Use of Scanner class for keyboard input in Java programs. Your email address will not be published. Save my name, email, and website in this browser for the next time I comment. Method Description nextBoolean Used to read a boolean value from the user nextByte It is used to read a byte value from the user nextDouble to read a double value from the user nextFloat for reading a float value from the user nextInt It is used to read a int value from the user nextLine Use this method to read a String value from the user nextLong We use it to read a long value from the user nextShort It is used to read a short value from the user.
Iconic One Theme Powered by Wordpress. Used to read a boolean value from the user. It is used to read a byte value from the user. Do you see issues with this article? Let us know. Input and Java When learning how to program computer games in Java, the input aspect of the program can cause a lot of trouble. The following image shows what is going on: The problem is, when the callback happens, you are now in some mystery thread. KeyEvent; import java. The reason for this is to have three states instead of two: Pressed , Released , and Once.
Pressed means the key is down, Released means the key is not down, and Once means that the key is down for the first time. To clarify, if the key was not down last frame and is down this frame, keyDownOnce will return true. On the next frame, if the key is still down, keyDownOnce will return false. Also note that the poll method and the KeyListeners are synchronized. Because this class is used from the main game thread and the mystery keyboard input thread, it is important to protect the shared currentKeys array.
Again, the difference between keyDown and keyDownOnce is this: keyDownOnce will only return true the first time the key is down, while keyDown will return true the entire time the key is down. GREEN ; g2d. Point; import java.
MouseEvent; import java. MouseListener; import java. BufferStrategy; import java. BufferedImage; import java. Vector; import javax. MouseMotionListener; import javax. There may still be times that you want absolute movement, such as configuring game options.
If relative is turned on, the mouse is re-centered right away so that the first delta calculations are set to zero. Notice that the delta position is reset each time the mouse is polled. This way if the mouse has been moved more that once, all the delta movements are accumulated until the program has a chance to poll again. If you are using relative mouse input in a full-screen application, then you should pass in the JFrame to the mouse input class. However, if you have a windowed application and you have used a Canvas to force the window size, pass in the Canvas object.
I had weird things happen when I did this with a windowed application and I passed in the JFrame. The reason for this is that whatever Component is passed into the constructor is used to calculate the coordinates for re-centering the mouse. If you are using the JFrame to re-center the mouse, but you have used a Canvas object to force the size of the window, then the mouse movements actually come from the Canvas , not the JFrame.
Since the centers are not the same for both objects because of the title bar and window resizing borders, the delta calculations will be incorrect.
Other than that, this wraps up the new methods in the MouseInput class. BufferedImage; import javax. WHITE ; g2d. Cancel Save. Latest Comments. Nobody has left a comment. You can be the first! You must log in to join the discussion. Covers building a polling interface for detecting input states. Myopic Rhino. Input they say, is captured by a seperate thread which Java has automatically spawned upon execution of the program.
That, in order for it to be processed the thread which I manage must be slept or at least a sleep 0 must be made or input won't ever get through. However, from what I can tell this is not true. Regardless of whether or not I sleep my thread I still receive and process input. Note I am implementing KeyListener.
Is this a result of Java halting my thread so that the code to handle key events can be run? I would appreciate some gritty details as to how input actually works in Java, and how it should properly get processed in a game loop. Since many people seem to program their game loops very differently depending on whether they are making a 2D or 3D game, please provide me with answers that apply to working with a 3D game.
Cancel Save. CaptainJester You do not need to start a new thread to use sleep. When your program starts, you are already in a thread, which can be put to sleep. Lend your shoulders to building the future! Thanks for the reply, you have answered my questions. This topic is closed to new replies. Josheir Internship Possibility Games Career Development.
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