Qt Quick Controls - Touch Gallery

Demonstrates UI controls for a touch interface.

Touch Gallery demonstrates how to implement a UI suitable for touch input using the following Qt Quick Controls:

The appearance of the controls is customized by using Qt Quick Controls Styles.

Running the Example

To run the example from Qt Creator, open the Welcome mode and select the example from Examples. For more information, visit Building and Running an Example.

Creating the Main Page

In the main.qml file, we use a Rectangle type within the ApplicationWindow type to create the main page of the application:

ApplicationWindow {
    visible: true
    width: 800
    height: 1280

    Rectangle {
        color: "#212126"
        anchors.fill: parent
    }

To use the Qt Quick Controls, we must import them:

import QtQuick.Controls 1.2

The toolBar property of the application window holds a BorderImage type that we use to create a separator between the application name and a list of additional pages:

    toolBar: BorderImage {
        border.bottom: 8
        source: "images/toolbar.png"
        width: parent.width
        height: 100

We use an Image type in a Rectangle type to create a back button. We use the onClicked signal handler to call the StackView pop() function that pops off the page when users tap the button:

        Rectangle {
            id: backButton
            width: opacity ? 60 : 0
            anchors.left: parent.left
            anchors.leftMargin: 20
            opacity: stackView.depth > 1 ? 1 : 0
            anchors.verticalCenter: parent.verticalCenter
            antialiasing: true
            height: 60
            radius: 4
            color: backmouse.pressed ? "#222" : "transparent"
            Behavior on opacity { NumberAnimation{} }
            Image {
                anchors.verticalCenter: parent.verticalCenter
                source: "images/navigation_previous_item.png"
            }
            MouseArea {
                id: backmouse
                anchors.fill: parent
                anchors.margins: -10
                onClicked: stackView.pop()
            }
        }

We use the opacity property to hide the back button on the main page.

We use a Text type to display the application name:

        Text {
            font.pixelSize: 42
            Behavior on x { NumberAnimation{ easing.type: Easing.OutCubic} }
            x: backButton.x + backButton.width + 20
            anchors.verticalCenter: parent.verticalCenter
            color: "white"
            text: "Widget Gallery"
        }

The x position of the Text type is bound to the position and width of the back button, and animated using a Behavior.

We use a ListModel type that contains ListElement definitions to define titles and source files for the other pages in the application:

    ListModel {
        id: pageModel
        ListElement {
            title: "Buttons"
            page: "content/ButtonPage.qml"
        }
        ListElement {
            title: "Sliders"
            page: "content/SliderPage.qml"
        }
        ListElement {
            title: "ProgressBar"
            page: "content/ProgressBarPage.qml"
        }
        ListElement {
            title: "Tabs"
            page: "content/TabBarPage.qml"
        }
        ListElement {
            title: "TextInput"
            page: "content/TextInputPage.qml"
        }
        ListElement {
            title: "List"
            page: "content/ListPage.qml"
        }
    }

Navigating in the Application

We implement a stack-based navigation model to link the application pages together. Items are pushed onto the stack as users navigate deeper into the application, and popped off again when they return to the main page.

In main.qml, we add a StackView type as a child of the application window:

    StackView {
        id: stackView
        anchors.fill: parent
        // Implements back key navigation
        focus: true
        Keys.onReleased: if (event.key === Qt.Key_Back && stackView.depth > 1) {
                             stackView.pop();
                             event.accepted = true;
                         }

The stack is used by invoking its navigation methods. To load the first item in the stack view, we assign it to initialItem:

        initialItem: Item {
            width: parent.width
            height: parent.height
            ListView {
                model: pageModel
                anchors.fill: parent
                delegate: AndroidDelegate {
                    text: title
                    onClicked: stackView.push(Qt.resolvedUrl(page))
                }
            }
        }
    }

}

We use a ListView type to display a list of the items provided by pageModel. The AndroidDelegate custom type defines each item instantiated by the view.

