如何修改NatTable列间自动调整尺寸的拖拽图标？

Got it, let's walk through how to swap out that default column resize drag icon in NatTable for your custom one. I've tackled this before, so here's a straightforward, actionable guide:

Step 1: Create a Custom Resize Icon Painter #

NatTable uses a ResizeIconPainter to draw that drag icon between columns. We'll extend the default implementation to use our own image instead:

import org.eclipse.nebula.widgets.nattable.painter.cell.ResizeIconPainter;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.widgets.Display;

public class CustomResizeIconPainter extends ResizeIconPainter {

    private final Image customResizeIcon;

    public CustomResizeIconPainter() {
        // Load your custom icon - use ClassLoader for project resources to avoid path issues
        this.customResizeIcon = new Image(
            Display.getDefault(),
            getClass().getClassLoader().getResourceAsStream("path/to/your/custom-resize-icon.png")
        );
    }

    @Override
    public void paintIcon(GC gc, int x, int y) {
        // Draw our custom icon, fall back to default if it fails to load
        if (customResizeIcon != null && !customResizeIcon.isDisposed()) {
            gc.drawImage(customResizeIcon, x, y);
        } else {
            super.paintIcon(gc, x, y);
        }
    }

    // Critical: Dispose the image to prevent memory leaks
    @Override
    public void dispose() {
        if (customResizeIcon != null && !customResizeIcon.isDisposed()) {
            customResizeIcon.dispose();
        }
        super.dispose();
    }
}

Step 2: Register the Custom Painter with NatTable Configuration #

Next, we'll create a custom configuration class to tell NatTable to use our painter instead of the default one:

import org.eclipse.nebula.widgets.nattable.config.AbstractRegistryConfiguration;
import org.eclipse.nebula.widgets.nattable.config.IConfigRegistry;
import org.eclipse.nebula.widgets.nattable.resize.mode.ColumnResizeDragMode;

public class CustomResizeIconConfig extends AbstractRegistryConfiguration {

    @Override
    public void configureRegistry(IConfigRegistry configRegistry) {
        // Replace the default resize icon painter with our custom implementation
        configRegistry.registerConfigAttribute(
            ColumnResizeDragMode.RESIZE_ICON_PAINTER,
            new CustomResizeIconPainter()
        );
    }
}

Step 3: Apply the Configuration to Your NatTable Instance #

Finally, add this configuration to your NatTable setup:

// Assume you have your NatTable and GridLayer set up already
NatTable natTable = new NatTable(parent, gridLayer, false);
natTable.addConfiguration(new CustomResizeIconConfig());
natTable.configure();

Key Notes to Remember #

• Resource Paths: Always use ClassLoader.getResourceAsStream for project-internal icons to avoid platform-specific path issues.
• Memory Management: Never forget to dispose the SWT Image when it's no longer needed—our custom painter handles this in the dispose() method.
• Fallback Logic: We included a fallback to the default icon in case your custom image fails to load (prevents broken UI behavior).

内容的提问来源于stack exchange，提问作者mahesh bhagirath