NullPointerException Error

hedning

in Integration and Hardware • 2 years ago

Hello, im very new to using processing and i've ran into a huge problem which i dont have enough knowledge to solve on my own, so here is the scenario, I need to get my computer to play a sound by pressing an button...

Here is the error:

processing.app.debug.RunnerException: NullPointerException

at processing.app.Sketch.placeException(Sketch.java:1543)

at processing.app.debug.Runner.findException(Runner.java:582)

at processing.app.debug.Runner.reportException(Runner.java:558)

at processing.app.debug.Runner.exception(Runner.java:498)

at processing.app.debug.EventThread.exceptionEvent(EventThread.java:367)

at processing.app.debug.EventThread.handleEvent(EventThread.java:255)

at processing.app.debug.EventThread.run(EventThread.java:89)

Exception in thread "Animation Thread" java.lang.NullPointerException

at ddf.minim.javasound.JSMinim.getAudioInputStream(JSMinim.java:604)

at ddf.minim.javasound.JSMinim.getAudioRecordingStream(JSMinim.java:200)

at ddf.minim.Minim.loadFile(Minim.java:357)

at sketch_apr20a.setup(sketch_apr20a.java:44)

at processing.core.PApplet.handleDraw(Unknown Source)

at processing.core.PApplet.run(Unknown Source)

at java.lang.Thread.run(Thread.java:619)

Here is the highlighted area player = minim.loadFile("SS1.mp3", 2048);

The file SS1.mp3 is in the data folder below the saved processing file

Replies(9)

anchnk

Re: NullPointerException Error

2 years ago

Hi, this is not easy to help you with only the error message.

Did you instanciate a new minim object (minim = new Minim ( this );) before trying to load the sample ?

Could you paste the code block in which you try to load the sample (that might be setup()) ?

hedning

Re: NullPointerException Error

2 years ago

I used a sketch taken from the Processing libraries, here is the whole code.

// This example code is in the public domain.

import ddf.minim.*;

AudioPlayer player;

Minim minim;

import processing.serial.*; // import the Processing serial library

Serial myPort; // The serial port

float bgcolor; // Background color

float fgcolor; // Fill color

float xpos, ypos; // Starting position of the ball

void setup() {

size(640,480);

minim = new Minim(this);

// load a file, give the AudioPlayer buffers that are 1024 samples long

// player = minim.loadFile("groove.mp3");

// load a file, give the AudioPlayer buffers that are 2048 samples long

player = minim.loadFile("SS1.mp3", 2048);

// play the file

// List all the available serial ports

println(Serial.list());

// I know that the first port in the serial list on my mac

// is always my Arduino module, so I open Serial.list()[0].

// Change the 0 to the appropriate number of the serial port

// that your microcontroller is attached to.

myPort = new Serial(this, Serial.list()[0], 9600);

// read bytes into a buffer until you get a linefeed (ASCII 10):

myPort.bufferUntil('\n');

// draw with smooth edges:

smooth();

}

void draw() {

background(bgcolor);

fill(fgcolor);

// Draw the shape

ellipse(xpos, ypos, 20, 20);

}

// serialEvent method is run automatically by the Processing applet

// whenever the buffer reaches the byte value set in the bufferUntil()

// method in the setup():

void serialEvent(Serial myPort) {

// read the serial buffer:

String myString = myPort.readStringUntil('\n');

// if you got any bytes other than the linefeed:

myString = trim(myString);

// split the string at the commas

// and convert the sections into integers:

int sensors[] = int(split(myString, ','));

// print out the values you got:

/* for (int sensorNum = 0; sensorNum < sensors.length; sensorNum++) {

print("Sensor " + sensorNum + ": " + sensors[sensorNum] + "\t");

}

int value = sensors[0];

println("value = " + value);

if(value==255){player.play();}

//if(value==0){player.close();}

// add a linefeed after all the sensor values are printed:

println();

if (sensors.length > 1) {

xpos = map(sensors[0], 0,1023,0,width);

ypos = map(sensors[1], 0,1023,0,height);

fgcolor = sensors[2];

}

// send a byte to ask for more data:

myPort.write("A");

}

void stop()

{

// always close Minim audio classes when you are done with them

player.close();

minim.stop();

super.stop();

}

anchnk

Re: NullPointerException Error

2 years ago

Humm i can't test the arduino part so it's not easy for me to help.
However, the problem might be raised because Serialevent() is fired before your sound is loaded.
I suggest to try to comment some part of code and find a minimal structure that works.
Then try to isolate where the problem is raise.
Just a try but if you change

if(value==255){player.play();}

by :

if (value == 255 && player != null)player.play();

Does it helps ?

PhiLho

Re: NullPointerException Error

2 years ago

Can you play your MP3 file in a simpler sketch (no Arduino)?

hedning

Re: NullPointerException Error

2 years ago

Couldnt get it to work it still highlight player = minim.loadFile("SS1.mp3", 2048);

and give me the error

Demonstration is in just half an hour, so i guess i have to just explain it

Jesse Sco..

Re: Re: NullPointerException Error

2 years ago

are you sure that file exists in the correct directory?

PhiLho

Re: NullPointerException Error

2 years ago

As Jesse says, and as I suspected, either your file isn't in the data folder (but you say it is, in the first message) or the file is corrupted or not compatible with Minim.

hedning

Re: NullPointerException Error

2 years ago

As the beginner i am i placed the sound file in all folders around the sketches, and it worked. Thanks for all the help :)

alkopop79

Re: NullPointerException Error

2 years ago

I keep getting the same error with an example sketch. Needless to say, the samples are added to the data folder, what is more I added them to the sketch folder, too. Still doesn't work...

the code:

import ddf.minim.*;

Minim minim;
AudioSample kick;
AudioSample snare;

void setup()
{
size(512, 200, P3D);
minim = new Minim(this);
// load BD.wav from the data folder
kick = minim.loadSample("alkofunk85.wav", 1024);
if ( kick == null ) println("Didn't get kick!");
// load SD.wav from the data folder
snare = minim.loadSample("snare.aif", 1024);
if ( snare == null ) println("Didn't get snare!");
}

void draw()
{
background(0);
stroke(255);
// use the mix buffer to draw the waveforms.
for (int i = 0; i < kick.bufferSize() - 1; i++)
{
    float x1 = map(i, 0, kick.bufferSize(), 0, width);
    float x2 = map(i+1, 0, kick.bufferSize(), 0, width);
    line(x1, 50 - kick.mix.get(i)*50, x2, 50 - kick.mix.get(i+1)*50);
    line(x1, 150 - snare.mix.get(i)*50, x2, 150 - snare.mix.get(i+1)*50);
}
}

void keyPressed()
{
if ( key == 's' ) snare.trigger();
if ( key == 'k' ) kick.trigger();
}

void stop()
{
// always close Minim audio classes when you are done with them
kick.close();
snare.close();
minim.stop();

super.stop();
}

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