Codename One: Connecting and populating a drop-down menu with an SQLite database - sqlite

Question

I am trying to connect an SQLite database file to a picker component (accepting strings). This should act similar to a drop-down menu. I have tried to follow previous advice and examples, but without success.
As indicated in a previous post, I have saved the database file in the source folder of the application. View of the source folder where I have saved the database file (highlighted).
The code I have used to implement my app is as follows with the below layout.
//-----------------------
database code
//-----------------------
public class MyApplication {
private Form current;
private Resources theme;
public void init(Object context) {
theme = UIManager.initFirstTheme("/theme");
// Pro only feature, uncomment if you have a pro subscription
// Log.bindCrashProtection(true);
}
private Container Home() {
Container home = new Container(new BoxLayout(BoxLayout.Y_AXIS));
return home;
}
private Container AddItem() {
Container addItem = new Container(new BoxLayout(BoxLayout.Y_AXIS));
TextArea item = new TextArea("Add Item");
addItem.addComponent(item);
Picker selectItem = new Picker();
selectItem.setType(Display.PICKER_TYPE_STRINGS);
//----------------------------------------------------------------------------------
Database db = null;
Cursor cur = null;
try {
db = Display.getInstance().openOrCreate("FoodAndBeverage.db");
if(selectItem.getText().startsWith("Still Water")) {
cur = db.executeQuery(selectItem.getText());
int columns = cur.getColumnCount();
addItem.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);
addItem.add(BorderLayout.CENTER, new Table(new DefaultTableModel(columnNames, arr)));
} else {
addItem.add(BorderLayout.CENTER, "Query returned no results");
}
} else {
addItem.add(BorderLayout.CENTER, "Query returned no results");
}
} else {
db.execute(selectItem.getText());
addItem.add(BorderLayout.CENTER, "Query completed successfully");
}
addItem.revalidate();
} catch(IOException err) {
Log.e(err);
addItem.removeAll();
addItem.add(BorderLayout.CENTER, "Error: " + err);
addItem.revalidate();
} finally {
Util.cleanup(db);
Util.cleanup(cur);
}
//---------------------------------------------------------------------------------------------
addItem.addComponent(selectItem);
TextField quantity = new TextField("", "Quantity (ml or g)", 4, TextArea.NUMERIC);
addItem.addComponent(quantity);
Button add = new Button("Add");
addItem.addComponent(add);
TextArea results = new TextArea("Results");
addItem.addComponent(results);
return addItem;
}
private Container Settings() {
Container settings = new Container(new BoxLayout(BoxLayout.Y_AXIS));
TextArea nutrients = new TextArea("Target");
settings.addComponent(nutrients);
TextField volume = new TextField("", "Volume (ml)", 4, TextArea.NUMERIC);
settings.addComponent(volume);
TextArea duration = new TextArea("Hydration Duration");
settings.addComponent(duration);
settings.add("Start:");
Picker start = new Picker();
start.setType(Display.PICKER_TYPE_TIME);
settings.addComponent(start);
settings.add("End:");
Picker end = new Picker();
end.setType(Display.PICKER_TYPE_TIME);
settings.addComponent(end);
Button save = new Button("Save");
settings.addComponent(save);
return settings;
}
public void start() {
if(current != null)
{
current.show();
return;
}
Form home = new Form("Hydrate", new BorderLayout());
Tabs t = new Tabs();
t.addTab("Home", Home());
t.addTab("Intake", AddItem());
t.addTab("Settings", Settings());
home.add(BorderLayout.NORTH, t);
home.show();
}
public void stop() {
current = Display.getInstance().getCurrent();
}
public void destroy() {
}
}
I would therefore appreciate any advice and guidance on exactly where I am going wrong and how to implement the suggested changes in my code.

Answer 1

I'm assuming the file under src does indeed end with the extension db as the Windows hidden extensions nonsense is turned on.
This code will NOT open a db placed in src:
db = Display.getInstance().openOrCreate("FoodAndBeverage.db");
You need to do something like this to implicitly initialize the DB the first time the app is installed:
String path = Display.getInstance().getDatabasePath("FoodAndBeverage.db");
FileSystemStorage fs = FileSystemStorage.getInstance();
if(!fs.exists(path)) {
try (InputStream is = Display.getInstance().getResourceAsStream(getClass(), "/FoodAndBeverage.db");
OutputStream os = fs.openOutputStream(path)) {
Util.copy(is, os);
} catch(IOException err) {
Log.e(err);
}
}
db = Display.getInstance().openOrCreate("FoodAndBeverage.db");
Notice that the code above doesn't check for updates of the DB so assuming the DB is read only you might want to update/merge it with app updates.

Answer 2

The above code doesn't work on Android device, this works only on simulator. I have tested multiple times in the android device. In the real android device ,the database is not loaded at all, shows sql exception error
"No such table sql exception".
Looks like preloaded sqlite .db file is never tested on real Android device.