I don't know if it's a duplicated Question cause I've found nothing and actually I didn't know what Keywords should I've been searching.
I want to have a class which gets an Element as input and then shows the Value of that Element.
for Example:
public void showValue(Object obj){
System.out.printLn("output: " + obj.getValue());
}
and then:
NativeSelect ns=new NativeSelect();
TextField tf=new TextField();
ns.addValue("Name");
ns.select("Name");
tf.setValue("LastName");
showValue(ns);
showValue(tf);
and have this output:
output: Name
output: LastName
could maybe someone help me or give me an idea how should i do that!
I'm new to Java and started programming after a long time.
Thanks alot!
You want a function that can print the value of every field. Like this:
public static void showValue(Field f) {
System.out.println("output: "f.getValue()); //Will print it via console
new Notification("output: "+f.getValue()).show(Page.getCurrent());
//Will show a text box in your current page
}
As from Field docs (link), every field has a getValue(). All that you should take care is that value types that you use in your fields should have overriden toString so this method doesn't show the default toString.
Related
this is my first question on here and I did a search before forming it, so I hope everything is as required.
I am working on a school assignment in Java. I am able to produce the required output but there are a lot of null instances created first. I don't understand why. Information about the library the professor created for the course and the code are below
Library included with this course: i2c.jar. It can be found here.
included in this Library are the classes Country and CountryDB. The API for the Country class can be found at http://130.63.94.24/~roumani/book/doc/i2c/ca/roumani/i2c/Country.html
The API for the CountryDB class can be found at http://130.63.94.24/~roumani/book/doc/i2c/ca/roumani/i2c/CountryDB.html
I am asked to create a class called Game, using the Country and CountryDB APIs.
The only attribute is db, which is an instance of CountryDB.
The constructor only sets the attribute (db) for this instance to a new CountryDB object.
The class is also meant to include a method (called qa) that follows this pseudocode:
get a reference to the database's capital city list
determine the size of this list. Cal it n.
generate a random number in [0,n) called index.
invoke get(index) on the list to get a random capital city. Call it c
get a reference to the database's data map
invoke get(c) on the map to get a reference to a country. Call it ref.
The method is then supposed to return one of two Strings (which will be clear in the code). Everything works as it should, except I get a lot of "nulls" before the desired output. When made into a List, db has size 241 so I suspect I am creating 241 null instances and 1 proper instance. I have no idea why though. I have tested every line of code in my method and the constructor was dictated by the textbook.
CODE
package ca.yorku.eecs.caps;
import java.util.List;
import java.util.Map;
import ca.roumani.i2c.Country;
import ca.roumani.i2c.CountryDB;
public class Game
{
private CountryDB db;
public Game()
{
this.db = new CountryDB();
}
public String qa()
{
List<String> capitals = db.getCapitals();
System.out.println(capitals.toString());
int n = capitals.size();
System.out.println(n);
int index = ((int) (n * Math.random()));
System.out.println(index);
String c = capitals.get(index);
System.out.println(c);
Map<String, Country> data = db.getData();
Country ref = data.get(c);
if (Math.random() > 0.5)
{
return "What is the capital of " + ref.getName() + "? \n" + ref.getCapital();
}
else
{
return ref.getCapital() + " is the capital of? \n" + ref.getName();
}
}
public static void main(String[] args)
{
Game g = new Game();
System.out.println(g.qa());
}
}
the System.out.println() statements are only there to test when the nulls occur. It clearly happens immediately because my psvm output is 241 nulls (on separate lines) followed by my desired output. Can somebody please tell me what I am doing wrong?
And, more generally (to help more people) how do you implement classes, the constructor of which instantiates another class and sets it as an attribute value?
I appreciate any help. Also, please note, I am not trying to get others to do my work for me. I've spent hours on this and my lab TA also wasn't sure why it happens either. He would have helped me correct it had he known how.
Thank you.
my goal is to be able to draw graphs and then save its values if required.
In the image above, I choose from the comboBox a specific type of graph to draw, except for Clear, which just clears the graph that is shown. This is already working correctly.
I have an arrayList of UserPattern(I created) objects that contains a string, a double and a double array.
I want to store the values from the graph in some variable (i'm currently using a double array) to use it later on.
With the double array I've had problems with the passing of values, since when I press "Save Pattern" it keeps the latest values of the graph (the last graph shown) and inputs it on every element of the UserPattern List that I have previously saved. So, even if I save multiple patterns, they all keep the value of the last save.
This is the code I use to store the values in the ArrayList:
private void readAndInsertPatternValues(List<UserPattern> patternLi, double[] graphValue) {
UserPattern tempUserPattern = new UserPattern(typePattern);
//extra code
tempUserPattern.setMonthlyConsump(consTemp);
tempUserPattern.setNameID(patternName);
tempUserPattern.setPatternValues(graphValue);
patternLi.add(tempUserPattern);
System.out.println("Inserted: ");
System.out.println(tempUserPattern);
}
}
I call this method within a mouse event on the button "Save Pattern":
JButton btnSaveUserPattern = new JButton("Save Pattern");
btnSaveUserPattern.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
if(!((comboBoxPattern.getSelectedItem()).equals(UserPattern.PatternType.CLEAR)))
readAndInsertPatternValues(patternList, patternValue);
for(UserPattern upTemp : patternList) {
System.out.println("Inside the Pattern List:");
System.out.println(upTemp.toString());
}
}
});
btnSaveUserPattern.setFont(new Font("Tahoma", Font.PLAIN, 13));
btnSaveUserPattern.setEnabled(false);
Also, I get the values that create the graph in the event from selecting an option of the combobox:
comboBoxPattern = new JComboBox<UserPattern.PatternType>();
comboBoxPattern.setFont(new Font("Tahoma", Font.PLAIN, 13));
comboBoxPattern.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
//this method creates the graphs, so I send the array "patternValue" to "get" the values.
printPatternGraph(comboBoxPattern, chartPanel, "User Pattern for Energy Consumption", "Hours", "Energy Consumption(Wh)", true, patternValue);
btnSaveUserPattern.setEnabled(true);
}
});
I initialized the patternValue array as a local variable in the method that calls and uses the above mentioned methods as such:
double[] patternValue = new double[1440];
With all this, happened the problem in transporting values. At the "insertion time", the console showed the correct values, however, when I clicked on the "Save Pattern" button, which shows all the objects in the UserPattern list, the graph values from the previously saved graphs were equal to the one I saved last. (The last one I saved corrupted all the others).
I tried to change the way of passing values and changed the method "printPatternGraph" to return a double[] array, and made like this:
patternValue=printPatternGraph(comboBoxPattern, chartPanel, "User Pattern for Energy Consumption", "Hours", "Energy Consumption(Wh)", true);
This, however, brought me the error,
Local variable patternValue defined in an enclosing scope must be final or effectively final.
Therefore, I tried making "patternValue" a global variable . This actually solved the problem, but I don't think that this is the best solution (I've read multiple times that global variables are "bad coding".
This way, which way do you think I should implement this?
Thanks for your attention and sorry for the long post,
nhekas
SOLUTION:
I understood what was wrong! Sorry to bother you guys.
My problem, was, that when I added the double array to the ArrayList, I did it like this:
patternLi.add(graphValues);
This, instead of storing the values inside the graphValue array, was storing the reference to it. Therefore, when I wanted to create a different graph, the reference to the graph was the same, but changed the values.
I had to do the following:
new double[] arrayTemp= new double[1440];
for ( int i=0; i<1440;i++) {
arrayTemp[i]=graphValues[i];
}
patternLi.add(arrayTemp);
This way, it worked! Because, since arrayTemp is local, is created everytime I call the method and passes the correct values.
Thanks for all your input guys !
nhekas
New to asking questions here on stack overflow. I have a program that has me stumped. I have been able to get it to work but just not in the manner I would prefer and I was wondering if some of you could take a look at it and help me figure out what I am doing wrong. Please see below:
For the beginning, the program doesnt compile in class Output at
String ageStr = Input.getAge().toString();
int ageInt = Integer.parseInt(ageStr);
because getAge() returns the address, not the Text of JTextField. Integer can't parse that, as it inhabits not only integers.
And so does all your static getters only return not intended data.
Try to change those in class Input after this sample:
public static String getAge() {
return age.getText();
}
and don't forget to add the outputPanel in class Output
add(outputPanel, BorderLayout.CENTER);
Additionally,
make those methods non-static as stated by others
separate / encapsulate code into fitting methods and improve your API
keep an overall persistent code appearance.
One option is to define an object variable and change your Output-Constructor:
Input input; // keeps a ref to input
public Output(Input input) {
super("Output", 300, 300);
this.input = input;
String ageStr = input.getAge();
...
