Update controller views from MIDI keyboard

This patch adds plumbing so that changing the controller values from
a USB MIDI keyboard updates the knob views as well.

android/src/com/levien/synthesizer/android/service/SynthesizerService.java

@@ -41,6 +41,7 @@ import android.util.Log;
 import com.levien.synthesizer.R;
 import com.levien.synthesizer.android.AndroidGlue;
 import com.levien.synthesizer.android.usb.UsbMidiDevice;
+import com.levien.synthesizer.core.midi.MessageForwarder;
 import com.levien.synthesizer.core.midi.MidiListener;
 import com.levien.synthesizer.core.model.composite.MultiChannelSynthesizer;
 
@@ -85,6 +86,15 @@ public class SynthesizerService extends Service {
       params.bufferSize = 64;
 
       androidGlue_ = new AndroidGlue();
+      midiListener_ = new MessageForwarder(androidGlue_) {
+        @Override
+        public void onController(int channel, int control, int value) {
+          super.onController(channel, control, value);
+          if (onCcListener_!= null) {
+            onCcListener_.onCcChange(channel, control, value);
+          }
+        }
+      };
       androidGlue_.start(params.sampleRate, params.bufferSize);
       InputStream patchIs = getResources().openRawResource(R.raw.rom1a);
       byte[] patchData = new byte[4104];
@@ -129,7 +139,7 @@ public class SynthesizerService extends Service {
   }
 
   public MidiListener getMidiListener() {
-    return androidGlue_;
+    return midiListener_;
   }
 
   /**
@@ -214,7 +224,7 @@ public class SynthesizerService extends Service {
           usbDevice_ = device;
           usbMidiConnection_ = connection;
           usbMidiInterface_ = intf;
-          usbMidiDevice_ = new UsbMidiDevice(androidGlue_, usbMidiConnection_, intf);
+          usbMidiDevice_ = new UsbMidiDevice(midiListener_, usbMidiConnection_, intf);
           usbMidiDevice_.start();
           return true;
         } else {
@@ -262,6 +272,16 @@ public class SynthesizerService extends Service {
     }
   };
 
+  public interface OnCcListener {
+    abstract void onCcChange(int channel, int cc, int value);
+  }
+
+  public void setOnCcListener(OnCcListener onCcListener) {
+    onCcListener_ = onCcListener;
+  }
+
+  private MidiListener midiListener_;
+
   // Binder to use for Activities in this process.
   private final IBinder binder_ = new LocalBinder();
 
@@ -275,4 +295,7 @@ public class SynthesizerService extends Service {
   private UsbMidiDevice usbMidiDevice_;
   private UsbInterface usbMidiInterface_;
   private UsbDevice usbDeviceNeedsPermission_;
+
+  // Plumbing for MIDI events
+  private OnCcListener onCcListener_;
 }

android/src/com/levien/synthesizer/android/ui/PianoActivity2.java

@@ -205,11 +205,16 @@ public class PianoActivity2 extends Activity {
       SynthesizerService.LocalBinder binder = (SynthesizerService.LocalBinder)service;
       synthesizerService_ = binder.getService();
       piano_.bindTo(synthesizerService_.getMidiListener());
+
+      // Populate patch names (note: we could update an existing list rather than
+      // creating a new adapter, but it probably wouldn't save all that much).
       List<String> patchNames = synthesizerService_.getPatchNames();
       ArrayAdapter<String> adapter = new ArrayAdapter<String>(
               PianoActivity2.this, android.R.layout.simple_spinner_item, patchNames);
       adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
       presetSpinner_.setAdapter(adapter);
+
+      // Handle any pending USB device events
       if (usbDevicePending_ != null) {
         synthesizerService_.connectUsbMidi(usbDevicePending_);
         usbDevicePending_ = null;
@@ -225,6 +230,23 @@ public class PianoActivity2 extends Activity {
           }
         }
       }
+
+      // Connect controller changes to knob views
+      synthesizerService_.setOnCcListener(new SynthesizerService.OnCcListener() {
+        public void onCcChange(final int channel, final int cc, final int value) {
+          runOnUiThread(new Runnable() {
+            public void run() {
+              if (cc == 1) {
+                cutoffKnob_.setValue(value * (1.0 / 127));
+              } else if (cc == 2) {
+                resonanceKnob_.setValue(value * (1.0 / 127));
+              } else if (cc == 3) {
+                overdriveKnob_.setValue(value * (1.0 / 127));
+              }
+            }
+          });
+        }
+      });
     }
     public void onServiceDisconnected(ComponentName className) {
       synthesizerService_ = null;

android/src/com/levien/synthesizer/android/widgets/knob/KnobView.java

@@ -147,7 +147,9 @@ public class KnobView extends View {
   }
 
   /**
-   * Sets the current value of the knob.
+   * Sets the current value of the knob. Note that this call does not
+   * invoke the listener. The assumption is that any caller will also
+   * update the client.
    */
   public void setValue(double value) {
     if (value < min_) {
@@ -157,9 +159,6 @@ public class KnobView extends View {
     } else {
       knobValue_ = (value - min_) / (max_ - min_);
     }
-    if (listener_ != null) {
-      listener_.onKnobChanged(value);
-    }
     invalidate();
   }