i was wondering if it would be possible to have one central class just for images. Also, how would i use an image from one class in another? I couldn't find the answer to this at all, on other sites. I'm sorry for this dumb question, but i'm fairly new to programming, and the loading of images and sprite animations is what frustrates me the most, and i won't be able to advance to anything else, unless i get these kinds of problems out my head! Thank you for everyone that helps!
create a new object in clasee and using this object to invoke the function
also you can set class as static class
Related
Let me explain,
Theirs a plugin (video game mod) I want to make to add things to Another plugin (a different mod) but I don't want to change anything in the plugin I'm not making. But to add the stuff I want, I'd have to add some variables to some arrays in a certain class, which I could totally do form another class but Their finalized, and all the spots are taken.
SO after looking into how final variables work (i kinda guessed) I though it might just be easier to
make a copy of the class in question, put it in my plugin, change the variables so their not final, and... OVERRIDE the original class when the program starts... some how.
Ok not easy, but that was the only thing that came to mind, where I still didn't edit the original files, and my plugin could be removed and added without changing anything.
I've looked into Classloaders and something someone called a patching assistant (it implements ClassFileTransformer) but I have no idea what I'm doing. SO I thought I'd post what I'm trying to do on here and see if anyone had any advice, I'll keep trying to figure out whether a class loader or patching assistant are viable for what I want in the mean time.
Thanks in advance!
You can do this with reflection:
http://java-performance.info/updating-final-and-static-final-fields/
Although it's probably not such a great idea - these fields are final for a reason.
I have been coding in java for about a year and a half, and have made some small games and programs that I think turned out very well. The problem is that I am mostly self taught and I most of my code and class structure is not organized or "correctly structured". This didn't matter to me for the smaller things I made, but if I were to take on a larger project I would want to structure it correctly and make it organized.
In a previous mini-RPG game I had
Main Class (Main loop + Main method)
Player Class (containing player position and player stats)
Engine Class (containing map and collision detection between player and map
Map Class (containing map data)
My Main class contained an instance of Player and of Engine, and Engine had an instance of Map. The problem is that Player then could't tell the Engine where it was, and the Engine couldn't adjust Player's position and stats when something happened on the Map. So I ended up having some static variables and methods in both Player and Engine to get them to communicate.
I guess my overall question is is this the correct structure of classes, and is it correct to use static methods and variables here? If not, how would you structure these classes, or would there need to be more or less classes?
My overall objective is to understand how to structure classes in this previous game so I can better structure classes in a bigger project I want to take on.
It is a rather broad question, but the general answer is no.
As a rule you shouldn't use static fields to connect instances. (There are a couple of possible exceptions, but as a rule of thumb it's a useful one.) The basic idea of OOP is that everybody has a reference to whoever they want to send messages to. So if a Player needs to tell the Engine something, it should have a reference to whichever Engine instance it belongs to. Or you can redesign your architecture so only Engine sends messages to Map and Player, it's difficult to tell without more detail about your setup whether that would be appropriate in this case.
Another piece of general advice is to try to sit down with a piece of paper, write down the name of all three of your classes and in a separate column write down all the things the system has to do. And then you should try to figure out who's responsible for what. In a good design this decision is simple, if you find yourself shoehorning different things into one class, that's a sign that you should maybe need a more detailed model with more classes.
I would also suggest you take a look at the observer pattern and the publish-subscribe pattern, as it might be what you need.
Try take take a look at some design-patterns.
Which design pattern you want to use depends on what you prefer. Some can be found here on Wikipedia.
I also take it that you are familiar with OOP? Some more general info can be found here on Wikipedia.
Looking at your specific story, I think a MVC-design would be a nice solution.
MVC meaning Model View Controller.
Here you have your Model, classes holding different forms of data.
Your Controller, controls your Model, contains all the real logic.
And your View, this is the graphic end of your application.
You'd probably want to put and instance of your player in your engine as well. That way your engine will control everything (the player and the map). Hope that helps!
From what you described there a few possible ways to handle this. One would be to use a messaging system. I would look into Java Messaging Service (JMS). Another would be to make your app event drive. Here is a neat little tutorial on how to do this using spring : https://spring.io/guides/gs/messaging-reactor/. Having said that, if your intent is get a better understanding of problem solving using Java, I would first try and mimic these two approaches on your own, without any bulky frameworks.
