I need to know how to set the ChildrenRect height and width for a grid element??
Grid {
id: grid1
anchors.fill: parent
rows: 10
columns: 10
childrenRect.height: background.height/10
childrenRect.width: background.width/10
}
it says its a read-only element that cannot be changed when i try to do this.
You can't set them. The childrenRect properties are calculated from the item's children. The only way to affect them is by setting the children's dimensions. There's no way to set them yourself.
Related
I have this statement inside my QML item:
Rectangle {
// ...
anchors.right: someItemID.right
// ...
}
I'm receiving this warning for my Rectangle item:
QML Rectangle: Detected anchors on an item that is managed by a layout. This is undefined behavior; use Layout.alignment instead.
How can I use Layout.alignment to resolve the above warning? How can I pass another item ID to Layout.alignment? Is it possibe?
A layout manages the positions and sizes of all of its child items. Using anchors inside child items is not allowed as it could override these rules. You can only influence those properties provided by the layout in the Layout object attached to its children, which is hinted at in the warning message. Layout.alignment controls how the item is aligned within the cell created for it by the layout. You can therefore align an item to the edges of its adjacent cells, but you can't directly anchor to their items by ID.
If you need more precise control, you should position the items outside the layout using position and/or anchor properties.
I made an observation with Cytoscape Layout and I am wondering how to change it. The layout manager CoSe produces different results depending on the length of the label name. I encountered this when I changed the node label from a long to a short id and also to no id. The best result is produced with no id.
How to deactivate this label layout effect ?
There is a planned feature to specify how the bounding box is calculated for nodes in a layout: https://github.com/cytoscape/cytoscape.js/issues/1626
Before that's implemented, you'll have to hide labels while the layout is running.
E.g.
cy.nodes().addClass('no-labels');
cy.one('layoutstop', () => cy.nodes().removeClass('no-labels'));
cy.makeLayout({ ... }).run();
Where node.no-labels { label: '' } is defined in your stylesheet.
I can show current selection QML ListView but similar thing doesn't work in TreeView.
Part of the problem is for TreeView it doesn't recognize index which is passed to delegate in case of ListView. I tried styleData.indexbut that doesn't work either.
rowDelegate: Item {
id: row_delegate
height: 40
Rectangle {
id: rectid
anchors.fill: parent
MouseArea {
id: mouse_area
anchors.fill: parent
onClicked: {
console.log("Row clicked " + rectid.styleData.index)
}
}
}
}
The output is:
qml: Row clicked undefined
As stated by the documentation, you have a set of properties within the namespace styleData that can be used for almost the same purposes from within a delegate.
As an example, you can set the text property of a label that is part of your delegate as it follows:
text: styleData.value
Where styleData.value is (documentation excerpt):
the value or text for this item
Similarly, you have:
styleData.pressed - true when the item is pressed
styleData.index - the QModelIndex of the current item in the model
styleData.hasChildren - true if the model index of the current item has or can have children
And so on... Please, refer to the documentation for the full list.
Be aware also of the note at the end of the documentation:
Note: For performance reasons, created delegates can be recycled across multiple table rows. This implies that when you make use of implicit properties such as styleData.row or model, these values can change after the delegate has been constructed. This means that you should not assume that content is fixed whenComponent.onCompleted is called, but instead rely on bindings to such properties.
I want to access delegate properties in ListView. I've tried with contentItem but sometimes it's undefined.
Here is my code:
ListModel{
id: modeldata
ListElement{
name:"don"
rank:1
}
ListElement{
name:"shan"
rank:2
}
ListElement{
name:"james"
rank:3
}
ListElement{
name:"jeggu"
rank:4
}
}
Component{
id: delegateitem
Row {
property int count: rank
Rectangle{
width: 100
height: 50
Text{
anchors.centerIn: parent
text: name
}
}
}
}
ListView{
id: listview
focus: true
anchors.fill: parent
model: modeldata
delegate: delegateitem
onCurrentIndexChanged: {
console.log("position",currentIndex)
console.log("property",contentItem.children[currentIndex].count);
}
}
Problem invalid output at position 1
qml: position 0
qml: property 1
qml: position 1
qml: property undefined
qml: position 2
qml: property 2
qml: position 3
qml: property 3
#Teimpz didn't really explain it well. Especially since there are bunch of qt project and ubuntu touch qml examples and use cases where you manage dynamically created list elements using javascript, and that is why they have javascript methods and properties
In QML there is more a notion of parent than a child, which is common in html. In bigger projects it is recommended (as you can also see in qt examples and in docs http://doc.qt.io/qt-5/qtqml-javascript-expressions.html#functions-in-imported-javascript-files) to have js logic separate from qml elements so you do access and manage elements from outside rather than pollute you qml elements with js logic, but not in a way of looking for children elements, but rather exposing children elements that you need.
In your case you should just use currentItem, same as you use currentIndex, so currentItem.count will give you what you need.
And if you don't need current item at all, you can access elements from model directly:
modelData.get(currentIndex).count, or listview.model.get(currentIndex).count
As for the hack that is mentioned by #Teimpz that is also one bad example. When you have more complex requirements and wanting specific elements inside delegate, every delegate has ListView.isCurrentItem property which you can attach and check. This would mean you can add property var myTargetItem to listview, and set it from child to whatever element you want if that delegate is current http://doc.qt.io/qt-5/qml-qtquick-listview.html#isCurrentItem-attached-prop
You can of course do that for any kind of event, maybe activeFocus so you could only reference activeFocused item.
This once again give you ability to expose only wanted elements without any advanced logic or lopping. Combining this with signals you can create very complex but clean interfaces without searching through children items.
So in the end maybe less nice but still better than searching for elements would be to add property int currentItemCount: 0 to listview. In delegate (Row element) you then add property bool isCurrentItem: ListView.isCurrentItem
so you get onIsCurrentItemChanged signal inside delegate, where you can do:
onIsCurrentItemChanged: if(isCurrentItem) listview.currentItemCount = count
so you have your current item count always set
The simple way is using itemAtIndex() like intemAt() in Repeater.
First of all: if you are trying to access list elements from outside your list, this is a good indicator that you should rethink your desing.
Now the solution: a listview has more children than only its items. You can filter them out by defining a property "property string type: "myType" " for example. Then find the items by looping over the children and only take those where the type property equals "myType".
Its somewhat of a hack but again you should really not be doing this in the first place.
myListView.itemAtIndex(currentIndex)).function_name()
I have two extjs items which are of variable height to be layed out vertically.
I am using Ext.container.Container for the vertical layout, using the following code.
Ext.create('Ext.container.Container', {
//height:50,
renderTo: this.renderTo,
layout: {
type: 'vbox'
},
items: [item1,item2],
//autoHeight:true
});
The problem is the items are not visible on the page unless the height of the container is specified. But, the height of the embedded widgets is not static.
Is there any way to fix this issue? Any other components I can make use of which can stretch automatically to the height of the items.
Instead of height, apply a flex of 1 to your child elements. If you wish the ratio to be different you can play with the flex number. For instance, if you apply flex: 2 and flex: 1 you will get 2 thirds fill on the first element, and 1 third fill on the second.
For reference: http://docs.sencha.com/ext-js/4-0/#!/api/Ext.layout.container.VBox-cfg-flex