Creating Push Buttons and Switches

In ButtonPage.qml we use the Button type to create two buttons that change color when users tap them and one that pops off the page and returns the user to the main page:

        Button {
            text: "Press me"
            style: touchStyle
        }

        Button {
            style: touchStyle
            text: "Press me too"
        }

        Button {
            anchors.margins: 20
            style: touchStyle
            text: "Don't press me"
            onClicked: if (stackView) stackView.pop()
        }

We use a Switch type to create two switches that users can turn on and off. They are placed within a Row type to lay them out horizontally:

        Row {
            spacing: 20
            Switch {
                style: switchStyle
            }
            Switch {
                style: switchStyle
            }
        }

A ButtonStyle type creates a custom appearance for the buttons:

    Component {
        id: touchStyle
        ButtonStyle {
            panel: Item {
                implicitHeight: 50
                implicitWidth: 320
                BorderImage {
                    anchors.fill: parent
                    antialiasing: true
                    border.bottom: 8
                    border.top: 8
                    border.left: 8
                    border.right: 8
                    anchors.margins: control.pressed ? -4 : 0
                    source: control.pressed ? "../images/button_pressed.png" : "../images/button_default.png"
                    Text {
                        text: control.text
                        anchors.centerIn: parent
                        color: "white"
                        font.pixelSize: 23
                        renderType: Text.NativeRendering
                    }

To use Qt Quick Controls Styles, we must import them:

import QtQuick.Controls.Styles 1.1

A SwitchStyle type creates a custom appearance for the switches:

    Component {
        id: switchStyle
        SwitchStyle {

            groove: Rectangle {
                implicitHeight: 50
                implicitWidth: 152
                Rectangle {
                    anchors.top: parent.top
                    anchors.left: parent.left
                    anchors.bottom: parent.bottom
                    width: parent.width/2 - 2
                    height: 20
                    anchors.margins: 2
                    color: control.checked ? "#468bb7" : "#222"
                    Behavior on color {ColorAnimation {}}
                    Text {
                        font.pixelSize: 23
                        color: "white"
                        anchors.centerIn: parent
                        text: "ON"
                    }
                }
                Item {
                    width: parent.width/2
                    height: parent.height
                    anchors.right: parent.right
                    Text {
                        font.pixelSize: 23
                        color: "white"
                        anchors.centerIn: parent
                        text: "OFF"
                    }
                }
                color: "#222"
                border.color: "#444"
                border.width: 2
            }
            handle: Rectangle {
                width: parent.parent.width/2
                height: control.height
                color: "#444"
                border.color: "#555"
                border.width: 2
            }
        }
    }
}

The groove property holds the background groove of the switch and the handle property defines the switch handle.

Creating Sliders

In SliderPage.qml, we use a Slider type to create three horizontal sliders that are placed within a Column type to lay them out in a column:

    Column {
        spacing: 12
        anchors.centerIn: parent

        Slider {
            anchors.margins: 20
            style: touchStyle
            value: 0
        }
        Slider {
            anchors.margins: 20
            style: touchStyle
            value: 0.5
        }
        Slider {
            anchors.margins: 20
            style: touchStyle
            value: 1.0
        }

    }

The value property holds the initial handle position on the slider.

A SliderStyle type creates a custom appearance for the sliders:

    Component {
        id: touchStyle
        SliderStyle {
            handle: Rectangle {
                width: 30
                height: 30
                radius: height
                antialiasing: true
                color: Qt.lighter("#468bb7", 1.2)
            }

            groove: Item {
                implicitHeight: 50
                implicitWidth: 400
                Rectangle {
                    height: 8
                    width: parent.width
                    anchors.verticalCenter: parent.verticalCenter
                    color: "#444"
                    opacity: 0.8
                    Rectangle {
                        antialiasing: true
                        radius: 1
                        color: "#468bb7"
                        height: parent.height
                        width: parent.width * control.value / control.maximumValue
                    }
                }
            }
        }
    }
}

The handle property defines the slider handle and the groove property holds the background groove of the slider.

Indicating Progress

In ProgressBar.qml, we use a ProgressBar type to create three progress bars:

    Column {
        spacing: 40
        anchors.centerIn: parent

        ProgressBar {
            anchors.margins: 20
            style: touchStyle
            width: 400
            value: progress
        }

        ProgressBar {
            anchors.margins: 20
            style: touchStyle
            width: 400
            value: 1 - progress
        }

        ProgressBar {
            anchors.margins: 20
            style: touchStyle
            value: 1
            width: 400
        }

We use a NumberAnimation type with a SequentialAnimation type to run two number animations in a sequence. We apply the animations on the progress custom property to animate the current value on the progress bars:

    property real progress: 0
    SequentialAnimation on progress {
        loops: Animation.Infinite
        running: true
        NumberAnimation {
            from: 0
            to: 1
            duration: 3000
        }
        NumberAnimation {
            from: 1
            to: 0
            duration: 3000
        }

A ProgressBarStyle type creates a custom appearance for the progress bars:

    Component {
        id: touchStyle
        ProgressBarStyle {
            panel: Rectangle {
                implicitHeight: 15
                implicitWidth: 400
                color: "#444"
                opacity: 0.8
                Rectangle {
                    antialiasing: true
                    radius: 1
                    color: "#468bb7"
                    height: parent.height
                    width: parent.width * control.value / control.maximumValue
                }
            }
        }
    }
}

Creating Tabs

In TabBarPage.qml, we use a TabView type with a Tab type to provide a tab-based navigation model for our application. We use tabs to display the ButtonPage, SliderPage, and ProgressBarPage on separate tab pages:

    TabView {
        anchors.fill: parent
        style: touchStyle
        Tab {
            title: "Buttons"
            ButtonPage{ visible: true }
        }
        Tab {
            title: "Sliders"
            SliderPage{ visible: true }
        }
        Tab {
            title: "Progress"
            ProgressBarPage{ visible: true }
        }

A TabViewStyle type creates a custom appearance for the tabs:

    Component {
        id: touchStyle
        TabViewStyle {
            tabsAlignment: Qt.AlignVCenter
            tabOverlap: 0
            frame: Item { }
            tab: Item {
                implicitWidth: control.width/control.count
                implicitHeight: 50
                BorderImage {
                    anchors.fill: parent
                    border.bottom: 8
                    border.top: 8
                    source: styleData.selected ? "../images/tab_selected.png":"../images/tabs_standard.png"
                    Text {
                        anchors.centerIn: parent
                        color: "white"
                        text: styleData.title.toUpperCase()
                        font.pixelSize: 16
                    }
                    Rectangle {
                        visible: index > 0
                        anchors.top: parent.top
                        anchors.bottom: parent.bottom
                        anchors.margins: 10
                        width:1
                        color: "#3a3a3a"
                    }
                }
            }
        }
    }
}

Creating Text Input Fields

In the TextInputPage.qml, we use a TextField type to create an input field and a read-only text field:

    Column {
        spacing: 40
        anchors.centerIn: parent

        TextField {
            anchors.margins: 20
            text: "Text input"
            style: touchStyle
        }

        TextField {
            anchors.margins: 20
            text: "Readonly Text input"
            style: touchStyle
            readOnly: true
        }
    }

A TextFieldStyle creates a custom appearance for the text fields:

    Component {
        id: touchStyle

        TextFieldStyle {
            textColor: "white"
            font.pixelSize: 28
            background: Item {
                implicitHeight: 50
                implicitWidth: 320
                BorderImage {
                    source: "../images/textinput.png"
                    border.left: 8
                    border.right: 8
                    anchors.bottom: parent.bottom
                    anchors.left: parent.left
                    anchors.right: parent.right
                }
            }
        }
    }
}

We use a BorderImage type with an image to create borders for the fields.

Creating Scrolling Lists

In ListPage.qml, we use a ScrollView type to provide a scrolling page with a vertical scoll bar:

ScrollView {
    width: parent.width
    height: parent.height

    flickableItem.interactive: true

We use a ListView type to display a list of 100 items by specifying an integer as the value of the model property. We reuse the AndroidDelegate custom type here to define each item instantiated by the view. The text property adds the string Item # to each list item:

    ListView {
        anchors.fill: parent
        model: 100
        delegate: AndroidDelegate {
            text: "Item #" + modelData
        }
    }

A ScrollViewStyle type creates a custom appearance for the scroll view:

    style: ScrollViewStyle {
        transientScrollBars: true
        handle: Item {
            implicitWidth: 14
            implicitHeight: 26
            Rectangle {
                color: "#424246"
                anchors.fill: parent
                anchors.topMargin: 6
                anchors.leftMargin: 4
                anchors.rightMargin: 4
                anchors.bottomMargin: 6
            }
        }
        scrollBarBackground: Item {
            implicitWidth: 14
            implicitHeight: 26
        }
    }
}

The transientScrollBars property is set to true to make the scroll bars appear when the content is scrolled and disappear when they are no longer needed.

The handle property controls the appearance of the scroll bar handle and the scrollBarBackground property that of the background.

Files:

Images:

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