Question

我正在尝试创建一个应用程序，在项目列表的顶部显示几行额外的行，并在顶部显示“实时搜索”字段：

list

当然，我最初尝试使用a KeywordFilterField with overriden setSize()。但这不能很好 - 因为我无法控制，KeywordFilterField何时以及如何调用setSize（）这给了我绘图问题（当我输入关键字并添加新项目时未绘制一行到列表等。）

所以我这次尝试“回归根”并使用 ListField （以及顶部的BasicEditField），因为我可以控制自己，何时以及如何使用setSize（）被称为。

下面是我的简化测试代码 - src \ mypackage \ MyList.java 和 border.png 。

代码运行良好，除了过滤问题 - 我将在下面介绍。

package mypackage;

import java.util.*;
import net.rim.device.api.collection.*;
import net.rim.device.api.collection.util.*; 
import net.rim.device.api.system.*;
import net.rim.device.api.ui.*;
import net.rim.device.api.ui.component.*;
import net.rim.device.api.ui.container.*;
import net.rim.device.api.ui.decor.*;
import net.rim.device.api.util.*;


public class MyList extends UiApplication {
    public static void main(String args[]) {
        MyList app = new MyList();
        app.enterEventDispatcher();
    }

    public MyList() {
        pushScreen(new MyScreen());
    }
} 

class MyScreen extends MainScreen {
    static final int EXTRA_ROWS = 3;

    BasicFilteredList myFilter = new BasicFilteredList();

    Background myBg = BackgroundFactory.createSolidBackground(0x111111);
    StringProvider myProvider = new StringProvider("Search");
    BasicEditField myFind = new BasicEditField(USE_ALL_WIDTH) {
        protected void paint(Graphics g) {
            if (getTextLength() == 0) {
                g.setColor(Color.LIGHTGRAY);
                g.drawText(myProvider.toString(), 0, 0);
            }

            g.setColor(Color.BLACK);
            super.paint(g);
        }
    };

    MyItemList myItems = new MyItemList();

    // add 1 row for the "* Empty *" string
    ListField myList = new ListField(EXTRA_ROWS + 1) {
        protected boolean navigationClick(int status, int time) {
            int index = getSelectedIndex();
            if (index >= EXTRA_ROWS && myItems.size() > 0) {
                String str = ((MyItem) myItems.getAt(
                    index - EXTRA_ROWS)).toString();
                Status.show("You have clicked - " + str);
            }
            return true;
        }
    };

    Border myBorder = BorderFactory.createBitmapBorder(
        new XYEdges(12, 12, 12, 12),
        Bitmap.getBitmapResource("border.png"));

    public MyScreen() {
        getMainManager().setBackground(myBg);

        myFind.setBorder(myBorder);
        setTitle(myFind);

        myItems.doAdd(new MyItem(1, "Eins"));
        myItems.doAdd(new MyItem(2, "Zwei"));
        myItems.doAdd(new MyItem(3, "Drei"));
        myItems.doAdd(new MyItem(4, "Vier"));

        myList.setCallback(new MyListFieldCallback());
        add(myList);

        myFilter.addDataSet(1, myItems.getElements(), "Test",
            BasicFilteredList.COMPARISON_IGNORE_CASE);
    }

    protected boolean keyChar(char key, int status, int time) {
        if (key == Characters.BACKSPACE && myFind.getTextLength() == 0) {
            Status.show("Kill kill kill!");
            return true;
        }

        if (myFind.getTextLength() > 0) {
            System.err.println("XXX filter for " + myFind.getText());
        }

        return super.keyChar(key, status, time);
    }

    private class MyListFieldCallback implements ListFieldCallback {

        public void drawListRow(ListField list, Graphics g, int index, int y, int width) {
            Font i = getFont().derive(Font.ITALIC);

            g.setColor(Color.DIMGRAY);
            g.drawLine(0, y-9, width, y-9);
            g.setColor(Color.WHITE);

            if (index < EXTRA_ROWS) {
                g.setFont(i);
                g.drawText("Add Item", 0, y, DrawStyle.ELLIPSIS|DrawStyle.HCENTER, width);
                return;
            } 

            if (myItems.size() == 0) {
                g.setFont(i);
                g.drawText(list.getEmptyString(), 0, y, DrawStyle.ELLIPSIS|DrawStyle.HCENTER, width);
                return;
            }

