java gwt图像不可见

Question

I'm trying to fill a CellTable and in one column I would like to display an Image. This image should be displayed for every row except one. Does anyone know how to add something like this?

Answer 1

This is what I did:

Column column = new Column<RowObject, ImageResource>(new ImageResourceCell()) {

    @Override
    public ImageResource getValue(RowObject object) {
        if (showImageFor(object)) {
            return getImageResource();
        } else {
            return null;
        }
    }
};

cellTable.addColumn(column);

In case you don't know how to obtain an ImageResource, check the docs here .

Update : If you want to use a custom cell, you should decide whether or not to draw the image in the cell's render method:

public class CustomCell extends AbstractCell<ColumnObject> {
    @Override
    public void render(Context context, ColumnObject value, SafeHtmlBuilder sb) {
        if (showImageFor(value)) {
            // Render the image
        }
    }
}

Then you can add the column to your cell like this:

Column column = new Column<RowObject, ColumnObject>(new CustomCell()) {
    @Override
    public ColumnObject getValue(RowObject object) {
        return getColumnObjectFrom(object);
    }
};

cellTable.add(column);

Answer 2

Use ImageCell or ImageResourceCell. In getValue() you either return null (no image will be shown), or you return a URL/ImageResource.