Error: A null PFont was passed to textFont()

Core Library Questions

mayenco

Error: A null PFont was passed to textFont()

in Core Library Questions • 1 year ago

Hello members.

I'm new in Processing and with Tutorials, Onlinesketches etc. I've created a sketch which shows rss feed lines, if you clap your hands or do a loud sound. Since I've pasted the code of a drop down menu in it, I get the error: A null PFont was passed to textFont().

The code includes two Fonts "Arial-BoldMT-22.vlw" and "ArialMT-22.vlw" as well as two png-Pictures "logo" and "logoklein". You can replace them with whatever you want, just to see how my code works.

The Code is splitted in three menus.

Menu #1:

/**
* Clap to load another RSS Feed, click on the news to move them,
* news fade out after the 20th.
*
* (c) 2012 M. Maier
*/

String s = "";

import ddf.minim.*;

Minim minim;
AudioInput input;

String[] fontList ;
String[] titles;
PFont myfont;
PVector [] positions;
PFont [] myFonts;
int [] myFontSize;
int Anzahl;
boolean fullList = false;
int[] BlockgroesseX;
int[] BlockgroesseY;

PFont fornt, fett;

String [] loadfeeds = {
"http://www.faz.net/aktuell/?rssview=1",
"http://rss.bild.de/bild.xml",
"http://rss.feedsportal.com/795/f/449002/index.rss",
"http://www.welt.de/?service=Rss"
};

int p; //descides a feed in Array "loadfeeds"

XMLElement[] titleXMLElements;
int CurrentTitle = 0;

float klatschen;

PImage Logoklein;
PImage Logo;

boolean startbildschirm;

void setup() {
startbildschirm = true;
size(screen.width, screen.height);
fontList = PFont.list();
minim = new Minim (this);
input = minim.getLineIn (Minim.STEREO, 512);
background(0);
//setzt den Hintergrund im Present-Mode auf Schwarz
frame.setBackground(new java.awt.Color(0, 0, 0));
Logoklein = loadImage("logoklein.png");
Logo = loadImage("logo.png");
setupMainMenu(); // erstelle Drop-Down Menü

fornt = loadFont("ArialMT-22.vlw");
fett = loadFont("Arial-BoldMT-22.vlw");
}

//-----------------------------------------------------------------------
// Main Menu
//-----------------------------------------------------------------------

void setupMainMenu() {
SMenu m=new SMenu(this); // create new main menu (at 0,0)
m.SMSubM("File"); // new submenu
m.SMSubM("Import");
m.SMItem("FAZ", new actn() {
    public void a() {
      p = 0;
    }
}
);

m.SMItem("BILD", new actn() {
    public void a() {
      p = 1;
    }
}
);
m.SMItem("Süddeutsche", new actn() {
    public void a() {
      p = 2;
    }
}
);
m.SMItem("Weltonline", new actn() {
    public void a() {
      p = 3;
    }
}
);

m.SMEnd();

m.SMItem("Close", new actn() {
    public void a() {
      exit();
    }
}
); // overwrite act.a() with own proc

m.SMEnd();

m.SMSubM("Save");
m.SMItem("png", new actn() {
    public void a() {
      s="png clicked";
    }
}
);
m.SMItem("tiff", new actn() {
    public void a() {
      s="tiff clicked";
    }
}
);

m.SMItem("targa", new actn() {
    public void a() {
      s="targa clicked";
    }
}
);

m.SMItem("jpeg", new actn() {
    public void a() {
      s="jpeg clicked";
    }
}
);

m.SMEnd();

m.SMSubM("Help");
m.SMItem("About", new actn() {
    public void a() {
      About();
    }
}
);

m.SMEnd(); // end all with SMEnd()
}

void About() {
fill(50, 200);
rect(0, 0, width, height);
fill(24);
rect(width/2-300, 160, 600, 340);
image(Logoklein, 620, 210, Logoklein.width, Logoklein.height);
strokeWeight(1);
stroke(80);
fill(255, 100);
textFont(fornt);
textSize(12);
text("M. Maier \n2.Semester \nInteraktive Medien \nProfessor Erich Schöls", width/2-260, 320);

fill(255);
text("Snapfeed visualisiert Nachrichten durch Interaktion mit dem Mikrofon.", width/2-260, 430);

ellipseMode(CENTER);
ellipse(width/2+300, 160, 30, 30);
textFont(fett);
if (mouseX > width/2+285 && mouseX < width/2+315 && mouseY > 145 && mouseY < 175) {
    fill(120);
}
}

void draw() {
if (startbildschirm == true) {
    smooth();
    fill(0);
    rect(0, 0, width, height);
    smooth();
    imageMode(CENTER);
    image(Logo, width/2, height/2);
    cursor(HAND);
}
else {