And the call to:
public void actionPerformed(ActionEvent e){
output = new Output(Input.this);
output.display();
...
Hope it helps you.
Ok here is what I changed, like I said I'm still getting an error. So far all I have tried to fix is the code associated with the age. I will work the rest when i figure out how to make this work. See new code below. I can get it to work if I leave everything static but I know that's not the appropriate method. Tried to fix the formatting as well.
I want to create an object of a class by referring to its object, I think. I've been able to make it in C# but in Java it wont work. This is what I want to do:
controller.getDal().getStudentData().getPerson() = new Person(student.getIdNumber(), student.getName(), student.getAddress(), student.getTel());
But I get a error message saying:The left-hand side of an assignment must be a variable
How can I fix the problem? I've tried like doing like this:
register.AddStudent(controller.getDal().getStudentData().getPerson());
and then
System.out.println("Show info: " + controller.getDal().getStudentData().getPerson());
and the output I get is : Person#7cd0a5d9
Java doesn't have the Property syntax that c# does. you have to use a setter.
controller.getDal().getStudentData().setPerson(
new Person(/*blah blah blah*/)
);
if you control whatever type getStudentData returns, than you might have to make one.
public void setPerson(Person newPerson)
{
this.person = newPerson;
}
Right now you are trying to set a new person using a get method. You cannot set an object to a function. You are on the right track with your code:
register.AddStudent(controller.getDal().getStudentData().getPerson());
I do wonder however if in your code that a student and a person are the same thing. You did not provide enough code for me to test and to give you an guaranteed answer, but I would assumg that your code should be more like this:
register.AddStudent(controller.getDal().getStudent());
This way you are getting the student and then adding the student. I'm not sure what you are trying to accomplish but you should really be looking into set methods such as something like:
Person p = controller.getDal().getStudentData().getPerson();
p.setIdNumber = 0011559966
p.setAddress('123 C St');
Or even something along the lines of:
register.AddStudent(new Student("Billy", "Crystal", "123 C st"));
Anyway, if you had more code, I would be able to help you more, but that is the best I can think of without any real context
About:
System.out.println("Show info: " + controller.getDal().getStudentData().getPerson());
You must override the toString() method inside the Person class to the fields or string representation you want to see upon printing.
An example could be:
#Override
public String toString() {
return "Name: " + this.getName() + " Id Num: " + this.getIdNumber();
}
I've been looking all over, and i cant find anyone who can solve this problem. I'm making a game, and in that game, i have editable controls. the controls window is a seperate JFrame, and when i click the confirm button, it is supposed to write the items in the JTextFields (holding the controls) to a file. but that wasnt working, so instead i have it print the arraylist that holds the values. here is the code:
public void writeControls() {
ArrayList<String> al = new ArrayList<String>();
al.add(up.getText());
al.add(down.getText());
al.add(left.getText());
al.add(right.getText());
al.add(jump.getText());
al.add(duck.getText());
al.add(attack.getText());
for (int i = 0; i < al.size(); i++) {
System.out.println(al.get(i));
}
System.exit(0);
}
the problem is this: if i change the final JTextField attack or any other one for that matter, and click submit, the system prints out the default controls. for example, if the JTextFields have the values w,a,s,d,r,t,q and i change the value q to i, it prints out q. what am i doing wrong? thanks in advance!
EDIT 1:
code for the textfields, and the FILES.... is simply a string stored in a different class. the class setText() is below the textfields.
up = new JTextField(setText(FILES.controlsFileFinalDir, 1));
down = new JTextField(setText(FILES.controlsFileFinalDir, 2));
left = new JTextField(setText(FILES.controlsFileFinalDir, 3));
right = new JTextField(setText(FILES.controlsFileFinalDir, 4));
jump = new JTextField(setText(FILES.controlsFileFinalDir, 5));
duck = new JTextField(setText(FILES.controlsFileFinalDir, 6));
attack = new JTextField(setText(FILES.controlsFileFinalDir, 7));
public String setText(String fileDir, int lineNum) {
String txt = "";
txt = io.readSpecificLine(fileDir, lineNum);
txt = switchCase(txt);
return txt;
}
switchcase() is only taking what you have written in the text file that these are getting the values from, and translating them. so if the value is 0, it is turned into Space, etc. io.readSpecificLine(); is only to get the line of text from the file. does this help?
