Difference between revisions of "Mobile App Development 2021W Lecture 2"
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(Created page with "==Video== Video from the lecture given on January 13, 2021 [https://homeostasis.scs.carleton.ca/~soma/mad-2021w/lectures/comp1601-2021w-lec02-20210113.m4v is now available]....") |
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Latest revision as of 14:51, 13 January 2021
Video
Video from the lecture given on January 13, 2021 is now available.
Notes
Lecture 2 ------------ Readings Swift Basics: https://docs.swift.org/swift-book/LanguageGuide/TheBasics.html TA's will be keeping track of participation, posting in cuLearn periodically - if you think you weren't given credit for a lecture, talk to a TA - note we have a record between the Teams chat and audio from lectures SwiftUI terminology is similar to HTML/CSS, but this is because both come from terminology for GUIs, which come from terminology for printing (on paper) - look up TeX, in particular the TeXbook Is swiftUI front end? - will answer later Cross-platform development - environment I'm developing for is different from the one in which I write code - developing on MacOS, but code will run on iOS - typically difficult, but with modern IDEs it is almost seamless - almost! @State variables - denotes variables that directly affect the interface - if their values change, the interface must be updated $ notation - in SwiftUI, means a binding to the variable should be passed - functionally it is like a pointer, but much safer, ie pass by reference not value "if let X" - checks whether X is nil or not - allows you to check for failed conversions, etc (e.g., if Double(s) finds that S was not a number) If you say "F = Double(Fs)", F is not of type Double, it is of type Double? - it could be a double, or it could be nil - you can't use it until you check, or you force usage with ! - don't use !, because if you are wrong your program crashes