Develop Reference

How can I increment the variable more than one time when sensor event changed?

As you can see that I am trying to increment the variable 'c' when the accelerometer z-axis value greater than 12. But I can do it at one time, it will change the value 0 to 1 after executing the program. But I want to collect how many times the z-axis value becomes more than 12.
#Override
public void onSensorChanged (SensorEvent event) {
textView.setText(event.values[0] + "");
textView1.setText(event.values[1] + "");
textView2.setText(event.values[2] + "");
String s = new String();
s = textView2.getText().toString().trim();
Float t = Float.parseFloat(s);
int c = 0;
if (t > 11) {
c++;
txt.setText(Integer.toString(c));
}
}

int counter = 0;
#Override
public void onSensorChanged (SensorEvent event) {
textView.setText(event.values[0] + "");
textView1.setText(event.values[1] + "");
textView2.setText(event.values[2] + "");
String s = new String();
s = textView2.getText().toString().trim();
Float t = Float.parseFloat(s);
int c = 0; // ???
if (t > 11) {
c++;
counter++;
txt.setText(Integer.toString(c));
System.out.println("I need to learn how to use global
variables.\n
also the thing has been greater than \"12\"
"+counter" times."
);
}
}
Also maybe using more meaningful variable names other than "textView#" would make it less of a pain for people to figure out what you're trying to do.

You can define the variable c as a field member like below:
public class MainActivity {
private int c = 0;
(...)
#Override
public void onSensorChanged (SensorEvent event) {
textView.setText(event.values[0] + "");
textView1.setText(event.values[1] + "");
textView2.setText(event.values[2] + "");
String s = new String();
s = textView2.getText().toString().trim();
Float t = Float.parseFloat(s);
if (t > 11) {
c++;
txt.setText(Integer.toString(c));
}
}
}

Making a simple toast work

I have this method which should output a toast at the end but it is coming up with the following error
Cannot resolve method Toast.makeText()
public Guess makeGuess() {
PegEnum[] data1 = new PegEnum[4];
PegEnum[] codeCpy = code.clone();
PegEnum[] guessCpy = guess.clone();
int correctCount = 0;
int correctColourCount =0;
for (int i = 0; i < codeCpy.length; i++) {
if(codeCpy[i]==guessCpy[i]) {
++correctCount;
codeCpy[i]=null;
guessCpy[i]=null;
}
}
for(int x =0; x<codeCpy.length; x++) {
if (codeCpy[x]!=null) {
for (int y = 0; y < guessCpy.length; y++) {
if (codeCpy[x]==guessCpy[y]) {
++correctColourCount;
guessCpy[y]=null;
}
}
}
}
return new Guess(guess.clone(), correctCount, correctColourCount);
Toast.makeText(this, "You have guessed: " + correctCount + " Correct Pegs" + " and "
+ correctColourCount + "Correct Colours", Toast.LENGTH_LONG).show();
}

There are some errors in your code -
1) Did you import Toast?2) Your toast is after the return statement, and that makes the code unreachable.

