textutil.java

现在大部分手机都不支持WTK2.0

/*
 * Created on 20-Apr-2004 at 01:30:49.
 *
 * Copyright (c) 2004-2005 Robert Virkus / Enough Software
 *
 * This file is part of J2ME Polish.
 *
 * J2ME Polish 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.
 * 
 * J2ME Polish 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 J2ME Polish; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 * 
 * Commercial licenses are also available, please
 * refer to the accompanying LICENSE.txt or visit
 * http://www.j2mepolish.org for details.
 */
package de.enough.polish.util;

import javax.microedition.lcdui.Font;


/**
 * <p>Provides some usefull String methods.</p>
 *
 * <p>Copyright Enough Software 2004, 2005</p>

 * <pre>
 * history
 *        20-Apr-2004 - rob creation
 * </pre>
 * @author Robert Virkus, [e-mail]
 */
public final class TextUtil {
	
	/**
	 * Splits the given String around the matches defined by the given delimiter into an array.
	 * Example:
	 * <value>TextUtil.split("one;two;three", ';')</value> results into the array
	 * <value>{"one", "two", "three"}</value>.
	 *
	 * @param value the String which should be split into an array
	 * @param delimiter the delimiter which marks the boundaries of the array 
	 * @return an array, when the delimiter was not found, the array will only have a single element.
	 */
	public static String[] split(String value, char delimiter) {
		char[] valueChars = value.toCharArray();
		int lastIndex = 0;
		ArrayList strings = null;
		for (int i = 0; i < valueChars.length; i++) {
			char c = valueChars[i];
			if (c == delimiter) {
				if (strings == null) {
					strings = new ArrayList();
				}
				strings.add( new String( valueChars, lastIndex, i - lastIndex ) );
				lastIndex = i + 1;
			}
		}
		if (strings == null) {
			return new String[]{ value };
		}
		// add tail:
		strings.add( new String( valueChars, lastIndex, valueChars.length - lastIndex ) );
		return (String[]) strings.toArray( new String[ strings.size() ] );
	}
	
	/**
	 * Splits the given string so it fits on the specified lines.
	 * First of al it is splitted at the line-breaks ('\n'), subsequently the substrings
	 * are splitted when they do not fit on a single line.
	 *  
	 * @param value the string which should be splitted
	 * @param font the font which is used to display the font
	 * @param firstLineWidth the allowed width for the first line
	 * @param lineWidth the allowed width for all other lines, lineWidth >= firstLineWidth
	 * @return the array containing the substrings
	 */
	public static String[] split( String value, Font font, int firstLineWidth, int lineWidth ) {
		if (firstLineWidth <= 0 || lineWidth <= 0) {
			//#debug error
			System.out.println("INVALID LINE WIDTH FOR SPLITTING " + firstLineWidth + " / " + lineWidth + " ( for string " + value + ")");
			return new String[]{ value };
		}
		boolean hasLineBreaks = (value.indexOf('\n') != -1);
		int completeWidth = font.stringWidth(value);
		if ( completeWidth <= firstLineWidth && !hasLineBreaks ) {
			// the given string fits on the first line:
			//if (hasLineBreaks) {
			//	return split( "complete/linebreaks:" + completeWidth + "> " + value, '\n');
			//} else {
				return new String[]{  value };
			//}
		}
		// the given string does not fit on the first line:
		ArrayList lines = new ArrayList();
		if (!hasLineBreaks) {
			split( value, font, completeWidth, firstLineWidth, lineWidth, lines );
		} else {
			// now the string will be splitted at the line-breaks and
			// then each line is processed:
			char[] valueChars = value.toCharArray();
			int lastIndex = 0;
			for (int i = 0; i < valueChars.length; i++) {
				char c = valueChars[i];
				if (c == '\n' || i == valueChars.length -1 ) {
					String line = null;
					if (i == valueChars.length -1) {
						line = new String( valueChars, lastIndex, (i + 1) - lastIndex );
					} else {
						line = new String( valueChars, lastIndex, i - lastIndex );
					}
					completeWidth = font.stringWidth(line);
					if (completeWidth <= firstLineWidth ) {
						lines.add( line );						
					} else {
						TextUtil.split(line, font, completeWidth, firstLineWidth, lineWidth, lines);
					}
					lastIndex = i + 1;
					// after the first line all line widths are the same:
					firstLineWidth = lineWidth;
				} // for each line
			} // for all chars
		}		
		return (String[]) lines.toArray( new String[ lines.size() ]);
	}
	
