Android 判断SD卡是否存在及容量查询

<!--?在SDCard中创建与删除文件权限?-->??
<uses-permission?android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>??
<!--?往SDCard写入数据权限?-->??
<uses-permission?android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

private?boolean?ExistSDCard()?{??
??if?(android.os.Environment.getExternalStorageState().equals(??
????android.os.Environment.MEDIA_MOUNTED))?{??
???return?true;??
??}?else??
???return?false;??
?}

public?long?getSDFreeSize(){??
?????//取得SD卡文件路径??
?????File?path?=?Environment.getExternalStorageDirectory();???
?????StatFs?sf?=?new?StatFs(path.getPath());???
?????//获取单个数据块的大小(Byte)??
?????long?blockSize?=?sf.getBlockSize();???
?????//空闲的数据块的数量??
?????long?freeBlocks?=?sf.getAvailableBlocks();??
?????//返回SD卡空闲大小??
?????//return?freeBlocks?*?blockSize;??//单位Byte??
?????//return?(freeBlocks?*?blockSize)/1024;???//单位KB??
?????return?(freeBlocks?*?blockSize)/1024?/1024;?//单位MB??
???}

public?long?getSDAllSize(){??
?????//取得SD卡文件路径??
?????File?path?=?Environment.getExternalStorageDirectory();???
?????StatFs?sf?=?new?StatFs(path.getPath());???
?????//获取单个数据块的大小(Byte)??
?????long?blockSize?=?sf.getBlockSize();???
?????//获取所有数据块数??
?????long?allBlocks?=?sf.getBlockCount();??
?????//返回SD卡大小??
?????//return?allBlocks?*?blockSize;?//单位Byte??
?????//return?(allBlocks?*?blockSize)/1024;?//单位KB??
?????return?(allBlocks?*?blockSize)/1024/1024;?//单位MB??
???}