Keyboard input from console

I have a swing GUI application which must show content reflecting to keyboard input.
Input must be readed from System.in. When I type anything in console it works, but when
I switch to GUI then keyboard input doesnt go to System.in. Any ideas how to solve this problem?
Make keyboard input go to System.in while looking the GUI?
Thank you in advance.

I registred JFrame as keydispatcher and everything worked fine, except the fact that every keystroke got catched in dispatchEvent() three times.
What concept am I missing? How to get one occurance of each keyevent?

Similar Messages

Keyboard input or Console Output

I'm self teaching java... I got stuck with one of the exercises that is supposed to demonstrate the basic input and output through entering data on console...
I went about writing the code as:
public class Program2 {
public static void main(final String [ ] args) {
KeyboardInput in = new KeyboardInput () ;
System.out.print ("Type your name: ") ;
It doesn't compile:((((.... it says "KeyboardInput" is not a type...
I would really appreciate if somebody could respond to this silly problem.

For keyboard input from console the program would be
public class Console{
public static void main(String[] args){
    try{
      BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
      System.out.print("Enter Your Name: ");
      String name = reader.readLine();
      System.out.println("Your Name is "+name);
    }catch(Exception ex){
      ex.printStackTrace();
}

Read Input from console !!!

Im am very new to java and trying to learn java ..
Now the problem i have is, I have to read input from console without using the BufferReader method..
Please tell me how to go about it..
I have a assignment to complete and im not able to figure out the way out.
Help ..

http://java.sun.com/j2se/1.4.1/docs/api/java/lang/System.html
Read first about the System class provided by Java.
Select the 'in' method of System class and it will take
you to the InputStream.
http://java.sun.com/j2se/1.4.1/docs/api/java/io/InputStream.html
An essay way of reading input is:
"value?"=System.in.read();
Try and see if this works. It will not use the
BufferReader portion, but it gives you another way
of reading from the console.

Keyboard input from numbers 1-0 not recognized

On my ibook G4 which I recently started using again, I've noticed that now all input from the "number bar", that is, digits one through zero, is not recognized, that is, it's as if I weren't pressing it at all. I've gone through system preferences, reset everything to default, and I've even done three separate PMU resets, but to no avail. Curiously, all the F keys function. I have access to some number input with the "number lock" feature, but any number that resides on the actual number bar like seven eight or nine cannot be entered. I have no problem with ~, -, +, or delete, either. Any help to point me in the right direction would be greatly appreciated.

Hey Danger and Welcome to Apple Discussions,
It sounds like the horizontal trace that links the numbers together has developed an open. I know of no way to repair this and the solution would be a replacement keyboard. Verify the problem isn't software related by plugging in a USB keyboard and checking function.
Richard

Capturing keyboard Scancodes from console

Hello,
I had tried captuaring what would be the scan code for left arrow by using Java.I used the System.in.read().but that did not help.
If some one is aware of how to get these scancodes from the console in Java,please let me know about that.
Thank you.

I fear this is not possible. The left arrow appears to be interpreted by the JVM as though you wish to move your input cursor one space to the left.
The way mine is working is the JVM won't actually send the input data, through System.in to the application code, until I enter a newline (hit enter). If I type "123<enter>" I get the three ascii codes for the numbers 1, 2, and 3, plus the linefeed (a 10). If I type "123<leftarrow><enter>", the JVM only passes in a 1 and a 2, along with the linefeed.
Perhaps someone has more insight on how the console input works, and whether there are any hooks or setting we can futz with to change its behavior.
Scan codes are of course very simple to get when dealing with AWT/Swing, by listening for key events, then interrogating the event data. But that's not a solution to this.

