JavaFX troubles with removing items from ArrayList - arraylist

Question

I have 2 TableViews (tableProduct, tableProduct2). The first one is populated by database, the second one is populated with selected by user items from first one (addMeal method, which also converts those to simple ArrayList). After adding/deleting few objects user can save current data from second Table to txt file. It seems to work just fine at beginning. But problem starts to show a bit randomly... I add few items, save it, delete few items, save it, everything is fine. Then after few actions like that, one last object stays in txt file, even though the TableView is empty. I just can't do anything to remove it and I get no errors...
Any ideas what's going on?
public void addMeal() {
productData selection = tableProduct.getSelectionModel().getSelectedItem();
if (selection != null) {
tableProduct2.getItems().add(new productData(selection.getName() + "(" + Float.parseFloat(weightField.getText()) + "g)", String.valueOf(Float.parseFloat(selection.getKcal())*(Float.parseFloat(weightField.getText())/100)), String.valueOf(Float.parseFloat(selection.getProtein())*(Float.parseFloat(weightField.getText())/100)), String.valueOf(Float.parseFloat(selection.getCarb())*(Float.parseFloat(weightField.getText())/100)), String.valueOf(Float.parseFloat(selection.getFat())*(Float.parseFloat(weightField.getText())/100))));
productlist.add(new productSimpleData(selection.getName() + "(" + Float.parseFloat(weightField.getText()) + "g)", String.valueOf(Float.parseFloat(selection.getKcal())*(Float.parseFloat(weightField.getText())/100)), String.valueOf(Float.parseFloat(selection.getProtein())*(Float.parseFloat(weightField.getText())/100)), String.valueOf(Float.parseFloat(selection.getCarb())*(Float.parseFloat(weightField.getText())/100)), String.valueOf(Float.parseFloat(selection.getFat())*(Float.parseFloat(weightField.getText())/100))));
}
updateSummary();
}
public void deleteMeal() {
productData selection = tableProduct2.getSelectionModel().getSelectedItem();
if(selection != null){
tableProduct2.getItems().remove(selection);
Iterator<productSimpleData> iterator = productlist.iterator();
productSimpleData psd = iterator.next();
if(psd.getName().equals(String.valueOf(selection.getName()))) {
iterator.remove();
}
}
updateSummary();
}
public void save() throws IOException {
File file = new File("C:\\Users\\Maciek\\Desktop\\test1.txt");
if(file.exists()){
file.delete();
}
FileWriter fw = null;
BufferedWriter bw = null;
try {
fw = new FileWriter(file);
bw = new BufferedWriter(fw);
Iterator iterator;
iterator = productlist.iterator();
while (iterator.hasNext()) {
productSimpleData pd;
pd = (productSimpleData) iterator.next();
bw.write(pd.toString());
bw.newLine();
}
} catch (IOException e) {
e.printStackTrace();
} finally {
bw.flush();
bw.close();
}
}
and yeah, I realize addMethod inside if statement looks scary but don't mind it, that part is allright after all...

Answer 1

You only ever check the first item in the productlist list to determine, if the item should be removed. Since you do not seem to write to the List anywhere without doing a similar modification to the items of tableProduct2, you can just do the same in this case.
public void deleteMeal() {
int selectedIndex = tableProduct2.getSelectionModel().getSelectedIndex();
if(selectedIndex >= 0) {
tableProduct2.getItems().remove(selectedIndex);
productlist.remove(selectedIndex);
}
updateSummary();
}
This way you also prevent issues, if there are 2 equal items in the list, which could lead to the first one being deleted when the second one is selected...
and yeah, I realize addMethod [...] looks scary
Yes, it does, so it's time to rewrite this:
Change the properties in productData and productSimpleData to float and don't convert the data to String until you need it as String.
if (selection != null) {
float weight = Float.parseFloat(weightField.getText());
float weight100 = weight / 100;
float calories = Float.parseFloat(selection.getKcal())*weight100;
float protein = Float.parseFloat(selection.getProtein())*weight100;
float carb = Float.parseFloat(selection.getCarb())*weight100;
float fat = Float.parseFloat(selection.getFat())*weight100;
ProductData product = new productData(
selection.getName() + "(" + weight + "g)",
calories,
protein,
carb,
fat);
productlist.add(new productSimpleData(product.getName(), calories, protein, carb, fat));
tableProduct2.getItems().add(product);
}
Also that this kind of loop can be rewritten to an enhanced for loop:
Iterator iterator;
iterator = productlist.iterator();
while (iterator.hasNext()) {
productSimpleData pd;
pd = (productSimpleData) iterator.next();
bw.write(pd.toString());
bw.newLine();
}
Assuming you've declared productlist as List<productSimpleData> or a subtype, you can just do
for (productSimpleData pd : productlist) {
bw.write(pd.toString());
bw.newLine();
}
furthermore you could rely on a try-with-resources to close the writers for you:
try (FileWriter fw = new FileWriter(file);
BufferedWriter bw = new BufferedWriter(fw)){
...
} catch (IOException e) {
e.printStackTrace();
}
Also there is no need to delete the file since java overwrites the file by default and only appends data if you specify this in an additional constructor parameter for FileWriter.