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Java iText7 get Table height [duplicate]

In iText5, we can get the PdfPTable's height when we need "public float calculateHeights(boolean firsttime)".
But in iText7, how can we get current table height value (especially before adding the table to its parent element)?
I already tested "table.getHeight()" method, but it returns null.
And I also found that in a table render object I can get this value, but the limitation is that the render need to be triggered when the table is adding into its parent element, so the time is not my need.
Cause sometimes we need this value for calculation to decide the "y-axis" value.

In iText5, elements and information about their position/size were a bit mixed together, which allowed you to call calculateWidths on a PdfPTable element.
In iText7, this functionality is separated, which allows different kind of flexibility for rendering/layouting elements.
Thus, model elements, which a Table instance is an example of, do not know anything about their position or size. And calling table.getHeight results in null because table did not have HEIGHT property previously set to it.
To calculate table height, one would have to make use of the rendering functionality.
For a model element, you can get the subtree of renderers representing this model element and all its children, and layout it in any given area. To really know the height of a table, you would want to create an area which knowingly will be sufficient to place the whole contents of the element.
PdfDocument pdfDoc = ...
Document doc = ...
Table table = new Table(2)
.addCell(new Cell().add(new Paragraph("cell 1, 1")))
.addCell(new Cell().add(new Paragraph("cell 1, 2")));
LayoutResult result = table.createRendererSubTree().setParent(doc.getRenderer()).layout(
new LayoutContext(new LayoutArea(1, new Rectangle(0, 0, 400, 1e4f))));
System.out.println(result.getOccupiedArea().getBBox().getHeight());
The code above prints 22.982422O for me, but the results may vary depending on the configuration and properties of elements.
I would like to point out two important parts of the code:
We pass 1e4f as the height of the LayoutArea, considering that this will be sufficient to place the whole table. Note that if the table cannot be placed into that height, the result will never exceed this given height and thus it will not be correct for your usecase (know the total height of the table). So make sure to pass the height which will be sufficient for placement of the whole table.
.setParent(doc.getRenderer()) part is important here and is used for retrieving inheritant properties. Note that we did not set a lot of properties to table element, even font, but this information is essential to know the area this element would occupy. So this information will be inherited from the parent chain during layout. You can test this by changing the document's font: document.setFont(newFont);, or font size: document.setFontSize(24); and watching the resultant height change

Well, due to the way the renderer framework is written in iText7, there isn't a way (yet) to calculate the height of a layout object before it is added to a parent document, since the actual calculation of the height for the layout objects happens when they are added to the a Document object.
You can however relayout a Document, allowing you to change the content of previously added elements. Using this, you can simulate the rendering of tables and get a hold of their heights when you add new elements. The table.getHeight() still won't work, since it retrieves the height property, and that property is currently not set anywhere in the table rendering process.
In the example below, I've written a convenience method that iterates over the renderer-tree and prints out the area each table occupies in the document, to show you how you can get the calculated heights.
The example itself adds some tables to the document, displays the occupied areas, adds some cells to each table, displays the occupied areas (they're the same since adding to an element that has been added before doesn't trigger a layout), and finally, manually triggers a relayout and displays the final occupied areas.
public class DelayedLayout {
public static String DEST = "target/output/StackOverflow/DelayedLayout/delayed.pdf";
public static void main(String[] args)throws IOException, FileNotFoundException{
File file = new File(DEST);
file.getParentFile().mkdirs();
new DelayedLayout().createPdf(DEST);
}
public void createPdf(String dest) throws IOException, FileNotFoundException{
PdfWriter writer = new PdfWriter(dest);
PdfDocument pdfDoc = new PdfDocument(writer);
boolean immediateFlush = false;
boolean relayout = true;
//Set immediate layout to false, so the document doesn't immediatly write render-results to its outputstream
Document doc = new Document(pdfDoc, PageSize.A4,immediateFlush);
Table tOne = createSimpleTable();
for(int i= 0; i< 5; i++) {
//Add a table and some whitespace
doc.add(tOne);
doc.add(new Paragraph(""));
}
System.out.println("\nInitial layout results");
printOccupiedAreasOfTableRenderers(doc.getRenderer());
System.out.println("\nAdding extra cells to the table");
addToTable(tOne);
printOccupiedAreasOfTableRenderers(doc.getRenderer());
System.out.println("\nForcing the document to redo the layout");
if(relayout)doc.relayout();
printOccupiedAreasOfTableRenderers(doc.getRenderer());
doc.close();
}
/**
* Create a very simple table
* #return simple table
*/
private Table createSimpleTable(){
int nrOfCols = 3;
int nrOfRows = 5;
Table res = new Table(nrOfCols);
for(int i= 0; i<nrOfRows;i++){
for(int j = 0; j<nrOfCols;j++){
Cell c = new Cell();
c.add(new Paragraph("["+i+", "+j+"]"));
res.addCell(c);
}
}
return res;
}
/**
* Add some extra cells to an exisiting table
* #param tab table to add cells to
*/
private void addToTable(Table tab){
int nrOfRows = 5;
int nrOfCols = tab.getNumberOfColumns();
for(int i=0; i<nrOfRows*nrOfCols;i++){
Cell c = new Cell();
c.add(new Paragraph("Extra cell"+ i));
tab.addCell(c);
}
}
/**
* Recursively iterate over the renderer tree, writing the occupied area to the console
* #param currentNode current renderer-node to check
*/
private void printOccupiedAreasOfTableRenderers(IRenderer currentNode){
if(currentNode.getClass().equals(TableRenderer.class)){
System.out.println("Table renderer with occupied area: " + currentNode.getOccupiedArea());
}
for (IRenderer child:currentNode.getChildRenderers()) {
printOccupiedAreasOfTableRenderers(child);
}
}