    //-----------------------------------------------------------------------
    // LOAD RSS FEED
    //-----------------------------------------------------------------------

    String url = loadfeeds[p];
    println("Loading feed: "+url);
    XMLElement rss = new XMLElement(this, url);
    titleXMLElements = rss.getChildren("channel/item/title");

    Anzahl = titleXMLElements.length;

    // Arrays für jede Art von Werten
    titles = new String[Anzahl];
    positions =new PVector[Anzahl];
    myFonts =new PFont[Anzahl];
    myFontSize = new int[Anzahl];
    BlockgroesseX = new int[Anzahl];
    BlockgroesseY = new int[Anzahl];

    for (int i = 0; i < titleXMLElements.length; i++) {
      String title = titleXMLElements[i].getContent();
      titles[i]=(new String(title));
    }

    // ********** MENÜ BEFEHLE ******************** //
    stroke(g.fillColor);
    if (s.length()>30) { // draw arrow
      pushMatrix();
      translate(20, 20);
      rotate(PI/4);
      line(15, 0, 135, 0);
      triangle(0, 0, 15, -3, 15, 3);
      popMatrix();
    }

    background(0);
    cursor(ARROW);
    smooth();
    image(Logoklein, width-80, 60);
    klatschen = input.mix.level() * width;

    if (klatschen > 100) {

      //immer wenn geklatscht wird fülle die werte abhängig vom Zähler CurrentTitle

      positions [CurrentTitle] = (new PVector(random(width/2), random(70, height))); // Positionen
      PFont font = createFont(fontList[(int)random(0, fontList.length)], 10);    // Fonts
      myFonts[CurrentTitle] = font;
      myFontSize[CurrentTitle] = (int)random(14, 200);                           // Font Size

      CurrentTitle += 1;

      // wenn CurrentTitle die Maximalanzahl erreicht hat setze CurrentTitle auf 0
      // ab jetzt werden schon vorhanden Werte in den Listen neu überschrieben
      // alle anderen bleiben in der Liste bis sie überschrieben werden
      if (CurrentTitle >= Anzahl) {
        CurrentTitle = 0;
      }
    }

    // solange die Liste noch nicht die maximalanzahl erreicht hat zähle hoch

    if (CurrentTitle < Anzahl && fullList == false)
    {
      for (int j = 0; j < CurrentTitle; j++) {
        int TheTextSize = myFontSize[j];
        textFont(myFonts[j], TheTextSize);
        String newString = titles[j];

        /*
         String[] m1 = match(titles[j], "Altmaier");
         if (m1 != null) {
         fill(farben[1]);
         }
         else {
         fill(255, 85);
         }
         */

        PVector newPosition = positions[j];
        text(newString, newPosition.x, newPosition.y);

        // ermittle die Groesse der Textbloecke
        BlockgroesseX [j] = (int)textWidth(newString);
        BlockgroesseY [j] = TheTextSize;

        // wenn die Maus über einem der Blöcke ist übergebe ihm den Mauswert als Koordinate
        if (mousePressed) {
          if (mouseX > (newPosition.x) && mouseX < (newPosition.x+BlockgroesseX[j]) && mouseY > (newPosition.y-BlockgroesseY[j]) && mouseY < (newPosition.y) )
          {
            println("über String Nummer " + j);
            newPosition.x -= (pmouseX-mouseX);
            newPosition.y -= (pmouseY-mouseY);
          }
        }
      }
    }
    else // wenn sie die Maximalanzahl erreicht hat zeichne das vorhandene und ändere immer nur das was CurrentTitle entspricht (von 0 bis 20)
    {
      for (int j = 0; j < Anzahl-1; j++) {
        int TheTextSize = myFontSize[j];
        textFont(myFonts[j], TheTextSize);
        String newString = titles[j];
        PVector newPosition = positions[j];
        text(newString, newPosition.x, newPosition.y);

