I use a CellTable with EditTextCell
When the EditTextCell fire the FieldUpdater, I want to do a validation and set the EditTextCell to the old value if validation fail. But I cant find how to update the CellTable or the specified row.
Here a piece of code:
titleColumn.setFieldUpdater(new FieldUpdater<QuestionDto, String>() {
#Override
public void update(int index, QuestionDto object, String value) {
if (!isValid(value))
// Here I need to set the EditTextCell to the value in my object
else
// It's valid I do the work
}
});
I was looking for something like : ((EditTextCell)titleColumn.getCell(index)).setValue(object.getTitle());
The other solution is to reset all the CellTable like that:
table.setRowData(dataProvider.getList());
But it's don't work too.
I'm not very knowledgeable of EditTextCell but for other widgets I would catch the ChangeEvent (is it possible to catch it the cell you're using ?) then call event.stopPropagation() if I don't want the user action to have any effect.
Related
I am using rxjava2 for the first time on an Android project, and am doing SQL queries on a background thread.
However I am having trouble figuring out the best way to do a simple SQL query, and being able to handle the case where the record may or may not exist. Here is the code I am using:
public Observable<Record> createRecordObservable(int id) {
Callable<Record> callback = new Callable<Record>() {
#Override
public Record call() throws Exception {
// do the actual sql stuff, e.g.
// select * from Record where id = ?
return record;
}
};
return Observable.fromCallable(callback).subscribeOn(Schedulers.computation());
}
This works well when there is a record present. But in the case of a non-existent record matching the id, it treats it like an error. Apparently this is because rxjava2 doesn't allow the Callable to return a null.
Obviously I don't really want this. An error should be only if the database failed or something, whereas a empty result is perfectly valid. I read somewhere that one possible solution is wrapping Record in a Java 8 Optional, but my project is not Java 8, and anyway that solution seems a bit ugly.
This is surely such a common, everyday task that I'm sure there must be a simple and easy solution, but I couldn't find one so far. What is the recommended pattern to use here?
Your use case seems appropriate for the RxJava2 new Observable type Maybe, which emit 1 or 0 items.
Maybe.fromCallable will treat returned null as no items emitted.
You can see this discussion regarding nulls with RxJava2, I guess that there is no many choices but using Optional alike in other cases where you need nulls/empty values.
Thanks to #yosriz, I have it working with Maybe. Since I can't put code in comments, I'll post a complete answer here:
Instead of Observable, use Maybe like this:
public Maybe<Record> lookupRecord(int id) {
Callable<Record> callback = new Callable<Record>() {
#Override
public Record call() throws Exception {
// do the actual sql stuff, e.g.
// select * from Record where id = ?
return record;
}
};
return Maybe.fromCallable(callback).subscribeOn(Schedulers.computation());
}
The good thing is the returned record is allowed to be null. To detect which situation occurred in the subscriber, the code is like this:
lookupRecord(id)
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Consumer<Record>() {
#Override
public void accept(Record r) {
// record was loaded OK
}
}, new Consumer<Throwable>() {
#Override
public void accept(Throwable throwable) {
// there was an error
}
}, new Action() {
#Override
public void run() {
// there was an empty result
}
});
I want to display data. I used AfterFieldChange method to display the data but it turns out the radio button doesn't change. I already insert the data customer table, the BAQ (Business Activity Query) also work just that the screen form doesn't work.
private void UD24_AfterFieldChange(object sender, DataColumnChangeEventArgs args)
{
// ** Argument Properties and Uses **
// args.Row["FieldName"]
// args.Column, args.ProposedValue, args.Row
// Add Event Handler Code
//EpiDataView edvUD24 = ((EpiDataView)(this.oTrans.EpiDataViews["UD24"]));
//System.Data.DataRow edvUD24Row = edvUD24.CurrentDataRow;
EpiDataView view = oTrans.EpiDataViews["UD24"] as EpiDataView;
switch (args.Column.ColumnName)
{
case "Character03":
DataTable tblcust=customer(args.Row["Character03"].ToString());
if(tblcust!=null && tblcust.Rows.Count>0)
{
string client = tblcust.Rows[0]["Customer_client1_c"].ToString();
view.dataView[view.Row]["ShortChar04"] = client;
//MessageBox.Show(Client);
}
break;
}
}
After changing the data in the EpiDataView you need to call Notify to make it call the UI elements that need to be updated:
view.dataView[view.Row]["ShortChar04"] = client;
view.Notify(new Ice.Lib.Framework.EpiNotifyArgs(this, view.Row, NotifyType.Initialize));
Kieym, perhaps try adding EpiNotifyArgs into your declaration, like so:
private void UD24_AfterFieldChange(object sender, DataColumnChangeEventArgs args, EpiNotifyArgs args)
I red a lot about sorting a CellTable. I also went trough the ColumnSorting with AsyncDataProvider. But my CellTable does not sort.
