diff --git a/src/net/micode/notes/ui/DropdownMenu.java b/src/net/micode/notes/ui/DropdownMenu.java
index 613dc74..0c4b307 100644
--- a/src/net/micode/notes/ui/DropdownMenu.java
+++ b/src/net/micode/notes/ui/DropdownMenu.java
@@ -30,14 +30,18 @@ import net.micode.notes.R;
 public class DropdownMenu {
     private Button mButton;
     private PopupMenu mPopupMenu;
+    //声明一个下拉菜单
     private Menu mMenu;
 
     public DropdownMenu(Context context, Button button, int menuId) {
         mButton = button;
         mButton.setBackgroundResource(R.drawable.dropdown_icon);
+        //设置这个view的背景
         mPopupMenu = new PopupMenu(context, mButton);
         mMenu = mPopupMenu.getMenu();
         mPopupMenu.getMenuInflater().inflate(menuId, mMenu);
+        //MenuInflater是用来实例化Menu目录下的Menu布局文件
+        //根据ID来确认menu的内容选项
         mButton.setOnClickListener(new OnClickListener() {
             public void onClick(View v) {
                 mPopupMenu.show();
@@ -48,14 +52,14 @@ public class DropdownMenu {
     public void setOnDropdownMenuItemClickListener(OnMenuItemClickListener listener) {
         if (mPopupMenu != null) {
             mPopupMenu.setOnMenuItemClickListener(listener);
-        }
+        }//设置菜单的监听
     }
 
     public MenuItem findItem(int id) {
         return mMenu.findItem(id);
-    }
+    }//对于菜单选项的初始化，根据索引搜索菜单需要的选项
 
     public void setTitle(CharSequence title) {
         mButton.setText(title);
-    }
-}
+    }//布局文件，设置标题
+}
\ No newline at end of file