I have an array of my custom made buttons:
Button buttons[5]
Now I want to swap two elements of this array, for example buttons[1] and buttons[2]. How do I do this? Just stating the following, doesnt work:
Button help = buttons[1];
buttons[1] = buttons[2];
buttons[2] = help;
Can anybody help me with this?
I have solved using a pointer array:
Button *pntArray[5];
Button *help;
pntArray[0]=&buttons[0];
pntArray[1]=&buttons[1];
help=pntArray[0];
pntArray[0]=pntArray[1];
pntArray[1]=help;
QObject base class does not allow the assignment operator or the copy constructor. Unless you have manually created these (which is usually unwise), declare your instances on the heap and use pointers in the array instead.
// Instantiate the buttons however you like, if you were just creating them
// on the stack before, a default initialisation should suffice. Though
// normally in Qt you would at least pass the 'owning' widget as the parent
// so you don't need to worry about deleting the buttons.
QVector<Button*> buttons(5);
for ( Button* button : buttons ) { // C++11 only!
button = new Button();
}
// Then whenever you need to swap two entries:
std::swap( buttons[1], buttons[2] );
Related
I am trying to make it so when i click a button another is created, and you can do this as many times as you want too. But I haven't been able to find a way to make it work, any ideas? I have tried creating a for loop but that just ends up overwriting the other buttons and deleting the tags.
Try something like this:
Form f = new Form(BoxLayout.y());
f.add(createButton("Click Me"));
f.show();
Then the method createButton():
private Button createButton(String title) {
Button b = new Button(title);
b.addActionListener(e -> {
Container c = b.getParent();
c.add(createButton(title));
c.revalidate();
});
return b;
}
I'm guessing the thing you missed is the call to revalidate() which must be invoked when you change a Form after it was already shown. Notice the first addition occurs before the form is shown and doesn't invoke revalidate().
I'm using a chart to render a piechart for my app. I have:
Ext.query('.highcharts-container')
that gives me an array of highchart-containers and I'd like to add a custom class to every one of them to add some custom css. I tried:
Ext.query('.highcharts-container').addCls("test")
but says "addCls" is not a function.
below is the img of how it looks:
and accord to the answers below, i tried adding it in seperate app, and it works, but for some reason in this case it constant shows undefined.no clue whts going on?
Ext.query returns an array. Instead, use Ext.select which returns a CompositeElement. It lets you run Ext.dom.Element methods on a group of elements:
Ext.select('.highcharts-container').addCls("test");
Ext.query will return an array of matching components. If you're sure there will always be exactly 1 item in the array, you can use:
Ext.ComponentQuery.query('.highcharts-container')[0].addCls("test")
Otherwise, you should loop through the items and add the class to each component.
Ext.ComponentQuery.query('.highcharts-container').forEach(function (item) {
item.addCls("test");
});
I not sure how to solve this issue. I am sure someone will know this very quickly.
I have an array of objects and modifying a property. I have a firebase listener 'child_changed'. When firebase is updated need to update the array. Here is the code below.
dbRefList.on('child_changed', function(snap) {
var len = this.grocerylist.length;
for(var i=len; i--;) {
if(this.grocerylist[i].key === snap.key) {
this.set(['grocerylist', i, 'selected'], snap.val().selected);
}
}
this.notifyPath('grocerylist', this.grocerylist.slice());
}.bind(this));
When the array is modified I want the template repeat-dom to trigger. I know this.set will not trigger array mutation sub properties but again I am not sure how to solve this. I done research and tried so many solutions.
I can force a render on the template dom-repeat but I would prefer the data binding way.
So this code (just the this.set you have in there now) should cause the value of grocerylist.i.selected to update inside the dom-repeat (assuming it's bound in there so it's actually showing up).
What behavior are you seeing? Are you trying to filter or sort the list based on the selected value? In that case, you might need to add observe="selected" on the dom-repeat.
(Also—have you confirmed that the child-changed callback is being called with the this value you expect—the element—rather than window or something else?)
You should be able to force a refresh by doing this.grocerylist = this.grocerylist.slice() or this.set('grocerylist', this.grocerylist.slice()); ... notifyPath doesn't work here because notifyPath doesn't change the value, it notifies the element about a prior change (the second argument is effectively ignored).
I'm almost finished with a quiz of mine. I've encountered an error which I have finally pinpointed. But first I'll tell you some background info on the code.
Background
On stage, there exist 4 button components registered as movie clips. These are later stored in an array. When a certain icon is clicked on stage, these buttons are to be activated by adding event listeners to all of them. When a button is pressed, it checks if it's the 'correct' answer and removes the event listeners.
Now I have done extensive checks and narrowed down the problem to the following.
Code
This function will add button listeners to each button recursively. Note that the variable 'num' is a fixed integer between 1 - 4 which is generated earlier into the code and used for many 'if' cases.
function addButtonListener(num:int):void
{
for (var obj:Object in _buttons)
{
_buttons[obj].addEventListener(MouseEvent.CLICK, checkans(num));
}
}
This function is basically the opposite and also disables the buttons
function removeButtonListener(num:int):void
{
for (var obj:Object in _buttons)
{
_buttons[obj].removeEventListener(MouseEvent.CLICK, checkans(num));
_buttons[obj].enabled = false;
}
}
Now one thing I noticed through the use of trace functions is that the code correctly adds the button listeners but it does not remove them.
This function calls for each button to be removed.
function checkans(num:int):Function
{
return function(e:MouseEvent):void
{
if (e.currentTarget.label == xmlNodes)
{
points = points + (2 * num);
scoreBox.text = points.toString();
}
else
{
trace("Incorrect!");
}
if(myText.parent){
myText.parent.removeChild(myText)
}
closeShowQuestion(num);//closes a previous function
removeButtonListener(num);//Should I pass this variable into the end function?
GoFishing.addEventListener(MouseEvent.CLICK, fish);//Starts the process again.
}
}
So am I removing the event listeners incorrectly?
Do you need to see more code to be sure?
Thanks in advance!
removeEventListener must use the SAME function that was used in addEventListener.
Your checkans function always returns a NEW function, so it will not be the same for add and remove.
If you have to pass a num into your listener function, do it other way. Make it a property of a button or store externally etc.
I have an array of items bound to <li> elements in a <ul> with AngularJS. I want to be able to click "remove item" next to each of them and have the item removed.
This answer on StackOverflow allows us to do exactly that, but because the name of the array which the elements are being deleted from is hardcoded it is not usable across lists.
You can see an example here on JSfiddle set up, if you try clicking "remove" next to a Game, then the student is removed, not the game.
Passing this back from the button gives me access to the Angular $scope at that point, but I don't know how to cleanly remove that item from the parent array.
I could have the button defined with ng-click="remove('games',this)" and have the function look like this:
$scope.remove = function (arrayName, scope) {
scope.$parent[arrayName].splice(scope.$index,1);
}
(Like this JSFiddle) but naming the parent array while I'm inside it seems like a very good way to break functionality when I edit my code in a year.
Any ideas?
I did not get why you were trying to pass this .. You almost never need to deal with this in angular. ( And I think that is one of its strengths! ).
Here is a fiddle that solves the problem in a slightly different way.
http://jsfiddle.net/WJ226/5/
The controller is now simplified to
function VariousThingsCtrl($scope) {
$scope.students = students;
$scope.games = games;
$scope.remove = function (arrayName,$index) {
$scope[arrayName].splice($index,1);
}
}
Instead of passing the whole scope, why not just pass the $index ? Since you are already in the scope where the arrays are located, it should be pretty easy from then.