Extracting Polynomial Coefficients From input String in JAVA

I made this code for extracting Polynomial coefficients and also evaluating equation in a point,and it is work.
but i want to modify that so the user can enter any shape of polynomial equation.
in my code you have to enter equation like this:
2*x^2+3*x^1+4
but i want :
2*x^5+1*x+6
also if there any term with same power , their coeffs must be added together.
Here is my code in java:
package Priest;
import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.List;
public class Equation {
private String Eq;
private final String[] C;
private int Deg;
private final String EqHolder;
public Equation(String Equation) {
this.Eq = Equation;
EqHolder = Equation;
Eq = Eq.replaceAll("[^0-9\\-\\.]+", " ");
Eq = Eq.replaceAll("-", " -");
this.C = Eq.split(" ");
}
public String SourceEquation() {
return EqHolder.toUpperCase().replaceAll("\\*", "").replaceAll("[a-zA-Z]", "\\*(X)").replaceAll("\\+", "\\ + ").replaceAll("\\-", "\\ - ");
}
public List<BigDecimal> CaptureCoeff() {
getDegree();
List<BigDecimal> Temp = new ArrayList<>();
for (String S : C) {
Temp.add(new BigDecimal(S));
}
int Location = Temp.indexOf(BigDecimal.valueOf(Deg));
List<BigDecimal> Coeffs = new ArrayList<>();
for (int Counter = Location - 1; Counter < Temp.size(); Counter += 2) {
Coeffs.add(Temp.get(Counter));
}
return Coeffs;
}
public int getDegree() {
int Degree = 0;
for (int Counter = 0; Counter < C.length; Counter += 2) {
if ((new Double(C[Counter])) != 0) {
Degree = new Integer(C[Counter + 1]);
this.Deg = Degree;
break;
}
}
return Degree;
}
public BigDecimal Evaluate(List<BigDecimal> Coefficients, double EvalPoint) {
BigDecimal Output = BigDecimal.ZERO;
for (int Index = 0; Index < Coefficients.size(); Index++) {
Output = Output.add(Coefficients.get(Index).multiply(BigDecimal.valueOf(EvalPoint).pow(Deg--)));
}
return Output;
}
}
and main class:
package Priest;
import java.math.RoundingMode;
public class MainClass {
public static void main(String[] args) {
long Start = System.nanoTime();
String Str = "3.1415x^5-12.6x^4+6x^3+12*x^2-6*x^1-0";
Equation E = new Equation(Str);
System.out.println("Equation is: " + E.SourceEquation());
System.out.println("Coefficients :" + E.CaptureCoeff());
System.out.println("Polynomial Degree: " + E.getDegree());
double Target = 47.784;
System.out.println("Equation # (X:" + Target + ")= " + E.Evaluate(E.CaptureCoeff(), Target).setScale(15, RoundingMode.HALF_UP));
System.out.println("Elapsed Time: " + String.format("%.20G", (System.nanoTime() - Start) / 1.0e6) + " ms.");
}
}
the output:
run:
Equation is: 3.1415*(X)^5 - 12.6*(X)^4 + 6*(X)^3 + 12*(X)^2 - 6*(X)^1 - 0
Coefficients :[3.1415, -12.6, 6, 12, -6, 0]
Polynomial Degree: 5
Equation # (X:47.784)= 717609084.382589022327914
Elapsed Time: 32.306242000000000000 ms.
BUILD SUCCESSFUL (total time: 0 seconds)