EDIT 2:
i just was dinking around and found out that if i set the JTextField text by using setText(""); then use getText(); it works. so the problem is that when i change it manually, and use getText(); it wont work. Why?
To update the text to a currently existing JTextField, I would establish the JTextField as a class variable, and create a setter/getter method to adjust it (which I'm assuming you're doing).
According to your methods, you would use something like:
up.setText(setText(FILES.controlsFileFinalDir, 7));
Edit: **The first setText is the JTextField.setText, the second setText is your public method you posted. I'm assuming your second getText() isn't working because you're probably not setting the text correctly.
Without seeing more code, I can't really give a better guess.
The main possibilities:
(1) The text fields have their editable property set to false.
(2) You are creating multiple copies of the JTextFields, then editing a new one on the screen, but referring to the old one when you get the value.
(3) You have a ValueChanged or LostFocus event handler that is resetting the text fields to their defaults
(4) It is actually JFormattedTextField not a JTextField
If I was you, I would try to debug the programm. You will probably do some Mistake in your code, you won't be able to see, by just checking the code.
For example in which order do you call the functions and so on, maybe you have a fault here, or maybe you have several threads, so you try to read the Textfields without even set them and so on ... It's hard to say without reviewing the whole Code.
So if you use eclipse you can follow this link for an explanation on how to debug: http://www.vogella.com/articles/EclipseDebugging/article.html
Netbeans or any other IDE should support debugging as well.
This may seem like a strange thing to suggest, but I think this is an issue with pointers. If you create a new string before passing it in, JTextField will be able to change it internally and return what you expect when asked for the modified value.
down = new JTextField("" + setText(FILES.controlsFileFinalDir, 2));
// or
down = new JTextField(new String(setText(FILES.controlsFileFinalDir, 2)));
You might want to try the following:
create a class Test.java
import java.util.ArrayList;
import javax.swing.JTextField;
public class Test implements Runnable {
private ArrayList<JTextField> textFields = null;
private ArrayList<String> stringList = null;
public Test(ArrayList<JTextField> textFields, ArrayList<String> stringList) {
this.textFields = textFields;
this.stringList = stringList;
}
#Override
public void run() {
for ( JTextField textField : this.textFields )
this.stringList.add( textField.getText() );
}
}
and then, at the place where you use the "getText() method .. "
do the following...
ArrayList<JTextField> textFields = new ArrayList<JTextField>();
// add all the JTextField to textFields
ArrayList<String> stringList = new ArrayList<String>();
Test test = new Test( textFields, stringList );
SwingUtilities.invokeLater( test );
// check if the stringList is populated.
If this work, then what I believe is that, for some reason, the JTextField hasn't finished
"setting" the text, and before it finishes your getText() was called. I've had similar problems before, and this solved my problem that time, but still, this might not be the perfect solution.
First, you should change your "setText()" method name to something like "getTextFromFile()" it would be more readable
Then, if you are setting and reading the new text in different threads, my bet is that the setText() is taking long to return, because it is accessing the file system, while the method that read the values run instantly
I would try to do run a little test:
public void test(){ // must be run after the JTextFields be initialized
up.setText("TEST")
System.out.println(up.getText());
up.setText(setText(FILES.controlsFileFinalDir, 1));
System.out.println(up.getText());
}
If the test() prints the correct values, then we can assume that if you set and read the new value in the same thread it works fine
The other test I would do is:
public void testThread(){
new Thread(){
public void run(){
while(true){
if(up!=null){
System.out.println(up.getText());
}
try{
Thread.sleep(1000);
}catch(Exception e){
e.printStackTrace();
}
}
}
}.start();
}
It will print the value of up each 1 second, so that you can see if after some time you get the new value. If it does, then the answer is: Your setText() is taking long to run and you are reading the value before the new value is set
SOLUTION
none of the above answers were working for me, so i finally decided to just start over with that class. the few things i changed were the way i made the JTextFields. I made them as an array instead of individual objects. Second is the way i put what they say. When i initialized them, i was unable to get them to create WITH the text in the parameters. so i had to do that seperately. i changed some of the method names so as to reduce future confusion, and it worked! so im not sure what was up with that, maybe it was the way i did it, maybe just a fluke. it happens sometimes, so im sorry for the delay and waste of your time! thanks for all the answers anyway!
Try this:
textbox.setText(setFile(args)); // your function for set file