I have a problem with my Java code. I am trying to search trough a JList, with key events, but it seems like it can't find anything.
With this event, I am adding values to my JList:
DefaultListModel<String> model = new DefaultListModel<>();
private void productButtonActionPerformed(java.awt.event.ActionEvent evt) {
for (Shop i : shopSettings.Products) {
model.addElement(i.getProductName()+i.getPrice()+i.getProductCategory()+i.getNumber());
}
jList1.setModel(model);
}
Here I am trying to search trough the JList, with this action, but anytime I write something, it just overwrites the list, and displays nothing.
private void jTextField1KeyReleased(java.awt.event.KeyEvent evt) {
DefaultListModel filteredProducts = new DefaultListModel();
for (Shop i: shopSettings.Products) {
String productName=i.getProductName()+i.getPrice()+i.getProductCategory()+i.getNumber().toLowerCase();
if(productName.contains(jTextField1.getText().toLowerCase()));
{
model.addElement(i.getProductName()+i.getPrice()+i.getProductCategory()+i.getNumber());
}
}
model=filteredProduct;
jList1.setModel(model);
}
Sorry, if the answer is way too obvious, I have just getting started with Java.
could be:
String productName= (i.getProductName()+i.getPrice()+i.getProductCategory()+i.getNumber()).toLowerCase();
Best to learn how the debugger works in your IDE of choice and step through the algorithm to see why it doesn't match.
Edit: To be more clear: Call toLowerCase on the result of the concatenation, not just the last part.
Related
how do i go do this, based on input in textfield, you get some results inside jlist, after you select option in jlist you then get an action, code examples would be appreciated... this is what i got so far:
final DefaultListModel<String> locations = new DefaultListModel<String>();
getTextFieldSearch().addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
for(int i=0;i<10;++i) {
locations.add(i, "blah");
}
}
});
JList<String> list_racentRaces = new JList<String>(locations);
Start by taking a look at How to Use Lists, which has lots of awesome code examples.
The basic idea would be to...
When your actionPerformed method is triggered, create a new DefaultListModel, assuming you don't have your own implementation, fill it with all the new items you need and apply it to the instance of list_racentRaces
If you want to maintain what was previously in the list, you should consider starting with a DefaultListModel and simply add the new items to it as you need to...
Then, attach a ListSelectionListener to list_racentRaces and when the valueChanged event is triggered, find the selected item(s) and do what ever you need to based on these result(s)
You can find more details and examples through How to Write a List Selection Listener
I have a JList which uses a DefaultListModel.
I then add values to the model which then appear in the JList. I have created a MouseListener which (when double clicked) allows the user to edit the current user number of that person they have selected.
I have checked that the actual object of that record is being changed, and it is. The only issue I'm having is getting the actual Jlist to update to show the new values of that object.
Snippets of the current code I have are:
Creating the JList and DefaultTableModel:
m = new DefaultListModel();
m.addListDataListener(this);
jl = new JList(m);
jl.addMouseListener(this);
Updating the object:
String sEditedNumber = JOptionPane.showInputDialog(this, "Edit number for " + name, number);
if (sEditedNumber != null) {
directory.update (name, sEditedNumber);
}
And (when jl is the JList and m is the DefaultTableModel):
public void contentsChanged(ListDataEvent arg0) {
jl.setModel(m);
}
Instead of setModel(), update your existing model using one of the DefaultListModel methods such as setElementAt(), which will fireContentsChanged() for you.
You need to call fireContentsChanged() on the ListModel.
You need to call DefaultListModel.fireContentsChanged(). But since this method is protected (I really wonder why), you can't do that directly. Instead, make a small subclass:
class MinoListModel<T> extends DefaultListModel<T>
{
public void update(int index)
{
fireContentsChanged(this, index, index);
}
}
Use it as your list model:
m = new MinoListModel<>();
jl = new JList(m);
After updating a user number, update the corresponding entry: m.update(theIndex);
Alternatively, if you don't want a subclass, you can just replace the JList element after the user number changed: m.setElementAt(theSameElement, theIndex);. Though this is somewhat cumbersome and having a subclass seems the cleaner approach.
I noticed I can use getName() as part of the trick.
What is java.awt.Component.getName() and setName() used for?
But I don't really have a clue where to start. What type of listener should I use (assuming the textfield / or box is currently blinking / selected)
This is my previous question, and thank you for the help guys.
How do I use requestFocus in a Java JFrame GUI?
I realize that for each component (Textfield) that I am creating, I have to insert a statement like requestFocus (or using transferFocus).
Is it possible to apply this policy to all the fields???
I have several textfields and ComboBox. The problem I hit is that I don't want to write methods for every single field / box.
For example, I write a method like this
private JTextField getFirstNameEntry() {
.... do something
}
because my instructor writes his program like this
private JPanel getJContentPane() {
jContentPane = new JPanel();
jContentPane.setLayout(new java.awt.FlowLayout(FlowLayout.LEADING));
jContentPane.add(makeLabel(" First Name *", 100, 20));
jContentPane.add(getFirstNameEntry(), null);
jContentPane.add(makeLabel(" Middle Initial", 100, 20));
jContentPane.add(getMiddleInitialEntry(), null);
// etc
return jContentPane;
However, to save redundancy (that was my motive at first), say I have a box, I can simply add the following code inside the method above: getJContentPane()
titleBox = new JComboBox(new String[]{"Mr.","Mrs.","Ms.","Dr.","Prof.","Rev."});
jContentPane.add(titleBox);
But doing this, I still need to create a method to do addItemListener
private void setComboBoxFocus() {
titleBox.addItemListener(
new ItemListener(){
public void itemStateChanged(ItemEvent e){
if(e.getStateChange() == ItemEvent.SELECTED)
{
String titleSelected = titleBox.getSelectedItem().toString();
System.out.println(titleSelected);
titleBox.transferFocus();
}
}
});
}
However, this doesn't really save redundancy at all. If I have more than one ComboBox to be added, I would have to write another similar method. In fact, even in the case with one ComboBox (titleBox), I would still end up with writing a method for titleBox.
