Problem changing position in hashmap with keyPressed '<' and '>'

thomasjam..

Problem changing position in hashmap with keyPressed '<' and '>'

in Contributed Library Questions • 2 years ago

Hi,

I have a sketch that collects tweets to a hashmap using Twitter4j. At the moment I have a very simple method setup that displays the tweet fom the hasmap to the screen as a string but I have the problem that it only displays the last tweet collected. What would be really great is if I could control the hashmap iterator with keypressed commands so that I can effectively scroll through the hashmap and have the updated string displayed for the user so they can explore the collected tweets.

So the code I have so far searches for and collects tweets to a hashmap and stores the last tweet in the hashmap to a string and displays it to the screen and what would be great is a method to press < to scroll back through the hashmap (thus updating the string displayed) and accordingly to be able to press > to scroll forwards through the hash.

Here is my code in full (apologies as it is quite long) with the important bits in bold. EDIT: here is a stripped down function from my program that includes the minimum number amount of code and libraries to run, I've attempted to integrate
amnon.owed's suggestions but I'm still stuck sadly.

Here is a link to the necessary library: http://twitter4j.org/en/index.html

import twitter4j.conf.*;
import twitter4j.internal.async.*;
import twitter4j.internal.org.json.*;
import twitter4j.internal.logging.*;
import twitter4j.http.*;
import twitter4j.api.*;
import twitter4j.util.*;
import twitter4j.internal.http.*;
import twitter4j.*;

int currentTweet;

String searchString;

String consumerKey = "---";
String consumerSecret = "---";
String accessToken = "---";
String accessTokenSecret = "---";

final int TIME_STEP = 1;
final int NUM_SEARCHES = 20;

final long DAY_DURATION = 1000*60*60*24;
Twitter twitter = new TwitterFactory().getInstance();
HashMap<Long,Tweet> tweets=new HashMap<Long,Tweet>();

public void setup(){

searchString = "News of the World";
searchTwitter(searchString);

twitter = new TwitterFactory().getOAuthAuthorizedInstance(consumerKey,consumerSecret, new AccessToken(accessToken,accessTokenSecret));
size(910,400);

}

public void searchTwitter(String searchQuery) {

      twitter4j.Query query = new twitter4j.Query(searchQuery);
       //twitter4j.Query.setGeoCode(new GeoLocation(52.30, 13.25), 1000.0, twitter4j.Query.KILOMETERS); // if we want to only get tweets from the region berlin

      query.rpp(100);
      Date referenceDate=new Date();
      for(int i=0; i<NUM_SEARCHES; i++) {




        String d=new SimpleDateFormat("yyyy-MM-dd").format(referenceDate);
        //println("executing search for date: "+d);
        query.until(d);
        // execute search
        try {

          QueryResult result = twitter.search(query);
            for (Tweet tweet : result.getTweets()) {
            // first check if ID is unique?
            if (tweets.get(tweet.getId())==null) {
              // filter out tweets with GPS loc
              GeoLocation loc=tweet.getGeoLocation();
              if (loc!=null) {
                tweets.put(tweet.getId(),tweet);

                //println("adding tweet: "+tweet);
              }
            } else {
              //println("skipping: "+tweet.getId());
            }
          }
        }
        catch(TwitterException e) {
          println(e.getMessage());
        }
        referenceDate.setTime(referenceDate.getTime()-TIME_STEP*DAY_DURATION);
      }
    }

    public void draw(){

      background (0);

      fill(242,242,242);

      // text(tweets.toString(), 15, 15,220,220);
       text((String)tweets.get(currentTweet), 15,15,220,220);


    }

// void addTweet(String value) {
//   int n = tweets.size();
//   tweets.put(n, value);
// }


     void keyPressed() {
   if (key == ',') {
     if (currentTweet>0) {
       currentTweet--;
     }
   }
   else if (key == '.') {
     if (currentTweet<tweets.size()-1) {
       currentTweet++;
     }
   }
}

EDIT: Here is my program in full, sorry that it is so long..

import processing.core.*;
import processing.xml.*;

