midp2layoutview.java

j2me polish学习的经典代码

//#condition polish.usePolishGui
/*
 * @(#)MIDP2LayoutView.java
 * Created on 6/02/2005
 * Copyright 2005 by Majitek International Pte. Ltd.  All Rights Reserved.
 *
 * This software is the proprietary information of Majitek International Pte Ltd.
 * Use is subject to license terms.
 * 
 * 
 *
 * 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.ui.containerviews;

import javax.microedition.lcdui.Canvas;
import javax.microedition.lcdui.Graphics;

import de.enough.polish.ui.Container;
import de.enough.polish.ui.ContainerView;
import de.enough.polish.ui.Item;
import de.enough.polish.util.ArrayList;

/**
 * <code>MIDP2LayoutView</code>.
 * <p>
 * 
 * @author Kin Wong
 */
public class MIDP2LayoutView extends ContainerView {
        static private final int LAYOUT_HORIZONTAL = Item.LAYOUT_LEFT
                        | Item.LAYOUT_CENTER | Item.LAYOUT_RIGHT;

        static private final int LAYOUT_VERTICAL = Item.LAYOUT_TOP
                        | Item.LAYOUT_VCENTER | Item.LAYOUT_BOTTOM;

        class RowItem {
                int x;
                int y;
                int width;
                int height;
                Item item;
        }
        private ArrayList allRows;
        private ArrayList currentRow;
        private int rowWidth;
        private int rowHeight;
        //private Style style;
        private int horizontalOffset = -1;

        /**
         * Constructs an instance of <code>MIDP2LayoutView</code>.
         * <p>
         */
        public MIDP2LayoutView() {
        	// just creating a default instance
        }

        /*
         * (non-Javadoc)
         * 
         * @see de.enough.polish.ui.ContainerView#initContent(de.enough.polish.ui.Container,
         *      int, int)
         */
        protected void initContent(Container parent, int firstLineWidth,
                        int lineWidth) 
        {
                Item[] myItems = parent.getItems();
                this.contentHeight = this.contentWidth = this.rowWidth = this.rowHeight = 0;
                this.currentRow = new ArrayList();
                this.allRows = new ArrayList();

                boolean hasFocusableItem = false;
                for (int i = 0; i < myItems.length; i++) {
                    Item item = myItems[i];
                    if (item.appearanceMode != Item.PLAIN) {
                            hasFocusableItem = true;
                    }
                    appendItemToRow(i, item, firstLineWidth, lineWidth);
                }
                // Make the remaining items a final line
                rowBreak(lineWidth);
                if (!hasFocusableItem) {
                	this.appearanceMode = Item.PLAIN;
                } else {
                    this.appearanceMode = Item.INTERACTIVE;
                }
        }

        /*
        protected void setStyle(Style style) {
                super.setStyle(style);
                this.style = style;
        }
        */

        void appendItemToRow(int index, Item item, int firstLineWidth, int lineWidth) {
                if (this.focusFirstElement && (item.appearanceMode != Item.PLAIN)) {
                        focusItem(index, item);
                        this.focusFirstElement = false;
                }
                int width = item.getItemWidth(firstLineWidth, lineWidth);
                int height = item.getItemHeight(firstLineWidth, lineWidth);
                int layout = item.getLayout();

                if ((Item.LAYOUT_NEWLINE_BEFORE == (layout & Item.LAYOUT_NEWLINE_BEFORE))
                                || (this.rowWidth + this.paddingHorizontal + width > lineWidth)) 
                {
                        // Break if the NEWLINE_BEFORE is specified or not enough
                        // room in the current row
                        rowBreak(lineWidth);
                }

                this.rowWidth += width;
                if (this.currentRow.size() == 0) {
                    this.rowHeight = height;
                } else {
                	if (this.rowHeight < height) {
                		this.rowHeight = height;
                    }
                    this.rowWidth += this.paddingHorizontal;
                }

                RowItem rowItem = new RowItem();
                rowItem.width = width;
                rowItem.height = height;
                rowItem.item = item;
                this.currentRow.add(rowItem);

                if (Item.LAYOUT_NEWLINE_AFTER == (layout & Item.LAYOUT_NEWLINE_AFTER)) {
                        rowBreak(lineWidth);
                }
        }

        private void rowBreak(int lineWidth) {
                if (this.currentRow.size() == 0) {
                        return; // Current row is empty
                }
                /**
                 * Horizontal Layout Starts Here!
                 */
                // Take away all the horizontal paddings
                int remainingWidth = lineWidth
                                - ((this.currentRow.size() - 1) * this.paddingHorizontal);
                RowItem[] requiredExpanded = null;
                int requiredExpandedIndex = 0;
                for (int i = 0; i < this.currentRow.size(); i++) {
                    RowItem rowItem = (RowItem) this.currentRow.get(i);
                    remainingWidth -= rowItem.width;
                    if (Item.LAYOUT_EXPAND == (rowItem.item.getLayout() & Item.LAYOUT_EXPAND)) {
                        if (requiredExpanded == null) {
                            requiredExpanded = new RowItem[this.currentRow.size() - i];
                        }
                        requiredExpanded[requiredExpandedIndex++] = rowItem;
                    }
                }
                // Distribute the remaining width to the items that require expanding
                if (requiredExpanded != null) {
                    int expansion = remainingWidth / requiredExpandedIndex;
                    remainingWidth = remainingWidth % requiredExpandedIndex;
                    for (int i = 0; i < requiredExpandedIndex; i++) {
                        RowItem rowItem = requiredExpanded[i];
                        rowItem.width += expansion;
                        if (i == 0) {
                            // The first item get all the rounding
                            rowItem.width += remainingWidth;
                        }
                    }
                }

                // Horizontal Positioning determined by the first item in a row
                RowItem rowItem = (RowItem) this.currentRow.get(0);
                int rowHorizontalLayout = (rowItem.item.getLayout() & LAYOUT_HORIZONTAL);
                if (requiredExpanded != null) {
                	rowHorizontalLayout = Item.LAYOUT_LEFT;
                }

                int x = 0;
                switch (rowHorizontalLayout) {