Here is my code:
public class EventTable extends CellTable<Event> {
public EventTable() {
EventsDataProvider dataProvider = new EventsDataProvider(this);
dataProvider.addDataDisplay(this);
SimplePager.Resources pagerResources = GWT.create(SimplePager.Resources.class);
SimplePager pager = new SimplePager(TextLocation.CENTER, pagerResources, false, 5, true);
pager.setDisplay(this);
[...]
TextColumn<Event> nameCol = new TextColumn<Event>() {
#Override
public String getValue(Event event) {
return event.getName();
}
};
nameCol.setSortable(true);
AsyncHandler columnSortHandler = new AsyncHandler(this);
addColumnSortHandler(columnSortHandler);
addColumn(nameCol, "Name");
getColumnSortList().push(endCol);
}
}
public class EventsDataProvider extends AsyncDataProvider<Event> {
private final EventTable eventTable;
public EventsDataProvider(EventTable eventTable) {
this.eventTable = eventTable;
}
#Override
protected void onRangeChanged(HasData<Event> display) {
int start = display.getVisibleRange().getStart();
int length = display.getVisibleRange().getLength();
// check false values
if (start < 0 || length < 0) return;
// check Cache before making a rpc
if (pageCached(start, length)) return;
// get Events async
getEvents(start, length);
}
}
I do now know, if all the methods are need here. If so, I will add them. But in short:
pageCached calls a method in my PageCache Class which holds a map and a list. Before making a rpc call, the cache is checked if the events where already taken and then displayed.
getEvents just makes an rpc call via asynccallback which updates the rowdata via updateRowData() on success.
My Table is displayed fast with currently around 500 entries (could be more, depends on the customer). No missing data and the paging works fine.
I just cannot get the sorting work. As far as I know, AsyncHandler will fire a setVisibleRangeAndClearData() and then an onRangeChanged(). onRangeChanged is never fired. As for the setVisibleRangeAndClearData() I do not know. But the sortindicator (arrow next to the columnname) does change on every click.
I do not want to let the server sort the list. I have my own Comparators. It is enough, if the current visible page of the table is sorted. I do now want to sort the whole list.
Edit:
I changed following code in the EventTable constructor:
public EventTable() {
[...]
addColumnSortHandler(new ColumnSortEvent.AsyncHandler(this) {
public void onColumnSort(ColumnSortEvent event) {
super.onColumnSort(event);
MyTextColumn<Event> myTextColumn;
if (event.getColumn() instanceof MyTextColumn) {
// Compiler Warning here: Safetytype unchecked cast
myTextColumn = (MyTextColumn<Event>) event.getColumn();
MyLogger.log(this.getClass().getName(), "asc " + event.isSortAscending() + " " + myTextColumn.getName(), Level.INFO);
}
List<Event> list = dataProvider.getCurrentEventList();
if (list == null) return;
if (event.isSortAscending()) Collections.sort(list, EventsComparator.getComparator(EventsComparator.NAME_SORT));
else Collections.sort(list, EventsComparator.descending(EventsComparator.getComparator(EventsComparator.NAME_SORT)));
}
});
addColumn(nameCol, "Name");
getColumnSortList().push(endCol);
}
I had to write my own TextColumn to determine the Name of the column. Otherwise how should I know, which column was clicked? The page gets sorted now but I have to click twice on the column. After then, the sorting is done with every click but in the wrong order.
This solution does need polishing and it seems kinda hacky to me. Any better ideas?
The tutorial, that you linked to, states:
This sorting code is here so the example works. In practice, you would
sort on the server.
Async provider is used to display data that is too big to be loaded in a single call. When a user clicks on any column to sort it, there is simply not enough objects on the client side to display "first 20 evens by name" or whatever sorting was applied. You have to go back to your server and request these first 20 events sorted by name in ascending order. And when a user reverses sorting, you have to go to the server again to get first 20 events sorted by name in a descending order, etc.
If you can load all data in a single call, then you can use regular DataProvider, and all sorting can happen on the client side.
EDIT:
The problem in the posted code was in the constructor of EventsDataProvider. Now it calls onRangeChanged, and the app can load a new sorted list of events from the server.
I have several fields in a screen, that are partially dependent each on other by validating rules.
If user changes one field then I can affect another fields using setValue(). But I am fighting with the problem, valueChange event is fired from setValue() just as from user activity.