//import javax.media.opengl.*;
//import processing.opengl.*;

import controlP5.*;
import peasy.org.apache.commons.math.*;
import peasy.*;
import peasy.org.apache.commons.math.geometry.*;

import twitter4j.conf.*;
import twitter4j.internal.async.*;
import twitter4j.internal.org.json.*;
import twitter4j.internal.logging.*;
import twitter4j.http.*;
import twitter4j.api.*;
import twitter4j.util.*;
import twitter4j.internal.http.*;
import twitter4j.*;

import toxi.geom.*;
import toxi.processing.*;

import peasy.*;

import java.applet.*;
import java.awt.Dimension;
import java.awt.Frame;
import java.awt.event.MouseEvent;
import java.awt.event.KeyEvent;
import java.awt.event.FocusEvent;
import java.awt.Image;
import java.io.*;
import java.net.*;
import java.text.*;
import java.util.*;
import java.util.zip.*;
import java.util.regex.*;

import twitter4j.internal.util.*;
import twitter4j.api.*;
import toxi.geom.mesh.*;
import peasy.org.apache.commons.math.geometry.*;
import twitter4j.util.*;
import peasy.org.apache.commons.math.*;
import twitter4j.*;
import toxi.geom.mesh2d.*;
import peasy.*;
import twitter4j.internal.org.json.*;
import twitter4j.internal.logging.*;
import toxi.util.datatypes.*;
import toxi.math.waves.*;
import toxi.geom.mesh.subdiv.*;
import toxi.geom.*;
import toxi.util.events.*;
import processing.xml.*;
import processing.core.*;
import twitter4j.conf.*;
import twitter4j.internal.async.*;
import peasy.test.*;
import toxi.math.conversion.*;
import twitter4j.internal.http.*;
import toxi.math.noise.*;
import toxi.processing.*;
import toxi.util.*;
import twitter4j.http.*;
import controlP5.*;
//import processing.opengl.*;
import toxi.math.*;

import java.applet.*;
import java.awt.Dimension;
import java.awt.Frame;
import java.awt.event.MouseEvent;
import java.awt.event.KeyEvent;
import java.awt.event.FocusEvent;
import java.awt.Image;
import java.io.*;
import java.net.*;
import java.text.*;
import java.util.*;
import java.util.zip.*;
import java.util.regex.*;

public class TwitterExp extends PApplet {

boolean a = true;
boolean button = false;
boolean buttona = false;

int x = 750;
int y = 106;
int w = 20;
int h = 20;

int xa = 750;
int ya = 50;
int wa = 20;
int ha = 20;

PImage bg, texmap;
PFont font;

int sDetail = 55; //Sphere detail
float[] cx, cz, sphereX, sphereY, sphereZ;
float sinLUT[], cosLUT[], sincos_precision = 0.5f;
int sincos_length = PApplet.parseInt(360.0f / sincos_precision);

float r = 600;

// r = earth radius in px. 6371 is earth radius in km.
float pxToKm = 6371.0f / r;
int inRange;

String searchString;
String searchState = "";

String consumerKey = "---";
String consumerSecret = "---";
String accessToken = "---";
String accessTokenSecret = "---";
PeasyCam cam;
PeasyDragHandler PanDragHandler;
PFont imhelix;
ControlP5 controlP5;
PMatrix3D currCameraMatrix;
//final String SEARCH_QUERY="hello";
final int TIME_STEP = 1;
final int NUM_SEARCHES = 20;

final long DAY_DURATION = 1000*60*60*24;
Twitter twitter = new TwitterFactory().getInstance();
Map<Long, Tweet> tweets = new LinkedHashMap<Long, Tweet>();
ListIterator<Tweet> iterator;
Tweet currentTweet;
ToxiclibsSupport gfx;
SimpleThread thread1;

public void setup(){

searchString = "";
imageMode(CENTER);