            MyItem item = (MyItem) myItems.getAt(index - EXTRA_ROWS);
            g.drawText(item.toString(), 0, y, DrawStyle.ELLIPSIS|DrawStyle.HCENTER, width);
        }

        public Object get(ListField list, int index) { 
            return myItems.getAt(index); 
        }

        public int getPreferredWidth(ListField list) { 
            return Display.getWidth(); 
        }

        public int indexOfList(ListField list, String prefix, int start) { 
            return 0; 
        }
    }

    class MyItemList extends SortedReadableList {
        public MyItemList() {
            super(new MyItem.MyComparator());        
        } 

        protected void doAdd(Object obj) {
            super.doAdd(obj);
            myList.setSize(size() + EXTRA_ROWS);  
        }

        protected boolean doRemove(Object obj) {
            // if the list is empty, add 1 row for "* Empty *" string
            int size = (size() == 0 ? EXTRA_ROWS + 1 : size() - 1 + EXTRA_ROWS);
            myList.setSize(size);
            return super.doRemove(obj);        
        }

        protected Object[] getElements() {
            return super.getElements();
        }
    }
}

class MyItem {
    int _num;
    String _name;

    public MyItem(int num, String name) {
        _num = num;
        _name = name;
    }

    public String toString() {
        return _num + ": " + _name;
    }

    static class MyComparator implements Comparator {
        public int compare(Object obj1, Object obj2) {
            MyItem item1 = (MyItem) obj1;
            MyItem item2 = (MyItem) obj2;

            return item1.toString().compareTo(item2.toString());
        }
    }

    static class MyProvider implements KeywordProvider {
        public String[] getKeywords(Object obj) {
            MyItem item = (MyItem) obj;
            return new String[]{ Integer.toString(item._num), item._name };
        }
    }
}

我的问题是我不知道如何添加过滤。

例如，当用户在myFind中输入“E”时，我的代码将在keyChar（）中检测到此事件，而且我理解，我将不得不调用myList.setSize（EXTRA_ROWS + 1）因为会有1过滤结果。

但是如何过滤myList显示的项目，如何实现呢？

也许我可以使用BasicFilteredList及其方法

public void addDataSet(int id,
                       Object[] objects,
                       String name,
                       long style)

但我不确定如何在这里申请？

更新

我在上面的测试代码中添加了一个BasicFilteredList，但我仍然不确定如何将它与ListField结合。

Answer 1

您必须在代码中进行过滤，然后存储结果。覆盖myFind.update（int）以在过滤文本更改时运行过滤。除了myItems之外，还需要存储myFilteredItems。过滤后，在列表字段上调用setSize（）。列表字段绘图代码还需要从过滤后的集合中绘制。然后你应该被设置。

Answer 2

我最终得到了这个代码，这对我来说似乎很有效（除了下面列出的两个小问题），绿色的答案标记是Michael Donohue的宝贵建议。

我使用2个向量：myData和myFilteredData。对于UI，我使用ListField和BasicEditField：

list

border.png：

SRC \ mypackage中\ MyList.java：

package mypackage;

import java.util.*;
import net.rim.device.api.collection.*;
import net.rim.device.api.collection.util.*; 
import net.rim.device.api.system.*;
import net.rim.device.api.ui.*;
import net.rim.device.api.ui.component.*;
import net.rim.device.api.ui.container.*;
import net.rim.device.api.ui.decor.*;
import net.rim.device.api.util.*;


public class MyList extends UiApplication {
    public static void main(String args[]) {
        MyList app = new MyList();
        app.enterEventDispatcher();
    }

    public MyList() {
        pushScreen(new MyScreen());
    }
} 

class MyScreen extends MainScreen {
    static final int EXTRA_ROWS = 3;

    Background myBg = BackgroundFactory.createSolidBackground(0x111111);
    StringProvider myProvider = new StringProvider("Search");
    BasicEditField myFind = new BasicEditField(USE_ALL_WIDTH|TextField.NO_NEWLINE) {
        protected void paint(Graphics g) {
            if (getTextLength() == 0) {
                g.setColor(Color.LIGHTGRAY);
                g.drawText(myProvider.toString(), 0, 0);
            }

            g.setColor(Color.BLACK);
            super.paint(g);
        }

        protected void update(int delta) {
            filterData(getText());
        }
    };

    Vector myData = new Vector();
    final static SimpleSortingVector myFilteredData = new SimpleSortingVector();

