Simplify algorithm and add info button to results to show details

TODO

@@ -1,10 +1,8 @@
-- simplify algorithm (first subtract conditions then split the rest)
-- snackbar on results screen showing (rest / number of persons)
-- prevent "snap in" after switching tabs (-> understand reason from source code of expansion panel / card widgets?)
-- is there a better solution than showing a snackbar if totalconditionsprice > money in the pot?
+- prevent "snap in" after switching tabs
+ (-> understand reason from source code of expansion panel / card widgets? elevation?)
 - replace "-" button with Icons.delete_forever can at the end of each row on persons tab
 - ask for confirmation when deleting
-- move unnecessary code out of setState
+- move unnecessary code out of set state
 - allow other currencies
 - option to save / restore data (or just store data, for now)
 - add other languages

lib/main.dart

@@ -233,6 +233,10 @@ class ScrollableTabsState extends State<ScrollableTabs>
 
  List<ConditionData> conditions = [];
 
+ double totalpaid = 0.0;
+ double totalconditions = 0.0;
+ double priceperperson = 0.0;
+
  String specialnote = '';
 
  @override
@@ -288,6 +292,7 @@ class ScrollableTabsState extends State<ScrollableTabs>
 
  void updateResults() {
  setState(() {
+ // update data structures
  conditions.removeWhere((c) => c.persons.isEmpty);
  for (int i = 0; i < personData.length; ++i) {
  if (personData[i].namecontroller.text.isNotEmpty)
@@ -296,33 +301,83 @@ class ScrollableTabsState extends State<ScrollableTabs>
  personData[i].paidcontroller.text.replaceAll(',', '.')) ??
  0.0;
  }
- double total = personData.fold(0.0, (total, p) => total + p.paid);
- double priceperperson = total / personData.length;
- for (int i = 0; i < personData.length; ++i)
- personData[i].hastopay = priceperperson - personData[i].paid;
- for (ConditionData c in conditions) {
- for (int i = 0; i < personData.length; ++i) {
- personData[i].hastopay += (c.persons.contains(i) ? c.price : 0);
- personData[i].hastopay -=
- c.price * c.persons.length / personData.length;
- }
+ // sum up what was paid
+ totalpaid = personData.fold(0.0, (total, p) => total + p.paid);
+ // sum up conditions
+ totalconditions = 0.0;
+ for (int i = 0; i < personData.length; ++i) {
+ personData[i].conditionstopay = 0.0;
+ for (ConditionData c in conditions)
+ if (c.persons.contains(i)) personData[i].conditionstopay += c.price;
+ totalconditions += personData[i].conditionstopay;
  }
- double totalconditionsprice = conditions.fold(
- 0.0,
- (totalconditionsprice, c) =>
- totalconditionsprice + c.price * c.persons.length);
- if (totalconditionsprice >= total + 0.01)
+ // compute final prices
+ priceperperson = (totalpaid - totalconditions) / personData.length;
+ for (PersonData p in personData)
+ p.hastopay = priceperperson + p.conditionstopay - p.paid;
+ // check consistency
+ if (totalconditions >= totalpaid + 0.01)
  specialnote = 'Note: Total price of the conditions (' +
- totalconditionsprice.toStringAsFixed(2) +
- ') is greater than the total amount in the pot (' +
- total.toStringAsFixed(2) +
+ totalconditions.toStringAsFixed(2) +
+ ') is greater than the total money spent (' +
+ totalpaid.toStringAsFixed(2) +
  ').';
  else
  specialnote = '';
  });
+ _scaffoldKey.currentState.removeCurrentSnackBar();
  if (specialnote.isNotEmpty)
- _scaffoldKey.currentState
- .showSnackBar(SnackBar(content: Text(specialnote)));
+ _scaffoldKey.currentState.showSnackBar(SnackBar(
+ content: Text(specialnote),
+ duration: Duration(seconds: 6),
+ ));
+ }
+
+ void displayInfoDialog(BuildContext context) {
+ showDialog(
+ context: context,
+ builder: (BuildContext context) {
+ return AlertDialog(
+ title: Text("Details"),
+ content: ListView(shrinkWrap: true, children: [
+ Row(children: [
+ Expanded(child: Text('Total money spent:')),
+ Text(totalpaid.toStringAsFixed(2) + '\€ '),
+ ]),
+ Divider(height: 5),
+ Row(children: [
+ Expanded(child: Text('Total price of conditions:')),
+ Text(totalconditions.toStringAsFixed(2) + '\€ '),
+ ]),
+ Divider(height: 5),
+ Row(children: [
+ Expanded(child: Text('Remaining price to pay:')),
+ Text((totalpaid - totalconditions).toStringAsFixed(2) + '\€ '),
+ ]),
+ Divider(height: 5),
+ Row(children: [
+ Expanded(child: Text('Remaining per person:')),
+ Text(priceperperson.toStringAsFixed(2) + '\€ '),
+ ]),
+ Divider(height: 5),
+ Text('\nEach person has to pay the remaining price of ' +
+ priceperperson.toStringAsFixed(2) +
+ '\€ minus what they already paid plus the ' +
+ 'sum over their respective conditions.'),
+ ]),
+ // 'Total money spent: ' + totalpaid.toStringAsFixed(2) + '\n'
+ // 'Total price of conditions: ' + totalconditions.toStringAsFixed(2)
+ actions: <Widget>[
+ new FlatButton(
+ child: Text('Close'),
+ onPressed: () {
+ Navigator.of(context).pop();
+ },
+ ),
+ ],
+ );
+ },
+ );
  }
 
  Widget createTabForms(BuildContext context, int pageidx) {
@@ -393,30 +448,33 @@ class ScrollableTabsState extends State<ScrollableTabs>
  ]);
 
  case PageID.Results:
- return Card(
- elevation: 2,
- child: DataTable(
- columns: [
- DataColumn(
- label: Text('Person'),
- onSort: (i, b) {},
- ),
- DataColumn(
- label: Text('Has to pay'),
- tooltip: 'The total amount of money this person has to pay.',
- numeric: true,
- onSort: (i, b) {},
- ),
- ],
- rows: personData
- .map((p) => DataRow(cells: [
- DataCell(Text(p.name), onTap: () {}),
- DataCell(Text(p.hastopay.toStringAsFixed(2) + ' \€'),
- onTap: () {}),
- ]))
- .toList(),
+ return Column(children: [
+ Card(
+ elevation: 5,
+ child: DataTable(
+ columns: [
+ DataColumn(
+ label: Text('Person'),
+ onSort: (i, b) {},
+ ),
+ DataColumn(
+ label: Text('Has to pay'),
+ tooltip: 'The total amount of money this person has to pay.',
+ numeric: true,
+ onSort: (i, b) {},
+ ),
+ ],
+ rows: personData
+ .map((p) => DataRow(cells: [
+ DataCell(Text(p.name), onTap: () {}),
+ DataCell(Text(p.hastopay.toStringAsFixed(2) + ' \€'),
+ onTap: () {}),
+ ]))
+ .toList(),
+ ),
  ),
- );
+ SizedBox(height: 72)
+ ]);
  }
  return null;
  }
@@ -445,6 +503,13 @@ class ScrollableTabsState extends State<ScrollableTabs>
  child: Icon(Icons.add),
  );
 
+ case PageID.Results:
+ return FloatingActionButton(
+ onPressed: () => displayInfoDialog(context),
+ tooltip: 'Info',
+ child: Icon(Icons.info_outline),
+ );
+
  default:
  return null;
  }