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我準備了一個簡單的測試用例來演示我的問題。黑莓：更改KeywordFilterField的排序
它只是1個文件（CheckMenu.java，下面列出），並可立即運行。
一旦用戶通過選擇2個MenuItems中的一個來更改排序方法，我該如何重新繪製底層的KeywordFilterField？我試過呼叫myList.updateList（）和myList.invalidate（） - 它沒有幫助 - myList項目不重組。
另外我想知道，使用什麼來代替棄用的MenuItem.setText（String）？
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：我已經更新了代碼，使用列出MakeMenu（）由Arhimed的建議。 我也發佈了我的問題at the BlackBerry forum。
謝謝！ Alex
+1對於完美結構化/準備好的問題。 – 2011-04-15 19:48:13