ArrayList<Tweet> messages = new ArrayList<Tweet>(tweets.values());
iterator = messages.listIterator();

controlP5 = new ControlP5(this);

cam = new PeasyCam(this, 1500);
cam.setMinimumDistance(750);
cam.setMaximumDistance(2000);
cam.rotateZ(-HALF_PI);
cam.rotateZ(-HALF_PI);
cam.rotateY(HALF_PI);
cam.rotateY(HALF_PI);
cam.rotateX(QUARTER_PI);
cam.setResetOnDoubleClick(false);
cam.setCenterDragHandler(null);

bezierDetail(30);

font = createFont("Verdana", 13);
textFont(font);

twitter = new TwitterFactory().getOAuthAuthorizedInstance(consumerKey,consumerSecret, new AccessToken(accessToken,accessTokenSecret));
size(910,400,P3D);
//hint(DISABLE_OPENGL_ERROR_REPORT);

frameRate(30);
rectMode(CENTER);
texmap = loadImage("Earthc.jpg");
initializeSphere(sDetail);

gfx=new ToxiclibsSupport(this);
//searchTwitter(SEARCH_QUERY);

thread1 = new SimpleThread(1000,"a");
thread1.start();

controlP5 = new ControlP5(this);

}

public void hud(PeasyCam cam)
{
cam.beginHUD();
pushMatrix();
translate(100, height-120, 0);
// fill(255, 200);
noStroke();

fill(242,242,242);

float tw = textWidth(searchString);
fill(210,210,210);
noStroke();
// rect(-90,107,tw+10,20);
//fill (175);
// rect (x, y, w, h);

   fill(242,242,242);
// text(tweets.toString(), 120, 120,220,220);

if (currentTweet != null) {
    text(currentTweet.toString(), 120,120,220,220);
}

    fill(242,242,242);

text(searchString, 10, 390);

text("Controls:", 736, 20);
text("1 = Geographic Map", 736, 37);
text("2 = Population Map", 736, 50);
text("3 = Economic Map", 736, 63);
text("Enter = Search", 736, 80);
text("Delete = Clear Search", 736, 93);
text("Backspace = Delete", 736, 106);
text("Mouse + Drag = Navigate", 736, 119);
text("MouseWheel = Zoom", 736, 132);

stroke(242,242,242);
if(second()%2 == 0)
    line(tw+-82, 110, tw+-87, 110);





popMatrix();
cam.endHUD();

}

public void searchTwitter(String searchQuery) {

      twitter4j.Query query = new twitter4j.Query(searchQuery);
       //twitter4j.Query.setGeoCode(new GeoLocation(52.30, 13.25), 1000.0, twitter4j.Query.KILOMETERS); // if we want to only get tweets from the region berlin

      query.rpp(100);
      Date referenceDate=new Date();
      for(int i=0; i<NUM_SEARCHES; i++) {




        String d=new SimpleDateFormat("yyyy-MM-dd").format(referenceDate);
        //println("executing search for date: "+d);
        query.until(d);
        // execute search
        try {

          QueryResult result = twitter.search(query);
            for (Tweet tweet : result.getTweets()) {
            // first check if ID is unique?
            if (tweets.get(tweet.getId())==null) {
              // filter out tweets with GPS loc
              GeoLocation loc=tweet.getGeoLocation();
              if (loc!=null) {
                tweets.put(tweet.getId(),tweet);

                //println("adding tweet: "+tweet);
              }
            } else {
              //println("skipping: "+tweet.getId());
            }
          }
        }
        catch(TwitterException e) {
          println(e.getMessage());
        }
        referenceDate.setTime(referenceDate.getTime()-TIME_STEP*DAY_DURATION);
      }
    }



public void draw() {



directionalLight(255, 255, 255, 0, -1, 0);
//lights();
ambientLight(255, 255, 255);
translate(80, 50, 0);
float fov = PI/3.0f;
float cameraZ = (height/2.0f) / tan(fov/2.0f);
perspective(fov, PApplet.parseFloat(width)/PApplet.parseFloat(height),
cameraZ/40.0f, cameraZ*40.0f);

inRange = 0;

background(25,25,25);

renderGlobe();
stroke(255);

//gfx.origin(300);

//searchTwitter(SEARCH_QUERY);
int a = thread1.getCount();

