Issue with toString() on float value

jorrebor

Issue with toString() on float value

in Contributed Library Questions • 1 year ago

Hi all,

i try to write an Pvector array to text file. My code works when i use PrintWriter. SInce PrintWriter doesn't have the ability to append data to files (not built in though), i decided to use FileWriter. My code trows an IO exception.

Please have look!

/**
This program receives motion data from phone
*/
import java.io.*;
import codeanticode.gsvideo.*;
import controlP5.*;
import oscP5.*;
import netP5.*;
NetAddress myRemoteLocation;
OscP5 oscP5;
ControlP5 controlP5;
ControlWindow controlWindow;
//PrintWriter output;
FileWriter output;
GSMovie front_view;
GSMovie profile_view;
//these hold the motion values
float x, y, z;
//needed for motion recording
boolean record;
int i;
//data sequences are stored as vectors
PVector [] mdata = new PVector [2000];
//to store which movies have been shown
int [] movies = new int [5];
/////////////////////////////////////////////////////SETUP/////////////////////////////////////////////
void setup() {
//setup the canvas
size(1280, 480, P3D);
frameRate(25);
background(0);
//make a connection with the OpenSoundControlProtocol
oscP5 = new OscP5(this, 25000);
myRemoteLocation = new NetAddress("192.168.1.77", 25000);
//create an interface framework
controlP5 = new ControlP5(this);
controlP5.setAutoDraw(true);
//create secondary control window for controlling video playback and motion recording
controlWindow = controlP5.addControlWindow("ControlWindow", 100, 100, 800, 600);
controlWindow.setTitle("Controls");
//get a reference to button objects
Button startButton = controlP5.addButton("Start Record", 1, 50, 50, 250, 100);
Button stopButton = controlP5.addButton("Stop Record", 2, 50, 175, 250, 100);
Button storeButton = controlP5.addButton("Store Record", 3, 50, 300, 250, 100);
Button movieStart = controlP5.addButton("Start Movie", 4, 350, 50, 250, 100);
Button moviePause = controlP5.addButton("Pauze Movie", 5, 350, 175, 250, 100);
Button nextMovie = controlP5.addButton("Setup Next Movie", 6, 350, 300, 250, 100);
//position buttons on the controlwindow
startButton.setWindow(controlWindow);
stopButton.setWindow(controlWindow);
storeButton.setWindow(controlWindow);
movieStart.setWindow(controlWindow);
moviePause.setWindow(controlWindow);
nextMovie.setWindow(controlWindow);
//populate mdata with actual filenames
for (int i = 0; i < mdata.length; i++) {
mdata[i] = new PVector();
}
//populate movies with actual filenames
for (int i = 0; i < movies.length - 1; i++) {
movies [i] = i + 1;
}
//setup first movies
setNextMovie();
//get a file writer to store the data in a file corresponding to the performed gesture
String filename = front_view.getFilename();
try {
FileWriter output = new FileWriter("4A.avi", true);
}
catch(IOException ioe) {
println("error: " + ioe);
}
//output = createWriter("4A.avi");
}
////////////////////////////////////////////DRAW////////////////////////////////////////////////
void draw() {
//draw the movies on the screen
image(front_view, 0, 0);
image(profile_view, 640, 0);
controlP5.draw();
}
///////////////////////////////////////////Button Event Handling/////////////////////////////////
public void controlEvent(ControlEvent theEvent) {
int button = int(theEvent.controller().defaultValue());
switch (button) {
case 1:
startRecord();
break;
case 2:
stopRecord();
break;
case 3:
storeRecord();
break;
case 4:
startMovie();
break;
case 5:
stopMovie();
break;
case 6:
setNextMovie();
break;
}
}
public void start (int theValue) {
println(theValue);
}
///////////////////////////////////////////Motion Recording//////////////////////////////////////
public void startRecord() {
record = true;
i = 0;
}
public void stopRecord() {
record = false;
for (int i = 0; i < mdata.length; i++) {
//why can i not do this?
//For printwriter i don't need to call toString()
String out = "[" + mdata[i].x.toString() + "\t" + mdata[i].y + "\t" + mdata[i].z+ "]; ";
String out_test = "this breaks";
output.write(out1);
}
output.write("\n==========================================================================================================");
output.flush(); // Write the remaining data
output.close(); // Finish the file
}
public void storeRecord() {
//TODO
}
//////////////////////////////////////////Movie Control/////////////////////////////////////////
//setup the next movie
public void setNextMovie() {
//get a unique integer
int i = getUniqueInt();
//create filenames
String movie_1 = i + "A.avi";
String movie_2 = i + "B.avi";
// init movies
front_view = new GSMovie(this, movie_1);
profile_view = new GSMovie(this, movie_2);
}
//start the movie
public void startMovie() {
println("in start movie");
//TODO get movie to play 2 times
front_view.loop();
profile_view.loop();
}
//pauze or stop playback
public void stopMovie() {
front_view.pause();
profile_view.pause();
}
/////////////////////////////////////////////////////////////////////////Utils////////////////////////////////////////////
//gets a unique integer
public int getUniqueInt() {
int pos = int(random(0, 4));
//pick movie based on position
int unique = movies[pos];
//make the value 0 so that we can identify that the movie has been picked
movies[pos] = 0;
//when movie has been picked its value has been set to zero, so we pick again
if (unique == 0) {
unique = getUniqueInt();
}
return unique;
}
//this reads the image from the movie in order to display it
void movieEvent(GSMovie thisMovie) {
thisMovie.read();
}
//Function reads motion data
void oscEvent(OscMessage theOscMessage) {
if (theOscMessage.checkAddrPattern("/motion"))
{
if (record == true) {
mdata[i].x = theOscMessage.get(0).floatValue();
mdata[i].y = theOscMessage.get(1).floatValue();
mdata[i].z = theOscMessage.get(2).floatValue();
i++;
}
}
}

