读写SD卡权限：
<uses-permission android:name
="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/
>
<uses-permission android:name
="android.permission.WRITE_EXTERNAL_STORAGE"/
>
读写SD卡 Environment.MEDIA_MOUNTED /mnt/sdcard目录才是可读可写
String state
;
String path
;
state
= Environment.getExternalStorageState
();
if
(state.equals
(Environment.MEDIA_MOUNTED
))｛
path
= Environment.getExternalStorageDirectory
().getAbsolutePath
();
｝