// iterate over all collected tweets
      for(Tweet tweet : tweets.values()) {

        GeoLocation loc=tweet.getGeoLocation();
        // convert geo location into cartesian world coordinates
        Vec3D p=new Vec3D(600,radians((float)loc.getLongitude())-HALF_PI,radians((float)loc.getLatitude())).toCartesian();
        // create a box at the computed position
        AABB box=new AABB(p,2);
        noStroke();
        fill(255,120,0);
        // draw box at position
        gfx.box(box);


      // text(tweets,15,15);




       fill(255);

}
textMode(SCREEN);
        hud(cam);
         controlP5.draw();
                  }

class SimpleThread extends Thread {
        boolean running;           // Is the thread running? Yes or no?
        int wait;                  // How many milliseconds should we wait in between executions?
        String id;                 // Thread name
        int count;                 // counter
        boolean doSearch = false; // search trigger

public boolean getRunning(){
    return running;
}

// Constructor, create the thread
// It is not running by default
        SimpleThread (int w, String s) {
          wait = w;
          running = false;
          id = s;
          count = 0;
        }

       public void start () {
    // Set running equal to true
    running = true;
    // Print messages
    println("Starting thread (will execute every " + wait + " milliseconds.)");
    // Do whatever start does in Thread, don't forget this!
    super.start();
}

   // We must implement run, this gets triggered by start()
public void run () {
    while (running) {
      if (doSearch) {

        searchTwitter(searchString);


           println("Search for " + searchString + " done");

        doSearch = false;


      }
     // println(id + ": " + count);
      count++;
      // Ok, let's wait for however long we should wait

//      try {

//      } catch (Exception e) {
//      }
    }
    System.out.println(id + ": thread is done!"); // The thread is done when we get to the end of run()
}

public void search() {
     doSearch = true;

}

public int getCount() {
    return count;
}
public void quit() {
    System.out.println("Quitting.");
    running = false; // Setting running to false ends the loop in run()
    // IUn case the thread is waiting. . .
    interrupt();
}
      }


public void keyPressed() {

    if (key == CODED && keyCode == LEFT && iterator.hasPrevious()) {
    currentTweet = iterator.previous();
}
else if (key == CODED && keyCode == RIGHT && iterator.hasNext()) {
    currentTweet = iterator.next();
}

     if(((key>='A')&&(key<='Z')) || ((key>='a')&&(key<='z')) || (key==' ')){
          searchString += key;

    }

if(key == DELETE){
   tweets.clear();
}

    if(key == '1'){
   texmap = loadImage("Earthc.jpg");
}

     if(key == '2'){
   texmap = loadImage("Earthd.jpg");
}

      if(key == '3'){
   texmap = loadImage("world32kc.jpg");
}

else if(key == ENTER){thread1.search();

}

   if(key == BACKSPACE){
    if(searchString.length()>0)
      searchString = searchString.substring(0,searchString.length()-1);
}

}

public void renderGlobe()
{
pushMatrix();
translate(0,0,0);

fill(255);
stroke(0);
//sphere(r);
noFill();
pushMatrix();
rotateY(radians(-90));
rotateZ(radians(180));
noStroke();
textureMode(IMAGE);
texturedSphere(r, texmap);
popMatrix();
popMatrix();
}

// Converts 3D cartesian coordinates to polar coordinates
//
// theVector : vector to convert
// returns   : vector containing 'length', 'angleY' and 'angleZ',
//             so that rotating a point (length, 0, 0) first
//             around the y-axis with angleY and then around the
//             z-axis with angleZ results again in point (x, y, z)

public PVector cartesianToPolar(PVector theVector) {
PVector res = new PVector();
res.x = theVector.mag();
if (res.x > 0) {
    res.y = -atan2(theVector.z, theVector.x);
    res.z = asin(theVector.y / res.x);
}
else {
    res.y = 0;
    res.z = 0;
}
return res;
}
class Satellite {
float lat, lng, x, y, z, elevation;
String[] positions;
int id;