Let's go with the following equation String Str2 = "3.1415x^5+6x^2+12*x-5";
Here is the code that I have added upon your code in order to preprocess this equation and made it compatible to your actual logic so that It will treat it without any major change to your code.
To be totally accurate I had to change the following in your equation class:
public List<BigDecimal> CaptureCoeff() {
getDegree();
List<BigDecimal> Temp = new ArrayList<BigDecimal>();
for (String S : C) {
if (! "".equals(S.trim())) {
Temp.add(new BigDecimal(S));
}
}
So I have added the control to check that none of these S strings is trim - empty.
Here is my preprocessing code.
I have added a method called powerSplitt that allows to splitt the equation on the basis of the '^' char.
Then I created another method called generateNullCoeffPolynomeWithDegree that generate a monome in the form 0*X^k. And a similar one that generate all the similar intermediate monomes between the greater power and the lesser power
Example:
String str3 = generateAllNullCoeffPolynomesWithDegreeExclusiveBetween(5, 2);
System.out.println("all poly = " + str3);
will generate: all poly = 0*x^4+0*x^3
Then I created a buildPreProcessedPolynome that takes the initial equation and pre process it to produce one with the null monomes inside of it. And then I just gave it to your equation program and it could process it fine!!!
Here is the code and a call example all done in the MainClass
import java.math.RoundingMode;
import java.util.ArrayList;
import java.util.List;
public class MainClass {
private static List<String> workList = new ArrayList<String>();
public static void powerSplitt(String equationText) {
char[] charsList = equationText.toCharArray();
boolean foundTargetChar = false;
int index = 0;
for (int i = 0; i < charsList.length; i++) {
index = i;
if (charsList[i] == '^') {
foundTargetChar = true;
break;
}
}
if (foundTargetChar) {
workList.add(equationText.substring(0, index));
if (index +1 < equationText.length()) {
powerSplitt(equationText.substring(index+1));
} else {
workList.add(equationText);
return;
}
} else {
workList.add(equationText);
}
}
public static String generateNullCoeffPolynomeWithDegree(int degree) {
return "0*x^" + degree;
}
public static String generateAllNullCoeffPolynomesWithDegreeExclusiveBetween(int startDegree, int endDegree) {
if (startDegree-endDegree <= 1) {
return "";
}
int index = 0;
StringBuilder builder = new StringBuilder();
for (int i = startDegree -1; i > endDegree; i--) {
if (index > 0) {
builder.append("+");
}
builder.append(generateNullCoeffPolynomeWithDegree(i));
index++;
}
return builder.toString();
}
public static String buildPreProcessedPolynome(String initialEquationText) {
workList.clear();
powerSplitt(initialEquationText);
StringBuilder resultBuilder = new StringBuilder();
assert workList.size() >= 3;
resultBuilder.append(workList.get(0));
for (int i = 1; i <= workList.size()-2; i++) {
int actualPower = Integer.parseInt( workList.get(i).substring(0,1));
int nextFoundPower = Integer.parseInt( workList.get(i+1).substring(0,1));
System.out.print("actual power = " + actualPower + " and next power = " + nextFoundPower);
System.out.println();
String additionalPolyParts = generateAllNullCoeffPolynomesWithDegreeExclusiveBetween(actualPower, nextFoundPower);
resultBuilder.append("^" + actualPower);
resultBuilder.append("+");
resultBuilder.append(additionalPolyParts);
resultBuilder.append(workList.get(i).substring(1));
}
resultBuilder.append("^" + workList.get(workList.size()-1));
return resultBuilder.toString();
}
public static void main(String[] args) {
workList.clear();
String Str2 = "3.1415x^5+6x^2+12*x-5";
powerSplitt(Str2);
for (String part: workList) {
System.out.println("PART:" + part);
}
System.out.println("-----------------");
long Start = System.nanoTime();
String str3 = generateAllNullCoeffPolynomesWithDegreeExclusiveBetween(5, 2);
System.out.println("all poly = " + str3);
String preprocessed = buildPreProcessedPolynome(Str2);
System.out.println("preprocessed = " + preprocessed);
System.out.println();
Equation E = new Equation(preprocessed);
System.out.println("Equation is: " + E.SourceEquation());
System.out.println("Coefficients :" + E.CaptureCoeff());
System.out.println("Polynomial Degree: " + E.getDegree());
double Target = 47.784;
System.out.println("Equation # (X:" + Target + ")= " + E.Evaluate(E.CaptureCoeff(), Target).setScale(15, RoundingMode.HALF_UP));
System.out.println("Elapsed Time: " + String.format("%.20G", (System.nanoTime() - Start) / 1.0e6) + " ms.");
}
}
And here is the produced results (I haved added some System.out.println to check the results of my methods calls. I just noticed I have to take into account the last constant as a monome of type K*X^0, but I will leave that to you):
PART:3.1415x
PART:5+6x
PART:2+12*x-5
all poly = 0*x^4+0*x^3
actual power = 5 and next power = 2
preprocessed = 3.1415x^5+0*x^4+0*x^3+6x^2+12*x-5
Equation is: 3.1415*(X)^5 + 0*(X)^4 + 0*(X)^3 + 6*(X)^2 + 12*(X) - 5
Coefficients :[3.1415, 0, 0, 6, 12]
Polynomial Degree: 5
Equation # (X:47.784)= 782631805.485054892561514
Elapsed Time: 18,441978000000000000 ms.

