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按後退按鈕在屏幕截圖1我有2個按鈕和雙給場變化監聽器都這樣。當我按下按鈕「A」它推說屏蔽2我在那裏所使用的每個按下相應的屏幕一個keywordFilter搜索從SQLite數據庫的話，是listed.These一切都是完美的，當我運行應用程序，但是當我按下後退（或前一個鍵），然後按下按鈕「A」從屏幕截圖1再次我不找到任何結果database.same的事情發生在按鈕b也。什麼cud b pblm幫助。 感謝ü提前 這麼多下面是按鈕後，叫「一」被點擊找不到數據庫列表黑莓
import net.rim.device.api.ui.*;
import net.rim.device.api.io.*;
import net.rim.device.api.ui.component.*;
import net.rim.device.api.system.*;
import java.util.*;
import net.rim.device.api.database.Database;
import net.rim.device.api.database.DatabaseFactory;
import net.rim.device.api.database.Row;
import net.rim.device.api.database.Statement;
public final class KeywordFilter
{
private KeywordFilterField _keywordFilterField;
private WordList _wordList;
private Vector _words;
public KeywordFilter()
{
_words = getDataFromDatabase();
if(_words != null)
{
_wordList = new WordList(_words);
_keywordFilterField = new KeywordFilterField();
_keywordFilterField.setSourceList(_wordList, _wordList);
CustomKeywordField customSearchField = new CustomKeywordField();
_keywordFilterField.setKeywordField(customSearchField);
KeywordFilterScreen screen = new KeywordFilterScreen(this);
screen.setTitle(_keywordFilterField.getKeywordField());
screen.add(_keywordFilterField);
UiApplication ui = UiApplication.getUiApplication();
ui.pushScreen(screen);
}
else
{
UiApplication.getUiApplication().invokeLater(new Runnable()
{
public void run()
{
Dialog.alert("Error reading data file.");
System.exit(0);
}
});
}
}
KeywordFilterField getKeywordFilterField()
{
return _keywordFilterField;
}
private Vector getDataFromDatabase()
{
Vector words = new Vector();
Database d;
for(;;)
{
try
{
URI myURI=URI.create("file:///SDCard/Databases/MyTestDatabase.db");
d=DatabaseFactory.open(myURI);
Statement st=d.createStatement("SELECT eng,mal FROM Malayalam m,English e where e.Ecode=m.Mcode");
st.prepare();
net.rim.device.api.database.Cursor c=st.getCursor();
Row r;
while(c.next())
{
r=c.getRow();
String w=r.getString(0);
String meaning=r.getString(1);
words.addElement(new Word(w,meaning));
}}
catch (Exception e)
{
System.out.println(e.getMessage());
e.printStackTrace();
}
return words;
}
}
void addElementToList(Word w)
{
_wordList.addElement(w);
_keywordFilterField.updateList();
}
final static class CustomKeywordField extends BasicEditField
{
CustomKeywordField()
{
super(USE_ALL_WIDTH|NON_FOCUSABLE|NO_LEARNING|NO_NEWLINE);
setLabel("Search: ");
}
protected boolean keyChar(char ch, int status, int time)
{
switch(ch)
{
case Characters.ESCAPE:
if(super.getTextLength() > 0)
{
setText("");
return true;
}
}
return super.keyChar(ch, status, time);
}
protected void paint(Graphics graphics)
{
super.paint(graphics);
getFocusRect(new XYRect());
drawFocus(graphics, true);
}
}
}
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.system.*;
final class KeywordFilterScreen extends MainScreen
{
private KeywordFilter _app;
private KeywordFilterField _keywordFilterField;
public KeywordFilterScreen(KeywordFilter app)
{
_app = app;
_keywordFilterField = _app.getKeywordFilterField();
}
protected boolean keyChar(char key, int status, int time)
{
if (key == Characters.ENTER)
{
displayInfoScreen();
return true;
}
return super.keyChar(key, status, time);
}
public boolean invokeAction(int action)
{
switch(action)
{
case ACTION_INVOKE:
displayInfoScreen();
return true;
}
return super.invokeAction(action);
}
private void displayInfoScreen()
{
Word w = (Word)_keywordFilterField.getSelectedElement();
if(w != null)
{
InfoScreen infoScreen = new InfoScreen(w);
UiApplication ui = UiApplication.getUiApplication();
ui.pushScreen(infoScreen);
ui.popScreen(this);
}
}
private final static class InfoScreen extends MainScreen
{
InfoScreen(Word w)
{
setTitle(w.toString());
BasicEditField popField = new BasicEditField(":",w.getMeaning(),20,Field.NON_FOCUSABLE);
add(popField);
}
}
}
public class Word
{
private String _word;
private String _meaning;
public Word(String word, String meaning)
{
_word = word;
_meaning = meaning;
}
String getMeaning()
{
return _meaning;
}
public String toString()
{
return _word;
}
}
import net.rim.device.api.ui.component .*;
import net.rim.device.api.collection.util.*;
import net.rim.device.api.util.*;
import java.util.*;
public class WordList extends SortedReadableList implements KeywordProvider
{
public WordList(Vector words)
{
super(new WordListComparator());
loadFrom(words.elements());
}
void addElement(Object element)
{
doAdd(element);
}
public String[] getKeywords(Object element)
{
if(element instanceof Word)
{
return StringUtilities.stringToWords(element.toString());
}
return null;
}
final static class WordListComparator implements Comparator
{
public int compare(Object o1, Object o2)
{
if (o1 == null || o2 == null)
throw new IllegalArgumentException("Cannot compare null words");
return o1.toString().compareTo(o2.toString());
}
}
}
沒有看到你的代碼之前在私人矢量getDataFromDatabase（）方法訪問數據庫之後它可能是許多事情之一。 – jprofitt
抱歉，我的錯誤，我沒有關閉數據庫連接後，現在打開它的罰款 – j2me
很高興聽到你明白了。作爲對其他人的幫助，您可能希望添加該答案作爲答案，並接受它以防將來遇到此問題。 – jprofitt