Satellite(int id, float _lat, float _lng, float _elevation) {
    this.id = id;
    elevation = _elevation;
    lat = radians(_lat);
    lng = radians(90f-_lng);
    positions = new String[0];
}

public void display() {
    lat += .001f;
    //lng += .008;

    pushMatrix();
    translate(x, y, z);
    fill(255);
    stroke(0);
    box(20);
    float[] rotations = cam.getRotations();
    rotateX(rotations[0]);
    rotateY(rotations[1]);
    rotateZ(rotations[2]);
    text("Satellite #" + id + " " + lat + " " + lng, 20, 0);
    fill(255);
    popMatrix();

}

}

class locationOnGlobe {
float lat, lng, x, y, z;

locationOnGlobe(float _lat, float _lng) {
    lat = radians(_lat);
    lng = radians(90f-_lng);
}

public void display() {
    lng += random(0.001f, 0.0005f);

    pushMatrix();
    translate(x, y, z);
    fill(255, 0, 0);
    noStroke();
    sphere(10);
    popMatrix();

    update();
}

public void update() {
    x = r*cos(lat)*cos(lng);
    y = r*cos(lat)*sin(lng);
    z = r*sin(lat);
}
}

public void initializeSphere(int res)
{
sinLUT = new float[sincos_length];
cosLUT = new float[sincos_length];
for (int i = 0; i < sincos_length; i++) {
    sinLUT[i] = (float) Math.sin(i * DEG_TO_RAD * sincos_precision);
    cosLUT[i] = (float) Math.cos(i * DEG_TO_RAD * sincos_precision);
}
float delta = (float)sincos_length/res;
float[] cx = new float[res];
float[] cz = new float[res];

// Calc unit circle in XZ plane
for (int i = 0; i < res; i++) {
    cx[i] = -cosLUT[(int) (i*delta) % sincos_length];
    cz[i] = sinLUT[(int) (i*delta) % sincos_length];
}

// Computing vertexlist vertexlist starts at south pole
int vertCount = res * (res-1) + 2;
int currVert = 0;

// Re-init arrays to store vertices
sphereX = new float[vertCount];
sphereY = new float[vertCount];
sphereZ = new float[vertCount];
float angle_step = (sincos_length*0.5f)/res;
float angle = angle_step;

// Step along Y axis
for (int i = 1; i < res; i++) {
    float curradius = sinLUT[(int) angle % sincos_length];
    float currY = -cosLUT[(int) angle % sincos_length];
    for (int j = 0; j < res; j++) {
      sphereX[currVert] = cx[j] * curradius;
      sphereY[currVert] = currY;
      sphereZ[currVert++] = cz[j] * curradius;
    }
    angle += angle_step;
}
sDetail = res;
}

public void texturedSphere(float r, PImage t)
{
int v1,v11,v2;
beginShape(TRIANGLE_STRIP);
texture(t);
float iu=(float)(t.width-1)/(sDetail);
float iv=(float)(t.height-1)/(sDetail);
float u=0,v=iv;
for (int i = 0; i < sDetail; i++) {
    vertex(0, -r, 0,u,0);
    vertex(sphereX[i]*r, sphereY[i]*r, sphereZ[i]*r, u, v);
    u+=iu;
}
vertex(0, -r, 0,u,0);
vertex(sphereX[0]*r, sphereY[0]*r, sphereZ[0]*r, u, v);
endShape();

// Middle rings
int voff = 0;
for(int i = 2; i < sDetail; i++) {
    v1=v11=voff;
    voff += sDetail;
    v2=voff;
    u=0;
    beginShape(TRIANGLE_STRIP);
    texture(t);
    for (int j = 0; j < sDetail; j++) {
      vertex(sphereX[v1]*r, sphereY[v1]*r, sphereZ[v1++]*r, u, v);
      vertex(sphereX[v2]*r, sphereY[v2]*r, sphereZ[v2++]*r, u, v+iv);
      u+=iu;
    }

    // Close each ring
    v1=v11;
    v2=voff;
    vertex(sphereX[v1]*r, sphereY[v1]*r, sphereZ[v1]*r, u, v);
    vertex(sphereX[v2]*r, sphereY[v2]*r, sphereZ[v2]*r, u, v+iv);
    endShape();
    v+=iv;
}
u=0;

