Check Sdcard is available in device in Android

*Check Whether Sd card is available on Device*

       public boolean isSDCardMounted()

             {

              return android.os.Environment.getExternalStorageState().equals(

                                 android.os.Environment.MEDIA_MOUNTED);

             }

             if(isSDCardMounted)

             {

                    //you code here...

             }

             else

             {

                    //No sdcard

             }

*Create Folder in Sdcard*

           File SDCardRoot = Environment.getExternalStorageDirectory();

            SDCardRoot = new File(SDCardRoot,"FolderName");

            if (!SDCardRoot.exists())

            {

                  SDCardRoot.mkdir();

            }

*Create File in Sdcard*

            file = new File(SDCardRoot,filename);

            if(file.createNewFile())

            {

                  file.createNewFile();

            }

Permission:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

 <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />