1. Acting on a JTable based on event on a MenuItem:
a> Register an event listener to the menu item.
b> Implement actionPerformed contract to take whatever action on the table you want.
c> Now, to obtain the table mentioned in the above point write method or a class. The way I have been doing this is writing an utility class that will take care of such concerns.
/**
* This method obtains the Parent Frame window of the Menu Item.
* @param menuItem where the action was taken
* @return JFrame parent frame
**/
public JFrame getMainFrame(JMenuItem menuItem) {
JPopupMenu popupMenu = (JPopupMenu) menuItem.getParent();
JMenu menu = (JMenu) popupMenu.getInvoker();
JComponent component = (JComponent) menu;
JFrame frame = (JFrame) component.getTopLevelAncestor();
return frame;
}
/**
* Make use of the Reflection APIs and recursion to grab the wanted component from the frame
* @param container - Container like JPanel, JScrollPane.
* className - Class name of the component to be obtained - javax.swing.JTable, etc
* @return JComponent Object of the class mentioned inside the container passed.
public static JComponent getComponent(Container container, String className) throws ClassNotFoundException{
if (container != null){
Class cl = Class.forName(className);
Component[] components = container.getComponents();
for (int i = 0; i < components.length; ++i){
Component c = components[i];
if (c.getClass().getName().equals(className)){
component = (JComponent)c;
}else if (c instanceof Container){
getComponent((Container)c, className);
}
}
}
return component;
}
Now what if you need a set of several similar components? For example, grab me a list of all the text fields present inside a container.
Use the similar recursive approach with a little modification. Instead of calling this method directly, call an intercepting method. This will, after resetting the instance Collection field, in turn, call the aforementioned method that may be considered to be of private scope. Hence it would go something like this:
public List getComponents(Container container, String className) throws ClassNotFoundException{
componentList = new ArrayList(); //Reset\initialize the Collection
return getComponentList(container, className); //Call the method that internally calls itself
}
private List getComponentList(Container container, String className) throws ClassNotFoundException{
if (container != null){
Class cl = Class.forName(className);
Component[] components = container.getComponents();
for (int i = 0; i < components.length; ++i){
Component c = components[i];
if (c.getClass().getName().equals(className)){
component = (JComponent)c;
componentList.add(component);
}else if (c instanceof Container){
isRecursiveCall = true;
getComponents((Container)c, className);
}
}
}
return componentList;
}
Method to obtain the root panel (JDialog or JFrame):
public Container getMainFrame(JButton button){ Container container = button.getParent(); while(true){ System.out.println(container); if (container instanceof JFrame){ return (JFrame)container; }else if (container instanceof JDialog){ return (JDialog)container; } else{ container = container.getParent(); System.out.println("Container: " + container); } } }
