我试图将地图添加到我的应用程序，但我看到的只是一个黑屏......为什么？

Im trying to make a map show up and give the users location in the map but all I get is a black screen. I feel like I set it up correctly but its not working for me. Does anyone see something in my code that is not right or something I forgot to add? Heres the code: Im trying to make a map show up and give the us