Android在sdcard建立文件失败

在android6.0或更高版本中建立文件失败，是由于设置里应用的权限没有打开的缘由形成的。这个问题困扰了我两天，试了网上的各类办法，从添加权限开始一路排查，都在建立文件失败了。最后在overstack找到了这个答案：

9down vote

I got the same problem,and I am sure I had put the permission tag in the right place,but mkdirs didn't work yet, my system is Android 6.0, I resolve it now , you can check as below: make sure your put the permission tag in . open "setting/application" in your phone,check your application's permission(I found the permission in my manifest statement is not here),open the switch of the permission like this.(I found it is closed in default which make "mkdirs" failed)