCallback#onRouteUnselected(android.media.MediaRouter, int, android.media.MediaRouter.RouteInfo)}
     * and
     * {@link android.media.MediaRouter.SimpleCallback#onRoutePresentationDisplayChanged(android.media.MediaRouter, android.media.MediaRouter.RouteInfo)}
     * are overridden to update the displayed {@link android.app.Presentation} in
     * {@link #updatePresentation()}. These callbacks enable or disable the
     * second screen presentation based on the routing provided by the
     * {@link android.media.MediaRouter} for {@link android.media.MediaRouter#ROUTE_TYPE_LIVE_VIDEO}
     * streams. @
     */
    private final MediaRouter.Callback mMediaRouterCallback =
            new MediaRouter.Callback() {

                // BEGIN_INCLUDE(SimpleCallback)

                /**
                 * A new route has been selected as active. Disable the current
                 * route and enable the new one.
                 */
                @Override
                public void onRouteSelected(@NonNull MediaRouter router, @NonNull MediaRouter.RouteInfo route, int reason) {
                    Log.d("Media route", "onRouteUnselected: route=" + route);
                    updatePresentation();
                }

                /**
                 * The route has been unselected.
                 */
                @Override
                public void onRouteUnselected(MediaRouter router, MediaRouter.RouteInfo info, int reason) {
                    Log.d("Media route", "onRouteUnselected: route=" + info);
                    updatePresentation();
                }

                /**
                 * The route's presentation display has changed. This callback
                 * is called when the presentation has been activated, removed
                 * or its properties have changed.
                 */
                @Override
                public void onRoutePresentationDisplayChanged(MediaRouter router, MediaRouter.RouteInfo route) {
                    updatePresentation();
                }
                // END_INCLUDE(SimpleCallback)
            };

    /**
     * Updates the displayed presentation to enable a secondary screen if it has
     * been selected in the {@link android.media.MediaRouter} for the
     * {@link android.media.MediaRouter#ROUTE_TYPE_LIVE_VIDEO} type. If no screen has been
     * selected by the {@link android.media.MediaRouter}, the current screen is disabled.
     * Otherwise a new {@link SamplePresentation} is initialized and shown on
     * the secondary screen.
     */
    private void updatePresentation() {

        // BEGIN_INCLUDE(updatePresentationInit)
        // Get the selected route for live video
        MediaRouter.RouteInfo selectedRoute = mMediaRouter.getSelectedRoute();

        // Get its Display if a valid route has been selected
        Display selectedDisplay = selectedRoute.getPresentationDisplay();
        // END_INCLUDE(updatePresentationInit)

        // BEGIN_INCLUDE(updatePresentationDismiss)
        /*
         * Dismiss the current presentation if the display has changed or no new
         * route has been selected
         */
        if (mPresentation != null && mPresentation.getDisplay() != selectedDisplay) {
            mPresentation.dismiss();
            mPresentation = null;
            mButton.setEnabled(false);
            mTextStatus.setText("not connected");
        }
        // END_INCLUDE(updatePresentationDismiss)

        // BEGIN_INCLUDE(updatePresentationNew)
        /*
         * Show a new presentation if the previous one has been dismissed and a
         * route has been selected.
         */
        if (mPresentation == null && selectedDisplay != null) {

            // Initialise a new Presentation for the Display
            mPresentation = new SamplePresentation(this, selectedDisplay);
            mPresentation.setOnDismissListener(mOnDismissListener);

            // Try to show the presentation, this might fail if the display has
            // gone away in the mean time
            try {
                mPresentation.show();
                mTextStatus.setText("test");
                mButton.setEnabled(true);
                showNextColor();
            } catch (WindowManager.InvalidDisplayException ex) {
                // Couldn't show presentation - display was already removed
                mPresentation = null;
            }
        }
        // END_INCLUDE(updatePresentationNew)

    }

    @Override
    protected void onResume() {
        super.onResume();

        // BEGIN_INCLUDE(addCallback)
        // Register a callback for all events related to live video devices
        mMediaRouter.addCallback(
                new MediaRouteSelector.Builder()
                        .addControlCategory(MediaControlIntent.CATEGORY_REMOTE_PLAYBACK)
                        .addControlCategory(MediaControlIntent.CATEGORY_LIVE_AUDIO)
                        .build(),
                mMediaRouterCallback, MediaRouter.CALLBACK_FLAG_REQUEST_DISCOVERY
        );
        // END_INCLUDE(addCallback)

        // Show the 'Not connected' status message
        mButton.setEnabled(false);
        mTextStatus.setText("not connected");

        // Update the displays based on the currently active routes
        updatePresentation();

    }

    @Override
    protected void onPause() {
        super.onPause();

        // BEGIN_INCLUDE(onPause)
        // Stop listening for changes to media routes.
        mMediaRouter.removeCallback(mMediaRouterCallback);
        // END_INCLUDE(onPause)
    }

    @Override
    protected void onStop() {
        super.onStop();

        // BEGIN_INCLUDE(onStop)
        // Dismiss the presentation when the activity is not visible.
        if (mPresentation != null) {
            mPresentation.dismiss();
            mPresentation = null;
        }
        // BEGIN_INCLUDE(onStop)
    }

    /**
     * Inflates the ActionBar or options menu. The menu file defines an item for
     * the {@link android.app.MediaRouteActionProvider}, which is registered here for all
     * live video devices using {@link android.media.MediaRouter#ROUTE_TYPE_LIVE_VIDEO}.
     */
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        getMenuInflater().inflate(R.menu.menu, menu);

        // BEGIN_INCLUDE(MediaRouteActionProvider)
        // Configure the media router action provider
        MenuItem mediaRouteMenuItem = menu.findItem(R.id.menu_media_route);

        MediaRouteActionProvider mediaRouteActionProvider =
                (MediaRouteActionProvider) MenuItemCompat.getActionProvider(mediaRouteMenuItem);
        mediaRouteActionProvider.setAlwaysVisible((true));
        mediaRouteActionProvider.setRouteSelector(
                new MediaRouteSelector.Builder()
                        .addControlCategory(MediaControlIntent.CATEGORY_REMOTE_PLAYBACK)
                        .addControlCategory(MediaControlIntent.CATEGORY_LIVE_AUDIO)
                        .build());

        mediaRouteActionProvider.setDialogFactory(new MediaRouteDialogFactory() {
            @Override
            public MediaRouteControllerDialogFragment onCreateControllerDialogFragment() {
                return new MediaRouteControllerDialogFragment() {
                    @Override
                    public MediaRouteControllerDialog onCreateControllerDialog(
                            Context context, Bundle savedInstanceState) {
                        MediaRouteControllerDialog mControllerDialog = new MediaRouteControllerDialog(MediaRouterPlaybackActivity.this);
                        return mControllerDialog;
                    }
                };
            }
        });
        // BEGIN_INCLUDE(MediaRouteActionProvider)

        return true;
    }

    /**
     * Listens for dismissal of the {@link SamplePresentation} and removes its
     * reference.
     */
    private final DialogInterface.OnDismissListener mOnDismissListener =
            new DialogInterface.OnDismissListener() {
                @Override
                public void onDismiss(DialogInterface dialog) {
                    if (dialog == mPresentation) {
                        mPresentation = null;
                    }
                }
            };

    // Views used to display status information on the primary screen
    private TextView mTextStatus;
    private Button mButton;

    /**
     * Displays the next color on the secondary screen if it is activate.
     */
    private void showNextColor() {

    }

}```

I working with this example I found in android docs.
Do you might know how to solve it ?

Im not trying to use google cast only to route to bluetooth speakers or headphones.