Firstly, a device should be backward compatible (though this is not a blanket statement) Android 6.0 APIs to run the app with a lower SDK. You need to ensure you have the SDK 22 installed in your ide.
The other is there are extra issues regarding permissions for android 6.
See here:
Requesting Permissions at Run Time
And the example taken from there Check For Permissions:
// Assume thisActivity is the current activity
int permissionCheck = ContextCompat.checkSelfPermission(thisActivity,
Manifest.permission.WRITE_CALENDAR);
And then Request the permissions you need:
// Here, thisActivity is the current activity
if (ContextCompat.checkSelfPermission(thisActivity,
Manifest.permission.READ_CONTACTS)
!= PackageManager.PERMISSION_GRANTED) {
// Should we show an explanation?
if (ActivityCompat.shouldShowRequestPermissionRationale(thisActivity,
Manifest.permission.READ_CONTACTS)) {
// Show an expanation to the user *asynchronously* -- don't block
// this thread waiting for the user's response! After the user
// sees the explanation, try again to request the permission.
} else {
// No explanation needed, we can request the permission.
ActivityCompat.requestPermissions(thisActivity,
new String[]{Manifest.permission.READ_CONTACTS},
MY_PERMISSIONS_REQUEST_READ_CONTACTS);
// MY_PERMISSIONS_REQUEST_READ_CONTACTS is an
// app-defined int constant. The callback method gets the
// result of the request.
}
}
This answer contains a more comprehensive explanation.
https://stackoverflow.com/a/32084038/3956566