caused by android.system.errnoexception open failed eacces (permission denied)解决方案，安卓6.0（API23）权限问题

在API23+以上，不止要在AndroidManifest.xml里面添加权限

1 <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
2 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

还要在JAVA代码中请求权限：

 1     // Storage Permissions
 2     private static final int REQUEST_EXTERNAL_STORAGE = 1;
 3     private static String[] PERMISSIONS_STORAGE = {
 4             Manifest.permission.READ_EXTERNAL_STORAGE,
 5             Manifest.permission.WRITE_EXTERNAL_STORAGE };
 6 
 7     /**
 8      * Checks if the app has permission to write to device storage
 9      * 
10      * If the app does not has permission then the user will be prompted to
11      * grant permissions
12      * 
13      * @param activity
14      */
15     public static void verifyStoragePermissions(Activity activity) {
16         // Check if we have write permission
17         int permission = ActivityCompat.checkSelfPermission(activity,
18                 Manifest.permission.WRITE_EXTERNAL_STORAGE);
19 
20         if (permission != PackageManager.PERMISSION_GRANTED) {
21             // We don't have permission so prompt the user
22             ActivityCompat.requestPermissions(activity, PERMISSIONS_STORAGE,
23                     REQUEST_EXTERNAL_STORAGE);
24         }
25     }

在保存的方法前面调用即可

官方文档：http://developer.android.com/training/permissions/requesting.html