- Qt Creator Documentation
- Create custom components
- Qt Creator 20.0.0

Create component instances ◦ Create scalable buttons and borders

# Create custom components

You can either use project wizard templates to create custom components and controls or move component instances into separate files to turn them into new components that you can create instances of. You can then use the instances of the new components in other components.

Custom components are stored in Components > My Components. You can create instances of custom components by dragging them from Components to the 2D or Navigator view.

## Create components from scratch

To use wizard templates to create custom components:

1. Select File > New File > Qt Quick Files > Qt Quick UI File > Choose to create a new `.ui.qml` file.

   Note: Components are listed in Components > My Components only if the filename begins with a capital letter.

2. Select Design to open the file in the 2D view.
3. Drag a component from Components to Navigator or the 2D view.
4. Edit component properties in the Properties view. The available properties depend on the component type. You can add properties for components on the Properties tab in the Connections view.
5. To change the appearance and behavior of the component instances in ways that are not supported in Qt Quick Designer by default, you can define custom properties on the Properties tab in the Connections view.

The following sections contain more information about how to use the 2D view to edit 2D content and examples of how to create UI controls using instances of basic components:

- The 2D view
- Create buttons
- Create scalable buttons and borders

## Naming conventions

Establish naming conventions to keep the components in your UI organized. Name your components accurately and give them suitable IDs. Particularly, check and modify the default names of the components you export from design tools to create reliable and self-explanatory names that follow the naming conventions you have established.

For example, a button symbol might have the ID myButton_symbol and the different layers might have it as a prefix with the states appended, thus producing IDs such as myButton_symbol_default. To prepare for additional mouse areas later in the project, you could use similar IDs for them, such as myButton_symbol_hotspot. When you use the button as instances in a screen, you would give each of these instances a unique ID that relates to that screen. For example, myButton_myMenu_home, myButton_myMenu_profile, and myButton_myMenu_settings

## Turn component instances into custom components

An alternative way of creating reusable components is to turn component instances into custom components by moving them into separate component files (`.ui.qml`). Right-click a component instance in Navigator or the 2D view, and select Create Component in the context menu.

Give the new component a name, and select whether properties are set for the new component or for the original one.

When you select OK, a new component file is created and an instance of the component is added to the code in the current component file. The look of your UI in the 2D view does not change.

To open the new component file for editing the properties that you want to change for all instances of the component, right-click the component, and then select Go into Component in the context menu. For additional ways of opening base components, see Move within components.

Custom components are listed in Components > My Components, and you can use instances of them to build more components.

## Merge files with templates

You can merge the current component file against an existing second component file using the second file in a way similar to using a CSS stylesheet.

To merge the current file with a template, right-click a component in the Navigator or 2D view and select Merge with Template in the context menu.

In the Template field, select the file to use as a template.

See also How to: Use UI components, Qt Quick UI design, and Designing Qt Quick UIs.