android: Move preferences class out of settings

android/app/src/main/java/org/musicpd/Preferences.java

@@ -0,0 +1,34 @@
+package org.musicpd;
+
+import static android.content.Context.MODE_PRIVATE;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+
+public class Preferences {
+    private static final String TAG = "Settings";
+
+    public static final String KEY_RUN_ON_BOOT ="run_on_boot";
+    public static final String KEY_WAKELOCK ="wakelock";
+    public static final String KEY_PAUSE_ON_HEADPHONES_DISCONNECT ="pause_on_headphones_disconnect";
+
+    public static SharedPreferences get(Context context) {
+        return context.getSharedPreferences(TAG, MODE_PRIVATE);
+    }
+
+    public static void putBoolean(Context context, String key, boolean value) {
+        final SharedPreferences prefs = get(context);
+
+        if (prefs == null)
+            return;
+        final SharedPreferences.Editor editor = prefs.edit();
+        editor.putBoolean(key, value);
+        editor.apply();
+    }
+
+    public static boolean getBoolean(Context context, String key, boolean defValue) {
+        final SharedPreferences prefs = get(context);
+
+        return prefs != null ? prefs.getBoolean(key, defValue) : defValue;
+    }
+}