我正在尝试创建一个应用程序,在顶部带有“实时搜索”字段的项目列表顶部显示几行额外的行:
当然,我首先尝试使用带有覆盖 setSize() 的 KeywordFilterField。但这效果不佳 - 因为我无法控制 KeywordFilterField 调用 setSize() 的时间和方式,这给我带来了绘图问题(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“回到根源”并使用ListField(以及顶部的 BasicEditField),因为在那里我可以控制自己,何时以及如何调用 setSize()。
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 - 我将在下面描述。
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,而且我明白,我将不得不调用 myList.setSize(EXTRA_ROWS + 1),因为会有 1 个过滤结果。
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应用它?
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 结合起来。