Java tutorial
/* ------------------------------------------------------------------------- OpenTripPlanner GWT Client Copyright (C) 2015 Mecatran - info@mecatran.com This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. ------------------------------------------------------------------------- */ package com.mecatran.otp.gwt.client.view; import com.google.gwt.event.dom.client.KeyCodes; import com.google.gwt.event.dom.client.KeyPressEvent; import com.google.gwt.event.dom.client.KeyPressHandler; import com.google.gwt.event.dom.client.KeyUpEvent; import com.google.gwt.event.dom.client.KeyUpHandler; import com.google.gwt.event.logical.shared.ValueChangeEvent; import com.google.gwt.user.client.ui.TextBox; /** * This widget allows only to introduce numbers. * * @author Carlos Tasada */ public class ValueTextBox extends TextBox { private int min = 0; private int max = 100; private boolean minConstrained = true; private boolean maxConstrained = true; private int minDigits = 1; private int step = 1; private KeyUpHandler keyUpHandler = new KeyUpHandler() { @Override public void onKeyUp(KeyUpEvent event) { if (isReadOnly() || !isEnabled()) { return; } int keyCode = event.getNativeEvent().getKeyCode(); boolean processed = false; switch (keyCode) { case KeyCodes.KEY_LEFT: case KeyCodes.KEY_RIGHT: case KeyCodes.KEY_BACKSPACE: case KeyCodes.KEY_DELETE: case KeyCodes.KEY_TAB: if (getText().isEmpty()) { setValue(formatValue(min)); } return; case KeyCodes.KEY_UP: if (step != 0) { increaseValue(); processed = true; } break; case KeyCodes.KEY_DOWN: if (step != 0) { decreaseValue(); processed = true; } break; } if (processed) { cancelKey(); } } }; private KeyPressHandler keyPressHandler = new KeyPressHandler() { @Override public void onKeyPress(KeyPressEvent event) { if (isReadOnly() || !isEnabled()) { return; } int keyCode = event.getNativeEvent().getKeyCode(); switch (keyCode) { case KeyCodes.KEY_LEFT: case KeyCodes.KEY_RIGHT: case KeyCodes.KEY_BACKSPACE: case KeyCodes.KEY_DELETE: case KeyCodes.KEY_TAB: case KeyCodes.KEY_UP: case KeyCodes.KEY_DOWN: return; } int index = getCursorPos(); String previousText = getText(); String newText; if (getSelectionLength() > 0) { newText = previousText.substring(0, getCursorPos()) + event.getCharCode() + previousText.substring(getCursorPos() + getSelectionLength(), previousText.length()); } else { newText = previousText.substring(0, index) + event.getCharCode() + previousText.substring(index, previousText.length()); } cancelKey(); setValue(newText, true); } }; public ValueTextBox(int value) { this(value, 0, 100); } public ValueTextBox(int value, int min, int max) { this(value, min, max, true); } public ValueTextBox(int value, int min, int max, boolean constrained) { this(value, min, max, constrained, constrained); } public ValueTextBox(int value, int min, int max, boolean minConstrained, boolean maxConstrained) { super(); addKeyPressHandler(keyPressHandler); addKeyUpHandler(keyUpHandler); this.min = min; this.max = max; this.minConstrained = minConstrained; this.maxConstrained = maxConstrained; setValue(formatValue(value), false); setAlignment(TextAlignment.CENTER); } public void setMinDigits(int minDigits) { if (minDigits > 0) { this.minDigits = minDigits; String value = getText(); long newValue = parseValue(value); setText(formatValue(newValue)); } } public void setSteps(int step) { this.step = step; } protected void increaseValue() { if (step != 0) { String value = getText(); long newValue = parseValue(value); newValue += step; if (maxConstrained && (newValue > max)) { return; } setValue(formatValue(newValue)); } } protected void decreaseValue() { if (step != 0) { String value = getText(); long newValue = parseValue(value); newValue -= step; if (minConstrained && (newValue < min)) { return; } setValue(formatValue(newValue)); } } /** * @param value * the value to format * @return the formatted value */ protected String formatValue(long value) { String newValue = String.valueOf(value); if (minDigits > newValue.length()) { String leading = repeat("0", (minDigits - newValue.length())); newValue = leading + newValue; } return newValue; } private static String repeat(String s, int n) { if (s == null) { return null; } final StringBuilder sb = new StringBuilder(); for (int i = 0; i < n; i++) { sb.append(s); } return sb.toString(); } @Override public void setValue(String value) { setValue(value, false); } @Override public void setValue(String value, boolean fireEvents) { try { long newValue = parseValue(value); if ((maxConstrained && (newValue > max)) || (minConstrained && (newValue < min))) { return; } String prevText = getValue(); super.setText(formatValue(newValue)); if (fireEvents) { ValueChangeEvent.fireIfNotEqual(this, getValue(), prevText); } } catch (Exception ex) { // Do Nothing } } /** * @param value * the value to parse * @return the parsed value */ protected long parseValue(String value) { return Long.valueOf(value); } }