Qt 嵌套模型视图
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【中文标题】Qt 嵌套模型视图【英文标题】：Qt nested model views 【发布时间】：2018-07-20 09:43:42 【问题描述】：我来自 C# 和 WPF，我们有很好的方法将集合绑定到视图，通过当前 DataContext 填充数据。
我一直在学习 Qt，我知道有一种方法可以为视图提供模型 (QAbstractItemModel)，然后通过修改模型，您可以自动更新视图，这很好，也是我想要的。
我当前的问题是我想为以下类创建一个编辑器视图Definition
class Definition
public:
vector<Step*> Steps;
bool SomeBoolMember1;
bool SomeBoolMember2;
int SomeIntMember1;
int SomeIntMember2;
Step是
class Step
public:
vector<Requirement*> Requirements;
bool SomeBoolMember1;
bool SomeBoolMember2;
int SomeIntMember1;
int SomeIntMember2;
而Requirement 是
class Requirement
public:
RequirementType Type;
我的目标是构建一个能够修改Definitions 集合的视图。可能的视图可能是这样的：
选择不同的定义时，更新所选项目视图（要加载所选定义的数据），然后我们有一个带有步骤列表的滚动视图。每个步骤都有一个要求列表。
如您所见，这不是火箭科学，但我知道这可能很乏味。有关如何构建模型/视图模型以实现所需功能的任何提示？
【问题讨论】：
请注意：“删除步骤”按钮应显示在每个步骤中，并且“删除请求” - 在每个要求旁边。 是的，它可能是，它也可以删除最后一个（或选定的）步骤/要求。 我明白了。另一个问题。你坚持使用模型/视图吗？ 好吧，我真的不在乎，如果它完成了工作，但我相信这是最有用的情况。你有什么想法？ 让我准备一个例子，向您展示我的想法。 【参考方案1】：你的问题很广泛。 Qt 的模型非常通用，有很多方法可以构造它们以实现相同的行为。我创建了一个简化的示例，您可以如何构建它们。我只使用了Definition和Step，将Requirement添加到Step类似于将Step添加到Definition...
struct Step
bool SomeBoolMember1 false;
int SomeIntMember1 0;
;
struct Definition
std::vector<std::shared_ptr<Step>> Steps;
bool SomeBoolMember1 false;
int SomeIntMember1 0;
;
struct Data
std::vector<std::shared_ptr<Definition>> definitions;
;
模型非常简单，我为Definition 创建了一个模型，为Step 创建了一个模型。每个模型都有代表这些对象属性的列，模型的行代表对象的一个实例。 Definition 的模型有一个 Step 的列，它返回给定 Definition 的 Step 的模型。
class StepModel : public QAbstractItemModel
Q_OBJECT
using BaseClass = QAbstractItemModel;
public:
enum Columns
E_BOOL_1,
E_INT_1,
E_REQUIREMENT,
_END
;
StepModel(Definition* definition, QObject* parent) :
BaseClass(parent),
definition(definition)
virtual QModelIndex index(int row, int column, const QModelIndex &parent = QModelIndex()) const override
return createIndex(row, column, nullptr);
virtual QModelIndex parent(const QModelIndex &child) const override
return QModelIndex();
virtual int rowCount(const QModelIndex &parent = QModelIndex()) const override
return definition->Steps.size();
virtual int columnCount(const QModelIndex &parent = QModelIndex()) const override
return _END;
virtual QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override
if (role != Qt::DisplayRole) return QVariant();
const auto& step = definition->Steps.at(index.row());
switch (index.column())
case E_BOOL_1:
return step->SomeBoolMember1;
case E_INT_1:
return step->SomeIntMember1;
case E_REQUIREMENT:
return QVariant();
virtual bool setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole) override
if (role != Qt::EditRole) return false;
auto& step = definition->Steps.at(index.row());
switch (index.column())
case E_BOOL_1:
step->SomeBoolMember1 = value.toBool();
return true;
case E_INT_1:
step->SomeIntMember1 = value.toInt();
return true;
case E_REQUIREMENT:
assert(false);
return false;
virtual bool insertRows(int row, int count, const QModelIndex &parent = QModelIndex()) override
assert(count == 1);
beginInsertRows(parent, row, row);
definition->Steps.push_back(std::make_shared<Step>());
endInsertRows();
return true;
virtual bool removeRows(int row, int count, const QModelIndex &parent = QModelIndex()) override
assert(count == 1);
beginRemoveRows(parent, row, row);
definition->Steps.erase(definition->Steps.begin() + row);
endRemoveRows();
return true;
private:
Definition* definition;
;
Q_DECLARE_METATYPE(StepModel*)
class DefinitionModel : public QAbstractItemModel
Q_OBJECT
using BaseClass = QAbstractItemModel;
public:
enum Columns
E_NAME,
E_BOOL_1,
E_INT_1,
E_STEPS,
_END
;
DefinitionModel(QObject* parent) :
BaseClass(parent)
virtual QModelIndex index(int row, int column, const QModelIndex &parent = QModelIndex()) const override
return createIndex(row, column, nullptr);
virtual QModelIndex parent(const QModelIndex &child) const override
return QModelIndex();
virtual int rowCount(const QModelIndex &parent = QModelIndex()) const override
return definitionData.definitions.size();
