Gadgetory

if you want to create a game for Androids there's plenty of different ways you can go about it probably the most official way though is to build a game yourself from scratch using Java in Android studio I'm going to go over how to create a very basic engine or show a sprite that bounces around the screen and from there you can build on that create a game or any other project that you're interested in put on the kettle and let's give it a shot okay so I'm going to assume for now so you've got Android studio already installed so go ahead load that up and you're going to create a new project I come with mine a 2-d game you can call yours whatever you want but select an empty activity because you don't need all that extra flux the fabs button etc all that xui just gets in the way when you're playing game so once you're in we're going to make a few changes right away first you're going to change at contact activities to just activity now we're going to make the game fullscreen you might be used to working with apps that use an XML script to find the layout and position as of youth we're not using one of those so you're going to change the line that reads step content views to new game view rackets this okay so what this is referring to is a class that we're going to build ourselves because 2-d game development requires two things that you might not be familiar with yet that's a thread and a canvas so a thread is like a parallel fork in your program that can run at the same time this allows you to do multiple tasks at once without slowing things down and without having to queue things up sequentially so we can handle our game code and show our graphics whilst doing other stuff and with next slow down at the same time the canvas is going to be what we show our graphics on this is basically just much like a canvas in the real world this is the surface that we can draw on we can put bitmaps on we can draw rectangles all sorts of stuff so we're going to create a class for each of those and the thread is going to run the canvas therefore we're able to update the graphics without slowing anything down the surface holder the surface view is what will hold the canvas you can think about a little bit like an easel okay so with that in mind what we need to create the new classes we're going to start with the canvas or the surface view I'm going to call that game view ok so right click on the apps package name of the window on the left and then choose new class you're going to call this classic game view and where it says superclass enter Android views surfaceview this means you'll be inheriting the methods from the surface view in other words it means that our class will be able to do the same things it needs to be able to do in order to create a surface view surface view is the superclass where it says interfaces right Android you surface holder callback okay so you should have something that looks like this so every class has a constructor and this is what builds the object that the class is designed to build so this is the case it will build abuse by calling the super we are calling the super class which if you recall is surface view and callback allows us to intercept events we're then going to override some of the methods from that class this means that we're taking control of them and so it's up to us what happens when they're called we're going to leave those blank for now okay so leave that to one side to simmer for a moment now we're going to create our other class which is going to handle the thread so right click and make that new class just like last time this class is going to be called main thread and it's going to have the superclass that's correct so once again we need to build a constructor this one's just going to call super which in this case refers to thread so essentially this is like having a script to wash the dishes and then all it does is call dishwasher or a script to wash your clothes and all it does is called white but might be in trouble on the plus the next part is a little more complicated we're overriding a method called run and this is where our main game loop is going to go this loop repeats over and over and on each cycle little rocks of canvas call a methods to update the positions of the characters and elements and then call a method to draw the new image those methods are in game view we're going to be adding them in a moment we need to lock the canvas before we can draw on it because that prevents more than one threads from attempting to draw on it at the same time the sets running methods sets are running boolean which is a variable that can be either true or false and therefore tells the programmer things ready to go we'll be handling that later to the trying catch block is there to handle errors should they arise and Java requires a good deal it'll compile okay so that's good so far now the class creates the surface the canvas and we have a class that creates the threat only problem is that the spread is never started so currently the program doesn't do anything so we need to go back to game view class in order to kick things off we're going to create a new instance of the thread in our constructor remember a class builds an object so the line new main thread will build one new thread for us to run our game in we're going to add code to start the thread in surface created and then we're going to add codes to stop the thread in steps destroyed it can take multiple attempts to stop the thread so we're adding a loop with a try-catch block again and just to save us time later on I'm also adding an empty updates method which is where our calculations will go and I've overridden the draw method which is where we paint our graphics and now the exciting flight can actually run the game and still be built so either plug in your device or set up an emulator and either way click Play pretty exciting it's a blank screen but it's a black screen of possibilities ok so what we really want to do is obviously put some graphics into there so that's what's coming next fortunately that quite easy all we need to do is include some statements in the draw method in our gauges in order to draw onto the canvas this isn't the best way to do it though it's not very memory efficient to be creating new objects in here and it's also not very well organized so the much more effective way to do this would be to create separate classes to handle all the different objects in our game world and this is also much more organized so that when you've got the loads of things going on the screens you have to read through reams of code to see what's happening so that means great news we need another class ok so let's start with a class called character sprites and as you might have guessed I'm going to use that to show our character on the screen so create that new class and then add in this code so this class basically just shows a bitmap I'm going to pass that bitmap from game view so likewise need to add this code to your game view class I'm loading the bitmaps and resources and I'm using an old character sprite from one of my previous games this guy is called BB Isis drawing on all my text books at school you can of course use whatever image you'd like here or you happen to have lying around okay now hit play and you should have fit map on the screen a little bit more impressive most of the best games that have some form of movement and that's often what makes them most enjoyable thankfully this is quite easy to add as well we just need to put in our calculation into the update method so going to add an update method to attach the sprite class and this will be called from the update method in the game view class we're also swap out the fixed coordinates of our bitmap for variables and then we can simply increase Y over time to make our character moves down the screen remember x and y coordinates measured from the left and then from the top okay press the play and now your character walk slowly moves down the screen thrilling okay let's mix things up a bit I'm not going to go into detail but this code makes the sprite bounce around the corners of the screen like there's old windows screen savers that were oddly hypnotizing if you pause and read it free will grab it from the company article you'll see it's fairly logical you can understand what it all does without me having to go into great set click plays and now you should have a sprite that bounces around the corners of the screen to convey all sorts of things this way all you need to do is to put your calculations in the update method and your sprites and your other drawings in the draw method of course the moments isn't so much the game as it is just a sprite that moves around the screen so if you wanted to make it more of a game you probably want to involve player inputs of some sort and thankfully that's pretty easy to handle - all you need to do is over either method in the game view class called on touch event this allows you to grab the coordinates of where the user is touching the screen and from there you can do all sorts of things you could have one of your sprites move towards that point excited move away or if you check the theater user is touching specific graphical elements then trigger an event there you go you have the groundwork laid for a full game obviously is all still quite basic so if you check the article you'll see that I've delved a little bit to help to speed things up and optimize the process I show you how to add an FPS counter your game and how you can cap the performance at a certain speed so it found this interesting guys if you did please consider leaving a like it really helps us out you've got any questions in the comments down below and I'll try and answer them and like I said check out the link in the description if you want the full article and tutorial that includes all of the code and all the step-by-step instructions 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