2017.5.8 更新：Record类要用指针，QObject 不能有拷贝函数。

我有一个C++中自定义的ReaderModel，继承自QAbstractListModel类，传递给了QML。

它的me成员是一个Reader指针，Reader有个成员是RecordModel。

通过reader获取的recordModel，在qml中类型是QVariant(RecordModel)，我没法把它作为一个ListView的model。

要怎么让它绑定给view呢？

我尝试者把数据拷贝到一个直接传给qml的recordModel，但是当数据之后发生了变化时，视图就不会更新，除非再次拷贝，这样效率不可观。

通过艰难地google查找相关问题，我最后的解决方案是：

取消这个RecordModel成员，用QVariantList来储存所有record。

简单地说就是传递自定义类中的自定义结构体数组。

作为解决方案的代码(如果不需要，完全可以不用ReaderModel，但是要用setContextProperty把reader变量传给qml)：

record.h

#ifndef RECORD_H

#define RECORD_H

#include

class Record: public QObject

{

Q_OBJECT

Q_PROPERTY(QString bookId READ bookId WRITE setBookId NOTIFY bookIdChanged)

Q_PROPERTY(int state READ state WRITE setState NOTIFY stateChanged)

public:

Record(const QString &bookId="",int state=0):

bookId_(bookId),state_(state){}

Record(const Record &r){

bookId_ = r.bookId_;

state_ = r.state_;

}

QString bookId() const;

int state() const;

public slots:

void setBookId(const QString &);

void setState(int);

private:

QString bookId_;

int state_;

signals:

void bookIdChanged();

void stateChanged();

};

Q_DECLARE_METATYPE(Record*)//元类型注册

#endif // RECORD_H

reader.h

#ifndef READER_H

#define READER_H

#include

#include

class Reader: public QObject

{

Q_OBJECT

Q_PROPERTY(QString id READ id WRITE setId NOTIFY idChanged)

Q_PROPERTY(QString password READ password WRITE setPassword NOTIFY passwordChanged)

Q_PROPERTY(QVariantList record READ record WRITE setRecord NOTIFY recordChanged)

public:

Reader(const QString &id = "",

const QString &password = "")

: id_(id),password_(password){}

QString id() const; //id

QString password() const; //密码

QVariantList record() const; //记录

Q_INVOKABLE void doSomething()const;

public slots:

void setId(const QString &);

void setPassword(const QString &);

void setRecord(const QVariantList &);

private:

QString id_;

QString password_;

QVariantList record_;//借书记录

signals:

void idChanged();

void passwordChanged();

void recordChanged();

};

#endif // READER_H

readerModel.h

#ifndef READERMODEL_H

#define READERMODEL_H

#include

#include

#include

#include "reader.h"

#include "record.h"

class ReaderModel : public QAbstractListModel

{

Q_OBJECT

Q_PROPERTY(Reader* me READ me WRITE setMe NOTIFY meChanged)

public:

enum ReaderRole {

IdRole = Qt::DisplayRole, //0

PasswordRole = Qt::UserRole,

RecordRole

};

Q_ENUM(ReaderRole)

ReaderModel(QObject *parent = nullptr){Q_UNUSED(parent);}

int rowCount(const QModelIndex & = QModelIndex()) const;

QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const;

QHash roleNames() const;

Q_INVOKABLE QVariantMap get(int row) const;

Q_INVOKABLE void append(const QString &id,

const QString &password);

Q_INVOKABLE void set(int row, const QString &id,

const QString &password);

Q_INVOKABLE void remove(int row);

Q_INVOKABLE Reader *me() const;//当前登录的用户对象指针

Q_INVOKABLE void setMe(Reader *r);

private:

QList m_readers;

Reader *me_;

signals:

void meChanged();

};

#endif // READERMODEL_H

reader.cpp

#include "reader.h"

#include "record.h"

#include

QString Reader::id() const

{

return id_;

}

QString Reader::password() const

{

return password_;

}

QVariantList Reader::record() const

{

return record_;

}

void Reader::setId(const QString &value)

{

if (id_ == value)

return;

id_ = value;

emit idChanged();

}

void Reader::setPassword(const QString &value)

{

if (password_ == value)

return;

password_ = value;

emit passwordChanged();

}

void Reader::setRecord(const QVariantList &value)

{

if (record_ == value)

return;

record_ = value;

emit recordChanged();

}

record.cpp

#include "record.h"

QString Record::bookId() const

{

return bookId_;

}

int Record::state() const

{

return state_;

}

void Record::setBookId(const QString &value)

{

if(bookId_ == value)

return;

bookId_ = value;

emit bookIdChanged();

}

void Record::setState(int value)

{

if(state_ == value)

return;

state_ = value;

emit stateChanged();

}

readerModel.cpp

#include "readermodel.h"

#include "reader.h"

int ReaderModel::rowCount(const QModelIndex & /*parent*/) const

{

return m_readers.count();

}

QVariant ReaderModel::data(const QModelIndex &index, int role) const

{

if(index.row() < rowCount())

switch(role){

case IdRole: return m_readers.at(index.row())->id();

case PasswordRole: return m_readers.at(index.row())->password();

case RecordRole: return m_readers.at(index.row())->record();

default: return QVariant();

}

return QVariant();

}

QHash ReaderModel::roleNames() const

{

static const QHash roles{

{IdRole, "id"},

{PasswordRole, "password"},

{RecordRole, "record"}

};

return roles;

}

QVariantMap ReaderModel::get(int row) const

{

Reader *reader = m_readers.value(row);

return { {"id", reader->id()},

{"password", reader->password()},

{"record", reader->record()}};

}

void ReaderModel::append(const QString &id, const QString &password)

{

int row = m_readers.count();

beginInsertRows(QModelIndex(), row, row);

Reader *r = new Reader(id, password, name, power, school, credit, money, unback);

m_readers.append(r);

endInsertRows();

}

void ReaderModel::set(int row, const QString &id, const QString &password)

{

if (row < 0 || row >= m_readers.count())

return;

Reader *r = new Reader(id, password == ""? m_readers[row]->password() : password);

m_readers.replace(row, r);

dataChanged(index(row, 0), index(row, 0), { IdRole,PasswordRole});

}

void ReaderModel::remove(int row)

{

if (row < 0 || row >= m_readers.count())

return;

beginRemoveRows(QModelIndex(), row, row);

m_readers.removeAt(row);

endRemoveRows();

}

Reader *ReaderModel::me() const

{

return me_;

}

void ReaderModel::setMe(Reader *r)

{

me_ = r;

emit meChanged();

}

main.cpp

#include

#include

#include

#include

#include "readermodel.h"

int main(int argc, char *argv[])

{

QGuiApplication app(argc, argv);

//向qml注册类型

qmlRegisterType("Backend", 1, 0, "ReaderModel");

ReaderModel *readerModel = new ReaderModel();

...//写入数据

QQmlApplicationEngine *engine = new QQmlApplicationEngine();

//向qml传递变量

engine->rootContext()->setContextProperty("readerModel", readerModel);

engine->load(QUrl(QLatin1String("qrc:/main.qml")));

return app.exec();

}

mail.qml：

ListView {

visible: true

id: recordView

width: parent.width

height: parent.height

model: readerModel.me.record

delegate:Rectangle{

property var record: readerModel.me.record[index]

RowLayout{

spacing: 10

Label {

text: record.bookId

}

Label {

text: record.state

}

}

Component.onCompleted: {

console.log(readerModel.me.record)

console.log("\n",readerModel.me.record[index])

console.log("\n",readerModel.me.record[index].state)

}

}

}