如何隐藏和显示带有可选内容的表格

Question

I am using iText Library for creating sort-able table. For this I am trying to hide/show the tables created at the same position. I read this can be achieved by using Optional Content . Can anyone please help me out to show/hide a Table with Optional Content?

Answer 1

Take a look at the SortingTable example. In this example, we add three overlapping tables to a document at the same location, but as each table belongs to a different layer of a radio group, only one table is visible at the same time. You can switch to another table by clicking on the column header.

Take a look at optionaltables.pdf . The default view looks like this:

But if you click on the words "Column 2", it looks like this:

How is this done?

First we create the OCGs:

ArrayList<PdfLayer> options = new ArrayList<PdfLayer>();
PdfLayer radiogroup = PdfLayer.createTitle("Table", writer);
PdfLayer radio1 = new PdfLayer("column1", writer);
radio1.setOn(true);
options.add(radio1);
radiogroup.addChild(radio1);
PdfLayer radio2 = new PdfLayer("column2", writer);
radio2.setOn(false);
options.add(radio2);
radiogroup.addChild(radio2);
PdfLayer radio3 = new PdfLayer("column3", writer);
radio3.setOn(false);
options.add(radio3);
radiogroup.addChild(radio3);
writer.addOCGRadioGroup(options);

Then we add 3 tables at the same location using ColumnText :

PdfContentByte canvas = writer.getDirectContent();
ColumnText ct = new ColumnText(canvas);
for (int i = 1; i < 4; i++) {
    canvas.beginLayer(options.get(i - 1));
    ct.setSimpleColumn(new Rectangle(36, 36, 559, 806));
    ct.addElement(createTable(i, options));
    ct.go();
    canvas.endLayer();
}

The table is created like this:

public PdfPTable createTable(int c, List<PdfLayer> options) {
    PdfPTable table = new PdfPTable(3);
    for (int j = 1; j < 4; j++) {
        table.addCell(createCell(j, options));
    }
    for (int i = 1; i < 4; i++) {
        for (int j = 1; j < 4; j++) {
            table.addCell(createCell(i, j, c));
        }
    }
    return table;
}

We want the words in the header to be clickable:

public PdfPCell createCell(int c, List<PdfLayer> options) {
    Chunk chunk = new Chunk("Column " + c);
    ArrayList<Object> list = new ArrayList<Object>();
    list.add("ON");
    list.add(options.get(c - 1));
    PdfAction action = PdfAction.setOCGstate(list, true);
    chunk.setAction(action);
    return new PdfPCell(new Phrase(chunk));
}

In this POC, the difference between the tables is different from what you want. You want the content to be sorted differently. For this simple example, I introduced a different background color:

public PdfPCell createCell(int i, int j, int c) {
    PdfPCell cell = new PdfPCell();
    cell.addElement(new Paragraph(String.format("row %s; column %s", i, j)));
    if (j == c) {
        cell.setBackgroundColor(BaseColor.LIGHT_GRAY);
    }
    return cell;
}