Increase of 3 variables

In my program, I have three variables: when one of these variables reaches 100, it must appear the words "variable came first to the finish line."
How do I organize the arrival of the second and third variable, so they come out like this:
variable1-arrived first
variable2-finished second
variable3 finished third
Help!
public Corsa(String name)
{
this.name = name;
System.out.println("Start: " + name);
System.out.println("---------------");
}
public void run()
{
while(finita == false)
{
try
{
avanza = (int) (Math.random()*20+1);
percorso = percorso + avanza;
System.out.println(name + " has path " + percorso + " meters");
if(percorso < 100)
{
System.out.println("---------------");
sleep = (int) (Math.random()*20+1);
Thread.sleep(sleep);
}
else
{
System.out.println("---------------");
System.out.println("---------------");
System.out.println(name + " came in first");
finita = true;
}
}
catch(InterruptedException e){}
Thread.yield();
}
}
}

I haven't tested this (so it might not even compile), but something like the following should work:
public class myRace
{
private int distance = 100;
private float offset = 20;
public int runners[3];
public void run()
{
// Set all runners to 0
for ( int i = 0; i < runners.length; i++ )
runners[i] = 0;
// Run the race and stop when at least 1 runner has reached the distance...
boolean finished = false;
while ( !finished )
{
for ( int i = 0; i < runners.length; i++ )
{
runners[i] += (int)((Math.random() * offset) + 1);
if ( runners[i] >= distance ) finished = true;
}
}
// Race finished now sort the runners
TreeMap<String, int> ranking = new TreeMap<String, int>();
for ( int i = 0; i < runners.length; i++ )
{
// A TreeMap is sorted on its key, not the value!
// The runners number is tagged on, just in case two runners have finished on the same distance.
String sortedKey = Integer.toString(runners[i]) + "." + Integer.toString(i);
ranking.put(sortedKey, i);
}
// Print the results
int pos = 1;
for ( Map.Entry entry : ranking.entrySet() )
{
String key = entry.getKey();
String distance = key.subString(0, key.indexOf(".")); // chop off the "." + runners number.
System.out.println("#" + pos + // position
"." + entry.getValue() + // who
", Distance = " + distance); // distance covered
pos++; // this does take in account whether multiple runners finished on the same distance.
}
}
}

