SDCardUtils 外部存储相关辅助工具类

    import java.io.File;  
      
    import android.os.Environment;  
    import android.os.StatFs;  
      
    //SD卡相关的辅助类  
    public class SDCardUtils  
    {  
        private SDCardUtils()  
        {  
            /* cannot be instantiated */  
            throw new UnsupportedOperationException("cannot be instantiated");  
        }  
      
        /** 
         * 判断SDCard是否可用 
         *  
         * @return 
         */  
        public static boolean isSDCardEnable()  
        {  
            return Environment.getExternalStorageState().equals(  
                    Environment.MEDIA_MOUNTED);  
      
        }  
      
        /** 
         * 获取SD卡路径 
         *  
         * @return 
         */  
        public static String getSDCardPath()  
        {  
            return Environment.getExternalStorageDirectory().getAbsolutePath()  
                    + File.separator;  
        }  
      
        /** 
         * 获取SD卡的剩余容量 单位byte 
         *  
         * @return 
         */  
        public static long getSDCardAllSize()  
        {  
            if (isSDCardEnable())  
            {  
                StatFs stat = new StatFs(getSDCardPath());  
                // 获取空闲的数据块的数量  
                long availableBlocks = (long) stat.getAvailableBlocks() - 4;  
                // 获取单个数据块的大小（byte）  
                long freeBlocks = stat.getAvailableBlocks();  
                return freeBlocks * availableBlocks;  
            }  
            return 0;  
        }  
      
        /** 
         * 获取指定路径所在空间的剩余可用容量字节数，单位byte 
         *  
         * @param filePath 
         * @return 容量字节 SDCard可用空间，内部存储可用空间 
         */  
        public static long getFreeBytes(String filePath)  
        {  
            // 如果是sd卡的下的路径，则获取sd卡可用容量  
            if (filePath.startsWith(getSDCardPath()))  
            {  
                filePath = getSDCardPath();  
            } else  
            {// 如果是内部存储的路径，则获取内存存储的可用容量  
                filePath = Environment.getDataDirectory().getAbsolutePath();  
            }  
            StatFs stat = new StatFs(filePath);  
            long availableBlocks = (long) stat.getAvailableBlocks() - 4;  
            return stat.getBlockSize() * availableBlocks;  
        }  
      
        /** 
         * 获取系统存储路径 
         *  
         * @return 
         */  
        public static String getRootDirectoryPath()  
        {  
            return Environment.getRootDirectory().getAbsolutePath();  
        }  
      
      
    }