Android在sdcard建立文件失敗

在android6.0或更高版本中建立文件失敗，是由於設置裏應用的權限沒有打開的緣由形成的。這個問題困擾了我兩天，試了網上的各類辦法，從添加權限開始一路排查，都在建立文件失敗了。最後在overstack找到了這個答案：

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)