Blackberry：更改KeywordFilterField的排序

时间：2011-04-15 13:09:50

标签： java blackberry java-me menu menuitem

我准备了一个简单的测试案例来证明我的问题。

它只是一个文件（CheckMenu.java，如下所示）并且可以立即运行。

一旦用户通过选择2个MenuItems中的一个来更改排序方法，如何重绘基础KeywordFilterField？我试过调用 myList.updateList（）和 myList.invalidate（） - 它没有帮助 - myList项目没有重新组织。

我也想知道，使用什么而不是弃用的MenuItem.setText（String）？

enter image description here 

package mypackage;

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.util.Comparator;
import net.rim.device.api.util.StringUtilities;
import net.rim.device.api.collection.util.*;

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

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

class MyScreen extends MainScreen {
    KeywordFilterField myList = new KeywordFilterField();
    MyItemList myItems = new MyItemList();

    public MyScreen() {
        setTitle(myList.getKeywordField());

        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.setSourceList(myItems, new MyItem.MyProvider());
        // XXX commenting the line below does not help
        myList.setCallback(new MyListFieldCallback());
        add(myList);
    }

    private MenuItem numMenu = new MenuItem("num sort", 0, 0) {  
        public void run() {
            MyItem.NUMERIC_SORT = true;
            Status.show("Use " + toString());
            setText("num sort \u221A");
            alphaMenu.setText("alpha sort");
            myList.updateList();
        }
    };
    private MenuItem alphaMenu = new MenuItem("alpha sort", 1, 0) {  
        public void run() {
            MyItem.NUMERIC_SORT = false;
            Status.show("Use " + toString());
            setText("alpha sort \u221A");
            numMenu.setText("num sort");
            myList.updateList();
        }
    };

    protected void makeMenu(Menu menu, int instance) {
        super.makeMenu(menu, instance);
        menu.add(numMenu);
        menu.add(alphaMenu);
    }

    private class MyListFieldCallback implements ListFieldCallback {

        public void drawListRow(ListField list, Graphics g, int index, int y, int width) {
            Object obj = ((KeywordFilterField)list).getElementAt(index);
            if(obj != null && obj instanceof MyItem) {
                MyItem item = (MyItem) obj;
                g.drawText(item.toString(), 20 * (1 + index), y);
            } else if(index == 0) {
                g.drawText(list.getEmptyString(), 0, y);
            }
        }

        public Object get(ListField list, int index) { 
            return null; 
        }

        public int getPreferredWidth(ListField list) { 
            return 0; 
        }

        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);   
    }

    protected boolean doRemove(Object obj) {
        return super.doRemove(obj);        
    }
}

class MyItem {
    public static boolean NUMERIC_SORT;

    private int _num;
    private 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) {
            if (! (obj1 instanceof MyItem && obj2 instanceof MyItem))
                throw new IllegalArgumentException("Cannot compare non-MyItems");

            MyItem item1 = (MyItem) obj1;
            MyItem item2 = (MyItem) obj2;

            if (MyItem.NUMERIC_SORT) {
                if (item1._num == item2._num)
                    return 0;
                return (item1._num > item2._num ? 1 : -1);
            }

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

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

更新：我已根据Arhimed的建议更新了代码以使用makeMenu（）。 我还发布了我的问题at the BlackBerry forum。

谢谢！ 亚历

2 个答案:

答案 0 :(得分：1)

也许我不明白你的问题.....但正如我所见，这段代码在模拟器上工作正常

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.util.Comparator;
import net.rim.device.api.util.StringUtilities;
import net.rim.device.api.collection.util.*;

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

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

class MyScreen extends MainScreen {
    KeywordFilterField myList = new KeywordFilterField();
    MyItemList myItems = new MyItemList();

    public MyScreen() {
        setTitle(myList.getKeywordField());

        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.setSourceList(myItems, new MyItem.MyProvider());
        // XXX commenting the line below does not help
        myList.setCallback(new MyListFieldCallback());
        add(myList);
    }

    private MenuItem numMenu = new MenuItem("num sort", 0, 0) {  
    public void run() {
        MyItem.NUMERIC_SORT = true;
        Status.show("Use " + toString());
        setText("num sort \u221A");
        alphaMenu.setText("alpha sort");
        myItems.sort();
        myList.updateList();
    }
};
private MenuItem alphaMenu = new MenuItem("alpha sort", 1, 0) {  
    public void run() {
        MyItem.NUMERIC_SORT = false;
        Status.show("Use " + toString());
        setText("alpha sort \u221A");
        numMenu.setText("num sort");
        myItems.sort();
        myList.updateList();
    }
};

protected void makeMenu(Menu menu, int instance) {
    super.makeMenu(menu, instance);
    menu.add(numMenu);
    menu.add(alphaMenu);
}

