I'm trying to find the best way to create a personalized contact List for an instant messaging app.
Maybe with a Tree View but I'm not sure.
I Need a way to view Groups in which there are Contacts.
A Contact contains different info and action buttons like "Send a message, View infos, ... "
An example # http://ycorpblog.com/wp-content/uploads/2007/10/yahoo-messenger-90-action-toolbar.jpg
here I am in my little research. I inherited one of my classes QAbstractItemDelegate.
I reimplements paint () and sizeHint ()
in the paint () for drawing my items (and here for example a button)
Code:
QStyleOptionButton buttonStyle;
buttonStyle.rect = option.rect;
buttonStyle.features = QStyleOptionButton::AutoDefaultButton;
buttonStyle.text = "Salut!";
QApplication::style()->drawControl(QStyle::CE_PushButton,&buttonStyle,painter);
But then it does involve reimplementing QAbstractItemDelegate: helpEvent () to retrieve the actions of clicking the buttons (compare the position of the mouse compared to my drawing and determine what the user clicks)?
Moreover, with the solution proposed above,
QAbstractItemDelegate::helpEvent () is a slot
Despite a careful reading of the documentation, I can not determine when this function is called, does it connect to something?
I also cast a glance at editorEvent (), I recovered well Mouse Click but no way of knowing exactly where the user clicked, so no way of knowing if it's a button or other element.
I asked about the method I use too. Is this good? Can you enlighten me?
Pending your answers / ideas. Thank you.
Related
We created a small painting application in JavaFX. A new requirement arose, where we have to warn the user, that he made changes, which are not yet persisted and asking him, if the user might like to save first before closing.
Sample Snapshot:
Unfortunately there are a lot of different Nodes, and Nodes can be changed in many ways, like for example a Polygon point can move. The Node itself can be dragged. They can be rotated and many more. So before firing a zillion events for every possible change of a Node object to the canvas I`d like to ask, if anyone might have an idea on how to simplify this approach. I am curious, if there are any listeners, that I can listen to any changes of the canvas object within the scene graph of JavaFX.
Especially since I just want to know if anything has changed and not really need to know the specific change.
Moreover, I also do not want to get every single event, like a simple select, which causes a border to be shown around the selected node (like shown on the image), which does not necessary mean, that the user has to save his application before leaving.
Anyone have an idea? Or do I really need to fire Events for every single change within a Node?
I think you are approaching this problem in the wrong way. The nodes displayed on screen should just be a visual representation of an underlying model. All you really need to know is that the underlying model has changed.
If, for example, you were writing a text editor, the text displayed on the screen would be backed by some sort of model. Let's assume the model is a String. You wouldn't need to check if any of the text nodes displayed on screen had changed you would just need to compare the original string data with the current string data to determine if you need to prompt the user to save.
Benjamin's answer is probably the best one here: you should use an underlying model, and that model can easily check if relevant state has changed. At some point in the development of your application, you will come to the point where you realize this is the correct way to do things. It seems like you have reached that point.
However, if you want to delay the inevitable redesign of your application a little further (and make it a bit more painful when you do get to that point ;) ), here's another approach you might consider.
Obviously, you have some kind of Pane that is holding the objects that are being painted. The user must be creating those objects and you're adding them to the pane at some point. Just create a method that handles that addition, and registers an invalidation listener with the properties of interest when you do. The structure will look something like this:
private final ReadOnlyBooleanWrapper unsavedChanges =
new ReadOnlyBooleanWrapper(this, "unsavedChanged", false);
private final ChangeListener<Object> unsavedChangeListener =
(obs, oldValue, newValue) -> unsavedChanges.set(true);
private Pane drawingPane ;
// ...
Button saveButton = new Button("Save");
saveButton.disableProperty().bind(unsavedChanges.not());
// ...
