APUS Notification lets you receive WhatsApp, Gmail, and text messages, as well as phone calls, in such a way that you cannot get rid of the notifications without opening the message itself. It's a good way to force yourself to read important messages.
Each of the four tools mentioned above can be enabled or disabled at any time within APUS Notification, so that, for example, you don't have to open WhatsApp each time it dings. If you're expecting an important email, you just have to turn on the Gmail one and then turn it off once you've received and read the message.
To use APUS Notification, you'll have to download the APUS launcher as it's a plug-in that works exclusively with this tool. Once installed, it adds a menu bar from which you can access your apps more easily.
If you need an alert system for an important message, APUS Notification will make sure you read everything, since the alert won't go away until you've viewed the message.