So my question is: is there a way to write a general method that can call focus to all (maybe one for ComboBox type)?
Thank you and sorry for the long post.
Why not take a JComboBox argument to your setComboBoxFocus() method, which allows you to set that listener to any JComboBox you may have? Like so:
private void setComboBoxFocus(JComboBox box) {
box.addItemListener(
new ItemListener(){
public void itemStateChanged(ItemEvent e){
if(e.getStateChange() == ItemEvent.SELECTED)
{
String titleSelected = box.getSelectedItem().toString();
System.out.println(titleSelected);
box.transferFocus();
}
}
});
}
I am trying to search for UserName and return values onto jComboBox, here is the code
public void actionPerformed(java.awt.event.ActionEvent e) {
sr = new Search(((String) jComboBoxReceiver.getSelectedItem()));
usrList = sr.searchUser();
String[] userList = new String[usrList.size()] ;
for(int i=0;i<usrList.size();i++){
userList[i]= usrList.get(i).getUserName();
}
model = new DefaultComboBoxModel(userList);
jComboBoxReceiver.setModel(model);
}
after you click to somewhere else or click enter,it will conduct the search, however, it will go search for the first item again, which is very confusing... then i tried using key Pressed
if(e.getKeyCode()==13){
sr = new Search(((String) jComboBoxReceiver.getSelectedItem()));
usrList = sr.searchUser();
String[] userList = new String[usrList.size()] ;
for(int i=0;i<usrList.size();i++){
userList[i]= usrList.get(i).getUserName();
}
model = new DefaultComboBoxModel(userList);
jComboBoxReceiver.setModel(model);
}
And this one does not react at all.
You need to set the listener(s) on the Editor not the ComboBox itself. See the answer here:
Detecting when user presses enter in Java
Wow, you're rebuilding a ComboBoxModel each time ? Isn't it a little expensive ? You know there is a MutableComboBoxModel, also implemented by DefaultComboBoxModel that would allow you to add/remove elements from you combobox without rebuilding its model each time ?
Concerning your question, I don't understand the statement
However, if i do that, it does perform correctly, however, it will go search for the first item again
Do you mean your JComboBox starts to blink with content being modified each time ?
if so, maybe is it because your ActionListener is linked to JComboBox, which content changes continuously.
Anyway, i suggest you add some logs, like
sr = new Search(((String) jComboBoxReceiver.getSelectedItem()));
DefaultComboBoxModel model = (DefaultComboBoxModel) jComboBoxReceiver.getModel();
model.remvoeAllElements();
usrList = sr.searchUser();
String[] userList = new String[usrList.size()] ;
for(int i=0;i<usrList.size();i++){
String username = usrList.get(i).getUserName();
System.out.println(username); // feel free to instead use one loger
model.addElement(username);
}
Besides, i would tend to suggest you an other approach, in which combo box model don't contain simple Strings, but rather User objects, with a ListCellRenderer displaying only the user name.
IMO, what will really be confusing for your users is to have the content and selection of a combo box changed as soon as they select one of its options.
Anyway, if you really want to do that, then you should remove the action listener (or deactivate it) before changing its content, and re-add it (or reactivate it) after :
public void actionPerformed(java.awt.event.ActionEvent e) {
sr = new Search(((String) jComboBoxReceiver.getSelectedItem()));
usrList = sr.searchUser();
String[] userList = new String[usrList.size()] ;
for(int i=0;i<usrList.size();i++){
userList[i]= usrList.get(i).getUserName();
}
model = new DefaultComboBoxModel(userList);
jComboBoxReceiver.removeActionListener(this);
jComboBoxReceiver.setModel(model);
jComboBoxReceiver.addActionListener(this);
}
I'm trying to set a combobox in my GUI to print the the information about a student in a JLabel.
private void studentComboBoxMouseClicked(java.awt.event.MouseEvent evt) {
if combobox1="student1"{
println.jlabel."name:a";
println.jlabel.""age:12";
println.jlabel."course:english";
}
if combobox1="student2"{
println.jlabel."name:b";
println.jlabel.""age:11";
println.jlabel."course:maths";
}
if combobox1="student3"{
println.jlabel."name:c";
println.jlabel.""age:10";
println.jlabel."course:science";
}
}
You have to listen for itemstatechange on your combobox,
Upon selecting your student , fetch the selected item and operate on to display appropriate messages.
Have a look at this example
If it is a pseudocode, then it's correct. But in java the same code would be:
if ("student1".equals(combobox1)) {
jlabel.setText("name:a age:12 course:english");
} else if ("student2".equals(combobox1)) {
jlabel.setText(...);
} else if ("student3".equals(combobox1)) {
jlabel.setText(...);
}
Of course, it works if combobox1 is String, which holds the value of your combobox.
You are on the right track but you need to read more tutorials. Start with the one suggested by Babban Shikaari. Your code should be something similar to this:
if (combobox.getSelectedItem().equals("student1")){
jlabel.setText("Your new information");
}