1：
self = [[[NSBundle mainBundle] loadNibNamed:@"XXX" owner:self options:nil] objectAtIndex:0];
addsubview:controller.view;
These methods may be risky.
2：
If you encounter the problem of "The model used to open the store is incompatible with the one used to create the store",the solution is: delete app , clean and rebuild project.
3:
self.fec != _fec;//This point is very important;
self = [[[NSBundle mainBundle] loadNibNamed:@"XXX" owner:self options:nil] objectAtIndex:0];
addsubview:controller.view;
These methods may be risky.
2：
If you encounter the problem of "The model used to open the store is incompatible with the one used to create the store",the solution is: delete app , clean and rebuild project.
3:
self.fec != _fec;//This point is very important;
