qt 使用 带有复选框的qlistwidget ，在外部通过按钮实现全选，全不选，并获取qlistwidget已选择的项，通过C++实现

要实现带有复选框的 QListWidget，并且可以通过按钮实现全选和全不选，可以按照以下步骤进行操作： 1. 创建 QListWidget 和 QPushButton 控件，并将它们添加到 QWidget 中。 ```c++ QListWidget *listWidget = new QListWidget(this); QPushButton *selectAllBtn = new QPushButton("Select All", this); QPushButton *deselectAllBtn = new QPushButton("Deselect All", this); ``` 2. 为 QListWidget 添加项，每个项都包含一个复选框和一些文本。 ```c++ QStringList items = {"Item 1", "Item 2", "Item 3", "Item 4", "Item 5"}; for (const auto &item : items) { QListWidgetItem *listItem = new QListWidgetItem(listWidget); QCheckBox *checkBox = new QCheckBox(); checkBox->setText(item); listItem->setSizeHint(checkBox->sizeHint()); listWidget->setItemWidget(listItem, checkBox); } ``` 3. 为 QPushButton 添加信号槽，分别实现全选和全不选功能。在槽函数中遍历 QListWidget 中的所有项，并将它们的复选框设置为选中或未选中状态。 ```c++ connect(selectAllBtn, &QPushButton::clicked, [=]() { for (int i = 0; i < listWidget->count(); ++i) { QCheckBox *checkBox = qobject_cast<QCheckBox *>(listWidget->itemWidget(listWidget->item(i))); checkBox->setChecked(true); } }); connect(deselectAllBtn, &QPushButton::clicked, [=]() { for (int i = 0; i < listWidget->count(); ++i) { QCheckBox *checkBox = qobject_cast<QCheckBox *>(listWidget->itemWidget(listWidget->item(i))); checkBox->setChecked(false); } }); ``` 4. 实现获取 QListWidget 中已选项的功能。遍历 QListWidget 中的所有项，如果一个项的复选框被选中，则将其文本添加到一个 QStringList 中。 ```c++ QStringList selectedItems; for (int i = 0; i < listWidget->count(); ++i) { QCheckBox *checkBox = qobject_cast<QCheckBox *>(listWidget->itemWidget(listWidget->item(i))); if (checkBox->isChecked()) { selectedItems << checkBox->text(); } } ``` 完整的代码示例如下： ```c++ #include <QApplication> #include <QListWidget> #include <QCheckBox> #include <QPushButton> int main(int argc, char *argv[]) { QApplication a(argc, argv); QWidget *widget = new QWidget; QListWidget *listWidget = new QListWidget(widget); QPushButton *selectAllBtn = new QPushButton("Select All", widget); QPushButton *deselectAllBtn = new QPushButton("Deselect All", widget); QStringList items = {"Item 1", "Item 2", "Item 3", "Item 4", "Item 5"}; for (const auto &item : items) { QListWidgetItem *listItem = new QListWidgetItem(listWidget); QCheckBox *checkBox = new QCheckBox(); checkBox->setText(item); listItem->setSizeHint(checkBox->sizeHint()); listWidget->setItemWidget(listItem, checkBox); } connect(selectAllBtn, &QPushButton::clicked, [=]() { for (int i = 0; i < listWidget->count(); ++i) { QCheckBox *checkBox = qobject_cast<QCheckBox *>(listWidget->itemWidget(listWidget->item(i))); checkBox->setChecked(true); } }); connect(deselectAllBtn, &QPushButton::clicked, [=]() { for (int i = 0; i < listWidget->count(); ++i) { QCheckBox *checkBox = qobject_cast<QCheckBox *>(listWidget->itemWidget(listWidget->item(i))); checkBox->setChecked(false); } }); QPushButton *getSelectedBtn = new QPushButton("Get Selected", widget); connect(getSelectedBtn, &QPushButton::clicked, [=]() { QStringList selectedItems; for (int i = 0; i < listWidget->count(); ++i) { QCheckBox *checkBox = qobject_cast<QCheckBox *>(listWidget->itemWidget(listWidget->item(i))); if (checkBox->isChecked()) { selectedItems << checkBox->text(); } } qDebug() << "Selected Items:" << selectedItems; }); QVBoxLayout *layout = new QVBoxLayout(widget); layout->addWidget(listWidget); layout->addWidget(selectAllBtn); layout->addWidget(deselectAllBtn); layout->addWidget(getSelectedBtn); widget->setLayout(layout); widget->show(); return a.exec(); } ```