Doubt getting i/p from KeyBoard (Not from console)

Hi Techies,
I want to know that how to get the i/p from KeyBoard always ant to store it in txt file (i know the getting i/p and store it in file --basic concepts) .
My java code want to do the background process (always get the i/p from Kb and store it in file )
If i'm working in different applications ,my java code should work (get the typed charac from KB and store it in file ) what is the way to solve this
Urgent

hi tsith
Is they have any way to solve this using JVM
you will likely need to write something closer to the
platform you want this key logger to run on. Java's
JVM makes writing code that deals with other
processes difficult.
Good Luck
Lee

Thunderbird 24.6.0 suddenly stops accepting keyboard input in the middle of typing a message

On a system running Debian Testing (kernel version 3.13.10-1), at times Thunderbird 24.6.0 suddenly stops accepting keyboard input in the middle of typing a message. Some times, it will not accept keyboard input from the time a new message window opens (both from click Write or Reply).
Regardless of when the problem starts, I can still copy text from another source and paste it into the message, and I can still send the message.
Sometimes, the problem will clear up itself after a few minutes, meaning I can suddenly start typing in the open message window, but sometimes not, and I will have to close the message window and restart Thunderbird or reboot the system.

Tasks: 290 total, %Cpu(s): 1.0 us, KiB Mem: 8101216 total, KiB Swap: 8388604 total, PID USER 9498 pete 1207 root 7904 pete 7349 pete 7539 pete 7670 pete 7793 pete 7845 pete 7877 pete 9666 pete 22931 pete 1 root 2 root 20 0 3 root 20 0 5 root 0 -20 7 root 20 0 8 root 20 0 9 root rt 0 10 root rt 0 11 root rt 0 12 root rt 0 13 root 20 0 15 root 0 -20 16 root rt 0 17 root rt 0 18 root 20 0 20 root 0 -20 21 root rt 0 22 root rt 0 23 root 20 0 25 root 0 -20 26 root 0 -20 27 root 20 0 28 root 0 -20 29 root 0 -20 30 root 0 -20 31 root 0 -20 32 root 0 -20 34 root 20 0 35 root 20 0 36 root 25 5 37 root 39 19 38 root 20 0 39 root 0 -20 44 root 0 -20 46 root 0 -20 86 root 0 -20 88 root 20 0 89 root 20 0 90 root 20 0 1 running, 242 sleeping, 47 stopped, 0 zombie
0.3 sy, 0.0 ni, 98.2 id, 0.4 wa, 0.0 hi, 0.0 si, 0.0 st
6406932 used, 1694284 free, 46440 buffers
280476 used, 8108128 free. 2714812 cached Mem
PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
20 0 905252 171068 60844 S 4.3 2.1 0:36.22 chrome
20 0 301372 31896 12592 S 1.0 0.4 40:04.04 Xorg
20 0 796904 75304 25496 S 1.0 0.9 0:54.16 chrome
20 0 1215536 345724 116416 S 0.7 4.3 3:29.51 chrome
20 0 879076 128096 26512 S 0.7 1.6 1:51.35 chrome
20 0 826900 70488 23812 S 0.7 0.9 0:13.12 chrome
20 0 872564 135004 68628 S 0.3 1.7 0:13.74 chrome
20 0 811680 80360 23580 S 0.3 1.0 0:06.61 chrome
20 0 812032 79888 23668 S 0.3 1.0 0:08.91 chrome
20 0 23796 1808 1136 R 0.3 0.0 0:00.01 top
20 0 1094964 186504 22808 S 0.3 2.3 14:28.61 thunderbird
20 0 193016 2860 1260 S 0.0 0.0 0:03.67 systemd
0 0 0 S 0.0 0.0 0:00.02 kthreadd
0 0 0 S 0.0 0.0 0:22.21 ksoftirqd/0
0 0 0 S 0.0 0.0 0:00.00 kworker/0:0H
0 0 0 S 0.0 0.0 1:09.66 rcu_sched
0 0 0 S 0.0 0.0 0:00.00 rcu_bh
0 0 0 S 0.0 0.0 0:00.34 migration/0
0 0 0 S 0.0 0.0 0:00.58 watchdog/0
0 0 0 S 0.0 0.0 0:00.58 watchdog/1
0 0 0 S 0.0 0.0 0:00.01 migration/1
0 0 0 S 0.0 0.0 0:13.05 ksoftirqd/1
0 0 0 S 0.0 0.0 0:00.00 kworker/1:0H
0 0 0 S 0.0 0.0 0:00.50 watchdog/2
0 0 0 S 0.0 0.0 0:00.02 migration/2
0 0 0 S 0.0 0.0 0:04.84 ksoftirqd/2
0 0 0 S 0.0 0.0 0:00.00 kworker/2:0H
0 0 0 S 0.0 0.0 0:00.52 watchdog/3
0 0 0 S 0.0 0.0 0:00.03 migration/3
0 0 0 S 0.0 0.0 0:11.02 ksoftirqd/3
0 0 0 S 0.0 0.0 0:00.00 kworker/3:0H
0 0 0 S 0.0 0.0 0:00.00 khelper
0 0 0 S 0.0 0.0 0:00.00 kdevtmpfs
0 0 0 S 0.0 0.0 0:00.00 netns
0 0 0 S 0.0 0.0 0:00.00 writeback
0 0 0 S 0.0 0.0 0:00.00 kintegrityd
0 0 0 S 0.0 0.0 0:00.00 bioset
0 0 0 S 0.0 0.0 0:00.00 kblockd
0 0 0 S 0.0 0.0 0:00.11 khungtaskd
0 0 0 S 0.0 0.0 3:41.37 kswapd0
0 0 0 S 0.0 0.0 0:00.00 ksmd
0 0 0 S 0.0 0.0 0:00.00 khugepaged
0 0 0 S 0.0 0.0 0:00.00 fsnotify_mark
0 0 0 S 0.0 0.0 0:00.00 crypto
0 0 0 S 0.0 0.0 0:00.00 kthrotld
0 0 0 S 0.0 0.0 0:00.00 deferwq
0 0 0 S 0.0 0.0 0:00.00 ata_sff
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Send a keyboard event from labview to C#