check of a java awt 2D game, jbutton background update problem

i'm posting a simple game code, written in java. It took my hours today to write this but now i'm stuck! The problem is, in the second level of this game (after failure or success) i can't see the red tiles. It works only the first time.
games logic:
it starts up with a 3x3 matrix and rebound the dimension of this matrix in case of success (testing the ability of memory, memorising the coordinates of red tiles in 1200 ms). So we show the red tiles first, than we check the estimations. If there became a wrong try, failure!. If it is a bigger matrix than 3x3, it gets smaller.
the code is a little bit long but just one class, so it is so easy yo execute it. If you have time i would be appreciate.
So there it goes:
package skeleton;
public class Memory extends JFrame implements ActionListener {
private static final long serialVersionUID = 5963518754230629235L;
private static int minDimX = 3, minDimY = 3;
private static int maxDimX = 15, maxDimY = 15;
private static int counter = 13;
private static int memoriseTime = 1200; // milliseconds
private static int memGridWidthX = 60;
private static int memGridWidthY = 60;
private JPanel centerPanel;
private JButton memTile;
private Random generator;
private int memGridDimX, memGridDimY, coef, numberOfMemTilesToGuess;
int[][] memTileCoordinates;
int[] randomNums;
Border grayBorder = LineBorder.createGrayLineBorder();
public Memory(int xDim, int yDim) {
waitALittleBit(1300);
memGridDimX = xDim;
memGridDimY = yDim;
coef = 3;
numberOfMemTilesToGuess = memGridDimX*memGridDimY / coef;
centerPanel = new JPanel();
centerPanel.setLayout(new GridLayout(memGridDimY, memGridDimX, 0, 0));
add(centerPanel, BorderLayout.CENTER);
System.out.println("int[" + memGridDimX + "][" + memGridDimY + "] array is created ");
randomNums = new int[numberOfMemTilesToGuess];
for (int i = 0 ; i < numberOfMemTilesToGuess ; i ++) {
System.out.println("> we are in for the "+ (i+1) +". time!");
int randomNum;
boolean randomNumberAlreadySelected = false;
do {
randomNum = calculateARandomNumber(memGridDimX * memGridDimY);
if (i != 0) { //for the first time, we don't need to compare any numbers
randomNumberAlreadySelected = isThisRandomNumberExistInAlreadyFoundRandomNumbersArray(randomNum, randomNums, i);
if (randomNumberAlreadySelected)
System.out.println("######## RECALCULATING RANDOM NUMBER !! ##########");
else
System.out.println("They are not equal, go on!");
}
} while (randomNumberAlreadySelected);
randomNums[i] = (Integer)randomNum;
}
//show the memory tiles
setMemTiles(randomNums, true);
waitALittleBit(memoriseTime);
//hide the memory tiles
setMemTiles(randomNums, false);
}
private int calculateARandomNumber(int limit) {
generator = new Random();
System.out.println("* Calculating random number which is smaller than " + memGridDimX * memGridDimY);
int randomNum = generator.nextInt() % (memGridDimX * memGridDimY);
System.out.println("- Calculated random number: " + randomNum);
if (randomNum < 0) {
System.out.println(".. it is negative, so we add: " + memGridDimX * memGridDimY);
randomNum += memGridDimX * memGridDimY;
}
System.out.println(".. and we add 1 to have a grid array between 1 and 12");
randomNum += 1;
System.out.println(".. and our new random number is: " + randomNum);
return randomNum;
}
private boolean isThisRandomNumberExistInAlreadyFoundRandomNumbersArray(int number, int[] numberArr, int numberArrSize) {
for (int j = 0 ; j < numberArrSize ; j ++) {
System.out.println("# Comparing random number: " + number + " and " + (j+1) + ". random number selected earlier: " + numberArr[j]);
if (number == numberArr[j])
return true;
}
return false;
}
private void setMemTiles(int[] randomNums, boolean showMemTiles) {
centerPanel.removeAll();
memTileCoordinates = new int[randomNums.length][2];
for (int i = 1 ; i <= memGridDimY ; i ++) {
for (int j = 1 ; j <= memGridDimX ; j ++) {
int rnX = -1;
int rnY = -1;
boolean isMemTile = false;
for (int k = 0 ; k < randomNums.length ; k ++) {
int rn = randomNums[k];
if (rn % memGridDimX == 0) {
rnY = rn / memGridDimX;
rnX = memGridDimX;
} else {
rnY = rn / memGridDimX + 1;
rnX = rn % memGridDimX;
}
if (i == 1 && j == 1 && !showMemTiles) { //do it once
System.out.println("********* ************");
System.out.println("Random label number: " + rn + " and it's position in the grid: " + rnX + "," + rnY);
memTileCoordinates[k][0] = rnX;
memTileCoordinates[k][1] = rnY;
System.out.println("> Memory Tiles coordinates: " + memTileCoordinates[k][0] + "," + memTileCoordinates[k][1]);
System.out.println("> Memory Tiles length: " + memTileCoordinates.length);
System.out.println("********* ************");