// Add the northern cap
beginShape(TRIANGLE_STRIP);
texture(t);
for (int i = 0; i < sDetail; i++) {
    v2 = voff + i;
    vertex(sphereX[v2]*r, sphereY[v2]*r, sphereZ[v2]*r, u, v);
    vertex(0, r, 0,u,v+iv);
    u+=iu;
}
//vertex(0, r, 0,u, v+iv);
vertex(sphereX[voff]*r, sphereY[voff]*r, sphereZ[voff]*r, u, v);
endShape();
}

static public void main(String args[]) {
    PApplet.main(new String[] { "--bgcolor=#c0c0c0", "TwitterExp" });
}
}

Many thanks for your help.

- Tom

Replies(19)

PhiLho

Re: Problem changing position in hashmap with keyPressed '<' and '>'

2 years ago

The HashMap might not be the best tool to store your tweets, in your case. Why not just store them in a simple ArrayList, for example?

thomasjam..

Re: Problem changing position in hashmap with keyPressed '<' and '>'

2 years ago

Hi Phi.lho, thanks for your suggestion. Yes I've heard that Arrays / ArrayLists are a more stable and organised method of storage so perhaps I'll try it particularly as accessing elements in the array would probably be easier and maybe more reliable given what I understand about them. However I'm quite pleased with the way that it runs now and it would be neat to be able to control it with keypressed if possible in the short term. I'm looking at this at the moment and having a go at adapting it. Any pointers would be really great.

http://processing.org/learning/topics/hashmapclass.html

Many thanks,

- Tom

thomasjam..

Re: Problem changing position in hashmap with keyPressed '<' and '>'

2 years ago

This looks promising too:

http://processing.org/discourse/yabb2/YaBB.pl?num=1225739603

The answer is within these somewhere I think!

PhiLho

Re: Problem changing position in hashmap with keyPressed '<' and '>'

2 years ago

Perhaps then you can opt for a LinkedHashMap. I never used them, but they seem to address your need.

thomasjam..

Re: Problem changing position in hashmap with keyPressed '<' and '>'

2 years ago

Thanks Phi.lho that seems like a good suggestion. I'll have a look into it. I'm quite a new programmer though so I'm really learning as I go and attempting to piece together examples and reverse engineer them for learning purposes. I think I'll stick with attempting to get my head around the second link I posted first as it seems to be zeroing in on the problem in a way that I can modify. If any experienced programmers were prepared to put together a simple example that would be really great.It seems like the two examples do dump the contents of the hash into array as you first suggested which seems like a good step.

PhiLho

Re: Problem changing position in hashmap with keyPressed '<' and '>'

2 years ago

Honestly, I don't think the second link is related in any way to your problem, but I can be wrong.
Now, your method is correct: search, experiment, learn, make errors, ask for help...
Note that most of us cannot use your large code to try and experiment, as it needs a specific library, errr, lot of libraries, and a Twitter account, and a developer key, etc.
Your problem somehow belongs to Programming Questions, but because of the nature of the code, it ends to Contributes Questions because of the issue above.
I know it is time consuming, but perhaps you can make a smaller sketch with no dependencies (taking a few strings from an array for example), that can be run easily, and allowing to concentrate on the specific problem.

thomasjam..

Re: Problem changing position in hashmap with keyPressed '<' and '>'

2 years ago

Hi Phi.lho, thank you very much for your suggestions. I will put together a smaller, focused sketch asap.

thomasjam..

Re: Problem changing position in hashmap with keyPressed '<' and '>'

2 years ago

Hi Phi.lho, ok I have added a more succinct sketch that demonstrates the logic of what I'm trying to do but sadly it doesn't quite run and throws the error 'cannot find anything named 'iter.'' I think this is close though and hopefully it is clear enough to enable experienced programmers like yourself to be able to experiment if you are happy to do so.

Many thanks,

- Tom

amnon.owed

Re: Problem changing position in hashmap with keyPressed '<' and '>'

2 years ago

I've never used a hashmap before, so I though it would be educational to give it a try.

