QML

https://juliagraphics.github.io/QML.jl/dev/
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QML.jl is a Julia module for building Qt6 QML graphical user interfaces for Julia programs, allowing...
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### Instantiate Project Environment

Source: https://juliagraphics.github.io/QML.jl/dev/developer

Navigates to the QML.jl folder and starts Julia with the project environment. Then, it installs all the necessary project dependencies.

```julia
using Pkg
Pkg.instantiate()
```

--------------------------------

### Load QML from a Julia Module

Source: https://juliagraphics.github.io/QML.jl/dev

This example demonstrates how to load a QML file from within a Julia module, ensuring proper function registration and context property setup. It requires a corresponding QML file in a subdirectory.

```julia
module QmlModuleTest

using QML
# absolute path in case working dir is overridden
const qml_file = joinpath(dirname(@__FILE__), "qml", "frommodule.qml")

# Propertymap is a pointer, so it needs to be a function and not a const value
props() = JuliaPropertyMap(
    "hi" => "Hi",
)

world() = " world!"

# Convenience function to call all relevant function macros
function define_funcs()
  @qmlfunction world
end

function main()
  define_funcs()
  loadqml(qml_file; props=props())
  exec()
end

end # module QmlModuleTest
```

--------------------------------

### Load and Create QML Component

Source: https://juliagraphics.github.io/QML.jl/dev

Loads QML code into a QQmlComponent and then creates an instance of it. This example uses a simple ApplicationWindow with a Text element that displays a context property.

```julia
component = QQmlComponent(an_engine);

set_data(component, QByteArray("""
          import QtQuick
          import QtQuick.Controls
          ApplicationWindow {
            visible: true
            Rectangle {
              Text {
                text: greeting
              }
              Timer {
                running: true; repeat: false
                onTriggered: Qt.exit(0)
              }
            }
          }
        """), QUrl())

create(component, qmlcontext())

exec()
```

--------------------------------

### Initialize QML Engine and Get Root Context

Source: https://juliagraphics.github.io/QML.jl/dev

Initializes a QML engine and retrieves its root context. This is a prerequisite for setting context properties and loading QML components.

```julia
using QML

an_engine = init_qmlengine();

context = root_context(an_engine);
```

--------------------------------

### Set and Get Context Property

Source: https://juliagraphics.github.io/QML.jl/dev

Demonstrates setting a property in the QML context and then retrieving it. This allows passing data from Julia to QML.

```julia
set_context_property(context, "greeting", "Hello, World!");

context_property(context, "greeting")
```

--------------------------------

### QML.exec_async

Source: https://juliagraphics.github.io/QML.jl/dev

Starts the QML event loop asynchronously without blocking the main process, polling the QML interface periodically.

```APIDOC
## QML.exec_async

### Description
Similar to `exec`, but does not block the main process. This method keeps the REPL active and periodically polls the QML interface for events using a timer within the Julia event loop.

### Function Signature
```julia
function exec_async()
```

### Usage
Use this when you need to interact with QML without halting your Julia program's execution.
```

--------------------------------

### Check Qt Prefix Path

Source: https://juliagraphics.github.io/QML.jl/dev

Verifies the Qt prefix path to ensure the correct Qt version is being used. This is useful for debugging installation issues.

```julia
using QML

isdir(qt_prefix_path())
```

--------------------------------

### Expand Dots Macro Example

Source: https://juliagraphics.github.io/QML.jl/dev

Demonstrates the usage of the `@expand_dots` macro to transform dot notation into function calls for nested object access.

```julia
using QML

QML.@expand_dots object_.field_ func
```

```julia
julia> using QML

julia> @macroexpand QML.@expand_dots a.b.c.d f
:(f(f(f(a, "b"), "c"), "d"))
```

--------------------------------

### Display Image in QML with JuliaDisplay

Source: https://juliagraphics.github.io/QML.jl/dev

Demonstrates how to send images from Julia to a QML interface using the JuliaDisplay type. The display can be added using `pushdisplay!` or passed by value. This example shows defining a Julia function and calling it from QML to display a random grayscale image.

```julia
using QML

using Colors

function simple_image(julia_display::JuliaDisplay)
          display(julia_display, Gray.(rand(50,50)))
          nothing
        end;

@qmlfunction simple_image
```

```qml
import QtQuick
import QtQuick.Controls
import QtQuick.Layouts
import jlqml
ApplicationWindow {
  visible: true
  JuliaDisplay {
    id: julia_display
    width: 50
    height: 50
    Component.onCompleted: {
      Julia.simple_image(julia_display)
    }
  }
  Timer {
    interval: 2000; running: true; repeat: false
    onTriggered: Qt.exit(0)
  }
}
```

