单击按钮会导致应用程序崩溃Android Studio

I am trying to create a BMI Calculator and for some reason, whenever I click the button, the app crashes. However, when building the app, it doesn't report any problems. I think there is a problem with the buttonClick method because Android Studio says that it is never used. I want to build the app so that after clicking the button, it will show your BMI in the textview. I am trying to create a BMI Calculator and for