My example: I have four fields "activity_status", "schedule_date", "start_date", "end_date". By editing any one field I want to affect another three fields (changing status, setting or shifting dates). How to avoid recursive calling valueChange method?
I can imagine a variable justProcessedField that can working as a lock, but has anybody a better hands-on solution?
Usually we do set a flag when we trigger the first valueChangeEvent() and then ignore all others, until the first trigger is finished processing.
The pseudocode looks like this:
private boolean _ignoreTriggers= false; // Set ignore triggers when we do manual setValue stuff
field1.addListener(new ValueChangeListener() {
#Override
public void valueChange(ValueChangeEvent event) {
if (!_ignoreTriggers) {
_ignoreTriggers= true;
// Do the processing and setValues(...) in the other fields
_ignoreTriggers= false;
}
}
}
);
With different booleans you can also make groups of fields "sensisble/insensible" to changes in other fields.
To avoid the ValueChangeEvents you can create custom fields, which are extentions of the fields you want to modify. This custom fields should have a public method which calls the setInternalValue method.
Example for Checkbox-Field:
public class CheckBoxSilent extends CheckBox {
/**
* Set the new value without calling a {#link ValueChangeListener}
*
* #param newValue the new value to be set.
*/
public void setValueSecretly(boolean newValue) {
setInternalValue(newValue);
markAsDirty();
}
}
The functionality I am trying to use is:
- Create a ObjectDataSource for selection and updating controls on a web page (User Control).
- Use the DataObjectTypeName to have an object created that would send the data to an UpdateMethod.
- Before the values are populated in the DataObjectTypeName’s object, I would like to pre-populate the object so the unused items in the class are not defaulted to zeros and empty strings without me knowing whether the zero or default string was set by the user or by the application.
I cannot find a way to pre-populate the values (this was an issue back in 2006 with framework 2.0). One might ask “Why would anyone need to pre-populate the object?”. The simple answer is: I want to be able to randomly place controls on different User Controls and not have to be concerned with which UpdateMethod needs to handle which fields of an object.
For Example, let’s say I have a class (that reflects a SQL Table) that includes the fields: FirstName, LastName, Address, City, State, Zip. I may want to give the user the option to change the FirstName and LastName and not even see the Address, City, State, Zip (or vice-versa). I do not want to create two UpdateMethods where one handled FirstName and LastName and the other method handles the other fields. I am working with a Class of some 40+ columns from multiple tables and I may want some fields on one screen and not another and decide later to change those fields from one screen to another (which breaks my UpdateMethods without me knowing).
I hope I explained my issue well enough.
Thanks
This is hardly a solution to the problem, but it's my best stab at it.
I have a GridView with its DataSourceID set to an ObjectDataSource.
Whenever a row is updated, I want the property values in the object to be selectively updated - that is - only updated if they appear as columns in the GridView.
I've created the following extension:
public static class GridViewExtensions
{
public static void EnableLimitUpdateToGridViewColumns(this GridView gridView)
{
_gridView = gridView;
if (_gridView.DataSourceObject != null)
{
((ObjectDataSource)_gridView.DataSourceObject)
.Updating += new ObjectDataSourceMethodEventHandler(objectDataSource_Updating);
}
}
private static GridView _gridView;
private static void objectDataSource_Updating(object sender, ObjectDataSourceMethodEventArgs e)
{
var newObject = ((object)e.InputParameters[0]);
var oldObjects = ((ObjectDataSource)_gridView.DataSourceObject).Select().Cast<object>();
Type type = oldObjects.First().GetType();
object oldObject = null;
foreach (var obj in oldObjects)
{
if (type.GetProperty(_gridView.DataKeyNames.First()).GetValue(obj, null).ToString() ==
type.GetProperty(_gridView.DataKeyNames.First()).GetValue(newObject, null).ToString())
{
oldObject = obj;
break;
}
}
if (oldObject == null) return;
var dynamicColumns = _gridView.Columns.OfType<DynamicField>();
foreach (var property in type.GetProperties())
{
if (dynamicColumns.Where(c => c.DataField == property.Name).Count() == 0)
{
property.SetValue(newObject, property.GetValue(oldObject, null), null);
}
}
}
}
And in the Page_Init event of my page, I apply it to the GridView, like so:
protected void Page_Init()
{
GridView1.EnableLimitUpdateToGridViewColumns();
}
This is working well for me at the moment.
You could probably apply similar logic to other controls, e.g. ListView or DetailsView.
I'm currently scratching my head to think of a way this can be done in a rendering-agnostic manner - i.e. without having to know about the rendering control being used.
I hope this ends up as a normal feature of the GridView or ObjectDataSource control rather than having to hack it.