- Qt 6.9
- Qt Quick
- Qt Quick Layouts - Responsive Layout Example
- Qt 6.9.1 Reference Documentation

# Qt Quick Layouts - Responsive Layout Example

Demonstrates how to use LayoutItemProxy to make a responsive UI.

This example shows how to use LayoutProxyItems in combination with layouts to create responsive layouts.

#### Running the Example

To run the example from Qt Creator, open the Welcome mode and select the example from Examples. For more information, see Qt Creator: Tutorial: Build and run.

#### Creating items

The LayoutItemProxy type allows to use the same item in different layouts, although only one layout can be visible at the same time. This can be used to create responsive layouts that adapt to the window or screen size.

First we need to define all items that should appear in or UI at some point. We use a AnnotatedRect, which is a simple Rectangle with some added text.

     Rectangle {
         id: contentItem
         Layout.fillWidth: true
         implicitHeight: grid.implicitHeight
         implicitWidth: grid.implicitWidth
         color: "#00414A"

         GridLayout {
             id: grid
             anchors {
                 fill: parent
                 margins: 8
             }
             columns: Math.min(Math.round(width / 130), 6)
             Repeater {
                 model: 60
                 delegate: Rectangle {
                     required property int index
                     Layout.fillWidth: true
                     Layout.margins: 8
                     implicitWidth: 200
                     implicitHeight: width
                     radius: width / 10
                     gradient: Gradient {
                         GradientStop { position: -0.2; color: "#2CDE85" }
                         GradientStop { position: 1.2; color: "#00414A" }
                     }
                     Text {
                         color: "#ffffff"
                         font.pointSize: 22
                         anchors.centerIn: parent
                         text: parent.index + 1
                     }
                 }
             }
         }
     }

     Button {
         id: a
         text: "Text"
         icon.source: "./icons/text.svg"
         Layout.fillWidth: true
         Layout.margins: 3
     }

     Button {
         id: b
         text: "Grid 1"
         icon.source: "./icons/grid.svg"
         Layout.fillWidth: true
         Layout.margins: 3
     }

     Button {
         id: c
         text: "Grid 2"
         icon.source: "./icons/grid.svg"
         Layout.fillWidth: true
         Layout.margins: 3
     }

     Button {
         id: d
         text: "Settings"
         icon.source: "./icons/settings.svg"
         Layout.fillWidth: true
         Layout.margins: 3
     }

#### Creating layouts

We can now declare various layouts using LayoutItemProxies, targeting the previously declare items. A single layout can be defined as follows.

     ColumnLayout {
         id: smallLayout
         anchors.fill: parent

         Flickable {
             Layout.fillHeight: true
             Layout.fillWidth: true
             contentWidth: width
             contentHeight: gl.implicitHeight
             clip: true
             ScrollIndicator.vertical: ScrollIndicator { }
             LayoutItemProxy {
                 id: gl
                 width: parent.width
                 height: implicitHeight
                 target: contentItem
             }
         }

         RowLayout {
             Layout.fillHeight: false
             Layout.fillWidth: true
             Layout.margins: 5
             LayoutItemProxy{ target: a; }
             LayoutItemProxy{ target: b; }
             LayoutItemProxy{ target: c; }
         }
     }

This snippet shows multiple ways to use the LayoutItemProxy. The simplest method is to add LayoutItemProxies to a Layout like the RowLayout here. In addition we set an additional Layout attached property to the LayoutProxyItem that will affect the target item only in this particular layout. Further, we see that the item `d` is not used in the first layout. Then it is automatically hidden by the LayoutItemProxy in the second layout. Another way of using it is shown by setting a LayoutItemProxy as the content of a Flickable.

Another layout is declared as follows.

     RowLayout {
         id: largeLayout
         anchors.fill: parent
         ColumnLayout {
             Layout.minimumWidth: 100
             Layout.fillWidth: true
             Layout.margins: 2
             LayoutItemProxy{ target: a }
             LayoutItemProxy{ target: b }
             LayoutItemProxy{ target: c }
             Item { Layout.fillHeight: true }
             LayoutItemProxy{ target: d }
         }

         LayoutItemProxy {
             Layout.fillHeight: true
             Layout.fillWidth: true
             target: contentItem
         }
     }

Here we show that LayoutItemProxies can be used together with real Items on the same hierarchy level. Generally, the LayoutItemProxy is flexible and allows nested structures of items and layouts.

#### Setting the layout

After two layouts, `smallLayout` and `largeLayout` are defined, we can continue with setting the layout that fits to the current size of the application. We define a new function for this code that we call when the window is initialized and whenever the width changes:

     function setFittingLayout() {
         if (width < 450) {
             smallLayout.visible = true
             largeLayout.visible = false
         } else {
             smallLayout.visible = false
             largeLayout.visible = true
         }
     }
     onWidthChanged: setFittingLayout()
     Component.onCompleted: setFittingLayout()

Alternatively to calling this function after initialization we can hide all but the correct layout for the initial size in the declarative code.

Example project @ code.qt.io