--------------------------------

### Add TestEnv Package

Source: https://juliagraphics.github.io/QML.jl/dev/developer

Installs the TestEnv package globally in Julia. This is a prerequisite for managing project environments.

```julia
using Pkg
Pkg.add("TestEnv")
```

--------------------------------

### QML.root_context

Source: https://juliagraphics.github.io/QML.jl/dev

Gets the root context of a `QQmlEngine`. This context can be used to set and get properties, enabling data exchange between Julia and QML.

```APIDOC
## QML.root_context

### Description
Get the context of `an_engine`. Equivalent to `QQmlEngine::rootContext`. Use `set_context_property` to modify the context. Use `context_property` to get a particular property. Use to get the context of an engine created with `init_qmlengine` before using `set_data` or from `engine`.

### Function Signature
```
root_context(an_engine::QQmlEngine)
```

### Example
```julia
using QML

an_engine = init_qmlengine()
context = root_context(an_engine)
set_context_property(context, "greeting", "Hello, World!")
context_property(context, "greeting")
component = QQmlComponent(an_engine)
set_data(component, QByteArray("""
          import QtQuick
          import QtQuick.Controls
          ApplicationWindow {
            visible: true
            Rectangle {
              Text {
                text: greeting
              }
              Timer {
                running: true; repeat: false
                onTriggered: Qt.exit(0)
              }
            }
          }
        """), QUrl())
create(component, qmlcontext())
exec()
```
```

--------------------------------

### Set and Get QML Context Property

Source: https://juliagraphics.github.io/QML.jl/dev

Demonstrates setting a context property for a QML view and accessing it within the QML code. The `greeting` property is set in Julia and displayed in a QML `Text` element.

```qml
import QtQuick
import QtQuick.Controls

Rectangle {
  Text {
    text: greeting
  }
  Timer {
    running: true; repeat: false
    onTriggered: parent.Window.window.close()
  }
}
```

```julia
using QML

mktempdir() do folder
          path = joinpath(folder, "main.qml")
          write(path, """
          import QtQuick
          import QtQuick.Controls
          Rectangle {
            Text {
              text: greeting
            }
            Timer {
              running: true; repeat: false
              onTriggered: parent.Window.window.close()
            }
          }
          """)
          quick_view = init_qquickview()
          context = root_context(engine(quick_view))
          set_context_property(context, "greeting", "Hello, World!")
          set_source(quick_view, QUrlFromLocalFile(path))
          QML.show(quick_view)
          exec()
        end
```

--------------------------------

### Get QML Content Item

Source: https://juliagraphics.github.io/QML.jl/dev

Retrieve the content item of a `QQuickView`. This is equivalent to `QQuickWindow::contentItem` and returns a `CxxPtr{QQuickItem}`.

```julia
using QML
using CxxWrap.CxxWrapCore: CxxPtr

quick_view = mktempdir() do folder
          path = joinpath(folder, "main.qml")
          write(path, """
          import QtQuick
          import QtQuick.Controls
          Rectangle {
            Timer {
              running: true; repeat: false
              onTriggered: Qt.exit(0)
            }
          }
          """)
          quick_view = init_qquickview()
          set_source(quick_view, QUrlFromLocalFile(path))
          @assert content_item(quick_view) isa CxxPtr{QQuickItem}
          exec()
        end
```

--------------------------------

### Build and Serve Documentation Locally

Source: https://juliagraphics.github.io/QML.jl/dev/developer

Builds and serves the QML.jl documentation locally using LiveServer.jl. Access the documentation via the provided localhost link.

```julia
using LiveServer
servedocs()
```