#SafeVarArgs
private final <T extends Node> void addNodeToDrawingPane(
T node, Function<T, ObservableValue<?>>... properties) {
Stream.of(properties).forEach(
property -> property.apply(node).addListener(unsavedChangeListener));
drawingPane.getChildren().add(node);
}
Now you can do things like
Rectangle rect = new Rectangle();
addNodeToDrawingPane(rect,
Rectangle::xProperty, Rectangle::yProperty,
Rectangle::widthProperty, Rectangle::heightProperty);
and
Text text = new Text();
addNodeToDrawingPane(text,
Text::xProperty, Text::yProperty, Text::textProperty);
I.e. you just specify the properties to observe when you add the new node. You can create a remove method which removes the listener too. The amount of extra code on top of what you already have is pretty minimal, as (probably, I haven't seen your code) is the refactoring.
Again, you should really have a separate view model, etc. I wanted to post this to show that #kleopatra's first comment on the question ("Listen for invalidation of relevant state") doesn't necessarily involve a lot of work if you approach it in the right way. At first, I thought this approach was incompatible with #Tomas Mikula's mention of undo/redo functionality, but you may even be able to use this approach as a basis for that too.
I am working in Qt4.7, and I have a QListWidget in my dialog. I have a QString that needs to match the current text in the row of this widget (the individual rows are editable). Looking at the signals associated with QListWidget, there seem to be signals for when a different index is selected but none for when the text of a the currently selected row changes. I thought currentTextChanged(QString) would do it, but it didn't. I also thought to try to connect each individual row to something, but QListWidgetItem doesn't have any built-in signals. Does anyone know of a way to do this? Thanks!
At first it seems like QListWidget::itemChanged is the way to go, but soon you run into a problem: the signal is sent for everything - inserts, changing colors, checking boxes, and anything else that "changes" the item! Predelnik pointed that out in his answer. Some people have tried to put in flags and filter everywhere by intercepting various signals to find out if editing was the actual event. It gets very messy.
There is also QAbstractItemModel::dataChanged , which would seem like a good solution. It even has a parameter "const QVector& lstRoles" so you could scan for Qt::EditRole and see if it was really edited. Alas, there's a catch - it gets called for everything just like QListWidget::itemChanged and unfortunately, for QListWidget anyway, the roles parameter is always empty when it's called (I tried it). So much for that idea...
Fortunately, there's still hope... This solution does the trick! :
http://falsinsoft.blogspot.com/2013/11/qlistwidget-and-item-edit-event.html
He uses QAbstractItemDelegate::closeEditor, but I prefer using QAbstractItemDelegate::commitData.
So make a connect like so...
connect(ui.pLstItems->itemDelegate(), &QAbstractItemDelegate::commitData, this, &MyWidget::OnLstItemsCommitData);
Then implement the slot like this...
void MyWidget::OnLstItemsCommitData(QWidget* pLineEdit)
{
QString strNewText = reinterpret_cast<QLineEdit*>(pLineEdit)->text();
int nRow = ui.pLstItems->currentRow();
// do whatever you need here....
}
Now you have a slot that gets called only when the list item's text has been edited!
I guess you need to look into the following signal:
void QListWidget::itemChanged(QListWidgetItem * item)
But be careful because it's being sent every time some property of item changed, not only text. I remember when we ran into the problem once when we changed item colors and got tons of false positive slots called because of that. If you need more fine tuning I guess it's better to write model/view classes yourself and not rely on QListWidget.
I'm starting a single page app and still haven't chosen any framework. The only complex thing it needs to do is allow the users to select an element from a tree structure for one of the fields of a form. It would be nice if it worked with both mouse selection and keyboard autocomplete. The tree is 5 levels deep and contains around 500 elements. What would be a good way to implement this?
Here's a fiddle to show you how to recursively build a tree: http://jsfiddle.net/KtbXb/ .
As far as input, binding a click function to each node will call a function with access to all data associated with clicked node:
view:
<li data-bind="text: name, click: yourFunction"></li>
viewmodel:
var yourFunction = function (data) {
//your function will have access to the node via data
};
For keyboard input, you can add an input to your view and bind the value to an observable value. From there, you can probably find a substring search algo online, or even a plugin (jquery.table-filter does a good job of this)
I want to display quite a bit of demographic data for a certain pin when someone touches on it, so providing a pop-up isn't going to cut it. I figured once the pin is touched I will just stick a tableviewController onto the NavigationController and the table view will have access to the object and display the single objects information, with one item per row and 1 section.
