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これでデータベースにデータを挿入するだけでなく、データをデータベースに挿入するときにエラーが発生します。トリガされるためアプリケーションがメインページに到着するたびにテーブルクエリを作成します。しかし、私はこの問題を解決する方法を知らない。以下はデータベースに2番目のレコードを追加した後のCodename Sqliteの問題
私のコードです： -
public class Calender {
private Form current;
private Resources theme;
Form calendar, saveEvent, DataEvent;
Label dateLabel;
TextField eventArea, descriptionArea;
Customised cal;
Database db = null;
Cursor cur = null;
public void init(Object context) {
theme = UIManager.initFirstTheme("/theme");
// Enable Toolbar on all Forms by default
Toolbar.setGlobalToolbar(true);
// Pro only feature, uncomment if you have a pro subscription
// Log.bindCrashProtection(true);
String path = Display.getInstance().getDatabasePath("Events.db");
FileSystemStorage fs = FileSystemStorage.getInstance();
if (!fs.exists(path)) {
try (InputStream is = Display.getInstance().getResourceAsStream(getClass(), "/Events.db");
OutputStream os = fs.openOutputStream(path)) {
Util.copy(is, os);
} catch (IOException err) {
Log.e(err);
}
}
try {
db = Display.getInstance().openOrCreate("Events.db");
db.execute("CREATE TABLE Personsse (Date date NOT NULL,Event varchar(255) NOT NULL, Description varchar(255) NOT NULL)");
} catch (IOException e) {
e.printStackTrace();
}
}
public void start() {
if (current != null) {
current.show();
return;
}
try {
SplashScreen spl = new SplashScreen();
spl.show();
new java.util.Timer().schedule(
new java.util.TimerTask() {
@Override
public void run() {
calendar.show();
}
}, 4000);
} catch (IOException e) {
e.printStackTrace();
}
DataEvent = new Form("Data Explorer", new BorderLayout());
Command back1 = new Command("Back") {
public void actionPerformed(ActionEvent ev) {
calendar.show();
}
};
DataEvent.setBackCommand(back1);
calendar = new Form("Events", new BoxLayout(BoxLayout.Y_AXIS));
cal = new Customised();
calendar.add(cal);
Label date = new Label("Event Date:- ");
dateLabel = new Label();
Label event = new Label("Event:- ");
eventArea = new TextField();
Label description = new Label("Event Description:- ");
descriptionArea = new TextField();
Container container = TableLayout.encloseIn(2, date, dateLabel, event, eventArea, description, descriptionArea);
container.setUIID("container");
calendar.add(container);
cal.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent evt) {
try {
SimpleDateFormat sdf = new SimpleDateFormat("EE MMM dd HH:mm:ss z yyyy");
String selectedDate = new Date(cal.getSelectedDay()).toString();
Date date1 = sdf.parse(selectedDate);
SimpleDateFormat df = new SimpleDateFormat("dd/MM/yyyy");
dateLabel.setText(df.format(date1));
} catch (ParseException ex) {
ex.printStackTrace();
}
cal.createDay();
}
});
Toolbar tb = new Toolbar();
calendar.setToolBar(tb);
tb.addCommandToRightBar("", FontImage.createMaterial(FontImage.MATERIAL_SAVE, UIManager.getInstance().getComponentStyle("TitleCommand")), (evt) -> {
saveEvent.show();
});
tb.addCommandToLeftBar("", FontImage.createMaterial(FontImage.MATERIAL_EVENT, UIManager.getInstance().getComponentStyle("TitleCommand")), (evt) -> {
DataEvent.show();
});
Button add = new Button("Add Event");
Button clear = new Button("Clear Event");
calendar.add(add);
calendar.add(clear);
