QT内省机制、自定义Model、数据库

 1 //Parameter.h
 2 //加粗单词为成员变量
 3 //假设数据库中某表有三个字段Index,Name,Describe
 4 
 5 class Parameter : public QObject
 6 {
 7     Q_OBJECT
 8 public:
 9     explicit Parameter( QObject *parent = 0);
10 
11     Q_INVOKABLE QVariant getIndex() const { return index;} //用Q_INVOKABLE声明后才能被元对象（QMetaObject）调用
12     Q_INVOKABLE void setIndex(const QVariant &value) { index = value.toInt(); }
13 
14     Q_INVOKABLE QVariant getName() const { return name; }
15     Q_INVOKABLE void setName(const QVariant &value) { name = value.toString(); }
16 
17     Q_INVOKABLE QVariant getDecribe() const { return describe; }
18     Q_INVOKABLE QVariant setDescribe(const QVariant &value) { describe = value; }
19 
20     QMap<int, int> getMethodGETIndexs()const;//获得“取值器”函数(即getXX函数)  的索引值列表，这些函数都被Q_INVOKABLE声明过
21     QMap<int, int> getMethodSETIndexs() const;//获得“设置器”函数（即setXX函数） 的索引值列表，这些函数都被Q_INVOKABLE声明过
22 
23 private:
24     void setMethodGETIndexs(); //设置“取值器”函数(即getXX函数) 的索引值列表，这些函数都被Q_INVOKABLE声明过
25     void setMethodSETIndexs(); //设置“设置器”函数(即setXX函数) 的索引值列表，这些函数都被Q_INVOKABLE声明过
26 
27     static int getNewIndex();
28 
29     int index;
30     QString name;
31     QString describe;
32 
33     QMap<int,int> methodGETIndexs;
34     QMap<int,int> methodSETIndexs;
35 };

 1 //Parameter.cpp
 2 
 3 Parameter::Parameter(QObject *parent) :
 4   QObject(parent),
 5   index(getNewIndex()),
 6   name("Unnamed"),
 7   describe("")
 8 {
 9    setMethodGETIndexs();
10    setMethodSETIndexs();   
11 }
12 
13 void Parameter::setMethodGETIndex()
14 {
15   int index1 = this->metaObject()->indexOfMethod("getIndex()");
16   methodGETIndexs.insert(0,index1);
17 
18   int index2 = this->metaObject()->indexOfMethod("getName()");
19   methodGETIndexs.insert(1,index2);
20 
21   int index3 = this->metaObject()->indexOfMethod("getDecribe()");
22   methodGETIndexs.insert(2,index3);
23 
24 }
25 
26 void Parameter::setMethodSETIndexs()
27 {
28   int index1 = this->metaObject()->indexOfMethod("setIndex(QVariant)");
29   methodSETIndexs.insert(0,index1);
30 
31   int index2 = this->metaObject()->indexOfMethod("setName(QVariant)");
32   methodSETIndexs.insert(1,index2);
33 
34   int index3 = this->metaObject()->indexOfMethod("setDescribe(QVariant)");
35   methodSETIndexs.insert(2,index3);
36 }
37 
38 QMap<int, int> Parameter::getMethodSETIndexs() const
39 {
40   return methodSETIndexs;
41 }
42 
43 QMap<int, int> Parameter::getMethodGETIndexs() const
44 {
45   return methodGETIndexs;
46 }
47 
48 int Parameter::getNewIndex()
49 {
50      //查询数据库
51      //返回最新的Index字段
52 }

//tablemodel.cpp

TableModel::TableModel(QObject *parent) :
    QAbstractTableModel(parent)，
    dataParameters（getTableParameters（））     
{

}

static TableModel::QList<Parameter*> getTableParameters()
{
     //查询数据库，返回字段值列表
}

int TableModel::rowCount(const QModelIndex &parent = QModelIndex())
{
     dataParameters.size();
}

int TableModel::columnCount(const QModelIndex &parent) const
{
     Q_UNUSED(parent);
     return dataParameters.getMethodGETIndexs().size();
}


QVariant TableModel::data(const QModelIndex &index, int role) const
{
    if(!index.isValid()){
        return QVariant();
    }
    return specificData(index,role);
}

QVariant TableModel::specificData(const QModelIndex &index, int role)const
{
  switch(role)
  {
  case Qt::TextAlignmentRole:
      return int(Qt::AlignHCenter | Qt::AlignVCenter);
  case Qt::DisplayRole:
     return specificIndexValue(index);
  case Qt::EditRole:
     return specificIndexValue(index);
  default:
     return QVariant();
  }
  return QVariant();
}

QVariant TableModel::specificIndexValue(const QModelIndex &index) const
{
  QVariant retValue;
  int methodIndex = methodGETIndex(index);
  QMetaMethod getMethod = getMetaMethod(index,methodIndex);
  getMethod.invoke(dataParameters.at(index.row()),Qt::DirectConnection,Q_RETURN_ARG(QVariant,retValue));
  return retValue;
}

int TableModel::getMethodGETIndex(const QModelIndex &index) const
{
 int methodIndex = dataParameters.at(index.row())->getMethodGETIndexs().value(index.column());
 return methodIndex;  
}

QMetaMethod TableModel::getMetaMethod(const QModelIndex &index,int methodIndex) const
{
    QMetaMethod method = dataParameters.at(index.row())->metaObject()->method(methodIndex);
    return method;
}

bool TableModel::setData(const QModelIndex &index, const QVariant &value, int role)
{
    if(!isIndexValid(index))
        return false;
    if(role == Qt::EditRole && setSpecificData(index,value))
        ResParameters::instance().modifyRecord(index);

    return QAbstractTableModel::setData(index,value);
}

bool TableModel::setSpecificData(const QModelIndex &index,
                                            const QVariant &value)
{
    if( specificIndexValue(index) != value){

        int methodIndex = getMethodSETIndex(index);
        QMetaMethod setMethod = getMetaMethod( index, methodIndex);
        return setMethod.invoke( dataParameters.at(index.row()), Qt::DirectConnection, Q_ARG(QVariant,value) );

    }
    return false;
}

int TableModel::getMethodSETIndex(const QModelIndex &index)
{
    int methodIndex = dataParameters.at(index.row())->getMethodSETIndexs().value(index.column());
    return methodIndex;
}