opt: main page, add polyline api, add back to launcher logic; bugfix: map resume when back to mainactivity

libraries/mogo-map/src/main/java/com/mogo/map/MogoOverlayManager.java

@@ -0,0 +1,40 @@
+package com.mogo.map;
+
+import com.mogo.map.overlay.IMogoOverlayManager;
+import com.mogo.map.overlay.IMogoPolyline;
+import com.mogo.map.overlay.MogoPolylineOptions;
+
+/**
+ * @author congtaowang
+ * @since 2020-03-10
+ * <p>
+ * 描述
+ */
+public class MogoOverlayManager implements IMogoOverlayManager {
+
+    private MogoOverlayManager() {
+        // private constructor
+    }
+
+    private static final class InstanceHolder {
+        private static final MogoOverlayManager INSTANCE = new MogoOverlayManager();
+    }
+
+    public static MogoOverlayManager getInstance() {
+        return InstanceHolder.INSTANCE;
+    }
+
+    private Object readResolve() {
+        // 阻止反序列化，必须实现 Serializable 接口
+        return InstanceHolder.INSTANCE;
+    }
+
+    @Override
+    public IMogoPolyline addPolyline( MogoPolylineOptions options ) {
+        try {
+            return MogoMap.getInstance().getMogoMap().addPolyline( options );
+        } catch ( Exception e ) {
+            return null;
+        }
+    }
+}