I am working on a project where I have a bunch of buttons, mostly split into two groups and I would like to work with these groups through an array. Each button is an instance of class Button extends JButton and each instance has its own value (this.value = "..")
The problem is that it seems like array is being filled with previously mentioned instances, but when I try to reach them, it acts like array is filled with nulls.
Button but1, but2, but3;
Button[] buttonNumbers = {but1, but2, but3};
System.out.println(buttonNumbers.length); // returns 3, so it acts like array IS filled
System.out.println(but1.value); // prints whatever the value is
System.out.println(buttonNumbers[0].value); // throws error, element acts like null
Could someone help me out, where is the problem or what am I missing ?
Thank you for every tip or answer!
It doesn't seem like you're initializing each Button! You need to call its constructor for each Button with whatever parameters you defined:
Button but1 = new Button(), but2 = new Button(), but3 = new Button();
Button[] buttonNumbers = {but1, but2, but3};
System.out.println(buttonNumbers.length); // returns 3, so it acts like array IS filled
System.out.println(but1.value); // prints whatever the value is
System.out.println(buttonNumbers[0].value);
Related
I am attempting to Dynamically Create Buttons to match Data Table. I was using this answer as a reference point however I keep getting this error code: Button (android.content.Context) in Button Cannot be Applied to (Java.lang.Object)
I tried multiple things to alleviate error code but I am at a loss of how to fix it I attempted to set the Map to an array but that isn't working either. The Code has successfully counted, and displayed the data but I cannot get it to add the Needed Buttons.
Backendless.Data.of( "Store" ).find( queryBuilder, new AsyncCallback<List<Map>>()
{
#Override
public void handleResponse( List<Map> response )
{
int numBrands = response.size();
Button brandButtons[] = new Button[numBrands];
System.out.println("The Count of Buttons:" + numBrands);
ArrayList<Brands> productList = new ArrayList<>();
Object[] arrayList = {response};
for(int i = 0; i < brandButtons.length; i++)
{
Button brans = new Button(productList[i]);
brans.setOnClickListener();
add(brans);
brandButtons[i] = brans;
//Object element = thisIsAStringArray[i];
System.out.println( "List of Brands" + response );
}
}
Your error is here in this line:
Button brans = new Button(productList[i]); // here
Button class expects Context passed to it's constructor invocation & you're passing Object type instead.
Use like this,
Button brans = new Button(context); // here context can be activity or fragment.
//now use this brans object to set property to your programmatically created Button,
//don't forget to add it to your parent view afterwards
As you can see in Button documentation, to create a button object you need to pass a Context object. In your code your passing an object of Brands which is causing the problem.
The solution would be to pass a context to the Button(Context) constructor. If your in an Activity it would be something like new Button(YourActivity.this), in a fragment you could use new Button(getContext())
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
Well, I have another doubt. Every row of my list have those components
Label - Button(-) - Button(+) - Label(0) when I clicked on Button(+) I need to get Label(0) value and increase one unit. So I need to get Label(0) reference to set new values. I am trying to find this component with:
Label l = (Label)findByName("lblVal", c.getParent());
Label l = findLblVal();
Label l = findLblVal(c);
Label l = findLblVal(c.getPrent());
My code in List Action Listener is:
List list = (List)c;
Button b = ((GenericListCellRenderer)list.getRenderer()).extractLastClickedComponent();
if(b != null)
{
//lblVal is the name of my component in the renderer
//MY PROBLEM IS HERE, I GET NULL REFERENCE
Label l = findLblVal(c);
}
but I always get a null reference. How can I get reference to this component?
Renderer's are stateless. I suggest reading the developer guide or following the How Do I? videos.
You need to edit your model so that it includes a field matching the name of the label with the proper string that you want.
I've put together a few methods that are suppose to delete a searched item from an array and the data from the array is also being put into a JTable through a method called createLoginTable().
When my delete button actionListener Method is carried out the element or login is successfully deleted from the array: 'listOfLogins' but the element does not appear to be deleted from the JTable as it is still there.
Here are the methods starting with the actionListener:
if(e.getSource()==deleteLoginButton)
{
int loopNo = list.nextLogin; ///Variables used in the 'removeLogin' Method
String foundLogin = list.listOfLogins[foundLocation].toString();
Login[] loginList = list.listOfLogins;
LoginList list = new LoginList(); //The 'list' is wiped
list.removeLogin(loginList, foundLogin, loopNo);
list.writeLoginsToFile(); //Writes logins to file (not integral to the array)
String[][] loginTableLogins = new String[50][2]; //Wipes the JTable Array
createLoginsTable(); //Creates the JTable
searchLoginButton.setEnabled(true);
editLoginButton.setEnabled(false);
deleteLoginButton.setEnabled(false);
addLoginButton.setEnabled(true);
}
This is the 'removeLogin' Method (This is in a seperate 'list' class):
public void removeLogin(Login[] array, String unwantedLogin, int loop)
{
for(int i=0;i<loop;i++)
{
String currentLogin = array[i].toString();
if(!currentLogin.equals(unwantedLogin))
{
Login login = new Login();
addLogin(array[i]);
}
}
}
plus 'addLogin' Method (although i am assured this is not the source of my issue):
public void addLogin(Login tempLogin)
{
listOfLogins[nextLogin] = tempLogin;
System.out.println(listOfLogins[nextLogin]);
nextLogin++;
System.out.println(nextLogin);
}
And the 'createLoginsTable' method:
public void createLoginsTable()
{
for(int i=0;list.nextLogin>i;i++)
{
loginTableLogins[i] = list.listOfLogins[i].toArray();
System.out.println(list.listOfLogins[i].toString());
}
JTable loginsTable = new JTable(loginTableLogins, loginTableTitles);
JScrollPane loginsScrollPane = new JScrollPane(loginsTable);
loginsScrollPane.setBounds(400, 200, 200, 250);
testPanel.add(loginsScrollPane);
}
I have used 'System.out.println's so I am 99% certain that the element has been removed from the array (it is also apparent through my writeLoginsToFile Method) So I hope this information helps.
Your code is a little bit hard to decipher, next time maybe put in also the enclosing class, or some details about that class. What does the following line do:
LoginList list = new LoginList(); //The 'list' is wiped
You say the list is wiped, I think what is does is: it declares a list local variable and assigns a new object to it (and it masks the other list variable which you used a few lines earlier). Now, in the createLoginsTable() method you don't have this local variable, you have the "list" which I guess is a public field in your class. Now what you can do, is or pass the local list variable to the above function as a parameter createLoginsTable(list) or try the wiping line without the declaration so only:
list = new LoginList(); //The 'list' is wiped
Anyway, your code seams a little bit troubled it, maybe you should refactor it a little bit. Hope it helps.
You're not returning the table after you delete the item.
When you call the method to delete it and write out the table, that table is not returned after you remake the table.
Take this:
JScrollPane loginsScrollPane = new JScrollPane(loginsTable);
Bring it outside of your method. What I think might be happening is when you create your loginsScrollPane locally inside the method, it's not being added properly to your testPanel.
I think what might be happening is when you add it, and the method ends it's loosing that data that is contained. Declare your scrollpane, and your jtable where you declare your frame.
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