获取不到存储大小？该怎么处理

获取不到存储大小？
从网上找的：

        public static int getSD(){                                              //SD卡大小
                long blockSize=0,availCount=0;
                File sdcardDir = Environment.getExternalStorageDirectory();
                StatFs sf = new StatFs(sdcardDir.getPath());
                if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2){
                           blockSize = sf.getBlockSizeLong();
                           availCount = sf.getAvailableBlocksLong();                        
                }else{
                   blockSize = sf.getBlockSize();
                   availCount = sf.getAvailableBlocks();
                }
                return count;
        }


        public static int getSYS(){                                           //内置大小
                long blockSize=0,availCount=0;
                File sys=Environment.getDataDirectory();
                StatFs sf=new StatFs(sys.getPath());
                if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2){
                           blockSize = sf.getBlockSizeLong();
                           availCount = sf.getAvailableBlocksLong();                        
                }else{
                   blockSize = sf.getBlockSize();
                   availCount = sf.getAvailableBlocks();
                }
                return count;
        }




对于原生态的系统，检测正常

像锤子这种版本系统的，怎么显示不正常，看了一下为负数，还是相同的数
------解决思路----------------------
既然原生的可以，锤子不行，那就是锤子自己的ROM给改坏了啊
------解决思路----------------------
应该是自定义rom修改了这个值，你看下获取内存的是否正确