How to set the SMS interface of Apple's 4s mobile phone?

Enter the main interface, click Settings, and click Notification in Settings. After entering the notification, click the information drop-down screen under the notification center, and you can see that the "Show Preview" switch is on, so it is closed. At this point, return to the main interface. When the screen is locked, you can only see who the sender is when you receive the text message, but you can't see the content of the text message.