Hi,
We currently have a program in c# that takes keyboard inputs from a user and will fly a quadrotor. We aim to have a LabView .vi generate keyboard commands based on our experiment and send the commands to the c# code creating a feedback loop where the .vi will keep track of sensor and experimental data.
Our problem is that we have tried many different methods to send the keyboard commands in LabView.
1) http://zone.ni.com/devzone/cda/epd/p/id/3711
2) http://forums.ni.com/t5/LabVIEW/Send-keyboard-commands-to-another-windows-program/td-p/330670/page/2
as well as other variations and similar .vi's that do the same thing. Here is an example of a .vi used to press the letter "t" once.
http://i.imgur.com/hwmjZ.png
All of them can write the string to a text (open notepad put cursor in blank window) file but none can do it in such a way that it is detected by the c# code. On my own I can open and run the c# code and press keyboard buttons myself and the commands are recognized, so I think it could be an issue with how LabView sends the keyboard events and how c# reads them. Here is the c# code segment that we are using to read the input commands:
public override List<String> GetPressedButtons()
KeyboardState state = device.GetCurrentKeyboardState();
  List<String> buttonsPressed = new List<String>();
  foreach (Key key in Enum.GetValues(typeof(Key)))
      if (state[key])
          if (!buttonsPressed.Contains(key.ToString()))
              buttonsPressed.Add(key.ToString());
  return buttonsPressed;
Can anyone help trying to figure out why using the keybd_event function in LabView can not interface correctly with the above detection code in c#? I can provide any code and clarification if you think it can be helpful.
Thanks,
Andy

Hi,
I can't say with certainty where the problem is or even how many there are. I do know that the KeyboardListener.cs class should work according to what I have read online. I also know that if I press the keyboard myself then the state is changed and the correct action is taken. If I try to issue an event from Labview then the event is not captured. Here is the code, it is rather large ~20 MB.
https://www.dropbox.com/s/vsvcje1ro364otu/ARDrone.zip
https://www.dropbox.com/s/p3h3tj8bcqc29gk/Forward_backward0924.vi
The key listener is in ARDroneInput>Utils>KeyboardListener.cs and the polling takes place in ARDroneInput>KeyboardInput.cs
The reason I wanted to use keyboard inputs is because the quadrotor we are using takes keyboard commands W,A,S,D,T and L. Initially I thought having Labview issue these commands would be the simplest method. That may not be the case.
I was just thinking that it is not necessary that key events are sent from Labview. Instead, one could send an array representing the frequency of each button press rather than the button press directly. In that case an array that is updated continuously from Labview will just have to be kept track of in the C# code. The C# can then convert that to whatever control input we want. Can it be easier to send a vector of numbers in real time to C#?
If you think it is better to establish a connection between Labview and C# using .NET to send keyboard commands (rather than the vector idea above) can you explain that a little more? How does one go about doing that? If you think the vector idea is simpler how should the interface be set-up?
I just talked with my collegue and we think that maintaing a .txt file in Labview and having C# read it is the best option. We will begin working on that and will update you tomorrow.
Thanks,
Andy

Automatic keyboard input

I have a pre-packaged program (an installer) that when it is run, it comes to points where it needs keyboard input from the user.
"Choose one of the choices:
1 - do this
2 - do that
3 - do something else"
waits for input
User: "1"
continues on
Is there a way of emulating that user input so that a java program that runs the installer could input the keyboard information to the installer without any user input. In other words, I want a java program to run the installer from start to finish without any user intervention.
I don't have access to the installer so there isn't the option of changing the installer (and even if I did, I wouldn't have it as an option).

this question has been asked a million times
search the forums first for general how-to questions like this
include Robot in your search

Keyboard Input Sans Keyboard

I'm looking for the most simple program that will let me do keyboard input from a bash script. (or if library I can write a quick script with). Being able to move the mouse as well is also desired, or a seperate program/library for that.
Thanks.
Last edited by Mardoct (2010-06-12 21:14:16)

Im not sure what you want? Do you want to simulate keypresses in an X environment?

Getting input from textbox as "console"