private class MyListFieldCallback implements ListFieldCallback {

    public void drawListRow(ListField listField, Graphics g, int index, int y, int    width) {
        Object obj = ((KeywordFilterField)listField).getElementAt(index);
        if(obj != null && obj instanceof MyItem) {
            MyItem item = (MyItem) obj;
            g.drawText(item.toString(), 20 * (1 + index), y);
        } else if(index == 0) {
            g.drawText("ssssssss", 0, y);
        }
    }

    public Object get(ListField listField, int index) { 
        return null; 
    }

    public int getPreferredWidth(ListField listField) { 
        return 0; 
    }

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

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

    protected void doAdd(Object obj) {
        super.doAdd(obj);   
    }

    protected boolean doRemove(Object obj) {
        return super.doRemove(obj);        
    }
 }

class MyItem {
    public static boolean NUMERIC_SORT;

    private int _num;
    private 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) {
            if (! (obj1 instanceof MyItem && obj2 instanceof MyItem))
                throw new IllegalArgumentException("Cannot compare non-MyItems");

            MyItem item1 = (MyItem) obj1;
            MyItem item2 = (MyItem) obj2;

            if (MyItem.NUMERIC_SORT) {
                if (item1._num == item2._num)
                    return 0;
                return (item1._num > item2._num ? 1 : -1);
            }

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

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

答案 1 :(得分：0)

  

1）。如何修改MenuItem文本？ ID   喜欢显示/隐藏复选标记   符号\ u221A - 取决于哪个   目前选择排序顺序   用户。 setText（String text）   方法已被弃用，我不确定   如何使用setText（StringProvider   文本）？

而不是使用addMenuItem(myMenu1);覆盖makeMenu(Menu menu, int instance)：

protected void makeMenu(Menu menu, int instance) {
    super.makeMenu(menu, instance);

    // add menu items on-the-fly
    // generating their labels in accordance to some conditions
    menu.add(new MenuItem("any label", 1, 1) {
        public void run() {
            // do smth useful
        }
    });
}
  

2）。一旦用户通过选择2中的1来更改排序方法   MenuItems，我该如何重绘   底层KeywordFilterField？我有   试着调用myList.updateList（）和   myList.invalidate（） - 它没有帮助。

尝试注释掉myList.setCallback(new MyListFieldCallback());行。我相信KeywordFilterField已经以某种特定方式实现了此回调，因此通过设置自定义ListFieldCallback，您可以打破默认/预期行为。

关于菜单项的

更新：

完全删除private MenuItem alphaMenu和private MenuItem numMenu字段。即时生成这些菜单项：

protected void makeMenu(Menu menu, int instance) {
    super.makeMenu(menu, instance);

    String label = "num sort" + (MyItem.NUMERIC_SORT ? " \u221A" : "");

    menu.add(new MenuItem(label, 0, 0) {  
        public void run() {
            MyItem.NUMERIC_SORT = true;
            Status.show("Use " + toString());
            // setText("num sort \u221A");
            // alphaMenu.setText("alpha sort");
            myList.updateList();
        }
    });

    label = "alpha sort" + (MyItem.NUMERIC_SORT ? "" : " \u221A");

    menu.add(new MenuItem(label, 1, 0) {
        public void run() {
            MyItem.NUMERIC_SORT = false;
            Status.show("Use " + toString());
            // setText("alpha sort \u221A");
            // numMenu.setText("num sort");
            myList.updateList();
        }
    });
}
关于主要问题的

更新：

class MyScreen extends MainScreen {
    KeywordFilterField myList = new KeywordFilterField();
    MyItemList myItems = new MyItemList();

    public MyScreen() {
        setTitle(myList.getKeywordField());

        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.setSourceList(myItems, new MyItem.MyProvider());

        // XXX commenting the line below does not help
        myList.setCallback(new MyListFieldCallback());
        add(myList);
    }

    protected void makeMenu(Menu menu, int instance) {
        super.makeMenu(menu, instance);

        String label = "num sort" + (MyItem.NUMERIC_SORT ? " \u221A" : "");

        menu.add(new MenuItem(label, 0, 0) {  
            public void run() {
                MyItem.NUMERIC_SORT = true;
                Status.show("Use " + toString());
                // setText("num sort \u221A");
                // alphaMenu.setText("alpha sort");

                myItems.setComparator(new MyItem.MyComparator());
                myList.updateList();
            }
        });

        label = "alpha sort" + (MyItem.NUMERIC_SORT ? "" : " \u221A");

        menu.add(new MenuItem(label, 1, 0) {
            public void run() {
                MyItem.NUMERIC_SORT = false;
                Status.show("Use " + toString());
                // setText("alpha sort \u221A");
                // numMenu.setText("num sort");

                myItems.setComparator(new MyItem.MyComparator());
                myList.updateList();
            }
        });

    }

// .. the rest of the code is the same
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