Reflecting on your code example, there are a few issues, but the most important are:

Your addTweet function doesn't work, mainly because you have the key and the value switched. When you put it in a hashmap you use the key first and the value second. So you will have to turn those around, otherwise it won't work.
You are using the keys '<' and '>' in your keyPressed method. However these are actually the keys ',' and '.'
I'm assuming you want to display one specific tweet, so I suggest to have a variable to keep track of which one.

I've taken these points and turned them into a small working example (see below).

Code Example

HashMap tweets = new HashMap();
int currentTweet;
void setup() {
size (910, 400);
addTweet("Tweet1");
addTweet("Tweet2");
addTweet("Tweet3");
addTweet("Tweet4");
addTweet("Tweet5");
addTweet("Tweet6");
addTweet("Tweet7");
textAlign(CENTER, CENTER);
textFont(createFont("SansSerif", 100));
}
void draw() {
background(0);
text((String)tweets.get(currentTweet), width/2, height/2);
}
void addTweet(String value) {
int n = tweets.size();
tweets.put(n, value);
}
void keyPressed() {
if (key == ',') {
if (currentTweet>0) {
currentTweet--;
}
}
else if (key == '.') {
if (currentTweet<tweets.size()-1) {
currentTweet++;
}
}
}

thomasjam..

Re: Problem changing position in hashmap with keyPressed '<' and '>'

2 years ago

Wicked! Thanks amnon.owed, that's really helped me move forwards with my project. Brilliant. Thanks to Phi.lho too for the suggestions!

- Tom

thomasjam..

Re: Problem changing position in hashmap with keyPressed '<' and '>'

2 years ago

hmmm, it seems like there is still a slight problem when I integrate this back into my program, it might be to do with the fact that my hashmap is setup like this:

HashMap<Long,Tweet> tweets=new HashMap<Long,Tweet>();

As my hashmap already gets populated with tweets from twitter4j I've just attempted to add in the hashmap position counter, the text display method, the addTweet function and the keypressed commands which returns the error: cannot cast from Tweet to String. Gah, so close! Sorry to spin this out but it would be really great to get it running smoothly if possible :)

- Tom

amnon.owed

Re: Problem changing position in hashmap with keyPressed '<' and '>'

2 years ago

With regard to the incoming twitter4j Tweets, check the javadocs. You probably should use getText() on them somewhere in your code. When moving from Hashmap to String, see line 19 from the example code. You can put (String) in front of it.

thomasjam..

Re: Problem changing position in hashmap with keyPressed '<' and '>'

2 years ago

OK thanks amnon.owed, I'll make some coffee and try to figure it out..it's the last step before the infographics!

thomasjam..

Re: Problem changing position in hashmap with keyPressed '<' and '>'

2 years ago

Hi everyone,

OK here I've created a stripped down program that just includes the bit of my code that is troubling me and the required libraries (as my program uses way too many to allow people to play with it although full code is available upon request.) I've tried to integrate amnon.owed's suggestions but I'm still stuck sadly although it workds really well in isolation it throws the error 'cannot cast from tweet to string.' I'm also confused as to how I would include the getText function as advised. Any help to finish this function would be really great! If we could combine the suggested example to search through the collected tweets it would be truly awesome!

Many thanks,

- Tom

NB - it runs with: text(tweets.toString(), 15, 15,220,220); uncommented and text((String)tweets.get(currentTweet), 15,15,220,220); commented.

PhiLho

Re: Problem changing position in hashmap with keyPressed '<' and '>'

2 years ago

With the code on the first message that keeps changing, it is hard to answer... Fortunately, I could build on amnon.owed's answer.
BTW, I removed the secret codes that are supposed to be... secret!

The problem with amnon.owed's answer is that he built on your simplification of code... which as oversimplified! I was about to point that out, had to do something else, then the code has changed...

The problem is that they keys of the hash map are not continuous, otherwise you wouldn't need a hash map! So you cannot use ++ or -- to iterate on the keys.