Anyway I'm having a hard time figuring out MKMapViewDelegates methods as it appears none of them do what I need and/or allow me to return a tableview or push that view onto the navigation controller.
I played around with:
- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation;
But that requires a MKAnnotationView be returned and I really just need this method to work by showing the user a table view of all the data. I was hoping for something simple like a userDidTouchPin method....
Anyone have any ideas how to accomplish what I am trying to do?
If you want to do something when the user selects the pin (and not a button on its callout), then implement the mapView:didSelectAnnotationView: delegate method and present or push your detail view controller there.
The selected annotation object is available as the annotation property of the view parameter:
- (void)mapView:(MKMapView *)mapView
didSelectAnnotationView:(MKAnnotationView *)view
{
YourDetailViewController *dvc = [[YourDetailViewController alloc] init...
dvc.annotation = view.annotation;
//present or push here
[dvc release];
}
You might need to check which type of annotation was selected (eg. if MKUserLocation was selected do nothing, etc) and you might need to cast the view.annotation to your own annotation class to easily access any custom properties you may have.
So I'm trying to build a tool that will allow me and other users to all open the same .swf, and then I as the Admin user am able to interact with mine while they all see my mouse movements and button clicks etc on theirs.
I'm using BlazeDS to manage this and I'm getting data sent back and forth etc - no difficulties there. The issue I'm running into is this:
In an "Admin" instance, I click a button. I capture that X and Y, then tell Blaze to tell my clients to dispatch a Click event at that X and Y. On my client side, I get that data and dispatch a Click event at that X and Y - but the click is actually caught at the stage level. The click on my client side takes place UNDER all of my buttons and other content - so the whole thing fails.
Does this make sense? Is there a way to tell it to start the click event at the top?
If you are unable to architect the loaded swf's to use a better architecture you could try something a little more hackish to get buttons working.
Have a look at the methods getObjectsUnderPoint and areInaccessibleObjectsUnderPoint of the DisplayObjectContainer. Combined with hasEventListener you should be able to emulate what you want.
Here is some untested pseudo-code:
function detectClick(pt:Point):void
{
var objsUnderPoint:Array = containerStage.getObjectsUnderPoint(pt);
var clickable:Array = [];
for each(dispObj:DisplayObject in objsUnderPoint)
{
if(dispObj.hasEventListener(MouseEvent.CLICK))
{
clickable.push(dispObj);
}
}
if(clickable.length)
{
// sort on depth here
// that might be tricky since you'll be looking at grandchildren
// and not just children but it is doable.
var topMostClickable:DisplayObject = ???
topMostClickable.dispatchEvent(new MouseEvent(MouseEvent.CLICK, true, false));
}
}
areInaccessibleObjectsUnderPoint is important if you think their might be security restrictions (e.g. cross-domain issues) so you can debug if things go wrong.
Also note that you may want to (or need to) fill in more details of the MouseEvent (like the proper target, localX, localyY etc.)
Sounds like you need to set focus to the top most component of the x and y positions before dispatching the click event.
That said, I wonder what the use case is for something like this; as opposed to using a screen sharing tool such as Connect.
This seems like a poor way to implement what you are trying to do. If you "click" in the admin tool you are probably actually triggering some event. Why not trigger that event instead of sending the mouse click?
I'd just keep a map of actions and then when something happens in the Admin interface send the key to the action.
e.g.
In the admin:
myButton.addEventListener(MouseEvent.CLICK, handleClickButton);
function handleClickButton(event:MouseEvent):void
{
doSomeAction();
sendTriggerToClient(MyActions.SOME_TRIGGER);
}
In the client:
var actionMap:Object = {};
actionMap[MyActions.SOME_TRIGGER] = doSomeAction;
function receiveTriggerFromAdmin(trigger:String):void
{
var responseFunc:Function = actionMap[trigger];
responseFunc();
}
I hope that pseudo-code makes sense. Just abstract what happens as a result of a click into a separate function (doSomeAction) and then have the admin send a message before calling that function. In the client wait for any trigger that comes through and map it to the same function.