Java tutorial
/* * Copyright 2008 Jeff Dwyer * * 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.apress.progwt.client.calculator; import com.google.gwt.i18n.client.NumberFormat; import com.google.gwt.user.client.ui.Composite; import com.google.gwt.user.client.ui.DockPanel; import com.google.gwt.user.client.ui.Grid; import com.google.gwt.user.client.ui.HorizontalPanel; import com.google.gwt.user.client.ui.MultiWordSuggestOracle; import com.google.gwt.user.client.ui.SuggestBox; import com.google.gwt.user.client.ui.SuggestionEvent; import com.google.gwt.user.client.ui.SuggestionHandler; import com.google.gwt.user.client.ui.TextArea; import com.google.gwt.user.client.ui.TextBox; public class Calculator extends Composite { /** * Format is postive;negative. We want to override the default * thousands separator ',' to help ease our parser. */ private static final NumberFormat nf = NumberFormat.getDecimalFormat().getFormat("###0.#####;-###0.#####"); private ControlAction lastAction; private boolean doClearOnNextDigit; private TextBox inputBox; private double lastNum = 0; private TextArea ticker; public Calculator() { DockPanel dockPanel = new DockPanel(); Grid controls = new Grid(5, 2); Grid numbersP = new Grid(4, 3); // initialize the 1-9 buttons for (int row = 0; row < 3; row++) { for (int col = 0; col < 3; col++) { numbersP.setWidget(row, col, new NumberButton(this, row * 3 + col + 1)); } } numbersP.setWidget(3, 0, new NumberButton(this, 0)); numbersP.setWidget(3, 1, new NumberButton(this, ".")); numbersP.setWidget(3, 2, new ControlButton(this, new ControlAction(this, "+/-") { @Override public boolean isMultiArg() { return false; } @Override public double performAction(ControlAction lastAction, double previous, double current) { return -1 * current; } })); controls.setWidget(0, 0, new ControlButton(this, new ControlAction(this, "/") { @Override public double performAction(ControlAction lastAction, double previous, double current) { return previous / current; } })); controls.setWidget(0, 1, new ControlButton(this, new ControlAction(this, "sqrt") { @Override public boolean isMultiArg() { return false; } @Override public double performAction(ControlAction lastAction, double previous, double current) { return Math.sqrt(current); } })); controls.setWidget(1, 0, new ControlButton(this, new ControlAction(this, "*") { @Override public double performAction(ControlAction lastAction, double previous, double current) { return previous * current; } })); controls.setWidget(1, 1, new ControlButton(this, new ControlAction(this, "%") { @Override public double performAction(ControlAction lastAction, double previous, double current) { return previous % current; } })); controls.setWidget(2, 0, new ControlButton(this, new ControlAction(this, "-") { @Override public double performAction(ControlAction lastAction, double previous, double current) { return previous - current; } })); controls.setWidget(2, 1, new ControlButton(this, new ControlAction(this, "1/x") { @Override public boolean isMultiArg() { return false; } @Override public double performAction(ControlAction lastAction, double previous, double current) { return 1 / current; } })); controls.setWidget(3, 0, new ControlButton(this, new ControlAction(this, "+") { @Override public double performAction(ControlAction lastAction, double previous, double current) { return previous + current; } })); controls.setWidget(3, 1, new ControlButton(this, new ControlAction(this, "=") { @Override public boolean isMultiArg() { return false; } @Override public double performAction(ControlAction lastAction, double previous, double current) { if (lastAction == null) { return current; } return lastAction.performAction(null, previous, current); } })); controls.setWidget(4, 0, new ControlButton(this, new ControlAction(this, "bksp") { @Override public boolean isMultiArg() { return false; } @Override public double performAction(ControlAction lastAction, double previous, double current) { String cStr = current + ""; if (cStr.endsWith(".0")) { cStr = cStr.substring(0, cStr.length() - 3); } else { cStr = cStr.substring(0, cStr.length() - 1); } if (cStr.equals("")) { cStr = "0"; } return Double.parseDouble(cStr); } })); controls.setWidget(4, 1, new ControlButton(this, new ControlAction(this, "clear") { @Override public boolean isMultiArg() { return false; } @Override public double performAction(ControlAction lastAction, double previous, double current) { return 0; } })); dockPanel.add(numbersP, DockPanel.CENTER); dockPanel.add(controls, DockPanel.EAST); inputBox = new TextBox(); inputBox.addStyleName("ResultBox"); dockPanel.add(inputBox, DockPanel.NORTH); ticker = new TextArea(); ticker.setSize("7em", "140px"); MultiWordSuggestOracle oracle = new MultiWordSuggestOracle(); oracle.add("Jill"); oracle.add("Jeff"); oracle.add("James"); oracle.add("Jennifer"); SuggestBox box = new SuggestBox(oracle); box.addEventHandler(new SuggestionHandler() { public void onSuggestionSelected(SuggestionEvent suggE) { String selected = suggE.getSelectedSuggestion().getReplacementString(); // do something with selected suggestion } }); dockPanel.add(box, DockPanel.SOUTH); HorizontalPanel mainP = new HorizontalPanel(); mainP.add(dockPanel); mainP.add(ticker); initWidget(mainP); setResult(0); } public void actionClick(ControlAction action) { if (action.isMultiArg()) { lastNum = getCurrentNum(); setDoClearOnNextDigit(true); this.lastAction = action; } else { setResult(action.performAction(lastAction, getLastNum(), getCurrentNum())); } } public void digitAction(String value) { if (isDoClearOnNextDigit()) { inputBox.setText(""); setDoClearOnNextDigit(false); } inputBox.setText(inputBox.getText() + value); } private double getCurrentNum() { return Double.parseDouble(inputBox.getText()); } private double getLastNum() { return lastNum; } public boolean isDoClearOnNextDigit() { return doClearOnNextDigit; } public void setDoClearOnNextDigit(boolean doClearOnNextDigit) { this.doClearOnNextDigit = doClearOnNextDigit; } private void setResult(double res) { inputBox.setText(nf.format(res)); ticker.setText(res + "\n" + ticker.getText()); GUIEffects.highlight(inputBox); if (res == 0) { setDoClearOnNextDigit(true); } } }