Bug 144225 [FieldAssist] NullPointerException in ContentProposalAdapter$ContentProposalPopup.open()
I am using Eclipse 3.2RC6 and was playing around with the org.eclipse.jface.fieldassist package. I wanted to implement a simple auto-complete textfield with the ContentProposalAdapter class. But if the first letter which is entered in the textfield does not yield any proposals, the call to getSelectedProposal() in line 859 of ContentProposalAdapter.java returns null and therefore a NPE is thrown, rather than just not showing the popup at all. The following snippet shows this behaviour (just type any letter except "p"): import org.eclipse.jface.fieldassist.ContentProposalAdapter; import org.eclipse.jface.fieldassist.IContentProposal; import org.eclipse.jface.fieldassist.IContentProposalProvider; import org.eclipse.jface.fieldassist.TextContentAdapter; import org.eclipse.swt.SWT; import org.eclipse.swt.layout.FillLayout; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.Shell; import org.eclipse.swt.widgets.Text; public class ExampleSnippet { public static void main(String[] args) { Display display = new Display(); Shell shell = new Shell(display); shell.setLayout(new FillLayout()); Text text = new Text(shell, SWT.NONE); ContentProposalAdapter adapter = new ContentProposalAdapter(text, new TextContentAdapter(), new TextProposalProvider(), null, null); adapter.setProposalAcceptanceStyle(ContentProposalAdapter.PROPOSAL_REPLACE); shell.setSize(200, text.getSize().y); shell.open(); while (!shell.isDisposed()) { if (!display.readAndDispatch()) display.sleep(); } display.dispose(); } } class TextProposalProvider implements IContentProposalProvider { private String str = "Proposal"; public IContentProposal[] getProposals(String contents, int position) { IContentProposal[] proposals; if (str.toLowerCase().startsWith(contents.toLowerCase())) { proposals = new IContentProposal[1]; proposals[0] = new IContentProposal() { public String getContent() { return str; } public int getCursorPosition() { return str.length(); } public String getDescription() { return null; } public String getLabel() { return null; } }; } else { proposals = new IContentProposal[0]; } return proposals; } }
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/ContentProposalAdapter.java
*            parameter is <code>null</code>, then only a specified
	 *            keyStroke will invoke content proposal. If this parameter is
	 *            <code>null</code> and the keyStroke value is
	 *            <code>null</code>, then all alphanumeric characters will
	 *            auto-activate content proposal.
	 * 
	 */
	public void setAutoActivationCharacters(char[] autoActivationCharacters) {
		this.autoActivateString = new String(autoActivationCharacters);
	}
	/**
	 * Set the delay, in milliseconds, used before any autoactivation is
	 * triggered.
	 * 
	 * @return the time in milliseconds that will pass before a popup is
	 *         automatically opened
	 */
	public int getAutoActivationDelay() {
		return autoActivationDelay;
	}
	/**
	 * Set the delay, in milliseconds, used before autoactivation is triggered.
	 * 
	 * @param delay
	 *            the time in milliseconds that will pass before a popup is
	 *            automatically opened
	 */
	public void setAutoActivationDelay(int delay) {
		autoActivationDelay = delay;
	}