i want to print to console while waiting for input. Can this be done with multi-threading? If so, i dont know how to multi-thread. I need help!
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Clarify your question. What do you mean by 'print to console while waiting for input'?Alberto Solano– Alberto Solano2014-03-10 13:51:21 +00:00Commented Mar 10, 2014 at 13:51
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'Yes' what? Explain with some pseudocode what you want and show what you have tried to achieve it!Alberto Solano– Alberto Solano2014-03-10 13:56:22 +00:00Commented Mar 10, 2014 at 13:56
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@AlbertoSolano I want to print to the console while using the Scanner class to get input.mid– mid2014-03-10 13:59:08 +00:00Commented Mar 10, 2014 at 13:59
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2 Answers
I am not sure if I understand your question but this is possible solution. There are two new threads created in main method. First read from console and write text back to it and second is only counting down from 50 to 0 and writing to console actual number:
public class App {
public static void main(String[] args) {
new Thread(new ReadRunnable()).start();
new Thread(new PrintRunnable()).start();
}
}
class ReadRunnable implements Runnable {
@Override
public void run() {
final Scanner in = new Scanner(System.in);
while(in.hasNext()) {
final String line = in.nextLine();
System.out.println("Input line: " + line);
if ("end".equalsIgnoreCase(line)) {
System.out.println("Ending one thread");
break;
}
}
}
}
class PrintRunnable implements Runnable {
@Override
public void run() {
int i = 50;
while(i>0) {
System.out.println("Beep: " + i --);
try {
Thread.sleep(1000);
} catch (InterruptedException ex) {
throw new IllegalStateException(ex);
}
}
System.out.println("!!!! BOOM !!!!");
}
}
Comments
use this code:
public class KeyboardInput extends Thread{
Scanner sc= new Scanner(System.in);
@Override
public void run()
{
while(true)
{
sc.hasNext();
}
}
}
Then just call this when you want to start the input:
Thread t1= new Thread(new KeyboardInput);
t1.start();
Now you have a thread that reads inputs while the main thread is free to print to screen
EDIT: be sure to only call the thread once!
1 Comment
Maow
Thread should not be directly inherited, implement Runnable instead and pass it as an argument of Thread's constructor like you attempted here. Furthermore, the second code snippet does not work.