        // wenn die Maus über einem der Blöcke ist übergebe ihm den Mauswert als koordinate
        if (mousePressed) {
          if (mouseX > (newPosition.x) && mouseX < (newPosition.x+BlockgroesseX[j]/2) && mouseY > (newPosition.y-BlockgroesseY[j]) && mouseY < (newPosition.y) )
          {
            newPosition.x -= (pmouseX-mouseX);
            newPosition.y -= (pmouseY-mouseY);
          }
        }
      }
    }

    if (CurrentTitle == Anzahl-1)
    {
      fullList = true;
    }
}

/* void keyPressed() {
   if (key=='s') saveFrame("##.png"); //save .png bei keyPressed oder saveFrame("##.tif") oder saveFrame("##.tga")
   }*/
}

void mousePressed() {
if (startbildschirm == true) {
    startbildschirm = false;
    fill(255, 255, 255, random(20, 255));
}
// deaktiviert ihn, wenn man mit Maus klickt
}

Menu #2 (has to be named SMenu.java):

import java.util.ArrayList;
import java.awt.Rectangle;
import java.awt.event.MouseEvent;
import processing.core.*;

public class SMenu extends ArrayList {
static PApplet app; static SMenu actm=null; static PFont font; static actn action=null;
String nam; actn act=null; SMenu m,par; Rectangle r,rm; int vis=-1;
public SMenu(PApplet ap) {this(ap,"Main",0,0);}
public SMenu(PApplet ap,int mx, int my) {this(ap,"Popup",mx,my);}
SMenu(PApplet ap,String s) {this(ap,s,0,0);}
SMenu(PApplet ap,String s,int mx,int my) {
    par=actm; nam=s;
    if (ap!=null) {
      app=ap; actm=this; font=app.createFont("Arial",12);
      app.registerDraw(this); app.registerMouseEvent(this);
      if (nam.equals("Main")) app.mouseY=-1; //to avoid appearing main menu at startup
      rm=new Rectangle(mx,my,0,0);
    } else {
      app.pushStyle(); app.textFont(font);
      if (par.nam.equals("Main")) {
        r=new Rectangle(par.rm.x+par.rm.width,par.rm.y,textW(s),textH(s));
        rm=new Rectangle(r.x,par.rm.y+textH(s),0,0);
        par.rm.width+=r.width; par.rm.height=textH(s);
      } else {
        r=new Rectangle(par.rm.x,par.rm.y+par.rm.height,textW(s),textH(s));
        rm=new Rectangle(r.x+r.width,r.y,0,0);
        par.rm.height+=textH(s); par.rm.width=app.max(par.rm.width,textW(s));
      }
      app.popStyle();
    }
}
public void SMSubM(String s) {
    actm.add(actm=new SMenu(null,s));
}
public void SMItem(String s,actn ac) {
    actm.add(m=new SMenu(null,s)); m.act=ac;
}
public void SMSep() {
    actm.add(new SMenu(null,null));
}
public void SMEnd() {
    actm=actm.par;
    if (actm==null) if (nam.equals("Main")) adjustH(); else adjustV();
}
void adjustH(){
    trimToSize();
    for (int i=0; i<size(); i++) {
      m=(SMenu)get(i);
      m.adjustV();
    }
}
void adjustV(){
    trimToSize();
    for (int i=0; i<size(); i++) {
      m=(SMenu)get(i);
      m.r.x=m.par.rm.x;
      m.r.width=m.par.rm.width; m.rm.x=m.r.x+m.r.width;
      m.adjustV();
    }
}
public void mouseEvent(MouseEvent event){
    if ((vis>=0)&&(event.getID()==MouseEvent.MOUSE_RELEASED)) {
      if (action!=null) {action.a(); action=null;};
      vis=-1;
      if (nam.equals("Popup")) {
        app.unregisterDraw(this); app.unregisterMouseEvent(this);
      }
    }
}
public void draw() {
    app.pushStyle(); app.textFont(font);app.fill(0);
    for (int i=0; i<size(); i++) {
      m=(SMenu)get(i);
      if (m.r.contains(app.mouseX,app.mouseY)) {vis=i; m.vis=999;}
    }
    if (vis>=0){
      action=null;
      app.fill(220,229,234);app.stroke(200);app.rect(rm.x,rm.y,rm.width,rm.height);
      for (int i=0; i<size(); i++) {
        m=(SMenu)get(i);
        if (vis==i){app.fill(210,225,230);app.stroke(180);app.rect(m.r.x,m.r.y,m.r.width,m.r.height);}
        if ((m.act!=null)||(m.size()>0)) app.fill(0); else app.fill(120);
        if (m.nam!=null) app.text(m.nam,m.r.x+10,m.r.y+app.textAscent());
        if ((m.par.par!=null)&&(m.size()>0))
          app.triangle(m.r.x+m.r.width-4,m.r.y+m.r.height/2-3,
                       m.r.x+m.r.width-4,m.r.y+m.r.height/2+3,
                       m.r.x+m.r.width-1,m.r.y+m.r.height/2);
        if (vis==i) m.draw();
        if (m.r.contains(app.mouseX,app.mouseY)) action=m.act;
      }
    }
    app.popStyle();
}
int textW(String s) {
    if (s==null) return(0); else
    return((int)app.textWidth(s)+20);
}
int textH(String s) {
    if (s==null) return(4); else
    return((int)(app.textAscent()+app.textDescent()));
}
}