//Saved Events Form Starts ====================================================================================
saveEvent = new Form("Saved Event", new BoxLayout(BoxLayout.Y_AXIS));
Command back = new Command("Back") {
public void actionPerformed(ActionEvent ev) {
calendar.show();
}
};
saveEvent.setBackCommand(back);
Toolbar tb1 = new Toolbar();
saveEvent.setToolBar(tb1);
tb1.addCommandToLeftBar("", FontImage.createMaterial(FontImage.MATERIAL_ARROW_BACK, UIManager.getInstance().getComponentStyle("TitleCommand")), back);
//Save Events Form Ends =======================================================================================
add.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent evt) {
Log.p(dateLabel.getText().toString());
//if((dateLabel.getText() == null) && (eventArea.getText() == null) && (descriptionArea.getText() == null)){
if ((dateLabel.getText() == "") || (eventArea.getText() == "") || (descriptionArea.getText() == "")) {
Dialog.show("Required field", "Please fill all the fields", "OK", "");
} //}
else {
Label date1 = new Label("Event Date:- ");
Label dateLabel1 = new Label(dateLabel.getText());
Label event1 = new Label("Event:- ");
Label eventArea1 = new Label(eventArea.getText());
Label description1 = new Label("Event Description:- ");
Label descriptionArea1 = new Label(descriptionArea.getText());
Container container1 = TableLayout.encloseIn(2, date1, dateLabel1, event1, eventArea1, description1, descriptionArea1);
container1.setUIID("container");
saveEvent.add(container1);
ToastBar.showMessage("Event successfull saved", FontImage.MATERIAL_SAVE, 4000);
//Databse Working
try {
String[] values = new String[]{dateLabel.getText(), eventArea.getText(), descriptionArea.getText()};
db.execute("INSERT INTO Personsse (Date,Event,Description) VALUES(?,?,?)", values);
Button database = new Button("Database");
calendar.add(database);
database.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent evt) {
try {
cur = db.executeQuery("SELECT * FROM Personsse");
int columns = cur.getColumnCount();
DataEvent.removeAll();
if (columns > 0) {
boolean next = cur.next();
if (next) {
ArrayList<String[]> data = new ArrayList<>();
String[] columnNames = new String[columns];
for (int iter = 0; iter < columns; iter++) {
columnNames[iter] = cur.getColumnName(iter);
}
while (next) {
Row currentRow = cur.getRow();
String[] currentRowArray = new String[columns];
for (int iter = 0; iter < columns; iter++) {
currentRowArray[iter] = currentRow.getString(iter);
}
data.add(currentRowArray);
next = cur.next();
}
Object[][] arr = new Object[data.size()][];
data.toArray(arr);
DataEvent.add(BorderLayout.CENTER, new Table(new DefaultTableModel(columnNames, arr)));
} else {
DataEvent.add(BorderLayout.CENTER, "Query returned no results");
}
} else {
DataEvent.add(BorderLayout.CENTER, "Query returned no results");
}
DataEvent.revalidate();
Util.cleanup(db);
Util.cleanup(cur);
} catch (IOException e) {
e.printStackTrace();
}
DataEvent.show();
}
});
} catch (IOException e) {
e.printStackTrace();
}
}
}
});
}
、エラーが以下の通りです： - ：
java.sql.SQLException: [SQLITE_ERROR] SQL error or missing database (table Personsse already exists)
at org.sqlite.DB.newSQLException(DB.java:886)
at org.sqlite.DB.newSQLException(DB.java:897)
at org.sqlite.DB.throwex(DB.java:864)
