Asettelut, luetelmanäkymät ja kortit

Figuring out the different ways of placing things on a page

Laying out your content

Now that we understand how pages work, it is time to add stuff to ours. We will be going through a number of important layout components and elements that will be useful when designing our app.

Don't be scared by the big chunks of code! We'll be going over everything that we haven't covered before, and by the end of this section you'll have a neat-looking app.

ListViews

If you've ever used Discover, NeoChat, or Plasma's System Settings, you will have come across a ListView. Quite simply, it lets you display data on a list.

Kirigami.CardsListView {
    id: cardsView
    model: kountdownModel
    delegate: kountdownDelegate
}

That seems cryptic, but don't worry. Let's start from the beginning.

We add this component inside our Kirigami.ScrollablePage from the last tutorial.

We're using Kirigami.CardsListView , which is a ListView that allows us to easily display cards in a list. However, ListViews are made to show data taken from a model - to automatically populate itself from a set of data that we point it to. That's where the model property comes in: in this example, it's pointing to kountdownModel.

Model

ListModel {
    id: kountdownModel
    // Each ListElement is an element on the list, containing information
    ListElement {
        name: "Dog birthday!!"
        description: "Big doggo birthday blowout."
        date: 100
    }
}

We add our kountdownModel inside our Kirigami.ApplicationWindow from the last tutorial.

A model defines the way that a data entry is structured. Our kountdownModel will consist of only one element for now. By looking at our ListElement above, we can see how the data of our kountdownModel are structured: it contains a name, a description, and a date. This isn't set in stone, and you may have different sorts of data in your model. The first two are just strings, and the third is a number we're using as a placeholder.

Models are also useful in how they can be modified through the use of several methods. Some important ones are:

Delegate

While our kountdownModel contains the data that will be displayed, our kountdownDelegate will handle how the data will be displayed in the ListView. Kirigami.CardsListView was designed to display card-type delegates, and we have indeed used a Kirigami.AbstractCard element as our delegate in the excerpt above.

Delegates automatically receive the properties of the ListElements that we have specified in our model. We can therefore just refer to the name, description, and date properties of our ListElements as if they were a conventional variable within our delegate.

Building our delegate card

The Component that will represent our delegate can be added inside our Kirigami.ApplicationWindow . We will then proceed by checking what each part of our delegate component does.

Component {
    id: kountdownDelegate
    Kirigami.AbstractCard {
        contentItem: Item {
            // implicitWidth/Height define the natural width/height of an item if no width or height
            // is specified. The setting below defines a component's preferred size based on its
            // content
            implicitWidth: delegateLayout.implicitWidth
            implicitHeight: delegateLayout.implicitHeight
            GridLayout {
                id: delegateLayout
                anchors {
                    left: parent.left
                    top: parent.top
                    right: parent.right
                }
                rowSpacing: Kirigami.Units.largeSpacing
                columnSpacing: Kirigami.Units.largeSpacing
                columns: root.wideScreen ? 4 : 2

                Kirigami.Heading {
                    Layout.fillHeight: true
                    level: 1
                    text: (date < 100000) ? date : i18n("%1 days", Math.round((date-Date.now())/86400000))
                }

                ColumnLayout {
                    Kirigami.Heading {
                        Layout.fillWidth: true
                        level: 2
                        text: name
                    }
                    Kirigami.Separator {
                        Layout.fillWidth: true
                        visible: description.length > 0
                    }
                    Controls.Label {
                        Layout.fillWidth: true
                        wrapMode: Text.WordWrap
                        text: description
                        visible: description.length > 0
                    }
                }
                Controls.Button {
                    Layout.alignment: Qt.AlignRight
                    Layout.columnSpan: 2
                    text: i18n("Edit")
                    // onClicked: to be done... soon!
                }
            }
        }
    }
}

implicitWidth and implicitHeight

The first part we will take a look at is how to manage the width and height of our component:

Kirigami.AbstractCard {
    contentItem: Item {
        implicitWidth: delegateLayout.implicitWidth
        implicitHeight: delegateLayout.implicitHeight
        GridLayout {
            id: delegateLayout
            ...
        }
    }
}

Looking at our Kirigami.AbstractCard , the first properties we set are implicitWidth and implicitHeight. We have set these to the delegateLayout.implicitWidth and delegateLayout.implicitHeight, i.e. the implicitWidth and implicitHeight of the GridLayout element. Implicit widths and heights are properties that are set as a default, i.e. if there is no explicit width or height set for these components. We have therefore set the implicitWidth and implicitHeight of our Kirigami.AbstractCard to that of the GridLayout below to ensure it does not spill out of the card.

Asettelut

The GridLayout is inside the Item component we have provided for the property contentItem. This is the Item that contains what will be displayed in your card.

We also need to choose a layout for our components so that they don't just pile on top of each other. There are three main types that we can choose from:

  • ColumnLayout lays out your components vertically, in a single column
  • RowLayout lays out your components horizontally, in a single row
  • GridLayout lays out your components in a grid with a composition of your choosing

With ColumnLayout and RowLayout, all we have to do is write our components inside the Layout component. As you can see, we went with a GridLayout, which entails a bit more handiwork.

GridLayout {
    id: delegateLayout
    anchors {
        left: parent.left
        top: parent.top
        right: parent.right
    }
    rowSpacing: Kirigami.Units.largeSpacing
    columnSpacing: Kirigami.Units.largeSpacing
    columns: root.wideScreen ? 4 : 2
    ...
}

The first thing you see is our anchors. QtQuick's anchoring system provides a useful way of making sure your components are positioned in certain parts of a parent component. We have anchored our GridLayout to the left, top, and right of the parent card, ensuring our content stretches across the whole card.

Next we specify the spacing between the rows and columns within our grid, so that our components don't bunch up. Kirigami provides a number of handy predefined units to use for this purpose:

Kirigami UnitPixels
smallSpacing4px
largeSpacing8px
gridUnit18px

As you might remember, root is the id of our Kirigami.ApplicationWindow . It provides the wideScreen property, used to determine whether the current device screen is a widescreen (i.e. a computer monitor or a phone in landscape). We use a ternary conditional here to vary the number of columns in our grid depending on the screen we are using: if it's a widescreen, the grid will have 4 columns, else it will have 2.

Inner components

We could just create three labels within our delegate component and call it a day. But that wouldn't look particularly nice.

GridLayout {
    ...
    Kirigami.Heading {
        Layout.fillHeight: true
        level: 1
        text: date
    }

    ColumnLayout {
        Kirigami.Heading {
            Layout.fillWidth: true
            level: 2
            text: name
        }

        Kirigami.Separator {
            Layout.fillWidth: true
            visible: description.length > 0
        }

        Controls.Label {
            Layout.fillWidth: true
            wrapMode: Text.WordWrap
            text: description
            visible: description.length > 0
        }
    }

    Controls.Button {
        Layout.alignment: Qt.AlignRight
        Layout.columnSpan: 2
        text: i18n("Edit")
    }
}

Screenshot showing how a Card looks like

  • Left, Kirigami.Heading : uses the ListElement's date as a level 1 heading.
  • Middle, ColumnLayout: has a Kirigami.Heading that displays the task name; a Kirigami.Separator , which provides the horizontal line; and a Controls.Label , that displays a task's optional description. The latter two components have a visible property, which checks if the description is empty or not and displays the components depending on the result of description.length > 0.
  • Right, Controls.Button : a button that will do something... soon!

Sovelluksemme tähän mennessä

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import QtQuick 2.15
import QtQuick.Controls 2.15 as Controls
import QtQuick.Layouts 1.15
import org.kde.kirigami 2.20 as Kirigami

Kirigami.ApplicationWindow {
    id: root

    title: i18nc("@title:window", "Day Kountdown")

    // ListModel needed for ListView, contains elements to be displayed
    ListModel {
        id: kountdownModel
        // Each ListElement is an element on the list, containing information
        ListElement {
            name: "Dog birthday!!"
            description: "Big doggo birthday blowout."
            date: 100
        }
    }

    Component {
        id: kountdownDelegate
        Kirigami.AbstractCard {
            contentItem: Item {
                implicitWidth: delegateLayout.implicitWidth
                implicitHeight: delegateLayout.implicitHeight
                GridLayout {
                    id: delegateLayout
                    anchors {
                        left: parent.left
                        top: parent.top
                        right: parent.right
                    }
                    rowSpacing: Kirigami.Units.largeSpacing
                    columnSpacing: Kirigami.Units.largeSpacing
                    columns: root.wideScreen ? 4 : 2

                    Kirigami.Heading {
                        // Heading will be as tall as possible while respecting constraints
                        Layout.fillHeight: true
                        // Level determines the size of the heading
                        level: 1
                        text: date
                    }

                    // Layout for positioning elements vertically
                    ColumnLayout {
                        Kirigami.Heading {
                            Layout.fillWidth: true
                            level: 2
                            text: name
                        }
                        // Horizontal rule
                        Kirigami.Separator {
                            Layout.fillWidth: true
                            visible: description.length > 0
                        }
                        // Labels contain text
                        Controls.Label {
                            Layout.fillWidth: true
                            // Word wrap makes text stay within box and shift with size
                            wrapMode: Text.WordWrap
                            text: description
                            visible: description.length > 0
                        }
                    }
                    Controls.Button {
                        Layout.alignment: Qt.AlignRight
                        // Column spanning within grid layout (vertically in this case)
                        Layout.columnSpan: 2
                        text: i18n("Edit")
                        //onClicked: to be done...
                    }
                }
            }
        }
    }

    pageStack.initialPage: Kirigami.ScrollablePage {
        title: i18nc("@title", "Kountdown")

        // List view for card elements
        Kirigami.CardsListView {
            id: cardsView
            // Model contains info to be displayed
            model: kountdownModel
            // Delegate is how the information will be presented in the ListView
            delegate: kountdownDelegate
        }
    }
}

Screenshot of the app appearance after completing this lesson

So there is our basic card!

With these steps, we have now laid the basic groundwork for adding all the functionality to our app.