Hi all. I am learning C# and have a Windows forms project that I am working on to learn various techniques. Basically it has a text box that I use to mimic a console. The user enters a command followed by the Enter key and the program reads that in and interprets
it. I also have some rudimentary "batch" commands, such as IF/THEN, INPUT and PRINT.
The application has two main components: The form and a class. The form takes care of interpreting the commands that the user enters and the class implements the three batch commands (more to follow in the near future). The issue that I am having is that
sometimes (maybe 2%) the INPUT functionality does not work. When I enter a string and press Enter an empty string is returned. I have tried to debug this as much as I can, but it is difficult since this problem only happens once in a while.
I have extracted the INPUT functionality and duplicated it in a simple app which I present here. The test app contains one button called btnConRead and a multi line text box called txtConsole. Clicking the button "forces" the app into "run"
mode where the batch commands are interpreted. For this example I run the code that runs when an INPUT command is being processed. The app prompts with "OK" and waits for the user to type something in. When the user presses the Enter key the entered
string is echoed on the console. The form module contains this code:
string sKBBuf = ""; //App wide KB buffer when form Key preview is enabled.
bool bEnter;
private delegate void DisplayMsgDelegate(string sMsg);
private void cEventPrint(object sender, PrintDataEventArgs e)
Display(txtConsole, e.sPrintLine);
private void cEventRead(object sender, ReadDataEventArgs e)
//Event that reads text from the console and returns it.
//This event requires input from the user. It traps the program here until the user
//presses Enter.
//Clear the KB buffer.
sKBBuf = "";
//Loop incessantly until user presses Enter key or Stop key (s).
do
//Braindead.
} while (!bEnter);
if (bEnter)
//User pressed the Enter key, return the KB buffer.
e.sReadLine = sKBBuf;
//Empty buffer.
sKBBuf = "";
//Reset Enter key flag.
bEnter = false;
//Push CRLF to console.
Display(txtConsole, Environment.NewLine);
private void DisplayMsg(string sMsg)
txtConsole.AppendText(sMsg);
private void Display(TextBox txtOutput, string sMsg, bool bToCon = true)
//Check output to console flag.
if (bToCon)
if (txtOutput.InvokeRequired)
txtOutput.Invoke(new DisplayMsgDelegate(DisplayMsg), sMsg);
else
txtOutput.AppendText(sMsg);
private void GetConInput()
clsExample cEx = new clsExample();
cEx.ReadData += cEventRead;
cEx.PrintData += cEventPrint;
System.Threading.Thread runThread = new System.Threading.Thread(() =>
cEx.Process();
this.KeyPreview = false;
this.KeyPreview = true;
runThread.Start();
private void btnReadCon_Click(object sender, EventArgs e)
//Prep stuff
sKBBuf = "";
txtConsole.Focus();
Display(txtConsole, "OK" + Environment.NewLine);
//Read console textbox
GetConInput();
private void Form1_KeyPress(object sender, KeyPressEventArgs e)
bEnter = e.KeyChar == 13;
//Save to buffer. At this time I am not distinguishing from letter or digits.
//But I do need to check for a BS.
if (e.KeyChar == 8)
//Yeah, BS, remove the last char, if any.
if (sKBBuf.Length > 0)
sKBBuf = sKBBuf.Substring(0, sKBBuf.Length - 1);
else
sKBBuf += e.KeyChar;
The class is called clsExample and contains the following code:
//Event raised when data needs to be printed to console.
public event EventHandler<PrintDataEventArgs> PrintData;
//Event raised when data needs to be read from console.
public event EventHandler<ReadDataEventArgs> ReadData;
protected virtual void OnReadData(ReadDataEventArgs e)
EventHandler<ReadDataEventArgs> handler = ReadData;
if (handler != null)
handler(this, e);
protected virtual void OnPrintData(PrintDataEventArgs e)
EventHandler<PrintDataEventArgs> handler = PrintData;
if (handler != null)
handler(this, e);
public void Process()
ReadDataEventArgs argsRead = new ReadDataEventArgs();
PrintDataEventArgs args = new PrintDataEventArgs();
string sMsg = "";
//Get input from user.
OnReadData(argsRead);
if (argsRead.sReadLine.Length > 0)
//I have something
sMsg = argsRead.sReadLine;
else
//No data
sMsg = "*";
args.sPrintLine = sMsg + Environment.NewLine;
OnPrintData(args);
Plus two more support classes for the Print and Read events:
public class PrintDataEventArgs : EventArgs
public string sPrintLine { get; set; }
public class ReadDataEventArgs : EventArgs
public string sReadLine { get; set; }
All the above was necessary so that the Process procedure running in a different thread could interact with the UI elements in the main form. The above mostly works, but I wonder if I am doing it the right way. I don't particularly like the use of
global flags, such as bEnter or having empty loops to just "kill" time, such as the one found in the cEventRead procedure.
In the cEventRead procedure I had the if() block immediately following the empty loop inside
the loop and moved it out of there to see if this made any difference, but apparently it did not. Can anyone provide any feedback or suggestions of what I could change to make it work 100% of the time? I appreciate your time and effort. Thank you, Saga
You can't take the sky from me