How would I be able to do this? I plan on having a class with every single image in my game, and then using that to carry out what i need done in each class. I don't need code, a simple answer is fine (Code would be appreciated though).
Hey guys I'm new to programing and I'm just gettin into UI design.
There are some things I've gotten so far, like I should only use a JFrame per application and other guidelines like that. What I don't understand is... what is the proper way to join your business logic with the GUI?
What I mean is, let's pretend I've just created an application that runs on console (or whatever), and I want to create a GUI for it, so, I've seen on the net that people create a JForm-derived class as a main class and that's it. But is this the proper way? I would like to keep my original "Main class" (the class that uses every other class I've created for my project) and define the form as a field of it, something like that.
Is it possible? If so, how can I achieve this? I have all my logic on that main class I just talked you about, so when I instantiate the form inside of it, I don't know how to make the form use and alter the fields and use the methods I defined in the main class (Sorry if I'm not making myself clear).
How you do, experienced people, do it? What is the "good practice" way? Thanks for taking your time and sorry if it's a noob question.
I'm no professional but I can't stand working with JFrames and Graphics objects.
Most of the time I use the lwjgl library. I know this library is for games but It is
great for UI's as well. The reason it is so easy is because you simply give buttons their
X and Y coordinates without having to worry about layouts. You can make your own images and
import them easily, so if you want your button to look like an image you created no problem.
Because it is made for games it is also very fast and fluid.
This may not be the best way but it works for me so I thought I would share anyway.
Hope it helps.
Here is the lwjgl website: http://www.lwjgl.org/
Here is a video series that helped get me started: http://www.youtube.com/watch?v=0v56I5UWrYY&feature=c4-overview-vl&list=PL19F2453814E0E315
Paranaix already mentioned in his comment about the model - view - controller architecture.
I mostly construct Java Swing GUI applications.
I build the model first. This could be considered a "first cut", since I update the model as I construct the view.
Next I build the view. I construct all of my Swing components by hand. I find that GUI builders harm more than they help. Building the view usually causes me to modify the model.
Finally I construct the controller.
Here's a more detailed description of how I put together a dice game from my blog.
I'm having a bit of trouble figuring this out so if you can help that would be great.
I have written a bit of code that gets a list of URLs from a sitemap. I then go each page, scrape all the links, and then test their status(200,404, etc).
I am using HttpClient. I have it all working OK but as I am new to Java I reckon my code is a complete hack/maze and I could most likely get far better performance if it was organised correctly. So what I have is
Main class - This builds the gui
Parse the sitemap class - This parses the sitemap and get a list of the urls.
Class called PingURl - I'm sure my above is poor but this is the bit I reckon is worst. This class opens all the urls, scrapes them for links, then tests the links for their status and returns it. I presume this class should be broken down? Most importantly I think I should be isolating the testing of the links in it's own class, so it would be easy to implement threads later on?
Basically I'm looking for advice. If someone could help me with laying out the project a bit better. Secondly I believe this is my weakest area so to improve I need to learn more about this, I don't even know what to call this(design/layout problem?). Can you also recommend resources to learn more about this?
Java is a language which IMO, embodies good OO design. Designing with OO in mind is very effective.
http://java.sun.com/developer/onlineTraining/Programming/BasicJava2/oo.html
In terms of your problem, I think it works pretty well. You are kind of following a Model-View-Controller pattern: http://www.codinghorror.com/blog/2008/05/understanding-model-view-controller.html
I can't tell you how to design your code, but I will tell you how I would do it if I were presented with the same problem:
I would get a class to represent a hyperlink. In that class there would be the hyperlink that has been scraped, and a getter and setter. As well as a boolean value and a ping function. That means that if I create a "hyperlink" object, then I can invoke ("ping") on that object because it is part of that class. That means that the ping function simply sets the boolean that represents connectivity.
That way, your parser basically gets a page, and for each link it finds, it creates a new "hyperlink" object based on your own "hyperlink" class. And puts it in an array. So once your parser executes you get an array of pointers to hyperlinks.
Then all you have to do is invoke the ping function on each one to see if it is there.
I think this design is the best because it scales from doing one hyperlink test to doing 1000 quite easily.
There is soooo much stuff out there about design, there are countless principals as well. There is never one absolute way to solve a problem. But the more experience you get, and the more you read up on design patterns and models the better you will get at it :)