Add a volume setting

This provides a complement to the system media volume, providing more
fine-grained control

res/values/strings.xml

@@ -26,6 +26,8 @@
 
 	<!-- Preferences -->
 	<string name="pref_output">Audio Output</string>
+	<string name="volume_title">Volume</string>
+	<string name="volume_summary">Music volume</string>
 	<string name="headset_only_title">External Output Only</string>
 	<string name="headset_only_summary">Only play music through an external output (e.g. headphones, Bluetooth)</string>
 	<string name="headset_pause_title">Pause When Unplugged</string>

res/xml/preferences.xml

@@ -3,6 +3,10 @@
 	xmlns:android="http://schemas.android.com/apk/res/android"
 	android:persistent="true">
 	<PreferenceCategory android:title="@string/pref_output">
+		<org.kreed.vanilla.VolumePreference
+			android:key="volume"
+			android:title="@string/volume_title"
+			android:summary="@string/volume_summary" />
 		<CheckBoxPreference
 			android:key="headset_only"
 			android:title="@string/headset_only_title"

src/org/kreed/vanilla/PlaybackService.java

@@ -258,6 +258,9 @@ public class PlaybackService extends Service implements Runnable, MediaPlayer.On
 		mHeadsetOnly = mSettings.getBoolean("headset_only", false);
 		mNotificationMode = Integer.parseInt(mSettings.getString("notification_mode", "1"));
 		mScrobble = mSettings.getBoolean("scrobble", false);
+		float volume = mSettings.getFloat("volume", 1.0f);
+		if (volume != 1.0f)
+			mMediaPlayer.setVolume(volume, volume);
 
 		PowerManager powerManager = (PowerManager)getSystemService(POWER_SERVICE);
 		mWakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "VanillaMusicSongChangeLock");
@@ -297,6 +300,11 @@ public class PlaybackService extends Service implements Runnable, MediaPlayer.On
 			updateNotification(getSong(0));
 		} else if ("scrobble".equals(key)) {
 			mScrobble = mSettings.getBoolean("scrobble", false);
+		} else if ("volume".equals(key)) {
+			float volume = mSettings.getFloat("volume", 1.0f);
+			synchronized (mMediaPlayer) {
+				mMediaPlayer.setVolume(volume, volume);
+			}
 		}
 	}
 

src/org/kreed/vanilla/VolumePreference.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2010 Christopher Eby <kreed@kreed.org>
+ *
+ * This file is part of Vanilla Music Player.
+ *
+ * Vanilla Music Player is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Library General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.
+ *
+ * Vanilla Music Player is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.kreed.vanilla;
+
+import android.app.AlertDialog.Builder;
+import android.content.Context;
+import android.preference.DialogPreference;
+import android.util.AttributeSet;
+import android.view.ViewGroup;
+import android.widget.LinearLayout;
+import android.widget.SeekBar;
+
+public class VolumePreference extends DialogPreference implements SeekBar.OnSeekBarChangeListener {
+	public VolumePreference(Context context, AttributeSet attrs)
+	{
+		super(context, attrs);
+	}
+
+	@Override
+	protected void onPrepareDialogBuilder(Builder builder)
+	{
+		// setting is applied instantly; no way to cancel
+		builder.setNegativeButton(null, null);
+
+		ViewGroup.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
+
+		LinearLayout layout = new LinearLayout(getContext());
+		layout.setLayoutParams(params);
+
+		SeekBar seekBar = new SeekBar(getContext());
+		seekBar.setPadding(20, 20, 20, 20);
+		seekBar.setLayoutParams(params);
+		seekBar.setMax(1000);
+		seekBar.setProgress((int)(Math.pow(getPersistedFloat(1.0f) / 3, 0.25f) * 1000));
+		seekBar.setOnSeekBarChangeListener(this);
+		layout.addView(seekBar);
+
+		builder.setView(layout);
+	}
+
+	public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser)
+	{
+		// Approximate an exponential curve with x^4. Produces a value from 0.0 - 3.0.
+		if (fromUser && shouldPersist()) {
+			float value = seekBar.getProgress() / 1000.0f;
+			value *= value;
+			value *= value;
+			persistFloat(value * 3);
+		}
+	}
+
+	public void onStartTrackingTouch(SeekBar seekBar)
+	{		
+	}
+
+	public void onStopTrackingTouch(SeekBar seekBar)
+	{
+	}
+}