    // add 1 row for the "* Empty *" string
    ListField myList = new ListField(EXTRA_ROWS + 1) {
        protected boolean navigationClick(int status, int time) {
            int index = getSelectedIndex();
            if (index >= EXTRA_ROWS && myFilteredData.size() > 0) {
                String str = ((MyItem) myFilteredData.elementAt(index - EXTRA_ROWS)).toString();
                Status.show("You have clicked - " + str);
            }
            return true;
        }
    };

    Border myBorder = BorderFactory.createBitmapBorder(
        new XYEdges(12, 12, 12, 12),
        Bitmap.getBitmapResource("border.png"));

    public MyScreen() {
        getMainManager().setBackground(myBg);

        myFind.setBorder(myBorder);
        setTitle(myFind);

        myData.addElement(new MyItem(1, "Eins"));
        myData.addElement(new MyItem(2, "Zwei"));
        myData.addElement(new MyItem(3, "Drei"));
        myData.addElement(new MyItem(4, "Vier"));

        myFilteredData.setSortComparator(new MyItem.MyComparator());
        filterData("");

        myList.setCallback(new MyListFieldCallback());
        add(myList);
    }

    private void filterData(String prefix) {
        myFilteredData.removeAllElements();
        if (prefix == null || prefix.length() == 0) {
            // no prefix specified - copy everything
            for (int i = myData.size() - 1; i >= 0; i--) {
                MyItem item = (MyItem) myData.elementAt(i);
                myFilteredData.addElement(item);
            }
        } else {
            // copy only strings starting with prefix
            for (int i = myData.size() - 1; i >= 0; i--) {
                MyItem item = (MyItem) myData.elementAt(i);
                String name = item.name.toLowerCase();

                if (name.startsWith(prefix.toLowerCase())) {
                    myFilteredData.addElement(item);
                }
            }
        }
        myFilteredData.reSort();

        // if the list is empty, add 1 row for "* Empty *" string
        int size = (myFilteredData.size() == 0 ? EXTRA_ROWS + 1 : myFilteredData.size() + EXTRA_ROWS);
        myList.setSize(size);
    }

    protected boolean keyChar(char key, int status, int time) {
        if (key == Characters.BACKSPACE && myFind.getTextLength() == 0) {
            int index = myList.getSelectedIndex();
            if (index >= EXTRA_ROWS && myFilteredData.size() > 0) {
                String str = ((MyItem) myFilteredData.elementAt(index - EXTRA_ROWS)).toString();
                Status.show("You're deleting - " + str);
            }
            return true;
        }

        return super.keyChar(key, status, time);
    }

    static class MyListFieldCallback implements ListFieldCallback {
        public void drawListRow(ListField list, Graphics g, int index, int y, int width) {
            Font i = g.getFont().derive(Font.ITALIC);

            g.setColor(Color.DIMGRAY);
            g.drawLine(0, y-9, width, y-9);
            g.setColor(Color.WHITE);

            if (index < EXTRA_ROWS) {
                g.setFont(i);
                g.drawText("Add Item", 0, y, DrawStyle.ELLIPSIS|DrawStyle.HCENTER, width);
                return;
            } 

            if (myFilteredData.size() == 0) {
                g.setFont(i);
                g.drawText(list.getEmptyString(), 0, y, DrawStyle.ELLIPSIS|DrawStyle.HCENTER, width);
                return;
            }

            MyItem item = (MyItem) myFilteredData.elementAt(index - EXTRA_ROWS);
            g.drawText(item.toString(), 0, y, DrawStyle.ELLIPSIS|DrawStyle.HCENTER, width);
        }

        public Object get(ListField list, int index) { 
            return myFilteredData.elementAt(index); 
        }

        public int getPreferredWidth(ListField list) { 
            return Display.getWidth(); 
        }

        public int indexOfList(ListField list, String prefix, int start) { 
            return myFilteredData.indexOf(prefix, start);
        }
    }
}

class MyItem {
    int num;
    String name;

    public MyItem(int num, String name) {
        this.num = num;
        this.name = name;
    }

    public String toString() {
        return num + ": " + name;
    }

    static class MyComparator implements Comparator {
        public int compare(Object obj1, Object obj2) {
            MyItem item1 = (MyItem) obj1;
            MyItem item2 = (MyItem) obj2;

            String name1 = item1.toString().toLowerCase();
            String name2 = item2.toString().toLowerCase();

            return name1.compareTo(name2);
        }
    }
}

我的小问题是：

为什么我需要在drawListRow（）中减去9以绘制线条？
使用后，为什么插入符号会在BasicEditField中消失？

screenshot

Blackberry：如何过滤ListField表示的行？

2 个答案: