Gui eclipse java1/21/2024 There are three layout managers that are most commonly used: Border, Flow, and Grid. Java uses things called “Layout Managers”, which basically defines how elements are laid out inside of the program window. You have the option to set that location in pixels, using x and y coordinates, but generally, I’ve found that the user expects the window to open in the center of the screen. In my opinion, that’s the easiest and most user friendly. SetLocationRelativeTo(null) allows us to center the window right in the middle of the screen. SetSize defines the window width and height in pixels. In this example, when the user hits the “x” in the corner of the window, we want our program to terminate, so we’ll use setDefaultCloseOperation(Frame.EXIT_ON_CLOSE). We have the option to let the program to continue running, even when the box is closed. This tells the computer what to do whenever the program is closed. Next, we define the default close operation. You can see in the image above that the title of the window is “Loan Calculator” as we’ve defined here. The setTitle property allows us to name the frame. Next, we’re going to define the properties for the frame (the program window). Private JTextField jtfAnnualInterestRate For the sake of being descriptive, I usually like to prefix my object names with jtf or jb or similar, so I know what it is quickly by looking at it. And after that, we just need to name our object. We’ll be using JTextField, which is just an input box, and JButton, which, obviously, is a button. Then we need to tell Java what kind of object we’ll be creating. There are some benefits to leaving things private, such as avoiding data corruption and a few other things, but that’s outside the scope of this tutorial. We could change it to public or even protected, but for this example, we’ll leave it how it is. Whenever you create an object and set it to private, that means that it can only be accessed within that same class. Notice in the image above that we have four input fields (Investment Amount, Years, Annual Interest Rate, and Future Value) and two buttons (Compute and Reset). Next, we’ll create the text fields and buttons that will be used in our program. Rather than having to rewrite code over and over, why don’t we write it once, store it in the Java API, and then import it into our program whenever we need it? Luckily, someone has already done that for us! The specifics of each of these libraries isn’t super important, but just know that these include the graphical components that we’ll need to build our program. Libraries are basically a repository of reusable code. It’s a free IDE that you can download, if you’re not interested in using a text editor.įirst, let’s import some libraries. Something this would work: javac SimpleGUIProgram.java java extension, and then compile it using the command line. If you have the Java JDK (a free download, here), you can easily import this code into a text editor, save it with a. When we’re finished, we’ll have a program that looks something like this:Īt the end of this post, I’ll show the complete code. Whenever learning a new programming language, it seems the first program you write is “Hello World.” The next program after that is a basic investment calculator, and so we’re going to continue that pattern. I’ve dabbled with C++, but never stuck with it long enough to get into the Object Oriented pieces of it. Java makes creating applications really simple. I’ll try to make it as easy as possible to understand, but you should have at least a basic understanding of programming to go through this. The code below might look daunting at first, but we’ll walk through it piece by piece to hopefully clear things up. So the fact that even I was able to create a simple GUI application should tell you how easy it is. I enjoy scripting and web development, but deep, low-level programming just simply isn’t my thing. Some people just have that natural itch to want to go out and code all day long, but that isn’t me.
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