virtual int columnCount(const QModelIndex &parent = QModelIndex()) const override
return _END;
virtual QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override
if (role != Qt::DisplayRole) return QVariant();
const auto& definition = definitionData.definitions.at(index.row());
switch (index.column())
case E_NAME:
return QString("Definition %1").arg(index.row() + 1);
case E_BOOL_1:
return definition->SomeBoolMember1;
case E_INT_1:
return definition->SomeIntMember1;
case E_STEPS:
return QVariant::fromValue(new StepModel(definition.get(), nullptr));
virtual bool setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole) override
if (role != Qt::EditRole) return false;
auto& definition = definitionData.definitions.at(index.row());
switch (index.column())
case E_BOOL_1:
definition->SomeBoolMember1 = value.toBool();
return true;
case E_INT_1:
definition->SomeIntMember1 = value.toInt();
return true;
default:
assert(false);
return false;
virtual bool insertRows(int row, int count, const QModelIndex &parent = QModelIndex()) override
assert(count == 1);
beginInsertRows(parent, row, row);
definitionData.definitions.push_back(std::make_shared<Definition>());
endInsertRows();
return true;
virtual bool removeRows(int row, int count, const QModelIndex &parent = QModelIndex()) override
assert(count == 1);
beginRemoveRows(parent, row, row);
definitionData.definitions.pop_back();
endRemoveRows();
return true;
private:
Data definitionData;
;
在此示例中，DefinitionModel 拥有 Data 的实例，这不是您在实际应用中想要做的事情，只是为了简单起见。
对话框有点复杂，因为您必须在创建新实例时为Steps 动态创建小部件。我为小部件创建了一个简单的映射，它映射到它的适当模型的列。每次选择新定义时，都会通过此映射从模型中加载数据。
namespace Ui
class MainWindow;
class MainWindow : public QMainWindow
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0) :
QMainWindow(parent),
ui(new Ui::MainWindow)
ui->setupUi(this);
auto definitionModel = new DefinitionModel(this);
ui->definitionView->setModel(definitionModel);
connect(ui->definitionView->selectionModel(), &QItemSelectionModel::currentRowChanged, this, [=]
update();
, Qt::QueuedConnection);
connect(ui->addDefinition, &QPushButton::pressed, this, [this]
auto* model = ui->definitionView->model();
model->insertRow(model->rowCount());
ui->definitionView->update();
ui->definitionView->setCurrentIndex(model->index(model->rowCount() - 1, 0));
);
connect(ui->removeDefinition, &QPushButton::pressed, this, [this]
auto* model = ui->definitionView->model();
if (model->rowCount() > 0)
const int row = model->rowCount() - 1;
for (const auto& widget : steps[row])
unmap(widget);
steps.erase(steps.find(row));
model->removeRow(row);
);
auto getCurrentDefinition = [this] return ui->definitionView->currentIndex().row(); ;
map(ui->definitionInt, definitionModel, DefinitionModel::E_INT_1, getCurrentDefinition);
map(ui->definitionBool, definitionModel, DefinitionModel::E_BOOL_1, getCurrentDefinition);
connect(ui->addStep, &QPushButton::pressed, this, [=]
if (getCurrentDefinition() == -1) return;
auto widget = new QWidget(this);
auto layout = new QHBoxLayout(widget);
auto checkBox = new QCheckBox(widget);
layout->addWidget(checkBox);
auto spinBox = new QSpinBox(widget);
layout->addWidget(spinBox);
auto removeButton = new QPushButton(widget);
removeButton->setText("remove");
layout->addWidget(removeButton);
ui->rightLayout->addWidget(widget);
const int currentDefinition = getCurrentDefinition();
steps[currentDefinition].push_back(widget);
auto model = definitionModel->data(definitionModel->index(currentDefinition, DefinitionModel::E_STEPS), Qt::DisplayRole).value<QAbstractItemModel*>();
model->setParent(widget);
const int rowCount = model->rowCount();
model->insertRow(rowCount);
auto getRow = [=]
auto it = std::find(steps[currentDefinition].begin(), steps[currentDefinition].end(), widget);
return std::distance(steps[currentDefinition].begin(), it);
;
map(checkBox, model, StepModel::E_BOOL_1, getRow);
map(spinBox, model, StepModel::E_INT_1, getRow);
connect(ui->definitionView->selectionModel(), &QItemSelectionModel::currentRowChanged, widget, [=] (const QModelIndex& current)
widget->setVisible(current.row() == currentDefinition);
);
connect(removeButton, &QPushButton::pressed, widget, [=]
model->removeRow(rowCount);
unmap(checkBox);
unmap(spinBox);
ui->rightLayout->removeWidget(widget);
auto it = std::find(steps[getCurrentDefinition()].begin(), steps[getCurrentDefinition()].end(), widget);
steps[currentDefinition].erase(it);
delete widget;
);
update();
);
~MainWindow()
delete ui;
private:
void map(QCheckBox* checkBox, QAbstractItemModel* model, int column, std::function<int()> getRow)
connect(checkBox, &QCheckBox::toggled, this, [=] (bool value)
model->setData(model->index(getRow(), column), value, Qt::EditRole);
);
auto update = [=]
checkBox->setChecked(model->data(model->index(getRow(), column), Qt::DisplayRole).toBool());
;
mapping.emplace(checkBox, update);
void map(QSpinBox* spinBox, QAbstractItemModel* model, int column, std::function<int()> getRow)
connect(spinBox, static_cast<void (QSpinBox::*)(int)>(&QSpinBox::valueChanged), this, [=] (int value)
model->setData(model->index(getRow(), column), value, Qt::EditRole);
);
auto update = [=]
spinBox->setValue(model->data(model->index(getRow(), column), Qt::DisplayRole).toInt());
;
mapping.emplace(spinBox, update);
void unmap(QWidget* widget)
mapping.erase(mapping.find(widget));
void update() const
for (const auto& pair : mapping)
pair.second();
Ui::MainWindow *ui;
std::map<QWidget*, std::function<void()>> mapping;
std::map<int, std::vector<QWidget*>> steps;
;
ui文件：
<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<class>MainWindow</class>
<widget class="QMainWindow" name="MainWindow">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>800</width>
<height>600</height>
</rect>
</property>
<property name="windowTitle">
<string>MainWindow</string>
</property>
<widget class="QWidget" name="centralWidget">
<layout class="QHBoxLayout" name="verticalLayout" stretch="1,2">
<item>
<layout class="QVBoxLayout" name="verticalLayout_3">
<property name="spacing">
<number>0</number>
</property>
<property name="leftMargin">
<number>10</number>
</property>
<item>
<widget class="QListView" name="definitionView">
<property name="showDropIndicator" stdset="0">
<bool>false</bool>
</property>
<property name="selectionBehavior">
<enum>QAbstractItemView::SelectRows</enum>
</property>
</widget>
</item>
<item>
<layout class="QHBoxLayout" name="horizontalLayout">
<property name="topMargin">
<number>10</number>
</property>
<item>
<widget class="QPushButton" name="addDefinition">
<property name="text">
<string>add</string>
</property>
</widget>
</item>
<item>
<widget class="QPushButton" name="removeDefinition">
<property name="text">
<string>remove</string>
</property>
</widget>
</item>
</layout>
</item>
</layout>
</item>
<item>
<layout class="QVBoxLayout" name="verticalLayout_2">
<property name="rightMargin">
<number>10</number>
</property>
<item>
<layout class="QVBoxLayout" name="rightLayout">
<item>
<layout class="QHBoxLayout" name="horizontalLayout_2">
<item>
<widget class="QCheckBox" name="definitionBool">
<property name="text">
<string>CheckBox</string>
</property>
</widget>
</item>
<item>
<widget class="QSpinBox" name="definitionInt"/>
</item>
</layout>
</item>
<item>
<layout class="QHBoxLayout" name="horizontalLayout_3">
<property name="topMargin">
<number>10</number>
</property>
<item>
<widget class="QLabel" name="label">
<property name="text">
<string>Steps</string>
</property>
</widget>
</item>
<item>
<widget class="QPushButton" name="addStep">
<property name="text">
<string>add</string>
</property>
</widget>
</item>
</layout>
</item>
</layout>
</item>
<item>
<spacer name="verticalSpacer">
<property name="orientation">
<enum>Qt::Vertical</enum>
</property>
<property name="sizeHint" stdset="0">
<size>
<width>20</width>
<height>40</height>
</size>
</property>
</spacer>
</item>
</layout>
</item>
</layout>
</widget>
</widget>
<layoutdefault spacing="6" margin="11"/>
<resources/>
<connections/>
</ui>
【讨论】：
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