Is an improper use of strings causing my app to not run?

Jaiden Cruger if I'm understanding your question correctly, it's that you have a warning in one of your .xml files. The warning you are seeing is probably a "hardcoded string" warning. If you hover your mouse over the xml you pasted you'll see the full warning message. You should see something like "Hardcoded string "Did you know?", should use @string resource".

The reason for this warning is that you shouldn't be using hardcoded strings in your application (java or xml), and instead use the strings.xml to keep all of your strings in one place. Two use cases where this comes up is 1. If you want to translate your application into other languages 2. If you constantly hardcode a value (let's say your app name) in multiple places, and then you decide to change your app name, you'll have to manually go and change that value everywhere. By using the strings.xml file to declare your strings you can solve the use cases mentioned.

Now, how do you go about fixing this?

One way you could do this in Android Studio is by clicking on the warning to place your cursor there, and then hit Alt + Enter. You should see a little window that lists possible actions. At the top of this list it should say "Extract string resource". Select that by hitting Enter and type in a valid name for the "Resource name" field and hit ok. You should see the xml update in front of you, and in the background, Android Studio has created a string resource for you in the strings.xml file.

The second (manual way) of doing this, would be to open up your strings.xml file and add a line <string name="example">Did you know?</string> and then updating your xml to be android:text="@string/example"

If you still need some help, let me know!