--------------------------------

### Load and Execute QML with QQmlApplicationEngine

Source: https://juliagraphics.github.io/QML.jl/dev

Demonstrates loading a QML file using `QQmlApplicationEngine` and executing it. The engine's lifetime is managed by C++.

```julia
using QML

mktempdir() do folder
  path = joinpath(folder, "main.qml")
  write(path, """
  import QtQuick
  import QtQuick.Controls
  ApplicationWindow {
    visible: true
    Text {
      text: greeting
    }
    Timer {
      running: true; repeat: false
      onTriggered: Qt.exit(0)
    }
  }
  """)
  loadqml(path; greeting = "Hello, World!")
  exec()
end
```

--------------------------------

### QML.init_qmlengine

Source: https://juliagraphics.github.io/QML.jl/dev

Initializes and returns a new QML engine. The context can be modified using root_context.

```APIDOC
## QML.init_qmlengine

### Description
Creates and returns a new QML engine. You can modify the engine's context using `root_context`. This engine can then be used to create `QQmlComponent`s. See the example for `set_data` for usage. Alternatively, you can obtain the engine for an existing `QQuickView` using the `engine` function.

### Function Signature
```julia
function init_qmlengine()
```

### Returns
* `QQmlEngine` - A newly created QML engine.

### Example
(See example for `QML.set_data`)
```

--------------------------------

### Display QML with QQuickView

Source: https://juliagraphics.github.io/QML.jl/dev

Demonstrates using `QQuickView` to display a QML file. `QQuickView` creates a window, so `ApplicationWindow` is not needed in the QML.

```julia
using QML

mktempdir() do folder
  path = joinpath(folder, "main.qml")
  write(path, """
  import QtQuick
  import QtQuick.Controls
  Rectangle {
    Text {
      text: "Hello, World!"
    }
    Timer {
      running: true; repeat: false
      onTriggered: parent.Window.window.close()
    }
  }
  """)
  quick_view = init_qquickview()
  set_source(quick_view, QUrlFromLocalFile(path))
  QML.show(quick_view)
  exec()
end
```

--------------------------------

### Create QML Component with QQmlComponent

Source: https://juliagraphics.github.io/QML.jl/dev

Shows how to create a QML component using `QQmlComponent`, set its data, create a window from it, and execute.

```julia
using QML

component = QQmlComponent(init_qmlengine())

set_data(component, QByteArray("""
  import QtQuick
  import QtQuick.Controls
  ApplicationWindow {
    visible: true
    Rectangle {
      Text {
        text: "Hello, World!"
      }
      Timer {
        running: true; repeat: false
        onTriggered: Qt.exit(0)
      }
    }
  }
"""), QUrl())

create(component, qmlcontext())

exec()
```

--------------------------------

### Load and Execute QML with Observables

Source: https://juliagraphics.github.io/QML.jl/dev

Loads a QML file and sets up an observable output. Includes a timer for doctests to set a default output and exit.

```julia
using QML

function loadqml_with_observables(path::String; output = 0.0)
  @qmlfunction isinteractive # For doctest
  loadqml(path; observables = JuliaPropertyMap("output" => output))
  if isinteractive()
    exec_async()
  else
    exec() # for doctest
  end
end
```

--------------------------------

### QML.init_qquickview

Source: https://juliagraphics.github.io/QML.jl/dev

Initializes and returns a new QQuickView object.

```APIDOC
## QML.init_qquickview

### Description
Creates and returns a new `QQuickView` object.

### Function Signature
```julia
function init_qquickview()
```

### Returns
* `QQuickView` - A newly created QQuickView instance.
```

--------------------------------

### Initialize QML Engine

Source: https://juliagraphics.github.io/QML.jl/dev

Create a QML engine using `init_qmlengine`. The engine's context can be modified via `root_context`, and it can be used to create `QQmlComponent`s. An engine for a `QQuickView` can also be obtained using the `engine` function.

```julia
using QML

init_qmlengine()
```

--------------------------------

### Initialize QQuickView

Source: https://juliagraphics.github.io/QML.jl/dev

Create a `QQuickView` object using the `init_qquickview` function. This object is used to display QML user interfaces.

```julia
using QML

init_qquickview()
```

--------------------------------

### QML.show

Source: https://juliagraphics.github.io/QML.jl/dev

Displays the QML view, equivalent to `QQuickView::show`. This makes the QML window visible to the user.

```APIDOC
## QML.show

### Description
Equivalent to `QQuickView::show`. See example for `QQuickView`.

### Function Signature
```
function QML.show()
```
```

--------------------------------

### QML.create

Source: https://juliagraphics.github.io/QML.jl/dev

Creates a QML component, parenting it to the given QQmlContext. Equivalent to QQmlComponent::create.

```APIDOC
## QML.create

### Description
Creates a QML component, equivalent to `QQmlComponent::create`. This function ensures the newly created object is parented to the provided `context`. See the example for `set_data` for usage.

### Function Signature
```julia
function create(component::QQmlComponent, context::QQmlContext)
```

### Parameters
* `component` (QQmlComponent) - The QQmlComponent to create.
* `context` (QQmlContext) - The QQmlContext to parent the created component to.

### Returns
* The created QML object.

### Example
(See example for `QML.set_data`)
```

--------------------------------

### Load QML File with Properties

Source: https://juliagraphics.github.io/QML.jl/dev

Load a QML file into the current QML view using the `loadqml` function. Additional properties can be passed as keyword arguments.

```julia
using QML

loadqml(qmlfilename; properties...)
```

--------------------------------

### Simulate Background Tasks with QTimer

Source: https://juliagraphics.github.io/QML.jl/dev

Illustrates using `QTimer` to simulate background tasks in Julia, connected to QML via `Connections`.

```julia
using QML

counter = Ref(0)

increment() = counter[] += 1

@qmlfunction increment

mktempdir() do folder
  path = joinpath(folder, "main.qml")
  write(path, """
  import QtQuick
  import QtQuick.Controls
  import jlqml
  ApplicationWindow {
      visible: true
      Connections {
        target: timer
        function onTimeout() {
          Julia.increment()
        }
      }
      Button {
          text: "Start counting"
          onClicked: timer.start()
      }
      Timer { # unrelated, this is a timer to stop and continue testing
        running: true; repeat: false
        onTriggered: Qt.exit(0)
      }
  }
  """)
  loadqml(path, timer=QTimer())
  exec()
end
```

--------------------------------

### QML.exec

Source: https://juliagraphics.github.io/QML.jl/dev

Executes the QML event loop, filling out a window. Use with QQmlApplicationEngine, QQuickView, or QQmlComponent.

```APIDOC
## QML.exec

### Description
Fills out a window by executing the QML event loop. This function can be used with `QQmlApplicationEngine`, `QQuickView`, or `QQmlComponent`. Note that after calling `exec`, you may need to re-register functions (e.g., using `[@qmlfunction]`) if you intend to call `exec` again.

### Function Signature
```julia
function exec()
```

### Usage
Call this function after setting up your QML components and engine/view.
```

--------------------------------

### Clone QML.jl Repository

Source: https://juliagraphics.github.io/QML.jl/dev/developer

Clones the QML.jl repository from GitHub to your local machine. Replace USERNAME with your GitHub username.

```bash
git clone https://github.com/USERNAME/QML.jl.git
```

--------------------------------

### QML Application Window Structure

Source: https://juliagraphics.github.io/QML.jl/dev

This QML code defines a basic ApplicationWindow with a red background and a text element that displays properties from Julia. It imports necessary QML modules.

```qml
import QtQuick
import QtQuick.Controls
import jlqml

ApplicationWindow {
  id: mainWin
  title: "My Application"
  width: 100
  height: 100
  visible: true

  Rectangle {
    anchors.fill: parent
    color: "red"

    Text {
      anchors.centerIn: parent
      text: props.hi + Julia.world()
    }
  }
}
```

--------------------------------

### Base.string

Source: https://juliagraphics.github.io/QML.jl/dev

Converts a QByteArray to a Julia String. This is equivalent to the QByteArray::toString method.

```APIDOC
## Base.string

### Description
Converts a `QByteArray` to a Julia `String`. This is equivalent to the `QByteArray::toString` method.

### Function Signature
```julia
function string(data::QByteArray)
```

### Parameters
* `data` (QByteArray) - The byte array to convert.

### Returns
* `String` - The converted string.

### Example
```julia
using QML

string(QByteArray("Hello, World!"))
```
```

--------------------------------

### QML.loadqml

Source: https://juliagraphics.github.io/QML.jl/dev

Loads a QML file and applies specified properties. This is a method of the QML module.

```APIDOC
## QML.loadqml

### Description
Loads a QML file specified by `qmlfilename` and applies any additional keyword arguments as properties.

### Method Signature
```julia
function loadqml(qmlfilename; properties...)
```

### Parameters
* `qmlfilename` (String) - The path to the QML file to load.
* `properties...` - Arbitrary keyword arguments to set as properties on the loaded QML object.

### Usage
This function is used to load and instantiate QML files within your Julia application.
```