	/**
	 * Splits the given string so that the substrings fit into the the given line-widths.
	 * It is expected that the specified lineWidth >= firstLineWidth.
	 * The resulting substrings will be added to the given ArrayList.
	 * When the complete string fits into the first line, it will be added
	 * to the list.
	 * When the string needs to be splited to fit on the lines, it is tried to
	 * split the string at a gab between words. When this is not possible, the
	 * given string will be splitted in the middle of the corresponding word. 
	 * 
	 * 
	 * @param value the string which should be splitted
	 * @param font the font which is used to display the font
	 * @param completeWidth the complete width of the given string for the specified font.
	 * @param firstLineWidth the allowed width for the first line
	 * @param lineWidth the allowed width for all other lines, lineWidth >= firstLineWidth
	 * @param list the list to which the substrings will be added.
	 */
	public static void split( String value, Font font, 
			int completeWidth, int firstLineWidth, int lineWidth, 
			ArrayList list ) 
	{
		char[] valueChars = value.toCharArray();
		int startPos = 0;
		int lastSpacePos = -1;
		int lastSpacePosLength = 0;
		int currentLineWidth = 0;
		for (int i = 0; i < valueChars.length; i++) {
			char c = valueChars[i];
			currentLineWidth += font.charWidth( c );
			if (c == '\n') {
				list.add( new String( valueChars, startPos, i - startPos ) );
				lastSpacePos = -1;
				startPos = i+1;
				currentLineWidth = 0;
				firstLineWidth = lineWidth; 
				i = startPos;
			} else if (currentLineWidth >= firstLineWidth ) {
				if ( lastSpacePos == -1 ) {
					i--;
					list.add( new String( valueChars, startPos, i - startPos ) );
					startPos =  i;
					currentLineWidth = 0;
				} else {
					currentLineWidth -= lastSpacePosLength;
					list.add( new String( valueChars, startPos, lastSpacePos - startPos ) );
					startPos =  lastSpacePos + 1;
					lastSpacePos = -1;
				}
				firstLineWidth = lineWidth; 
			} else if (c == ' ' || c == '\t') {
				lastSpacePos = i;
				lastSpacePosLength = currentLineWidth;
			}
			
		} 
		// add tail:
		list.add( new String( valueChars, startPos, valueChars.length - startPos ) );
		
		/*
		try {
		int widthPerChar = (completeWidth * 100) / valueChars.length;
		int startIndex = 0;
		while (true) {
			int index = (firstLineWidth * 100) / widthPerChar;
			int i = index + startIndex;
			if (i >= valueChars.length) {
				// reached the end of the given string:
				list.add( new String( valueChars, startIndex, valueChars.length - startIndex ) );
				break;
			}
			// find the last word gap:
			while (valueChars[i] != ' ') {
				i--;
				if (i < startIndex ) {
					// unable to find a gap:
					i = index + startIndex;
					break;
				}
			}
			//TODO rob maybe check whether the found string really fits into the line
			list.add( new String( valueChars, startIndex, i - startIndex ) );
			if (valueChars[i] == ' ' || valueChars[i] == '\t') {
				startIndex = i + 1;
			} else {				
				startIndex = i;
			}
			firstLineWidth = lineWidth;
		}
		} catch (ArithmeticException e) {
			System.out.println("unable to split: " + e);
			e.printStackTrace();
			System.out.println("complete width=" + completeWidth + " number of chars=" + value.length());
		}
		*/
	}

}