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();  
    }  
  
  
}