android: Main is now a service

- add Settings: Activity to start / stop MPD Service (Main).

- Main is a service that run in foreground with a notification. See
  Service.startForeground documentation for more details.

- Main.Client is used to control the service: start or stop it and also receive
  callbacks when service encounters an error, is killed, is started or is
  stopped.

- Main.start to start the service without any fallback.

Makefile.am

@@ -301,18 +301,29 @@ ANDROID_BUILD_TOOLS_DIR = $(ANDROID_SDK)/build-tools/$(ANDROID_SDK_BUILD_TOOLS_V
 ANDROID_SDK_PLATFORM_DIR = $(ANDROID_SDK)/platforms/$(ANDROID_SDK_PLATFORM)
 
 JAVAC = javac
+AIDL = $(ANDROID_BUILD_TOOLS_DIR)/aidl
 AAPT = $(ANDROID_BUILD_TOOLS_DIR)/aapt
 DX = $(ANDROID_BUILD_TOOLS_DIR)/dx
 ZIPALIGN = $(ANDROID_BUILD_TOOLS_DIR)/zipalign
 
 ANDROID_XML_RES := $(wildcard $(srcdir)/android/res/*/*.xml)
 ANDROID_XML_RES_COPIES := $(patsubst $(srcdir)/android/%,android/build/%,$(ANDROID_XML_RES))
 
-JAVA_SOURCE_NAMES = Bridge.java Loader.java Main.java
+JAVA_SOURCE_NAMES = Bridge.java Loader.java Main.java Settings.java
 JAVA_SOURCE_PATHS = $(addprefix $(srcdir)/android/src/,$(JAVA_SOURCE_NAMES))
 
 JAVA_CLASSFILES_DIR = android/build/classes
 
+AIDL_FILES = $(wildcard $(srcdir)/android/src/*.aidl)
+AIDL_JAVA_FILES = $(patsubst $(srcdir)/android/src/%.aidl,android/build/src/org/musicpd/%.java,$(AIDL_FILES))
+
+android/build/src/org/musicpd/IMain.java: android/build/src/org/musicpd/IMainCallback.java
+
+$(AIDL_JAVA_FILES): android/build/src/org/musicpd/%.java: $(srcdir)/android/src/%.aidl
+	@$(MKDIR_P) $(@D)
+	@cp $< $(@D)/
+	$(AIDL) -Iandroid/build/src -oandroid/build/src $(patsubst %.java,%.aidl,$@)
+
 $(ANDROID_XML_RES_COPIES): $(ANDROID_XML_RES)
 	@$(MKDIR_P) $(dir $@)
 	cp $(patsubst android/build/%,$(srcdir)/android/%,$@) $@
@@ -330,7 +341,7 @@ android/build/resources.apk: $(ANDROID_XML_RES_COPIES) android/build/res/drawabl
 # R.java is generated by aapt, when resources.apk is generated
 android/build/gen/org/musicpd/R.java: android/build/resources.apk
 
-android/build/classes.dex: $(JAVA_SOURCE_PATHS) android/build/gen/org/musicpd/R.java
+android/build/classes.dex: $(JAVA_SOURCE_PATHS) $(AIDL_JAVA_FILES) android/build/gen/org/musicpd/R.java
 	@$(MKDIR_P) $(JAVA_CLASSFILES_DIR)
 	$(JAVAC) -source 1.6 -target 1.6 -Xlint:-options \
 		-cp $(ANDROID_SDK_PLATFORM_DIR)/android.jar:$(JAVA_CLASSFILES_DIR) \

NEWS

@@ -1,6 +1,9 @@
 ver 0.20.22 (not yet released)
 * storage
   - curl: URL-encode paths
+* Android
+  - now runs as a service
+  - add button to start/stop MPD
 
 ver 0.20.21 (2018/08/17)
 * database

android/AndroidManifest.xml

@@ -8,14 +8,14 @@
   <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="26"/>
 
   <application android:icon="@drawable/icon" android:label="@string/app_name">
-    <activity android:name=".Main"
-              android:label="@string/app_name"
-              android:launchMode="singleInstance">
+    <activity android:name=".Settings"
+              android:label="@string/app_name">
       <intent-filter>
         <action android:name="android.intent.action.MAIN" />
         <category android:name="android.intent.category.LAUNCHER" />
       </intent-filter>
     </activity>
+    <service android:name=".Main" />
   </application>
 
   <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

android/res/layout/custom_notification_gb.xml

@@ -0,0 +1,22 @@
+<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/layout"
+    android:layout_width="fill_parent"
+    android:layout_height="fill_parent"
+    android:padding="10dp" >
+    <ImageView android:id="@+id/image"
+        android:layout_width="wrap_content"
+        android:layout_height="fill_parent"
+        android:layout_alignParentLeft="true"
+        android:layout_marginRight="10dp" />
+    <TextView android:id="@+id/title"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_toRightOf="@id/image"
+        style="Custom Notification Title" />
+    <TextView android:id="@+id/text"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_toRightOf="@id/image"
+        android:layout_below="@id/title"
+        style="Custom Notification Text" />
+</RelativeLayout>

android/res/values/strings.xml

@@ -2,4 +2,6 @@
 
 <resources>
   <string name="app_name">MPD</string>
+  <string name="notification_title_mpd_running">Music Player Daemon is running</string>
+  <string name="notification_text_mpd_running">Touch for MPD options.</string>
 </resources>

android/src/IMain.aidl

@@ -0,0 +1,12 @@
+package org.musicpd;
+import org.musicpd.IMainCallback;
+
+interface IMain
+{
+    void start();
+    void stop();
+    void setWakelockEnabled(boolean enabled);
+    boolean isRunning();
+    void registerCallback(IMainCallback cb);
+    void unregisterCallback(IMainCallback cb);
+}

android/src/IMainCallback.aidl

@@ -0,0 +1,9 @@
+package org.musicpd;
+
+interface IMainCallback
+{
+    void onStarted();
+    void onStopped();
+    void onError(String error);
+    void onLog(int priority, String msg);
+}