--------------------------------

### QML.qt_prefix_path

Source: https://juliagraphics.github.io/QML.jl/dev

Returns the Qt prefix path, equivalent to `QLibraryInfo::location(QLibraryInfo::PrefixPath)`. Useful for verifying the correct Qt version.

```APIDOC
## QML.qt_prefix_path

### Description
Equivalent to `QLibraryInfo::location(QLibraryInfo::PrefixPath)`. Useful to check whether the intended Qt version is being used.

### Function Signature
```
function qt_prefix_path()
```

### Example
```julia
using QML

isdir(qt_prefix_path())
```
```

--------------------------------

### Activate Test Environment

Source: https://juliagraphics.github.io/QML.jl/dev/developer

Activates the test environment for the QML.jl project using the TestEnv package.

```julia
using TestEnv; TestEnv.activate()
```

--------------------------------

### QML.qmlcontext

Source: https://juliagraphics.github.io/QML.jl/dev

Creates an empty context for QML. This is required for the `create` function when initializing a QML application.

```APIDOC
## QML.qmlcontext

### Description
Create an empty context for QML. Required for `create`.

### Function Signature
```
function qmlcontext()
```
```

--------------------------------

### Create and Use JuliaItemModel in QML ListView

Source: https://juliagraphics.github.io/QML.jl/dev

Illustrates the creation of a `JuliaItemModel` from a Julia array of structs to be used in QML views like `ListView`. It shows how to define a mutable struct with properties, construct the model, and interact with it from QML, including updating data and appending rows.

```julia
using QML

mutable struct Fruit
          name::String
          cost::Float64
        end

fruits = JuliaItemModel([Fruit("apple", 1.0), Fruit("orange", 2.0)])
```

```qml
import QtQuick
import QtQuick.Controls
import QtQuick.Layouts
ApplicationWindow {
  visible: true
  ListView {
    model: fruits
    anchors.fill: parent
    delegate:
      Row {
        Text {
          text: name
        }
        Button {
          text: "Sale"
          onClicked: cost = cost / 2
        }
        Button {
          text: "Duplicate"
          onClicked: fruits.appendRow({"name": name, "cost": cost})
        }
        Timer {
          running: true; repeat: false
          onTriggered: Qt.exit(0)
        }
      }
    }
  }
}
```

--------------------------------

### QML.set_source

Source: https://juliagraphics.github.io/QML.jl/dev

Sets the source file for a `QQuickView`. This function is used to load a QML file into a view, typically a window.

```APIDOC
## QML.set_source

### Description
Equivalent to `QQuickView::setSource`. See the example for `init_qquickview`. The file path should be a path wrapped with `QUrl`.

### Function Signature
```
function set_source(window::QQuickView, file::QUrl)
```
```

--------------------------------

### Register Julia Functions for QML

Source: https://juliagraphics.github.io/QML.jl/dev

Shows how to register Julia functions for use in QML using the `@qmlfunction` macro. Functions are accessible via `Julia.function_name`.

```julia
@qmlfunction function_names...
```

```julia
julia> using QML

julia> greet() = "Hello, World!";

julia> @qmlfunction greet

julia> mktempdir() do folder
          path = joinpath(folder, "main.qml")
          write(path, """
          import jlqml
          import QtQuick
          import QtQuick.Controls
          ApplicationWindow {
            visible: true
            Text {
              text: Julia.greet()
            }
            Timer {
              running: true; repeat: false
              onTriggered: Qt.exit(0)
            }
          }
          """)
          loadqml(path)
          exec()
        end
```

--------------------------------

### QUrl Type

Source: https://juliagraphics.github.io/QML.jl/dev

Used to pass filenames to `set_source`. An empty URL can be passed to `set_data`.

```julia
struct QUrl([filename::String])
end
```