Menu #3 (has to be named actn.java):

public abstract class actn {
public abstract void a();
}

Can please someone tell me, what creates the error, and maybe fix it, too?

Another problem I have is, when you go in the Dropdown menu to "Help" --> "About", my credit note is shown for only 1 sec. and disappears...

What also would be cool, if the code could be more structured in menus for example. It's hard for me to keep track of the codes.

Replies(11)

calsign

Re: Error: A null PFont was passed to textFont()

1 year ago

Which line of code is highlighted? Does it highlight a line of code at all?
Most likely, one of your (numerous) fonts isn't initialized properly... this could be because you never initialize it with loadFont() or because the font doesn't exist at the path specified.

mayenco

Re: Re: Error: A null PFont was passed to textFont()

1 year ago

The line "textFont(myFonts[j], TheTextSize);" is highlighted.

I wrote the code that way, because I don't want to use only one font. The code searchs via random a font.
Without the dropdown menu, the loadscreen and some other little changes the code worked properly without initializing a font.

calsign

Re: Error: A null PFont was passed to textFont()

1 year ago

Well... your font wasn't initialized properly...
My guess is that is has to do with the fact that you are only initializing one of the fonts...

myFonts[CurrentTitle] = font;

...and then trying to reference all of the fonts from within a loop. I'd have to test your code to be sure, but this looks like what's happening...

mayenco

Re: Re: Error: A null PFont was passed to textFont()

1 year ago

This would be so nice! I'm very desperate because I tried fixing the error for hours, but nothing changed.

calsign

Re: Error: A null PFont was passed to textFont()

1 year ago

That's the problem... the solution depends on how it's supposed to be fixed, depending on how you want it to work... I can't really help you too much...

mayenco

Re: Re: Error: A null PFont was passed to textFont()

1 year ago

Can you give me some options to choose, how it can be fixed?
If the error occurs only with the random fonts then it would be okay to write an array, with about 20 fonts to choose from. I just want to get rid of the error to resume programming.

calsign

Re: Error: A null PFont was passed to textFont()

1 year ago

You need to load the fonts... presumably, there are two options, and you'll have to refine from there once you get the code working:

You can fill the array of fonts with loaded fonts beforehand so that none of the elements can be null
You can, instead of referencing a new font every time in the loop, access a single font

mayenco

Re: Re: Error: A null PFont was passed to textFont()

1 year ago

When I replace all "empty" font arrays with a helvetica font for example, I get a Null Pointer Exception in line: text(newString, newPosition.x, newPosition.y);

The thing is, that the code worked properly before I pasted in the Dropdown Menu.

calsign

Re: Error: A null PFont was passed to textFont()

1 year ago

That's probably not your font anymore, then... are you sure that newPosition is initialized properly?

mayenco

Re: Re: Error: A null PFont was passed to textFont()

1 year ago

I've deleted the dropdown menu and replaced it with a right-click menu. now everything works properly without changing something of the fonts.

