JellyBean external display not found with MediaRouter or DisplayManager

问题

I am trying to use Presenter feature in JellyBean to show custom graphics on additional large screen. I am connected with MHL compliant HDMI adapter (microUSB -> HDMI). Piece of my code trying to detect external display is below. For some reason - I do get output on my external monitor but DisplayManager won't detect external display. I wonder if this has to do with adapter or it would be the case if I connected phone to external display with HDMI cable directly?

My logcat: http://postimg.org/image/sloflge1b/

My code piece:

@SuppressLint("NewApi")
private void updatePresentation() {
    // Get the current route and its presentation display.
    Log.d(EXTRA_DISPLAY_TAG, "Inside updatePresentation() call...");

    MediaRouter.RouteInfo route = mediaRouter.getSelectedRoute(MediaRouter.ROUTE_TYPE_LIVE_VIDEO);

    Log.d(EXTRA_DISPLAY_TAG, "Route name: " + route.getName() + " , route status: " + route.getStatus());
    Display externalDisplay = null;
    if(route != null && route.getName().equals("HDMI")){
        externalDisplay = route.getPresentationDisplay();
        if(externalDisplay == null){ //Maybe not ready...
            Log.d(EXTRA_DISPLAY_TAG, "Waiting for external display to become ready...");
            SystemClock.sleep(2000);
            DisplayManager displayManager = (DisplayManager)getSystemService(DISPLAY_SERVICE);
            Display[] presentationDisplays = displayManager.getDisplays(DisplayManager.DISPLAY_CATEGORY_PRESENTATION);
            if(null == presentationDisplays || presentationDisplays.length == 0){
                Log.d(EXTRA_DISPLAY_TAG, "Didn't find any presentation displays by category...");
            }else{
                externalDisplay = presentationDisplays[0]; //OK: Take first
            }
            //Try to manually select display...
            if(externalDisplay == null){
                Display[] allDisplays = displayManager.getDisplays();
                for(int i=0; i<allDisplays.length; i++){
                    Log.d(EXTRA_DISPLAY_TAG, "Detected display  "+(i+1)+ " : " + allDisplays[i].getName());
                }


                //externalDisplay = allDisplays[0]; //FIXME: Take by some criteria...
            }
        }
    }

    if(externalDisplay != null){
        Log.i(EXTRA_DISPLAY_TAG, "Detected external display...");
        Point size = new Point();
        externalDisplay.getSize(size);
        int width = size.x;
        int height = size.y;
        Log.i(EXTRA_DISPLAY_TAG, "External display resolution: " + width + "px x " + height + "px");
    }

    // Dismiss current presentation if display changes
    if(quantumPresentation != null && quantumPresentation.getDisplay() != externalDisplay){

        Log.i(EXTRA_DISPLAY_TAG, "Leaving presentation because current route no longer has a presentation display.");
        quantumPresentation.dismiss();
        quantumPresentation = null;
    }

    // Show new presentation if needed
    if(quantumPresentation == null && externalDisplay != null) {
        Log.i(EXTRA_DISPLAY_TAG, "Showing presentation on display: "  + externalDisplay);
        quantumPresentation = new QuantumPresentation(this, externalDisplay);
        quantumPresentation.setOnDismissListener(onPresentationDismissListener);            
        try{
            Log.i(EXTRA_DISPLAY_TAG, "Starting additional display presentation...");
            quantumPresentation.show();
        } catch (WindowManager.InvalidDisplayException ex){
            Log.w(EXTRA_DISPLAY_TAG, "Couldn't show presentation! External display was removed in the meantime!", ex);
            quantumPresentation = null;
        }

    }
    // Update the contents playing in activity...
    updateContents();


}

回答1:

The Galaxy Nexus does not support multiple independent displays, as has been reported: https://code.google.com/p/android/issues/detail?id=42509

来源：https://stackoverflow.com/questions/16699317/jellybean-external-display-not-found-with-mediarouter-or-displaymanager