How can I fill the remaining blank portion of the page in Itext5?

As seen above，i used pdfTable as the body part of the page. Now i want to fill the entire body with the border,column,row of the table, if the table does not fill the entire body part.As shown in the picture below.
Thanks very much!

You can sort of cheat to accomplish this if you do it while you are creating the table.
I'll offer a partial solution that takes advantage of one of the complexities tables in PDFs: Tables are just lines in PDFs. They aren't structured content.
You can take advantage of this though- keep track of where you are are drawing vertical lines while rendering the table and simply continue them to the bottom of the page.
Let's create a new cell event. It keeps track of 4 things: left which is the far left x coordinate of the table, right which is the far right x coordinate of the table, xCoordinates which is a set of all the x coordinates we draw vertical lines, and finally cellHeights which is a list off all the cell heights.
class CellMarginEvent implements PdfPCellEvent {
Set<Float> xCoordinates = new HashSet<Float>();
Set<Float> cellHeights = new HashSet<Float>();
Float left = Float.MAX_VALUE;
Float right = Float.MIN_VALUE;
public void cellLayout(PdfPCell pdfPCell, Rectangle rectangle, PdfContentByte[] pdfContentBytes) {
this.xCoordinates.add(rectangle.getLeft());
this.xCoordinates.add(rectangle.getRight());
this.cellHeights.add(rectangle.getHeight());
left = Math.min(left,rectangle.getLeft());
right = Math.max(right, rectangle.getRight());
}
public Set<Float> getxCoordinates() {
return xCoordinates;
}
}
We'll then add all of our cells to the table, but not add the table to the document just yet
Document document = new Document();
PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(OUTPUT_FILE));
document.open();
PdfPTable table = new PdfPTable(4);
CellMarginEvent cellMarginEvent = new CellMarginEvent();
for (int aw = 0; aw < 320; aw++) {
PdfPCell cell = new PdfPCell();
cell.addElement(new Paragraph("Cell: " + aw));
cell.setCellEvent(cellMarginEvent);
table.addCell(cell);
}
No we add get top- the top position of our table, and add the table to the document.
float top = writer.getVerticalPosition(false);
document.add(table);
Then we draw the vertical and horizontal lines of the completed table. For the height of each cell I just used the first element in cellHeights.
Set<Float> xCoordinates = cellMarginEvent.getxCoordinates();
//Draw the column lines
PdfContentByte canvas = writer.getDirectContent();
for (Float x : xCoordinates) {
canvas.moveTo(x, top);
canvas.lineTo(x, 0 + document.bottomMargin());
canvas.closePathStroke();
}
Set<Float> cellHeights = cellMarginEvent.cellHeights;
Float cellHeight = (Float)cellHeights.toArray()[0];
float currentPosition = writer.getVerticalPosition(false);
//Draw the row lines
while (currentPosition >= document.bottomMargin()) {
canvas.moveTo(cellMarginEvent.left,currentPosition);
canvas.lineTo(cellMarginEvent.right,currentPosition);
canvas.closePathStroke();
currentPosition -= cellHeight;
}
And finally close the document:
document.close()
Example output:
Note that the only reason I say this is an incomplete examples is because there may be some adjustments you need to make to top in the case of header cells, or there may be custom cell styling (background color, line color, etc) you need to account for yourself.
I'll also note another downfall that I just thought of- in the case of tagged PDFs this solution fails to add tagged table cells, and thus would break compliance if you have that requirement.