Menu #2 and #3 stayed the same. The new code for the "Main-Sketch" is:

/**
(c) 2012 MM
*/

import ddf.minim.*;

Minim minim;
AudioInput input;

String[] fontList ;
String[] titles;
PFont myfont;
PVector [] positions;
PFont [] myFonts;
int [] myFontSize;
int Anzahl;
boolean fullList = false;
int[] BlockgroesseX;
int[] BlockgroesseY;

String [] loadfeeds = {
"http://www.faz.net/aktuell/?rssview=1",
"http://rss.bild.de/bild.xml",
"http://rss.feedsportal.com/795/f/449002/index.rss",
"http://www.welt.de/?service=Rss"
};

int h; //Bestimmt Feed im Array "loadfeeds"

XMLElement[] titleXMLElements;
int CurrentTitle = 0;

float klatschen;

PImage Logoklein;
PImage Logo;

boolean startbildschirm;

final String ss="rightclick somewhere ...";
String s=ss;
int mill;

void setup() {
startbildschirm = true;
size(screen.width, screen.height);
fontList = PFont.list();
minim = new Minim (this);
input = minim.getLineIn (Minim.STEREO, 512);
background(0);
//setzt den Hintergrund im Present-Mode auf Schwarz
frame.setBackground(new java.awt.Color(0, 0, 0));
loadXml();
Logoklein = loadImage("logoklein.png");
Logo = loadImage("logo.png");

textFont(createFont("Times", 24));
}

//-----------------------------------------------------------------------
// Popup Menu
//-----------------------------------------------------------------------

void popupMenu() {
SMenu p=new SMenu(this, mouseX, mouseY);
p.SMSubM("File"); // new submenu
p.SMSubM("Import");
p.SMItem("FAZ", new actn() {
    public void a() {
      h = 0;
    }
}
);
p.SMItem("BILD", new actn() {
    public void a() {
      h = 1;
    }
}
);
p.SMItem("Süddeutsche", new actn() {
    public void a() {
      h = 2;
    }
}
);
p.SMItem("Weltonline", new actn() {
    public void a() {
      h = 3;
    }
}
);
p.SMEnd();
p.SMItem("About", null);
p.SMEnd();
p.SMItem("Close", new actn() {
    public void a() {
      exit();
    }
}
);
p.SMEnd();
}

void loadXml() {
String url = loadfeeds[h];
println("Loading feed: "+url);
XMLElement rss = new XMLElement(this, url);
titleXMLElements = rss.getChildren("channel/item/title");

Anzahl = titleXMLElements.length;

// Arrays für jede Art von Werten
titles = new String[Anzahl];
positions =new PVector[Anzahl];
myFonts =new PFont[Anzahl];
myFontSize = new int[Anzahl];
BlockgroesseX = new int[Anzahl];
BlockgroesseY = new int[Anzahl];

for (int i = 0; i < titleXMLElements.length; i++) {
    String title = titleXMLElements[i].getContent();
    titles[i]=(new String(title));
}
}

void draw() {

if (startbildschirm == true) {
    smooth();
    fill(0);
    rect(0, 0, width, height);
    smooth();
    imageMode(CENTER);
    image(Logo, width/2, height/2);
}
else {
    background(0);
    smooth();
    klatschen = input.mix.level() * width;

    text(s, (width-textWidth(s))/2, 150);
    if ((millis()-mill)>3000) s=ss;

    image(Logoklein, width-80, 60);

    if (klatschen > 100) {

      //immer wenn geklatscht wird fülle die werte abhängig vom Zähler CurrentTitle

      positions [CurrentTitle] = (new PVector(random(width/2), random(70, height))); // Positionen
      PFont font = createFont(fontList[(int)random(0, fontList.length)], 10);    // Schriften
      myFonts[CurrentTitle] = font;
      myFontSize[CurrentTitle] = (int)random(14, 200);                           // Schriftgrößen

      CurrentTitle += 1;

      // wenn CurrentTitle die Maximalanzahl erreicht hat setze CurrentTitle auf 0
      // ab jetzt werden schon vorhanden Werte in den Listen neu überschrieben
      // alle anderen bleiben in der Liste bis sie überschrieben werden
      if (CurrentTitle >= Anzahl) {
        CurrentTitle = 0;
      }
    }