Hi all. I am learning C# and have a Windows forms project that I am working on to learn various techniques. Basically it has a text box that I use to mimic a console. The user enters a command followed by the Enter key and the program reads that in and interprets
it. I also have some rudimentary "batch" commands, such as IF/THEN, INPUT and PRINT.
//Loop incessantly until user presses Enter key or Stop key (s).
do
//Braindead.
} while (!bEnter);
Hi Saga,
Please don't use such kind of loop in your code, if you want to monitor the user input, just use the KeyPress event provided by the TextBox control.
Control.KeyPress
Event
If you just want to execute some standard commands, I recommend that you use
Process to start cmd.exe to execute the command, for example:
void ExecuteCommand(string command)
int exitCode;
ProcessStartInfo processInfo;
Process process;
processInfo = new ProcessStartInfo("cmd.exe", "/c " + command);
processInfo.CreateNoWindow = true;
processInfo.UseShellExecute = false;
// *** Redirect the output ***
processInfo.RedirectStandardError = true;
processInfo.RedirectStandardOutput = true;
process = Process.Start(processInfo);
process.WaitForExit();
// *** Read the streams ***
string output = process.StandardOutput.ReadToEnd();
string error = process.StandardError.ReadToEnd();
exitCode = process.ExitCode;
Console.WriteLine("output>>" + (String.IsNullOrEmpty(output) ? "(none)" : output));
Console.WriteLine("error>>" + (String.IsNullOrEmpty(error) ? "(none)" : error));
Console.WriteLine("ExitCode: " + exitCode.ToString(), "ExecuteCommand");
process.Close();
If it's powershell script, you can also use the existing library to execute it, check this blogpost:
Executing PowerShell scripts from C#
We are trying to better understand customer views on social support experience, so your participation in this interview project would be greatly appreciated if you have time. Thanks for helping make community forums a great place.
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Keyboard shortcuts from Greek Input not working for my account only

I just upgraded to Leopard from Tiger 10.4.11 on my MBP 2.4 listed below. The Installer took care of everything, and after it was finished, my own account, the only Admin account, misbehaves when it comes to keyboard shortcuts in the Finder or any other app. To use the shortcuts, the Input flag must US English. If it's Greek, nothing works.
If I switch to the other two accounts on my Mac, one of which was carried over from the Tiger setup, the other I setup after the OS upg, both of which are Std accounts, not Admin, shortcuts work regardless of the keyboard input flag.
Tips, anyone?

That's alright, folks, problem solved:
Ran Leopard Cache Cleaner, and selected from Caches the third option (deep clean).
Thanks, anyway. Hope this may help some other poor sod.

How to read input from handheld scanner on a keyboard port

Hi everybody,
i have an application that should read input from a scanner.
If i use a jTextField to input scanned data it works fine.
the problem is that i don't want to use any text component to input data into it.
And if i set the jtextField not visible then the focus sustem doesnt work.
I tried to read a buffered input stream from System.in but it doesnt work.
If the scanner was installed on a serial port i could use javax.comm to monitor it.
But unfortunately i must use the keyboard wedge thing...
Do you have any ideas?
Thank you in advance

BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()))
null

Inputting from the keyboard

hi everyone, can anyone help me on how to read what the user inputs from the keyboard when running a program in command-line(ms-dos prompt)interface.Does it have something to do with System.in any help would be appreciated.
(Example)
System.out.println("Please enter your name ");
String name = //capture the name in string
System.out.println("Enter your choice");
int choice = //capture what the choice is
System.out.println("your choice is "+ choice);
}

Modified version of example code in working test file.
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;
//Class
public class KeyBoardInput
//data members declared static
static BufferedReader buff = new BufferedReader(
new InputStreamReader ( System.in) );
static String buffin;
//main method
public static void main ( String[] args )
    int test = readInt("enter a number");
    System.out.println("you have entered " + test );
//reads strings and converts to integers
public static int readInt( String prompt )
        try
     System.out.println(prompt);
        buffin = buff.readLine();
        buff.close();
     catch (IOException IoE) {}
        return Integer.parseInt ( buffin );
//needs work
public static String readString( String prompt )
     //?? need to work on this one
}

Can anyone explain to me why sometimes my ipad2 locks up and won't respond to any input from the keyboard.

My iPad 2 locks up sometimes and won't respond to any input from the keyboard. Have to reboot in order to fix the problem.

You have 3 choices:
1. Do a reset (Hold Sleep/Wake and Home buttons about 10 secs or more till Apple logo appears, ignore the Slide to Power Off that appears)
Note: You will not lose any data.
2. Restore from backup using iTunes
3. Restore as new without the backup

Keyboard input from console

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