JavaFX - Stop Table Column from Resizing with Parent

I have table with 3 columns. The table is using a CONSTRAINED_RESIZE_POLICY.
All three columns can be resized by the user.
When the table's width increases or decreases, I would like for the middle column to stay the same width as it was (in pixels) and for the excess space be distributed (or taken) from the other columns in the same basic way that it's happening now.
Basically, I would the SplitPane.setResizableWithParent( <child>, false ) functionality for a table column.
Any idea how to accomplish this?

How about to reset min and max width only when the column is dragged. This is a example as a inner class.
class CustomResizePolicy implements Callback<TableView.ResizeFeatures, Boolean> {
static final double DEFAULT_MIN_WIDTH = 10.0F, DEFAULT_MAX_WIDTH = 5000.0F;
#Override
public Boolean call(TableView.ResizeFeatures feature) {
final TableColumn<?,?> c = feature.getColumn();
if (c == column2) {
c.setMinWidth(DEFAULT_MIN_WIDTH);
c.setMaxWidth(DEFAULT_MAX_WIDTH);
}
boolean result = TableView.CONSTRAINED_RESIZE_POLICY.call(feature);
if (c == column2) {
c.setMinWidth(c.getWidth());
c.setMaxWidth(c.getWidth());
}
return result;
}
}
and
tableView.setColumnResizePolicy(new CustomResizePolicy());
column2.setMaxWidth(200); // Need to fix column2's width in this case
column2.setMinWidth(200);
column1.setMaxWidth(5000); // Divide left margin with a ratio of 1:2
column3.setMaxWidth(10000);

Java JTable header word wrap

I am trying to get the header on a table to have word wrap. I have managed to do this but the first data row is expanding. The code for the table is:
public class GenerateTable extends JTable {
private JCheckBox boxSelect = new JCheckBox();
private JTableHeader hdGen;
public class LineWrapCellRenderer extends JTextArea implements TableCellRenderer {
private static final long serialVersionUID = 1L;
int rowHeight = 0; // current max row height for this scan
#Override
public Component getTableCellRendererComponent(
JTable table,
Object value,
boolean isSelected,
boolean hasFocus,
int row,
int column)
{
/*
* row < 0 means header
*/
if(row >= 0) {
setWrapStyleWord(false);
return this;
}
setText((String) value);
setWrapStyleWord(true);
setLineWrap(true);
// current table column width in pixels
int colWidth = table.getColumnModel().getColumn(column).getWidth();
// set the text area width (height doesn't matter here)
setSize(new Dimension(colWidth, 1));
// get the text area preferred height and add the row margin
int height = getPreferredSize().height + table.getRowMargin();
// ensure the row height fits the cell with most lines, row = -1 for header
if (column == 2 || height > rowHeight) {
table.setRowHeight(row, height);
rowHeight = height;
}
return this;
}
}
LineWrapCellRenderer lwHeader = new LineWrapCellRenderer();
public GenerateTable(GenerateTableModel model) {
super(model);
this.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
/*
* Select
*/
TableColumn colSelect = this.getColumnModel().getColumn(0);
colSelect.setCellEditor(new DefaultCellEditor(boxSelect));
colSelect.setPreferredWidth(60);
/*
* category
*/
this.getColumnModel().getColumn(1).setResizable(false);
this.getColumnModel().getColumn(1).setPreferredWidth(200);
/*
* Amount values
*/
for (int i=2;i<model.getColumnCount();i++) {
colSelect = this.getColumnModel().getColumn(i);
colSelect.setPreferredWidth(100);
colSelect.setResizable(false);
colSelect.setHeaderRenderer(lwHeader);
}
}
}
The output is:
I have followed the code through in debug and LineWrapCellRenderer is not being called for the data lines. If I take the code out I get a normal table but no wrap on the header. Is this a recognised problem or am I missing something?
Any help appreciated

You can achieve multi-line headers much easier.
As with many Swing components you can use HTML code. In HTML specify <br> elements to indicate where line breaks / new lines should occur.
For example if you use the following header values (column names):
String[] columnNames = {
"<html>First<br>column</html>",
"<html>Second<br>column</html>",
"<html>Third<br>column</html>"
};
Then the headers will be properly rendered in 2 lines. You don't even need to create/use a custom header renderer, the default header renderer properly handles HTML code.
Note: The header height will be determined by the height of the first column. So you have to use a 2-line HTML value for the first column too. If you only have 1 word for the first column, you may additionally add an empty second line like this: "<html>Select<br> </html>"