    // solange die Liste noch nicht die maximalanzahl erreicht hat zähle hoch

    if (CurrentTitle < Anzahl && fullList == false)
    {
      for (int j = 0; j < CurrentTitle; j++) {
        int TheTextSize = myFontSize[j];
        textFont(myFonts[j], TheTextSize);
        String newString = titles[j];

        /*
         String[] m1 = match(titles[j], "Altmaier");
         if (m1 != null) {
         fill(farben[1]);
         }
         else {
         fill(255, 85);
         }
         */

        PVector newPosition = positions[j];
        text(newString, newPosition.x, newPosition.y);

        // ermittle die Groesse der Textbloecke
        BlockgroesseX [j] = (int)textWidth(newString);
        BlockgroesseY [j] = TheTextSize;

        // wenn die Maus über einem der Blöcke ist übergebe ihm den Mauswert als Koordinate
        if (mousePressed) {
          if (mouseX > (newPosition.x) && mouseX < (newPosition.x+BlockgroesseX[j]) && mouseY > (newPosition.y-BlockgroesseY[j]) && mouseY < (newPosition.y) )
          {
            println("über String Nummer " + j);
            newPosition.x -= (pmouseX-mouseX);
            newPosition.y -= (pmouseY-mouseY);
          }
        }
      }
    }
    else // wenn sie die Maximalanzahl erreicht hat zeichne das vorhandene und ändere immer nur das was CurrentTitle entspricht (von 0 bis 20)
    {
      for (int j = 0; j < Anzahl-1; j++) {
        int TheTextSize = myFontSize[j];
        textFont(myFonts[j], TheTextSize);
        String newString = titles[j];
        PVector newPosition = positions[j];
        text(newString, newPosition.x, newPosition.y);

        // wenn die Maus über einem der Blöcke ist übergebe ihm den Mauswert als koordinate
        if (mousePressed) {
          if (mouseX > (newPosition.x) && mouseX < (newPosition.x+BlockgroesseX[j]/2) && mouseY > (newPosition.y-BlockgroesseY[j]) && mouseY < (newPosition.y) )
          {
            newPosition.x -= (pmouseX-mouseX);
            newPosition.y -= (pmouseY-mouseY);
          }
        }
      }
    }

    if (CurrentTitle == Anzahl-1)
    {
      fullList = true;
    }
}
}
void mouseClicked() {
mill=millis();
if (mouseButton==RIGHT) popupMenu();
}

void mousePressed() {
if (startbildschirm == true) {
    startbildschirm = false;
    fill(255, 255, 255, random(20, 255));
}
// deaktiviert ihn, wenn man mit Maus klickt
}

Now I want, that if I rightlclick on "About", a credit note appears. I've coded it, but I don't know how to paste it in, that it doesn't appear after only 1 sec.

Here's the code:

fill(50, 200);
rect(0, 0, width, height);
fill(24);
rect(width/2-300, 160, 600, 340);
image(Logoklein, 620, 210, Logoklein.width, Logoklein.height);
strokeWeight(1);
stroke(80);
fill(255, 100);
textFont(fornt);
textSize(12);
text("MM \n2.Semester \nInteraktive Medien \nProfessor Erich Schöls", width/2-260, 320);

fill(255);
text("Snapfeed visualisiert Nachrichten \ndurch Interaktion mit dem Mikrofon.", width/2-260, 430);

ellipseMode(CENTER);
ellipse(width/2+300, 160, 30, 30);
textFont(fett);
if (mouseX > width/2+285 && mouseX < width/2+315 && mouseY > 145 && mouseY < 175) {
fill(120);
}

The ellipse in the right corner should contain a "x" with whom you can close the window.

calsign

Re: Error: A null PFont was passed to textFont()

1 year ago

So this is a different problem with the same program...
Okay, I think I understand what's going on now:

You have your popup menu working, and you want an about screen. You've written the code to display it, but it will only show for one frame...

When the "About" button is pressed, you need to set a global boolean to be true. This variable contains whether or not the About menu should be displayed... then, in draw(), check for the value of this boolean and display the menu accordingly. Similarly, when the "X" button is pressed, set the boolean to be false.

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