}
if (rnX == j && rnY == i)
isMemTile = true;
}
memTile = new JButton();
if (isMemTile) {
update(getGraphics());
if (showMemTiles) {
memTile.setBackground(Color.red);
System.out.println("%%%% PAINTING MEM TILES IN RED %%%%");
} else
memTile.setBackground(Color.white);
update(getGraphics());
} else
memTile.setBackground(Color.white);
if (!showMemTiles) // we listen actions after the memory tiles disappears
memTile.addActionListener(this);
centerPanel.add(memTile);
update(getGraphics());
}
}
setJPanelSettings();
}
private void setJPanelSettings() {
setSize(memGridDimX * memGridWidthX, memGridDimY * memGridWidthY);
setTitle("Memory :: " + memGridDimX + "x" + memGridDimY);
setResizable(false);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
setVisible(true);
}
private void waitALittleBit(long waitingMillisSeconds) {
long t0 = System.currentTimeMillis();
long t1 ;
do {
t1 = System.currentTimeMillis();
} while (t1 - t0 < waitingMillisSeconds);
}
public static void main(String[] args) {
new Memory(minDimX,minDimY);
}
#Override
public void actionPerformed(ActionEvent e) {
System.out.println(">>> An action came >>>");
JButton memTile = (JButton) e.getSource();
Dimension size = memTile.getSize();
int chosenMemTileDimX = memTile.getX();
int chosenMemTileDimY = memTile.getY();
int chosenMemTilePosX = chosenMemTileDimX / size.width + 1; // we add 1 becausee we present our tile numbers as 1:1, 1:2, ... ( instead of 0:0,0:1, ... )
int chosenMemTilePosY = chosenMemTileDimY / size.height + 1;
System.out.println("Chosen Tile's x dimension: " + chosenMemTileDimX + " ans y dimension: " + chosenMemTileDimY);
System.out.println("Chosen Tile's width: " + size.width + " and height: " + size.height);
System.out.println("Chosen Tile's coordinates: " + chosenMemTilePosX + ", " + chosenMemTilePosY);
boolean tileIsMemTile = false;
System.out.println("Memory Tiles Coordinates: ");
for (int i = 0 ; i < memTileCoordinates.length ; i ++) {
int memTileDimX = memTileCoordinates[i][0];
int memTileDimY = memTileCoordinates[i][1];
System.out.println("x: " + memTileDimX + ", y: " + memTileDimY);
if (chosenMemTilePosX == memTileDimX && chosenMemTilePosY == memTileDimY)
tileIsMemTile = true;
}
if (tileIsMemTile) {
System.out.println("!!! Right Tile !!!");
memTile.setBackground(Color.red);
numberOfMemTilesToGuess -= 1;
System.out.println("It rest " + numberOfMemTilesToGuess + " tiles to guess");
} else {
System.out.println("!!! Wrong Tile !!!");
Icon falseTileIcon;
try {
falseTileIcon = new ImageIcon(getClass().getResource("wrong.png"));
if (falseTileIcon.getIconHeight() > 0)
memTile.setIcon(falseTileIcon);
} catch (Exception e1) {
memTile.setBackground(Color.black);
}
update(getGraphics()); // good trick!!
waitALittleBit(1000);
//TODO !!! FAILED IN LEVEL MESSAGE !!!
dispose();
if (memGridDimX == minDimX && ( memGridDimY == minDimY || memGridDimY == minDimY + 1))
new Memory(minDimX, minDimY);
else if (memGridDimX == memGridDimY)
new Memory(memGridDimX - 1, memGridDimY);
else
new Memory(memGridDimX, memGridDimY -1);
}
System.out.println(">>> Action processed >>>");
if (numberOfMemTilesToGuess == 0) {
System.out.println("\n END OF THE LEVEL");
System.out.println("Congratulations, you guessed all the tiles without error !! \n");
dispose();
//TODO !!!! SHOW INTERLEVEL INFORMATION !!!!
if (memGridDimX != maxDimX && memGridDimY != maxDimY) {
if (memGridDimX == memGridDimY)
new Memory(memGridDimX, memGridDimY + 1);
else
new Memory(memGridDimX + 1, memGridDimY);
} else
System.out.println("You have a really good memory my friend!");
}
}}
I used update(getGraphics()); many times, it was just for a test...
Thanks in advance.

You where told in your last posting to NOT use the update() method.
do
{
t1 = System.currentTimeMillis();
}
while (t1 - t0 < waitingMillisSeconds);
Also, never use a tight loop like that. Its just as bad as using Thread.sleep(...);
You where given suggestions in your last posting!

I think you can use LWJGL, which is a java game library.
https://www.lwjgl.org

Some of the issues may be due to the thread on which the various bit of code run. The first time through you are running on the "Main" thread, and to be completely correct calls to update the AWT/Swing GUI should be done using the "Event Dispatcher Thread".
The actionPerformed method is called from the "Event Dispatcher Thread" and so then the second time you call into the constructor for Memory you are in this thread.
Also, aside from the fact you have implemented a delay with a spin-loop, which is not efficient; you should not delay the "Event Dispatcher Thread".
See this short overview: http://www.javamex.com/tutorials/threads/swing_ui.shtml