Replies(8)

PhiLho

Re: Issue with toString() on float value

1 year ago

Moved to Contributed Library section, as we cannot run your code without all of them. And even so, we probably need additional hardware, apparently...
So, unless carefully reading and understanding your long code, we cannot answer your half question.
It is generally preferable to reproduce your problem in a simple, small, standalone sketch.

Ah, I was lucky, I stumbled upon your comment while scrolling over your code. You should make such comment standing out (using red, for example).
Why do you use toString()?
x component of PVector is a primitive, a float. In Java, you cannot call methods on such primitive.
But string concatenation can handle such values:
String out = "[" + mdata[i].x + "\t" + mdata[i].y + "\t" + mdata[i].z+ "]; ";

At worst, in some cases, you can use for example Float.toString(floatValue);

jorrebor

Re: Issue with toString() on float value

1 year ago

my mistake.

I actually tried float.toString but it didnt work. But found out that my problem lies with the FileWriter setup. i'll post my problem when fixed.

jorrebor

Re: Issue with toString() on float value

1 year ago

Although the file is created and exists, FileWriter does not find it and raises a null pointer exception...

please have a look a this code:

import java.io.*;
FileWriter output;
void setup()
{
size(200, 200);
//create a filename string
String filename = "D:\\test_file.txt";
createWriter(filename);
//get this file as a file
File my_file = new File(filename);
print(my_file.exists()); //printstrue
try {
FileWriter output = new FileWriter(my_file, true);
}
catch(IOException ioe) {
println("error: " + ioe);
}
}
void draw()
{
try {
output.write("print this!!!!");
output.flush();
output.close(); // Finish the file
}
catch(IOException e) {
println("error:" + e);
}
exit(); // Stop the program (do i need this???)
}
void write_to_file(String theString) {
}

PhiLho

Re: Issue with toString() on float value

1 year ago

Classical error:
FileWriter output = new FileWriter(my_file, true);
You redefine a local output variable here, shadowing the global one, which remains null.

jorrebor

Re: Re: Issue with toString() on float value

1 year ago

Ok, so the solution would be to put

try {
FileWriter output = new FileWriter(my_file, true);
}
catch(IOException ioe) {
println("error: " + ioe);
}

outside of the setup () ?

I can't reach my computer from here :(

thanks anyway, and you're right: should've deleted this thread in favor of the other.

PhiLho

Re: Issue with toString() on float value

1 year ago

And I deleted your other thread, duplicate of the question above. It was OK to create this thread (as the question was different from the original one) if you deleted first this question: avoid duplications, it makes people answering in parallel, doing duplicate work.

PhiLho

Re: Issue with toString() on float value

1 year ago

You don't delete threads (where people answered) but you can delete a specific message, if nobody answered it yet.

And, no, you don't put the code out of setup() (it won't work), you just avoid to declare again the variable:

try {
output = new FileWriter(my_file, true); // Don't redeclare the type here!
}
catch(IOException ioe) {
println("error: " + ioe);
}

See http://wiki.processing.org/w/What_are_setup%28%29_and_draw%28%29%3F

jorrebor

Re: Issue with toString() on float value

1 year ago

Thanks alot!

I knew this btw ;)

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