Removing Widgets from a composite

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Written by Prakash G. R.

One of the frequent questions from Swing-to-SWT developers is: What is the equivalent of the Container.remove method in SWT? AFAIK, there is none. The Composite doesn't have any method to remove its children. But then we have a workaround. We can dispose the child widget! Let me give a simple code to explain. The problem statement is simple: Have a Combo box for different UI elements and fill a composite based on the selection. Hope the code is clear and doesn't require any clarifications.

composite = new Composite(parent, SWT.NONE);
composite.setLayout(new GridLayout(2, false));

Label label = new Label(composite, SWT.None);
label.setText("Select Control:");

combo = new Combo(composite, SWT.READ_ONLY | SWT.DROP_DOWN);
combo.add("Text Box");
combo.add("Combo");
combo.add("Radio Button");

combo.addSelectionListener(new SelectionAdapter() {

    @Override
    public void widgetSelected(SelectionEvent e) {

	    if (control != null)
	    	control.dispose();
	
	    switch (combo.getSelectionIndex()) {
	    case 0:
			control = new Text(composite, SWT.BORDER);
			break;
	    case 1:
	    	control = new Combo(composite, SWT.DROP_DOWN);
	    	break;
	    case 2:
	    	control = new Button(composite, SWT.RADIO);
	    	break;
	    }
	
	    GridData data = new GridData(SWT.FILL, SWT.NONE, false, false);
	    data.horizontalSpan = 2;
	    control.setLayoutData(data);
	
	    composite.layout(true);
    }
});

Here is the result: