Presenting Data with Views

Views are containers for collections of items. They are feature-rich and can be customizable to meet style or behavior requirements.

A set of standard views are provided in the basic set of Qt Quick graphical elements:

• ListView arranges items in a horizontal or vertical list
• GridView arranges items in a grid within the available space
• PathView arranges items on a path
• WebView - available from the QtWebKit QML Module.

Unlike other views, WebView is not a fully-featured view item, and needs to be combined with a Flickable item to create a view that performs like a Web browser.

These elements have properties and behaviors exclusive to each element. Visit their respective documentation for more information.

Models

Views display models onto the screen. A model could be a simple list of integer or a C++ model.

To assign a model to a view, bind the view's model property to a model.

 ListModel {
     id: petlist
     ListElement { type: "Cat" }
     ListElement { type: "Dog" }
     ListElement { type: "Mouse" }
     ListElement { type: "Rabbit" }
     ListElement { type: "Horse" }
 }
 ListView {
     id: view
     anchors.fill: parent

     model: petlist
     delegate: petdelegate
 }

For more information, consult the QML Data Models article.

View Delegates

Views need a delegate to visually represent an item in a list. A view will visualize each item list according to the template defined by the delegate. Items in a model are accessible through the index property as well as the item's properties.

 Component {
     id: petdelegate
     Text {
         id: label
         font.pixelSize: 24
         text: if (index == 0)
             label.text = type + " (default)"
         else
             text: type
     }
 }

Decorating Views

Views allow visual customization through decoration properties such as the header, footer, and section properties. By binding an object, usually another visual object, to these properties, the views are decoratable. A footer may include a Rectangle element showcasing borders or a header that displays a logo on top of the list.

Suppose that a specific club wants to decorate its members list with its brand colors. A member list is in a model and the delegate will display the model's content.

 ListModel {
     id: nameModel
     ListElement { name: "Alice" }
     ListElement { name: "Bob" }
     ListElement { name: "Jane" }
     ListElement { name: "Harry" }
     ListElement { name: "Wendy" }
 }
 Component {
     id: nameDelegate
     Text {
         text: name;
         font.pixelSize: 24
     }
 }

The club may decorate the members list by binding visual objects to the header and footer properties. The visual object may be defined inline, in another file, or in a Component element.

 ListView {
     anchors.fill: parent
     clip: true
     model: nameModel
     delegate: nameDelegate
     header: bannercomponent
     footer: Rectangle {
         width: parent.width; height: 30;
         gradient: clubcolors
     }
     highlight: Rectangle {
         width: parent.width
         color: "lightgray"
     }
 }

 Component {     //instantiated when header is processed
     id: bannercomponent
     Rectangle {
         id: banner
         width: parent.width; height: 50
         gradient: clubcolors
         border {color: "#9EDDF2"; width: 2}
         Text {
             anchors.centerIn: parent
             text: "Club Members"
             font.pixelSize: 32
         }
     }
 }
 Gradient {
     id: clubcolors
     GradientStop { position: 0.0; color: "#8EE2FE"}
     GradientStop { position: 0.66; color: "#7ED2EE"}
 }

ListView Sections

ListView contents may be grouped into sections, where related list items are labeled according to their sections. Further, the sections may be decorated with delegates.

A list may contain a list indicating people's names and the team on which team the person belongs.

 ListModel {
     id: nameModel
     ListElement { name: "Alice"; team: "Crypto" }
     ListElement { name: "Bob"; team: "Crypto" }
     ListElement { name: "Jane"; team: "QA" }
     ListElement { name: "Victor"; team: "QA" }
     ListElement { name: "Wendy"; team: "Graphics" }
 }
 Component {
     id: nameDelegate
     Text {
         text: name;
         font.pixelSize: 24
         anchors.left: parent.left
         anchors.leftMargin: 2
     }
 }

The ListView element has the section attached property that can combine adjacent and related elements into a section. The section's property property is for selecting which list element property to use as sections. The criteria can dictate how the section names are displayed and the delegate is similar to the views' delegate property.

 ListView {
     anchors.fill: parent
     model: nameModel
     delegate: nameDelegate
     focus: true
     highlight: Rectangle {
         color: "lightblue"
         width: parent.width
     }
     section {
         property: "team"
         criteria: ViewSection.FullString
         delegate: Rectangle {
             color: "#b0dfb0"
             width: parent.width
             height: childrenRect.height + 4
             Text { anchors.horizontalCenter: parent.horizontalCenter
                 font.pixelSize: 16
                 font.bold: true
                 text: section
             }
         }
     }
 }