I followed my idea of LinkedHashMap, but unfortunately, it doesn't expose the doubly-linked list's ListIterator that would allow to walk it in both directions. There is an old bug about this in Sun's bug database...
I found a workaround where the values (their references, actually) are copied to an array list to get its list iterator. So it can work fine if the list of tweets doesn't change often, otherwise it will be slightly more costly (and you have to update the array list each time it is changed/starts iterating).

Here is my version:

Map<Long, Tweet> tweets = new LinkedHashMap<Long, Tweet>();
ListIterator<Tweet> iterator;
Tweet currentTweet;
void setup() {
size(910, 400);
addTweet("Tweet1");
addTweet("Tweet2");
addTweet("Tweet3");
addTweet("Tweet4");
addTweet("Tweet5");
addTweet("Tweet6");
addTweet("Tweet7");
ArrayList<Tweet> messages = new ArrayList<Tweet>(tweets.values());
iterator = messages.listIterator();
textAlign(CENTER, CENTER);
textFont(createFont("Arial", 100));
}
void draw() {
background(0);
if (currentTweet != null) {
text(currentTweet.toString(), width/2, height/2);
}
}
void addTweet(String value) {
tweets.put(Long.valueOf((long) random(4000000)), new Tweet(value));
}
void keyPressed() {
if (key == CODED && keyCode == LEFT && iterator.hasPrevious()) {
currentTweet = iterator.previous();
}
else if (key == CODED && keyCode == RIGHT && iterator.hasNext()) {
currentTweet = iterator.next();
}
}
class Tweet {
String tweetMessage;
Tweet(String msg) {
tweetMessage = msg;
}
@Override String toString() {
return tweetMessage;
}
}

I also used a pseudo-Tweet class, to have a more realistic behavior (you were bitten by that when trying to display: you still need to use the toString() on the result of get()).
There is a little issue when changing direction (displaying the same tweet, not sure why), otherwise it works OK.

thomasjam..

Re: Problem changing position in hashmap with keyPressed '<' and '>'

2 years ago

Wow, that's brilliant thanks Phi.lho! This has really helped me with my project and I really appreciate your time and skill. Thanks also to amnon.owed as well for your time and skill and suggestions!

:) It's like coding Christmas!

- Tom

thomasjam..

Re: Problem changing position in hashmap with keyPressed '<' and '>'

2 years ago

OK bad news guys, I'm still having a bit of trouble integrating this great piece of code back into my program. The program runs and the transition to the LinkedHashmap works great e.g. I am getting the same display from the hashmap info as I was before however I am having a bit of trouble increasing and decreasing the iterator and displaying the tweets e.g. I get no tweets displayed as text and currentTweet always remains null. I'm sorry that my code is long but if someone could help me integrate this back into my program it would be amazing! If anybody wants to use my twitter keys or wants a link a library please just private message. Sorry for the long post but please help me finish this piece of my program!

PhiLho

Re: Problem changing position in hashmap with keyPressed '<' and '>'

2 years ago

messages array list is created too early, when the hash map is empty...
As I wrote, you need to create it when you need an iterator on the current list of tweets, so it suppose the hash map is already loaded (and stable). It isn't a magical link to the hash map, it is a static view of this structure.

thomasjam..

Re: Problem changing position in hashmap with keyPressed '<' and '>'

2 years ago

Awesome! Sorry you did mention that quite clearly. I've added

ArrayList<Tweet> messages = new ArrayList<Tweet>(tweets.values());
iterator = messages.listIterator();

to the tail end of the search function like this:

public void run () {
    while (running) {
      if (doSearch) {

        searchTwitter(searchString);


           println("Search for " + searchString + " done");

        doSearch = false;
          ArrayList<Tweet> messages = new ArrayList<Tweet>(tweets.values());
iterator = messages.listIterator();


      }

and it works really smoothly! In fact it even updates when I perform a new search which is really fanastic! So now I need to add some conditions to avoid null pointer exceptions and to perhaps clear out the previous display prior to updating the array.

Anyhow, it works really well, thank you so much Phi.lho!

- Tom

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