Make SynthActivity superclass

New activities can subclass from the SynthActivity, and that will keep
the sound going. We'll actually do something a little different for
preferences, but this will be useful for other activities.

android/res/menu/synth_menu.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<menu xmlns:android="http://schemas.android.com/apk/res/android">
+  <item android:id="@+id/settings" android:title="@string/settings" />
+</menu>

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

@@ -19,20 +19,17 @@ package com.levien.synthesizer.android.ui;
 import java.util.List;
 
 import android.annotation.TargetApi;
-import android.app.Activity;
 import android.app.PendingIntent;
 import android.content.BroadcastReceiver;
-import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
-import android.content.ServiceConnection;
 import android.hardware.usb.UsbDevice;
 import android.hardware.usb.UsbManager;
 import android.os.Build;
 import android.os.Bundle;
-import android.os.IBinder;
 import android.util.Log;
+import android.view.Menu;
 import android.view.View;
 import android.view.WindowManager;
 import android.widget.AdapterView;
@@ -41,7 +38,6 @@ import android.widget.ArrayAdapter;
 import android.widget.Spinner;
 
 import com.levien.synthesizer.R;
-import com.levien.synthesizer.android.service.SynthesizerService;
 import com.levien.synthesizer.android.widgets.keyboard.KeyboardSpec;
 import com.levien.synthesizer.android.widgets.keyboard.KeyboardView;
 import com.levien.synthesizer.android.widgets.keyboard.ScrollStripView;
@@ -55,7 +51,7 @@ import com.levien.synthesizer.core.midi.MidiListener;
  * This version is hacked up to send MIDI to the C++ engine. This needs to
  * be refactored to make it cleaner.
  */
-public class PianoActivity2 extends Activity {
+public class PianoActivity2 extends SynthActivity {
   @Override
   public void onCreate(Bundle savedInstanceState) {
     Log.d("synth", "activity onCreate " + getIntent());
@@ -79,6 +75,12 @@ public class PianoActivity2 extends Activity {
     }
   }
 
+  @Override
+  public boolean onCreateOptionsMenu(Menu menu) {
+    getMenuInflater().inflate(R.menu.synth_menu, menu);
+    return true;
+  }
+
   @Override
   protected void onDestroy() {
     Log.d("synth", "activity onDestroy");
@@ -100,19 +102,6 @@ public class PianoActivity2 extends Activity {
     super.onResume();
   }
 
-  @Override
-  protected void onStart() {
-    super.onStart();
-    bindService(new Intent(this, SynthesizerService.class),
-      synthesizerConnection_, Context.BIND_AUTO_CREATE);
-  }
-
-  @Override
-  protected void onStop() {
-    super.onStop();
-    unbindService(synthesizerConnection_);
-  }
-
   @Override
   protected void onNewIntent(Intent intent) {
     Log.d("synth", "activity onNewIntent " + intent);
@@ -173,21 +162,8 @@ public class PianoActivity2 extends Activity {
     }
   }
 
-  private ServiceConnection synthesizerConnection_ = new ServiceConnection() {
-    @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR1)
-    public void onServiceConnected(ComponentName className, IBinder service) {
-      SynthesizerService.LocalBinder binder = (SynthesizerService.LocalBinder)service;
-      synthesizerService_ = binder.getService();
-      onSynthConnected();
-    }
-    public void onServiceDisconnected(ComponentName className) {
-      onSynthDisconnected();
-      synthesizerService_ = null;
-    }
-  };
-
   @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR1)
-  private void onSynthConnected() {
+  protected void onSynthConnected() {
     final MidiListener synthMidi = synthesizerService_.getMidiListener();
     //piano_.bindTo(synthMidi);
     keyboard_.setMidiListener(synthMidi);
@@ -278,12 +254,10 @@ public class PianoActivity2 extends Activity {
     }
   }
 
-  private void onSynthDisconnected() {
+  protected void onSynthDisconnected() {
     synthesizerService_.setMidiListener(null);
   }
 
-  private SynthesizerService synthesizerService_;
-
   //private PianoView piano_;
   private KeyboardView keyboard_;
   private KnobView cutoffKnob_;

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

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.levien.synthesizer.android.ui;
+
+import com.levien.synthesizer.android.service.SynthesizerService;
+
+import android.annotation.TargetApi;
+import android.app.Activity;
+import android.content.ComponentName;
+import android.content.Context;
+import android.content.Intent;
+import android.content.ServiceConnection;
+import android.os.Build;
+import android.os.IBinder;
+
+/**
+ * A base class that handles making a synthesizer connection. All activities should subclass from
+ * this if sound should keep going during the activity.
+ */
+public class SynthActivity extends Activity {
+  @Override
+  protected void onStart() {
+    super.onStart();
+    bindService(new Intent(this, SynthesizerService.class),
+      synthesizerConnection_, Context.BIND_AUTO_CREATE);
+  }
+
+  @Override
+  protected void onStop() {
+    super.onStop();
+    unbindService(synthesizerConnection_);
+  }
+
+  protected void onSynthConnected() {
+  }
+
+  protected void onSynthDisconnected() {
+  }
+
+  private ServiceConnection synthesizerConnection_ = new ServiceConnection() {
+    @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR1)
+    public void onServiceConnected(ComponentName className, IBinder service) {
+      SynthesizerService.LocalBinder binder = (SynthesizerService.LocalBinder)service;
+      synthesizerService_ = binder.getService();
+      onSynthConnected();
+    }
+    public void onServiceDisconnected(ComponentName className) {
+      onSynthDisconnected();
+      synthesizerService_ = null;
+    }
+  };
+
+  protected SynthesizerService synthesizerService_;
+}

android/src/com/levien/synthesizer/android/widgets/keyboard/ScrollStripView.java

@@ -54,7 +54,7 @@ public class ScrollStripView extends View {
     int min = -(int)(offset_ / spacing);
     int max = -(int)((offset_ - drawingRect_.width()) / spacing) + 1;
     for (int i = min; i <= max; i++) {
-      float x = offset_ + i * 10f * density * zoom_;
+      float x = offset_ + i * spacing;
       canvas.drawCircle(x, y, 3.0f * density, paint_);
     }
   }