面向对象 Java 程序设计

Welcome to the first week of our course. In this week, we'll get started by introducing ourselves and the Google engineers who will be making appearances throughout the course. We'll also give you of the unique video series we provide and help you understand how to navigate the course to get the most out of it given your background and learning speed. Finally, we'll jump right into objects and designing classes. This might be a bit of review for some of you who might have learned this in your first programming course. If that's the case, feel free to jump ahead to the Practice Quiz at the end of the week. Let's get started!

We hope you’re excited about the project that we're starting to build -- we sure are! In this second part of this week, we'll walk you through setting up your system and working through your first assignment so you'll be having fun with it in no time. Before that though, we'll finish going over some of the fundamentals fundamentals of object oriented programming. Specifically, being able to trace code is a key skill in becoming a stronger programmer. Like the end of last week, the first part of this week might be a bit of a review of material you already learned in your first Java programming course. If that’s the case, you are always welcome to skip to the first graded assignment on Objects, Memory Models, and Scope.

Now that you have the tools to write and trace object oriented code, let’s get back to developing the project! In this first (real) part of the project, you will create an interactive graphical map that will display geospatial data. This is a highly interactive week, so make sure you’ve got Eclipse loaded up! We encourage you to play around as you watch the videos. Some of the code that we use in the videos is in the demos package in the starter code you set up for this course. Open it up and experiment with it while you're watching the videos. We also encourage you to dive right into the programming project, even before watching the videos, if you want. The programming assignment instructions are in the last lesson of this week - you can watch a video walkthrough of the instructions and also read the step-by-step directions in the accompanying reading. There’s lots of room for creativity, too, so have fun!

Now that you’re in full swing with the project, let’s take a closer look at some concepts that you have already been using in your code. Specifically, the keyword “extends”. What exactly does it mean that your program “extends PApplet”? To answer this question we’ll need to dive into the details of how Java allows for Class Hierarchies through Inheritance and Polymorphism. These fundamental and powerful concepts will serve you well in the future! We’ll use these ideas to allow for displaying markers differently. If you feel you’re already comfortable with Inheritance and Polymorphism, feel free to dive straight into the project (programming assignment) for this week. As you work with the project, feel free to have some fun and introduce new levels of class hierarchies for improved functionality.