QCheckBox

main.cpp

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#include <QApplication>
#include <QWidget>
#include <QCheckBox>
#include <QVBoxLayout>
#include <QLabel>
#include <QPushButton>
#include <QDebug>

void setupCheckBoxDemo(QWidget *parent) {
    QVBoxLayout *layout = new QVBoxLayout(parent);

    // --- 1. 基础用法：开关控制 ---
    QCheckBox *agreeCheck = new QCheckBox("我已阅读并同意服务协议", parent);
    QPushButton *regBtn = new QPushButton("注册", parent);
    regBtn->setEnabled(false); // 初始状态禁用按钮

    // 逻辑：只有勾选了协议，注册按钮才可用
    QObject::connect(agreeCheck, &QCheckBox::stateChanged, [regBtn](int state) {
        // state 的值：Qt::Unchecked (0), Qt::Checked (2)
        regBtn->setEnabled(state == Qt::Checked);
    });

    // --- 2. 进阶用法：三态复选框 (Tristate) ---
    // 常用于“全选”按钮：部分选中、全部选中、未选中
    QCheckBox *triCheck = new QCheckBox("开启高级选项（支持半选）", parent);
    triCheck->setTristate(true);

    QLabel *statusLabel = new QLabel("当前状态：未选中", parent);

    QObject::connect(triCheck, &QCheckBox::stateChanged, [statusLabel](int state) {
        if (state == Qt::Checked) {
            statusLabel->setText("当前状态：已选中 (Checked)");
        } else if (state == Qt::PartiallyChecked) {
            statusLabel->setText("当前状态：半选中 (PartiallyChecked)");
        } else {
            statusLabel->setText("当前状态：未选中 (Unchecked)");
        }
    });

    layout->addWidget(new QLabel("<h3>注册流程演示：</h3>"));
    layout->addWidget(agreeCheck);
    layout->addWidget(regBtn);
    layout->addSpacing(20);
    layout->addWidget(new QLabel("<h3>三态逻辑演示：</h3>"));
    layout->addWidget(triCheck);
    layout->addWidget(statusLabel);
    layout->addStretch();
}

int main(int argc, char *argv[]) {
    QApplication a(argc, argv);
    QWidget w;
    w.setWindowTitle("QCheckBox 交互演示");
    w.resize(350, 300);
    setupCheckBoxDemo(&w);
    w.show();
    return a.exec();
}