Focus Handling

Certain elements such as TextInput accept input from the mouse/finger and also key events originating from (virtual) keyboards. In order for an item to receive these events, it must have focus. This is visible through the has-focus (out) property.

You can manually activate the focus on an element by calling focus():

import { Button } from "std-widgets.slint";

export component App inherits Window {
    VerticalLayout {
        alignment: start;
        Button {
            text: "press me";
            clicked => { input.focus(); }
        }
        input := TextInput {
            text: "I am a text input field";
        }
    }
}

slint

Similarly, you can manually clear the focus on an element that’s currently focused, by calling clear-focus():

import { Button } from "std-widgets.slint";

export component App inherits Window {
    VerticalLayout {
        alignment: start;
        Button {
            text: "press me";
            clicked => { input.clear-focus(); }
        }
        input := TextInput {
            text: "I am a text input field";
        }
    }
}

slint

After clearing the focus, keyboard input to the window is discarded until another element is explicitly focused. For example by calling focus(), an element acquiring focus when the user clicks on it, or when pressing tab and the first focusable element is found.

If you have wrapped the TextInput in a component, then you can forward such a focus activation using the forward-focus property to refer to the element that should receive it:

import { Button } from "std-widgets.slint";

component LabeledInput inherits GridLayout {
    forward-focus: input;
    Row {
        Text {
            text: "Input Label:";
        }
        input := TextInput {}
    }
}

export component App inherits Window {
    GridLayout {
        Button {
            text: "press me";
            clicked => { label.focus(); }
        }
        label := LabeledInput {
        }
    }
}

slint

If you use the forward-focus property on a Window, then the specified element will receive the focus the first time the window receives the focus - it becomes the initial focus element.