--------------------------------

### Convert QByteArray to String

Source: https://juliagraphics.github.io/QML.jl/dev

Use the `string` function to convert a `QByteArray` back to a Julia string. This is equivalent to `QByteArray::toString`.

```julia
using QML

string(QByteArray("Hello, World!"))
```

--------------------------------

### QML.setheadergetter!

Source: https://juliagraphics.github.io/QML.jl/dev

Sets a function to be called when retrieving header data for a `JuliaItemModel`. This customizes how header information is accessed.

```APIDOC
## QML.setheadergetter!

### Description
Set `f` as function to call when getting header data. The signature of of should be:
```
  f(data, row_or_col, orientation, role)
```

Here, `data` is the internal data array stored in the model, `row_or_col` is the index of the row or column, `orientation` is either `QML.Horizontal` for column headers or `QML.Vertical` for row headers and `role` is an integer describing the role (e.g. QML.DisplayRole)

### Method Signature
```
setheadergetter!(itemmodel::JuliaItemModel, f::Function)
```
```

--------------------------------

### QML.engine

Source: https://juliagraphics.github.io/QML.jl/dev

Retrieves the QML engine associated with a QQuickView. Equivalent to QQuickView::engine.

```APIDOC
## QML.engine

### Description
Retrieves the QML engine associated with a `QQuickView`. This is equivalent to `QQuickView::engine`. To modify the context of a `QQuickView`, you can obtain the engine using this function and then get the root context using `root_context`.

### Function Signature
```julia
function engine(quick_view::QQuickView)
```

### Parameters
* `quick_view` (QQuickView) - The QQuickView whose engine to retrieve.

### Returns
* `QQmlEngine` - The QML engine of the QQuickView.

### Example
```julia
using QML

mktempdir() do folder
    path = joinpath(folder, "main.qml")
    write(path, """
    import QtQuick
    import QtQuick.Controls
    Rectangle {
      Text {
        text: greeting
      }
      Timer {
        running: true; repeat: false
        onTriggered: parent.Window.window.close()
      }
    }
    """)
    quick_view = init_qquickview()
    context = root_context(engine(quick_view))
    set_context_property(context, "greeting", "Hello, World!")
    set_source(quick_view, QUrlFromLocalFile(path))
    QML.show(quick_view)
    exec()
end
```
```

--------------------------------

### QML.setheadersetter!

Source: https://juliagraphics.github.io/QML.jl/dev

Sets a function to be called when setting header data for a `JuliaItemModel`. This allows custom logic for updating header information.

```APIDOC
## QML.setheadersetter!

### Description
Set `f` as function to call when setting header data. The signature of of should be:
```
  f(data, row_or_col, orientation, value, role)
```

Here, `value` is the value for the given header item. The other arguments are the same as in `setheadergetter!`

### Method Signature
```
setheadersetter!(itemmodel::JuliaItemModel, f::Function)
```
```

--------------------------------

### Emit Signal from Julia to QML

Source: https://juliagraphics.github.io/QML.jl/dev

Defines a Julia function that emits a signal, registers it with QML, and demonstrates its usage within a QML file. The QML file uses a JuliaSignals block to handle the emitted signal.

```julia
using QML

duplicate(value) = @emit duplicateSignal(value);

@qmlfunction duplicate

mktempdir() do folder
          path = joinpath(folder, "main.qml")
          write(path, """
          import QtQuick
          import QtQuick.Controls
          import QtQuick.Layouts
          import jlqml
          ApplicationWindow {
              visible: true
              Column {
                TextField {
                    id: input
                    onTextChanged: Julia.duplicate(text)
                }
                Text {
                    id: output
                }
                JuliaSignals {
                  signal duplicateSignal(var value)
"""
          )
end
```

--------------------------------

### QByteArray Type

Source: https://juliagraphics.github.io/QML.jl/dev

Used to pass text to `set_data`.

```julia
function QByteArray(a_string::String)
end
```

--------------------------------

### QML.content_item

Source: https://juliagraphics.github.io/QML.jl/dev

Retrieves the content item of a QQuickView, equivalent to QQuickWindow::contentItem.

```APIDOC
## QML.content_item

### Description
Retrieves the content item of a `QQuickView`. This is equivalent to `QQuickWindow::contentItem`.

### Function Signature
```julia
function content_item(quick_view::QQuickView)
```

### Parameters
* `quick_view` (QQuickView) - The QQuickView from which to get the content item.

### Returns
* `QQuickItem` - The content item of the QQuickView.

### Example
```julia
using QML
using CxxWrap.CxxWrapCore: CxxPtr

quick_view = mktempdir() do folder
    path = joinpath(folder, "main.qml")
    write(path, """
    import QtQuick
    import QtQuick.Controls
    Rectangle {
      Timer {
        running: true; repeat: false
        onTriggered: Qt.exit(0)
      }
    }
    """)
    quick_view = init_qquickview()
    set_source(quick_view, QUrlFromLocalFile(path))
    @assert content_item(quick_view) isa CxxPtr{QQuickItem}
    exec()
end
```
```

--------------------------------

### Synchronize Julia Observable with QML Slider

Source: https://juliagraphics.github.io/QML.jl/dev

Shows how to use `JuliaPropertyMap` to store Julia values for QML access and enable two-way synchronization. Changes to an `Observable` in Julia update the QML element (e.g., a slider), and changes in QML update the `Observable`.

```julia
using QML

using Observables: Observable, on

output = Observable(0.0)

on(println, output)
```

```qml
import QtQuick
import QtQuick.Controls
import jlqml
ApplicationWindow {
  visible: true
  Slider {

```

--------------------------------

### QML.roles

Source: https://juliagraphics.github.io/QML.jl/dev

Retrieves all defined roles for a `JuliaItemModel`. This is used in conjunction with `addrole!` to manage model data roles.

```APIDOC
## QML.roles

### Description
See all roles defined for a `JuliaItemModel`. See the example for `addrole!`.

### Method Signature
```
function roles(model::JuliaItemModel)
```
```

--------------------------------

### Execute QML Synchronously

Source: https://juliagraphics.github.io/QML.jl/dev

Use `exec` to display and interact with a QML window. This function blocks the main process until the QML window is closed. Note that functions may need to be reregistered with `@qmlfunction` if `exec` is called multiple times.

```julia
using QML

exec()
```

--------------------------------

### Execute QML Asynchronously

Source: https://juliagraphics.github.io/QML.jl/dev

Use `exec_async` to run a QML interface without blocking the main process. This method keeps the REPL active by periodically polling the QML interface using a timer in the Julia event loop.

```julia
using QML

exec_async()
```

--------------------------------

### QML.context_property

Source: https://juliagraphics.github.io/QML.jl/dev

Retrieves a context property from a QQmlContext.

```APIDOC
## QML.context_property

### Description
Retrieves a context property from a `QQmlContext`. Refer to the example for `root_context` for usage.

### Function Signature
```julia
function context_property(context::QQmlContext, item::AbstractString)
```

### Parameters
* `context` (QQmlContext) - The QQmlContext to retrieve the property from.
* `item` (AbstractString) - The name of the context property.

### Returns
* The value of the context property.

### Example
(See example for `QML.root_context`)
```

--------------------------------

### QML.addrole!

Source: https://juliagraphics.github.io/QML.jl/dev

Adds custom getter and setter functions to a JuliaItemModel for QML access. The setter is optional, making the role read-only if omitted.

```APIDOC
## QML.addrole!

### Description
Adds custom `getter` (and optionally `setter`) functions to a `JuliaItemModel` for use by QML. If `setter` is not provided, the role becomes read-only. The `getter` processes an item before it is returned. The arguments for `setter` are `collection`, `new_value`, and `index`, similar to the standard `setindex!` function. Use `roles` to view defined roles.

### Function Signature
```julia
function addrole!(model::JuliaItemModel, name::String, getter, [setter])
```

### Parameters
* `model` (JuliaItemModel) - The model to add the role to.
* `name` (String) - The name of the role to add.
* `getter` - The function to retrieve the role's value.
* `setter` (optional) - The function to set the role's value.

### Example
```julia
using QML

items = ["A", "B"]
array_model = JuliaItemModel(items, false)
addrole!(array_model, "item", identity, setindex!)

roles(array_model)[256]
"item"

mktempdir() do folder
    path = joinpath(folder, "main.qml")
    write(path, """
    import QtQuick
    import QtQuick.Controls
    import QtQuick.Layouts
    ApplicationWindow {
      visible: true
      ListView {
        model: array_model
        anchors.fill: parent
        delegate: TextField {
          placeholderText: item
          onTextChanged: item = text;
        }
      }
      Timer {
        running: true; repeat: false
        onTriggered: Qt.exit(0)
      }
    }
    """)
    loadqml(path; array_model = array_model)
    exec()
end
```
```

