Question

我对处理和arduino都很新。我把3株植物和3个人连接到Arduino的简单测谎仪中。我将值发送到处理小瓶Seriel端口。在处理中我想根据Arduino字符串的输入值触发声音。这是到目前为止我走了多远（2个方法）。我在这一行得到一个Null指针异常：

int iv = int（val.trim（））;

非常感谢任何提示。我已经浏览论坛好几天了:)我觉得我很接近。

代码1：

import processing.serial.*;

import ddf.minim.*;
import ddf.minim.analysis.*;
import ddf.minim.effects.*;
import ddf.minim.signals.*;
import ddf.minim.spi.*;
import ddf.minim.ugens.*;

Serial myPort;
String val;
String portName = Serial.list()[2];
int iv = 0;

Minim minim;
AudioSample a;
AudioSample b;
AudioSample c;
AudioSample d;
AudioSample e;
AudioSample f;
AudioSample g;
AudioSample h;
AudioSample i;
AudioSample j;
AudioSample k;
AudioSample l;
AudioSample m;
AudioSample n;
AudioSample o;
AudioSample p;
AudioSample q;
AudioSample r;
AudioSample s;
AudioSample t;
AudioSample u;
AudioSample v;
AudioSample w;
AudioSample aa;
AudioSample ab;
AudioSample ac;
AudioSample ad;
AudioSample ae;
AudioSample af;
AudioSample ag;
AudioSample ah;
AudioSample ai;
AudioSample aj;
AudioSample ak;
AudioSample al;
AudioSample am;
AudioSample an;
AudioSample ao;
AudioSample ap;
AudioSample aq;
AudioSample ar;



void setup() {
  size(200, 100, P3D);
  background(0);
  println(Serial.list());
  myPort = new Serial(this, portName, 9600);
  minim = new Minim(this);
  a = minim.loadSample("1.mp3",128);
  b = minim.loadSample("2.mp3",128);
  c = minim.loadSample("3.mp3",128);
  d = minim.loadSample("4.mp3",128);
  e = minim.loadSample("5.mp3",128);
  f = minim.loadSample("6.mp3",128);
  g = minim.loadSample("7.mp3",128);
  h = minim.loadSample("8.mp3",128);
  i = minim.loadSample("9.mp3",128);
  j = minim.loadSample("10.mp3",128);
  k = minim.loadSample("11.mp3",128);
  l = minim.loadSample("12.mp3",128);
  m = minim.loadSample("13.mp3",128);
  n = minim.loadSample("14.mp3",128);
  o = minim.loadSample("15.mp3",512);
  p = minim.loadSample("16.mp3",512);
  q = minim.loadSample("17.mp3",512);
  r = minim.loadSample("18.mp3",512);
  s = minim.loadSample("19.mp3",512);
  t = minim.loadSample("20.mp3",512);
  u = minim.loadSample("21.mp3",512);
  w = minim.loadSample("22.mp3",512);
  aa = minim.loadSample("23.mp3",512);
  ab = minim.loadSample("24.mp3",512);
  ac = minim.loadSample("25.mp3",512);
  ad = minim.loadSample("26.mp3",512);
  ae = minim.loadSample("27.mp3",512);
  af = minim.loadSample("28.mp3",512);
  ag = minim.loadSample("29.mp3",512);
  ah = minim.loadSample("30.mp3",512);
  ai = minim.loadSample("31.mp3",512);
  aj = minim.loadSample("32.mp3",512);
  ak = minim.loadSample("33.mp3",512);
  al = minim.loadSample("34.mp3",512);
  am = minim.loadSample("35.mp3",512);
  an = minim.loadSample("36.mp3",512);
  ao = minim.loadSample("37.mp3",512);
  ap = minim.loadSample("38.mp3",512);
  aq = minim.loadSample("39.mp3",512);
  ar = minim.loadSample("40.mp3",512);


}

void draw() {
  //delay(2000);
  if (myPort.available() >= 0) {
    val = myPort.readStringUntil('\n');
  }

  int iv = int(val.trim());
  if(val != null) println(val);
  if(iv == 0) a.trigger();
  if(iv == 1) b.trigger();
  if(iv == 2) c.trigger();
  if(iv == 3) d.trigger();
  if(iv == 4) e.trigger();
  if(iv == 5) f.trigger();
  if(iv == 6) g.trigger();
  if(iv == 7) h.trigger();
  if(iv == 8) i.trigger();
  if(iv == 9) j.trigger();
  if(iv == 10) k.trigger();
  if(iv == 11) l.trigger();
  if(iv == 12) m.trigger();
  if(iv == 13) n.trigger();
  if(iv == 14) o.trigger();
  if(iv == 15) p.trigger();
  if(iv == 16) q.trigger();
  if(iv == 17) r.trigger();
  if(iv == 18) s.trigger();
  if(iv == 19) t.trigger();
  if(iv == 20) u.trigger();
  if(iv == 21) w.trigger();
  if(iv == 22) aa.trigger();
  if(iv == 23) ab.trigger();
  if(iv == 24) ac.trigger();
  if(iv == 25) ad.trigger();
  if(iv == 26) ae.trigger();
  if(iv == 27) af.trigger();
  if(iv == 28) ag.trigger();
  if(iv == 29) ah.trigger();
  if(iv == 30) ai.trigger();
  if(iv == 31) aj.trigger();
  if(iv == 32) ak.trigger();
  if(iv == 33) al.trigger();
  if(iv == 34) am.trigger();
  if(iv == 35) an.trigger();
  if(iv == 36) ao.trigger();
  if(iv == 37) ap.trigger();
  if(iv == 38) aq.trigger();
  if(iv == 39) ar.trigger();


}

码2：

import processing.serial.*;

Serial myPort;  // Create object from Serial class
String val;     // Data received from the serial port
String portName = Serial.list()[2];
int v = 0;


import ddf.minim.*;
import ddf.minim.analysis.*;
import ddf.minim.effects.*;
import ddf.minim.signals.*;
import ddf.minim.spi.*;
import ddf.minim.ugens.*;

static final int BITRATE = 128;
static final String EXT = ".mp3";


//String[] names = new String[250];

final static String[] names = {
 "1","2","3","4","5","6","7","8","9","10","11","12","13","14","15","16","17","18","19","20","20", "20", "21", "22","23","24","25","26","27","28","29","30","31","32","33","34","35","36","37","38","39","40"
};

final static int numSongs  = names.length;
AudioPlayer [] songs = new AudioPlayer[numSongs];

Minim minim;


void setup()
{
size(512,320,P3D);
frameRate(60);
smooth(4);

//println(Serial.list());
myPort = new Serial(this, portName, 9600);
minim = new Minim(this);

}

void draw()
{
  background(0);
  stroke(255);
    if (myPort.available() > 0) {
    val = myPort.readString(); 
  }

  int v = int(val.trim());  
  if (val != null) println(val);

  for (int i = 0; i != numSongs; 
    songs[i] = minim.loadFile(names[i++] + EXT, BITRATE));

  songs[v].play();
  delay(9000);



}

第二个代码最重要的是。过了一会儿，他抛出一个java头内存错误（像那样的事情）

再次感谢您的帮助

Answer 1

您的val变量为null。看看你的代码的这一部分：

int iv = int(val.trim());
if(val != null) println(val);

请注意，您在使用之后检查了null 。你可能想要这样的东西：

if(val != null){ println(val); int iv = int(val.trim()); //rest of your code } else{ println("Val is null!"); //maybe do something else in this case }

最小处理3 arduino输入触发样本空指针异常

1 个答案: