请任何人帮助我从列表字段复选框中获取选定的列表项，并将它们添加到数组列表中。如果可能，也提供任何有用的链接。到目前为止，这是我的代码（我是黑莓应用程序开发的新手）。请帮忙。
package mypackage;
import java.util.Vector;
import net.rim.device.api.system.Characters;
import net.rim.device.api.system.Display;
import net.rim.device.api.ui.Graphics;
import net.rim.device.api.ui.MenuItem;
import net.rim.device.api.ui.component.Dialog;
import net.rim.device.api.ui.component.ListField;
import net.rim.device.api.ui.component.ListFieldCallback;
import net.rim.device.api.ui.component.Menu;
import net.rim.device.api.ui.container.HorizontalFieldManager;
import net.rim.device.api.ui.container.MainScreen;
import net.rim.device.api.ui.container.VerticalFieldManager;
import net.rim.device.api.util.IntVector;
/**
* A class extending the MainScreen class, which provides default standard
* behavior for BlackBerry GUI applications.
*/
public final class MyScreen extends MainScreen implements ListFieldCallback
{
private Vector _listData = new Vector();
private Vector _checkedData = new Vector();
private ListField listField;
private static final String[] _elements = {"First element", "Second element","Third element"
};
//private static final String[] _elements1 = {"hai","welcome","where r u"
//};
private MenuItem _getDataMenu,selectall,Delete;
Vector result = new Vector();
protected void makeMenu(Menu menu, int instance)
{
menu.add(_getDataMenu);
menu.add(selectall);
menu.add(Delete);
//Create the default menu.
super.makeMenu(menu, instance);
}
private class ChecklistData
{
private String _stringVal;
private boolean _checked;
ChecklistData(String stringVal, boolean checked)
{
_stringVal = stringVal;
_checked = checked;
}
//Get/set methods.
private String getStringVal()
{
return _stringVal;
}
private boolean isChecked()
{
return _checked;
}
//Toggle the checked status.
private void toggleChecked()
{
_checked = !_checked;
}
}
public Vector getCheckedItems() {
return _checkedData;
}
/**
* Creates a new MyScreen object
*/
public MyScreen()
{
// Set the displayed title of the screen
setTitle("MyTitle");
VerticalFieldManager main = new VerticalFieldManager(VerticalFieldManager.USE_ALL_HEIGHT|
VerticalFieldManager.USE_ALL_WIDTH|VerticalFieldManager.VERTICAL_SCROLL);
this.add(main);
HorizontalFieldManager hfm = new HorizontalFieldManager();
main.add(hfm);
listField = new ListField(){
//Allow the space bar to toggle the status of the selected row.
protected boolean keyChar(char key, int status, int time)
{
boolean retVal = false;
//If the spacebar was pressed...
if (key == Characters.SPACE)
{
//Get the index of the selected row.
int index = getSelectedIndex();
//Get the ChecklistData for this row.
ChecklistData data = (ChecklistData)_listData.elementAt(index);
//Toggle its status.
data.toggleChecked();
//Update the Vector with the new ChecklistData.
_listData.setElementAt(data, index);
//Invalidate the modified row of the ListField.
invalidate(index);
//Consume this keyChar (key pressed).
retVal = true;
}
return retVal;
}
};
listField.setCallback(this);
reloadList();
int elementLength = _elements.length;
for(int count = 0; count < elementLength; ++count)
{
_listData.addElement(new ChecklistData(_elements[count], false));
//_listData.addElement(new ChecklistData(_elements1[count], false));
listField.insert(count);
}
main.add(listField);
_getDataMenu =new MenuItem("Get Data", 200, 10) {
public void run(){
int index = listField.getSelectedIndex();
ChecklistData data = (ChecklistData)_listData.elementAt(index);
String message = "Selected data: " + data.getStringVal() + ", and status: " + data.isChecked();
//Dialog.alert(message);
// get all the checked data indices
IntVector selectedIndex = new IntVector(0, 1);
//ChecklistData data;
for (int i=0;i<_listData.size();i++) {
data = (ChecklistData)_listData.elementAt(i);
if(data.isChecked()) {
selectedIndex.addElement(i);
String selectedvalues = data.getStringVal();
System.out.println("Selected items are:"+selectedvalues);
}
}
data = null;
// now selectedIndex will contain all the checked data indices.
//String message = "Selected data: " + data.getStringVal() + ", and status: " + data.isChecked();
}
};
selectall = new MenuItem("Selectall", 200, 10){
public void run(){
int elementLength = _elements.length;
for(int count = 0; count < elementLength; ++count)
{
_listData.setElementAt(new ChecklistData(_elements[count], true), count);
}
}
};
Delete = new MenuItem("Delete", 200, 10){
public void run(){
int index = listField.getSelectedIndex();
_listData.removeElementAt(index);
// update the view
listField.delete(index);
listField.invalidate(index);
}
};
}
private void reloadList() {
// TODO Auto-generated method stub
_listData.setSize(_listData.size());
}
public void drawListRow(ListField list, Graphics graphics, int index, int y, int w)
{
ChecklistData currentRow = (ChecklistData)this.get(list, index);
StringBuffer rowString = new StringBuffer();
if (currentRow.isChecked())
{
rowString.append(Characters.BALLOT_BOX_WITH_CHECK);
}
else
{
rowString.append(Characters.BALLOT_BOX);
}
//Append a couple spaces and the row's text.
rowString.append(Characters.SPACE);
rowString.append(Characters.SPACE);
rowString.append(currentRow.getStringVal());
//Draw the text.
graphics.drawText(rowString.toString(), 0, y, 0, w);
/*if (currentRow.isChecked()) {
if( -1 ==_checkedData.indexOf(currentRow))
_checkedData.addElement(currentRow);
rowString.append(Characters.BALLOT_BOX_WITH_CHECK);
}
else {
if( -1 !=_checkedData.indexOf(currentRow))
_checkedData.removeElement(currentRow);
rowString.append(Characters.BALLOT_BOX);
} */
}
//Returns the object at the specified index.
public Object get(ListField list, int index)
{
return _listData.elementAt(index);
}
public int indexOfList(ListField list, String p, int s)
{
//return listElements.getSelectedIndex();
return _listData.indexOf(p, s);
}
//Returns the screen width so the list uses the entire screen width.
public int getPreferredWidth(ListField list)
{
return Display.getWidth();
}
protected boolean navigationClick(int status, int time) {
int index1 = listField.getSelectedIndex();
/*System.out.println("Selected item index:"+index1);
//int[] list =listField.getSelection();
//String s = Integer.toString(list);
System.out.println(" items are:"+_elements[index1]);
//ChecklistData data = (ChecklistData)_listData.elementAt(index1);*/
//Get the ChecklistData for this row.
ChecklistData data = (ChecklistData)_listData.elementAt(index1);
String message = "Selected data: " + data.getStringVal() + ", and status: " + data.isChecked();
System.out.println("message is:"+message);
//Toggle its status.
data.toggleChecked();
//Update the Vector with the new ChecklistData.
_listData.setElementAt(data, index1);
//Invalidate the modified row of the ListField.
listField.invalidate(index1);
return true;
}
}