--------------------------------

### QML.set_data

Source: https://juliagraphics.github.io/QML.jl/dev

Sets the QML code for a `QQmlComponent` from a Julia string. This allows dynamic creation and loading of QML components.

```APIDOC
## QML.set_data

### Description
Equivalent to `QQmlComponent::setData`. Use this to set the QML code for a `QQmlComponent` from a Julia string literal wrapped in a `QByteArray`. Also requires an empty `QUrl`. See `QQmlComponent` for an example.

### Function Signature
```
function set_data(component::QQmlComponent, data::QByteArray, file::QUrl)
```
```

--------------------------------

### Add Custom Roles to JuliaItemModel

Source: https://juliagraphics.github.io/QML.jl/dev

Add custom getter and setter functions to a `JuliaItemModel` for use in QML. The setter is optional, making the role read-only if omitted. The getter processes an item before it's returned.

```julia
using QML

items = ["A", "B"]

array_model = JuliaItemModel(items, false)

addrole!(array_model, "item", identity, setindex!)

roles(array_model)[256]
```

```qml
import QtQuick
import QtQuick.Controls
import QtQuick.Layouts

ApplicationWindow {
  visible: true
  ListView {
    model: array_model
    anchors.fill: parent
    delegate: TextField {
      placeholderText: item
      onTextChanged: item = text;
    }
  }
  Timer {
    running: true; repeat: false
    onTriggered: Qt.exit(0)
  }
}
```

```julia
mktempdir() do folder
          path = joinpath(folder, "main.qml")
          write(path, """
          import QtQuick
          import QtQuick.Controls
          import QtQuick.Layouts
          ApplicationWindow {
            visible: true
            ListView {
              model: array_model
              anchors.fill: parent
              delegate: TextField {
                placeholderText: item
                onTextChanged: item = text;
              }
            }
            Timer {
              running: true; repeat: false
              onTriggered: Qt.exit(0)
            }
          }
          """)
          loadqml(path; array_model = array_model)
          exec()
        end
```

--------------------------------

### QML.@emit

Source: https://juliagraphics.github.io/QML.jl/dev

Emits a signal from Julia to QML, allowing Julia code to trigger events or send data to QML components. QML handles these signals using a `JuliaSignals` block.

```APIDOC
## QML.@emit

### Description
Emit a signal from Julia to QML. Handle signals in QML using a `JuliaSignals` block. See the example below for syntax.

Warning
There must never be more than one JuliaSignals block in QML

### Macro Signature
```
@emit signal_name(arguments...)
```

### Example
```julia
using QML

duplicate(value) = @emit duplicateSignal(value)

@qmlfunction duplicate

mktempdir() do folder
    path = joinpath(folder, "main.qml")
    write(path, """
      import QtQuick
      import QtQuick.Controls
      import QtQuick.Layouts
      import jlqml
      ApplicationWindow {
          visible: true
          Column {
            TextField {
                id: input
                onTextChanged: Julia.duplicate(text)
            }
            Text {
                id: output
            }
            JuliaSignals {
              signal duplicateSignal(var value)
"""
    )
end
```
```

--------------------------------

### QML.qmlfunction

Source: https://juliagraphics.github.io/QML.jl/dev

Registers a Julia function with a specified name for use in QML. This allows QML to call Julia functions directly.

```APIDOC
## QML.qmlfunction

### Description
Register `a_function` using `function_name`. If you want to register a function under its own name, you can use `@qmlfunction`. Note, however, that you can't use the macro for registering functions from a non-exported module or registering functions with `!` in the name.

### Function Signature
```
function qmlfunction(function_name::String, a_function)
```
```

--------------------------------

### QML.set_context_property

Source: https://juliagraphics.github.io/QML.jl/dev

Sets a property on a given QML context. This function is crucial for passing data from Julia to the QML environment.

```APIDOC
## QML.set_context_property

### Description
Set properties. See `root_context` for an example.

### Function Signature
```
set_context_property(context::QQmlContext, name::String, value::Any)
```
```
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