Java tutorial
/* * Copyright 2007 Google Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); you may not * use this file except in compliance with the License. You may obtain a copy of * the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations under * the License. */ package com.google.gwt.user.client.ui; import com.google.gwt.user.client.DOM; import com.google.gwt.user.client.Element; /** * A flexible table that creates cells on demand. It can be jagged (that is, * each row can contain a different number of cells) and individual cells can be * set to span multiple rows or columns. * <p> * <img class='gallery' src='doc-files/Table.png'/> * </p> * <p> * <h3>Example</h3> * {@example com.google.gwt.examples.FlexTableExample} * </p> */ public class FlexTable extends HTMLTable { /** * FlexTable-specific implementation of {@link HTMLTable.CellFormatter}. The * formatter retrieved from {@link HTMLTable#getCellFormatter()} may be cast * to this class. */ public class FlexCellFormatter extends CellFormatter { /** * Gets the column span for the given cell. This is the number of logical * columns covered by the cell. * * @param row the cell's row * @param column the cell's column * @return the cell's column span * @throws IndexOutOfBoundsException */ public int getColSpan(int row, int column) { return DOM.getElementPropertyInt(getElement(row, column), "colSpan"); } /** * Gets the row span for the given cell. This is the number of logical rows * covered by the cell. * * @param row the cell's row * @param column the cell's column * @return the cell's row span * @throws IndexOutOfBoundsException */ public int getRowSpan(int row, int column) { return DOM.getElementPropertyInt(getElement(row, column), "rowSpan"); } /** * Sets the column span for the given cell. This is the number of logical * columns covered by the cell. * * @param row the cell's row * @param column the cell's column * @param colSpan the cell's column span * @throws IndexOutOfBoundsException */ public void setColSpan(int row, int column, int colSpan) { DOM.setElementPropertyInt(ensureElement(row, column), "colSpan", colSpan); } /** * Sets the row span for the given cell. This is the number of logical rows * covered by the cell. * * @param row the cell's row * @param column the cell's column * @param rowSpan the cell's row span * @throws IndexOutOfBoundsException */ public void setRowSpan(int row, int column, int rowSpan) { DOM.setElementPropertyInt(ensureElement(row, column), "rowSpan", rowSpan); } } private static native void addCells(Element table, int row, int num)/*-{ var rowElem = table.rows[row]; for(var i = 0; i < num; i++){ var cell = $doc.createElement("td"); rowElem.appendChild(cell); } }-*/; public FlexTable() { super(); setCellFormatter(new FlexCellFormatter()); setRowFormatter(new RowFormatter()); setColumnFormatter(new ColumnFormatter()); } /** * Appends a cell to the specified row. * * @param row the row to which the new cell will be added * @throws IndexOutOfBoundsException */ public void addCell(int row) { insertCell(row, getCellCount(row)); } /** * Gets the number of cells on a given row. * * @param row the row whose cells are to be counted * @return the number of cells present * @throws IndexOutOfBoundsException */ @Override public int getCellCount(int row) { checkRowBounds(row); return getDOMCellCount(getBodyElement(), row); } /** * Explicitly gets the {@link FlexCellFormatter}. The results of * {@link HTMLTable#getCellFormatter()} may also be downcast to a * {@link FlexCellFormatter}. * * @return the FlexTable's cell formatter */ public FlexCellFormatter getFlexCellFormatter() { return (FlexCellFormatter) getCellFormatter(); } /** * Gets the number of rows. * * @return number of rows */ @Override public int getRowCount() { return getDOMRowCount(); } /** * Inserts a cell into the FlexTable. * * @param beforeRow the cell's row * @param beforeColumn the cell's column */ @Override public void insertCell(int beforeRow, int beforeColumn) { super.insertCell(beforeRow, beforeColumn); } /** * Inserts a row into the FlexTable. * * @param beforeRow the row to insert */ @Override public int insertRow(int beforeRow) { return super.insertRow(beforeRow); } /** * Remove all rows in this table. */ public void removeAllRows() { int numRows = getRowCount(); for (int i = 0; i < numRows; i++) { removeRow(0); } } @Override public void removeCell(int row, int col) { super.removeCell(row, col); } /** * Removes a number of cells from a row in the table. * * @param row the row of the cells to be removed * @param column the column of the first cell to be removed * @param num the number of cells to be removed * @throws IndexOutOfBoundsException */ public void removeCells(int row, int column, int num) { for (int i = 0; i < num; i++) { removeCell(row, column); } } @Override public void removeRow(int row) { super.removeRow(row); } /** * Ensure that the cell exists. * * @param row the row to prepare. * @param column the column to prepare. * @throws IndexOutOfBoundsException if the row is negative */ @Override protected void prepareCell(int row, int column) { prepareRow(row); if (column < 0) { throw new IndexOutOfBoundsException("Cannot create a column with a negative index: " + column); } // Ensure that the requested column exists. int cellCount = getCellCount(row); int required = column + 1 - cellCount; if (required > 0) { addCells(getBodyElement(), row, required); } } /** * Ensure that the row exists. * * @param row The row to prepare. * @throws IndexOutOfBoundsException if the row is negative */ @Override protected void prepareRow(int row) { if (row < 0) { throw new IndexOutOfBoundsException("Cannot create a row with a negative index: " + row); } // Ensure that the requested row exists. int rowCount = getRowCount(); for (int i = rowCount; i <= row; i++) { insertRow(i); } } }