Arduino and Processing code error "disabling_serialevent()"

You have to surround your serialEvent method body in try-catch:

void serialEvent (Serial myPort) {

  try {
    ...
    your code
    ...
  }
  catch(RuntimeException e) {
    e.printStackTrace();
  }

}

There is probably an exception thrown from your serialEvent implementation.

Put your code inside the draw() function, and just use serialEvent() to change the value of variables (remember to initialize them).

Make inStr a global variable. You can define its length and initialize it maybe with 0.

It should be something like:

import processing.serial.*;

Serial myPort;        // The serial port
int[] inStr = {0, 0};

void setup () {
  size(1043, 102);
  background(255);
  myPort = new Serial(this, Serial.list()[1], 9600);
  println(Serial.list());
  myPort.bufferUntil('\n');
}

void draw () {
  fill(0);
  rect(10, 2, inStr[0], 46);

  rect(10, 52, inStr[1], 46);

  fill(255);
  rect(400, 14, 245, 21);

  fill(0);
  textAlign(CENTER);
  textSize(14);
  text("1st value: " + inStr[0] + " 2nd value: " + inStr[1], width/2, 30);
}

void serialEvent (Serial myPort) {
  String inString = myPort.readStringUntil('\n');
  if (inString != null) {
    inString = trim(inString);
    inStr = int(split(inString, '-'));
    println(inStr);
  }
}

In the future, try not to use serialEvent to do the work of draw().

// At the top of the program:
float xPos = 400; // Horizontal position of the graph
float yPos = 300; // Vertical position of the graph
float zPos = 300;
float regiypos = yPos;
float regizpos = zPos;
int par = 5;

import processing.serial.*;
Serial myPort;        // The serial port

int lf = 10;    // Linefeed in ASCII
String myString = null;
float num;

void setup () {

  size(800, 600);        // (Width, Height) window size

  myPort = new Serial(this, "COM4", 115200);

  background(#081640);
  noLoop();  //-- Ne fussál folyamatosan
}

void draw () {
  // Draw the line in a pretty color:
  stroke(#A8D9A7);
  line(xPos-par, regiypos, xPos, yPos);  // (x1, y1, x2, y2) Origó a bal felső sarokban
  regiypos = yPos;                       // ami most új volt azt megőrzi, hogy legyen mivel összekötni

  stroke(#ff00A7);
  line(xPos-par, regizpos, xPos, zPos);
  regizpos = zPos;

  // At the edge of the screen, go back to the beginning:
  if (xPos >= width) {
    xPos = 0;
    // Clear the screen by resetting the background:
    background(#EDA430);
    background(#081640);
  }
  else {
    // Increment the horizontal position for the next reading:
    xPos += par;
  }
}

void serialEvent (Serial myPort) {  // -- Nem fut folyamatosan, hanem csak akkor ha adat érkezik, mert akkor meghívodik ez a fv.

  // Get the byte:
  //   float inByte = myPort.read();
  //   print it:
  //   println(inByte);
  myString = myPort.readStringUntil(lf);
  if (myString != null) {
    print(myString);  // Prints String
    String[] q = splitTokens(myString, ":");
    if (q.length == 2) {
      print(q[0]);  // Acceltoroll print
      print(q[1]);  // Gyrotoroll print

      num = float(q[0]);  // Converts and prints float
      yPos = height/2 - num;
      num = float(q[1]);  // Converts and prints float
      zPos = height/2 - num;
      redraw();             // -- Melynek a végén van a redraw() parancs, mely egyszer lefutattaja a draw()-ban lévő részt.
    }
  }
}

And the highlighted part is this:

if (q.length == 2) {

  print(q[0]);  // Acceltoroll print
  print(q[1]);  // Gyrotoroll print

  num = float(q[0]);  // Converts and prints float
  yPos = height/2 - num;
  num = float(q[1]);  // Converts and prints float
  zPos = height/2 - num;
  redraw();           // -- Melynek a végén van a redraw() parancs, mely egyszer lefutattaja a draw()-ban lévő részt.
}

This will solve your problem. The problem is that q1 may not exist if the buffer is full and begins to overwrite the data...

Just paste the code to Notepad++ to get a better view.