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Form

A local form surface that validates fields and emits a submit signal.

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Live C++Source and licences
#include <QApplication>
#include <QFile>
#include <QHBoxLayout>
#include <QLabel>
#include <QPainter>
#include <QStandardItemModel>
#include <QUrl>
#include <QVBoxLayout>
#include <array>
#ifdef SHADCN_GALLERY_MEDIA
#include <shadcn/media.hpp>
#endif
#include <shadcn/shadcn.hpp>

QWidget* example(QWidget* parent = nullptr) {
    using namespace shadcn;
    auto* canvas = new QWidget(parent);
    canvas->setAutoFillBackground(true);
    auto* outer = new QHBoxLayout(canvas);
    outer->setContentsMargins(32, 32, 32, 32);
    auto* host = new QWidget(canvas);
    auto* layout = new QVBoxLayout(host);
    layout->setContentsMargins(0, 0, 0, 0);
    layout->setSpacing(16);
    outer->addStretch();
    outer->addWidget(host, 0, Qt::AlignCenter);
    outer->addStretch();
    auto* form = new Form(host);
    form->setFixedWidth(340);
    auto* input = new Input(form);
    input->setPlaceholderText("alex");
    auto& field = form->addField("Username", input);
    field.setDescription("This is your public display name.");
    field.setValidator([input] {
        return input->text().size() < 2 ? QString("Use at least 2 characters.") : QString{};
    });
    auto* submit = new Button("Submit", form);
    form->content().addWidget(submit, 0, Qt::AlignLeft);
    QObject::connect(submit, &Button::clicked, form, &Form::submit);
    layout->addWidget(form);
    return canvas;
}

Installation​

add_subdirectory(shadcn-cpp)
target_link_libraries(app PRIVATE shadcn::widgets)

Usage​

#include <shadcn/data.hpp>

shadcn::Form form(parent);
auto& email = shadcn::make_child<shadcn::Input>(form);
auto& field = form.addField("Email", &email);
field.setValidator([&] {
    return email.text().isEmpty()
        ? QString{"Email is required."} : QString{};
});
QObject::connect(&form, &shadcn::Form::submitted,
                 receiver, onSubmitted);

API​

addField creates a Field and returns a borrowed reference. validate runs every validator. submit emits submitted only when valid.

Variations​

Place any QWidget control inside a field and use content() for custom rows.

Keyboard and accessibility​

Qt supplies native focus, keyboard interaction and accessible object roles. Give the component a visible label or an accessible name when its text alone does not explain the action.

Ownership​

The parent widget owns the component. Child widgets created through a component layout follow Qt parent ownership. References returned by helper methods are borrowed.