at org.sqlite.NativeDB.prepare(Native Method)
at org.sqlite.DB.prepare(DB.java:207)
at org.sqlite.PrepStmt.<init>(PrepStmt.java:50)
at org.sqlite.SQLiteConnection.prepareStatement(SQLiteConnection.java:616)
at org.sqlite.SQLiteConnection.prepareStatement(SQLiteConnection.java:606)
at org.sqlite.SQLiteConnection.prepareStatement(SQLiteConnection.java:578)
at com.codename1.impl.javase.SEDatabase.execute(SEDatabase.java:92)
at com.pivotal.calendar.Calender.init(Calender.java:76)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.codename1.impl.javase.Executor$1$1.run(Executor.java:117)
at com.codename1.ui.Display.processSerialCalls(Display.java:1154)
at com.codename1.ui.Display.mainEDTLoop(Display.java:971)
at com.codename1.ui.RunnableWrapper.run(RunnableWrapper.java:120)
at com.codename1.impl.CodenameOneThread.run(CodenameOneThread.java:176)
java.io.IOException: [SQLITE_ERROR] SQL error or missing database (table Personsse already exists)
at com.codename1.impl.javase.SEDatabase.execute(SEDatabase.java:96)
at com.pivotal.calendar.Calender.init(Calender.java:76)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.codename1.impl.javase.Executor$1$1.run(Executor.java:117)
at com.codename1.ui.Display.processSerialCalls(Display.java:1154)
at com.codename1.ui.Display.mainEDTLoop(Display.java:971)
at com.codename1.ui.RunnableWrapper.run(RunnableWrapper.java:120)
at com.codename1.impl.CodenameOneThread.run(CodenameOneThread.java:176)
[EDT] 0:0:0,1 - Codename One revisions: 16f9f308f6ef10ac0e25a8afbd37b8066f5a391d
2348
- をアプリケーションの起動時に次のエラーを取得
アプリケーションによってスローされたデータベース次のエラーの2番目の記録： -
[EDT] 0:0:0,46 - 26/04/2017
**** WARNING! DB Cursor was released by the GC without being closed first! This might cause crashes on iOS *****
[EDT] 0:0:15,345 - 26/04/2017
java.lang.NullPointerException
[EDT] 0:0:16,278 - Exception: java.lang.NullPointerException - null
at com.codename1.impl.javase.SEDatabase.execute(SEDatabase.java:103)
at com.pivotal.calendar.Calender$5.actionPerformed(Calender.java:212)
at com.codename1.ui.util.EventDispatcher.fireActionEvent(EventDispatcher.java:349)
at com.codename1.ui.Button.fireActionEvent(Button.java:435)
at com.codename1.ui.Button.released(Button.java:467)
at com.codename1.ui.Button.pointerReleased(Button.java:566)
at com.codename1.ui.Form.pointerReleased(Form.java:2642)
at com.codename1.ui.Form.pointerReleased(Form.java:2578)
at com.codename1.ui.Component.pointerReleased(Component.java:3266)
at com.codename1.ui.Display.handleEvent(Display.java:2025)
at com.codename1.ui.Display.edtLoopImpl(Display.java:1070)
at com.codename1.ui.Display.mainEDTLoop(Display.java:999)
at com.codename1.ui.RunnableWrapper.run(RunnableWrapper.java:120)
at com.codename1.impl.CodenameOneThread.run(CodenameOneThread.java:176)
そして私はまた、1つのSQLiteのようなコードネームに関連するいくつかのクエリ持っています：昇順でラベルに表データを印刷する - どのように、どのようにしSpanLabelで一度に1行ずつ印刷します。
私はあなたのソリューションの助けを借りてその問題を解決しますので、ありがとう、しかし、私はデータベースに2番目のレコードを追加しているとき、それはエラーをスローされます： - EDT] 0：0：23,685 - 例外：java.lang .NullPointerException - null –
mmmいいえ、これは何かが初期化されていないか、nullであることを意味します。あなたのコードでこれが起こったかどうかを正確に表示できますか？@GRV_Droid –
Insert queryが2回目に呼び出されるとエラーになります。最初にメインページを開くと、複数のレコードをデータベースに追加できますが、アプリケーションが別のページに移動してアプリケーションの表を表示し、再度レコードを追加するためのメインページに移動すると、JavaNullPointerExceptionというエラーが発生します。 @YCF_L 24 –