Displaying empty rows in Android listview

So I'm wondering how to go about filling a ListView with empty rows. The ListView is populated via SQLite db so say for instance there is only 3 items in the list I want to fill the rest of the screen with empty rows. Here is a screenshot of what I mean. Yes I know it's from iPhone but it demonstrates what I mean:

The cheap way is to add extra "rows" in your layout xml. Any extra rows will be cut off by the screen. This can get messy: a higher-res screen might require you add many extra TextViews. Since they get cut off, I suppose you could add as many as you'd like. It would look something like this:
<LinearLayout>
<ListView></ListView>
<TextView/>
<TextView/>
<TextView/>
...
</LinearLayout>
Another option is to add extra rows to your ListView, as mentioned previously. If you are bound to an array, add extra blank rows to the array and handle it appropriately. Coincidentally, if you are using a Cursor you can use a MaxtrixCursor & MergeCursor as described in this answer
I ended up using a combination of these methods. I try my best to calculate the number of rows I want to add to my ListView, but I error on the side of caution and have a couple TextViews underneath my ListView that make it all come together.

When you create the Array the is going to be bound to the ListView you just need to add a few rows at the end of the Array with empty strings.

Using a textview below the listview seems to give the illusion of what I was going for.

#kabir's solution works. Now if you are like me (wanted to have two alternate colors in background, this is his dispached method rewritten (or let's say edited)
#Override
protected void dispatchDraw(Canvas canvas) {
super.dispatchDraw(canvas);
int caseLastChildBottom = -1;
int caselastChildHeight = -1;
int caseNrOfLines = -1;
//makes the colors follow the order (alternateColor1 - alternateColor2 - alternateColor1 - etc.)
int plusIndex = 1;
if (this.getChildCount() % 2 == 0)
plusIndex = 0;
// ListView's height
final int currentHeight = getMeasuredHeight();
// this will let you know the status for the ListView, fitting/not fitting content
final int scrolledHeight = computeVerticalScrollRange();
//empty listview (no item)
if (scrolledHeight == 0) {
//no childs exist so we take the top
caseLastChildBottom = 0;
//last child doesn't exist, so we set a default height (took the value in dp in the item row's height)
caselastChildHeight = convertDpToPx(DEFAULT_CHILD_ROW_S_HEIGHT);
// determine the number of lines required to fill the ListView
caseNrOfLines = currentHeight / caselastChildHeight;
}
//there is a remaining gap to fill
else {
final View lastChild = getChildAt(getChildCount() - 1);
if (lastChild == null) return;
// values used to know where to start drawing lines
caseLastChildBottom = lastChild.getBottom();
// last child's height(use this to determine an appropriate value for the row height)
caselastChildHeight = lastChild.getMeasuredHeight();
// determine the number of lines required to fill the ListView
caseNrOfLines = (currentHeight - caseLastChildBottom) / caselastChildHeight;
}
// values used to know where to start drawing lines
final int lastChildBottom = caseLastChildBottom;
// last child's height(use this to determine an appropriate value for the row height)
final int lastChildHeight = caselastChildHeight;
// determine the number of lines required to fill the ListView
final int nrOfLines = caseNrOfLines;
int i = 0;
for (i = 0; i < nrOfLines; i++) {
Rect r = new Rect(0, lastChildBottom + i * lastChildHeight, getMeasuredWidth(), lastChildBottom + (i + 1) * lastChildHeight);
canvas.drawRect(r, (i + plusIndex) % 2 == 0 ? alternateColorView1 : alternateColorView2);
}
//is there a gap at the bottom of the list
if(currentHeight - (nrOfLines *lastChildHeight) > 0){
Rect r = new Rect(0, lastChildBottom + i * lastChildHeight,getMeasuredWidth(), currentHeight);
canvas.drawRect(r, (i + plusIndex) % 2 == 0 ? alternateColorView1 : alternateColorView2);
}
return;
}
I forgot these two Paint colors (just as #kabir declared the colors):
alternateColorView1.setColor(....);
alternateColorView1.setStyle(Paint.Style.FILL);
alternateColorView2.setColor(....);
alternateColorView2.setStyle(Paint.Style.FILL);