Qt之模型/视图（实时更新数据）

上两节简单介绍了Qt中对于模型/视图的编程，大部分助手里说的很清楚了，现在就开始实战部分吧！
在实际应用中，视图展示的数据往往并非一成不变的，那么如何实时更新成了一个很重要的问题！
功能：
（1）添加委托（进度条）
（2）显示文件名称、大小、进度、速度、剩余时间、状态等。
（3）可进行添加、更新、删除、清空等操作。
（4）实时更新数据
先看一个效果图：


委托（进度条）：
ProgressBarDelegate::ProgressBarDelegate(QObject *parent)
: QItemDelegate(parent)
{

}

void ProgressBarDelegate::paint(QPainter* painter, const QStyleOptionViewItem& option, const QModelIndex& index) const
{
if(index.column() == 2)
{
int progress = index.model ()->data(index, Qt::DisplayRole).toInt ();
QStyleOptionProgressBarV2 progressBarOption;
progressBarOption.state = QStyle:: State_Enabled;
progressBarOption.direction = QApplication:: layoutDirection ();
progressBarOption.rect = option.rect;
progressBarOption.fontMetrics = QApplication:: fontMetrics ();
progressBarOption.minimum = 0;
progressBarOption.maximum = 100;
progressBarOption.textAlignment = Qt:: AlignCenter;
progressBarOption.textVisible = true;
progressBarOption.progress = progress;
progressBarOption.text = QString("%1%").arg(progressBarOption.progress);
QApplication:: style ()->drawControl(QStyle::CE_ProgressBar, &progressBarOption, painter);
} else {
return QItemDelegate::paint (painter, option, index);
}
}

模型:
TableModel::TableModel(QObject *parent)
: QAbstractTableModel(parent), arr_row_list(NULL)
{

}

TableModel::~TableModel(void)
{
arr_row_list = NULL;
}

void TableModel::setHorizontalHeaderList(QStringList horizontalHeaderList)
{
horizontal_header_list = horizontalHeaderList;
}

void TableModel::setVerticalHeaderList(QStringList verticalHeaderList)
{
vertical_header_list = verticalHeaderList;
}

int TableModel::rowCount(const QModelIndex &parent) const
{
if(vertical_header_list.size() > 0)
return vertical_header_list.size();

if(NULL == arr_row_list)
return 0;
else
return arr_row_list->size();
}

int TableModel::columnCount(const QModelIndex &parent) const
{
if(horizontal_header_list.size() > 0)
return horizontal_header_list.size();

if(NULL == arr_row_list)
return 0;
else if(arr_row_list->size() < 1)
return 0;
else
return arr_row_list->at(0).size();
}

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

if(NULL == arr_row_list)
return QVariant();

if(arr_row_list->size() < 1)
return QVariant();

if (role == Qt::TextAlignmentRole)
{
return int(Qt::AlignLeft | Qt::AlignVCenter);
}
else if (role == Qt::DisplayRole)
{
if(index.row() >= arr_row_list->size())
return QVariant();
if(index.column() >= arr_row_list->at(0).size())
return QVariant();
return arr_row_list->at(index.row()).at(index.column());
}
return QVariant();
}

QVariant TableModel::headerData(int section, Qt::Orientation orientation, int role) const
{
if(role==Qt::DisplayRole)
{
if(orientation==Qt::Horizontal) // 水平表头
{
if(horizontal_header_list.size() > section)
return horizontal_header_list[section];
else
return QVariant();
}
else
{
if(vertical_header_list.size() > section)
return vertical_header_list[section]; // 垂直表头
else
return QVariant();
}
}

return QVariant();
}

Qt::ItemFlags TableModel::flags(const QModelIndex &index) const
{
if (!index.isValid())
return Qt::NoItemFlags;

Qt::ItemFlags flag = QAbstractItemModel::flags(index);

// flag|=Qt::ItemIsEditable // 设置单元格可编辑,此处注释,单元格无法被编辑
return flag;
}

void TableModel::setModalDatas(QList< QStringList > *rowlist)
{
arr_row_list = rowlist;
}

void TableModel::refrushModel()
{
beginResetModel();
endResetModel();

emit updateCount(this->rowCount(QModelIndex()));
}

视图：
TableView::TableView(QWidget *parent)
: QTableView(parent)
{
this->setAlternatingRowColors(true);
this->setStyleSheet( "QTableView{background-color: rgb(250, 250, 115);"
"alternate-background-color: rgb(141, 163, 215);}" );
this->setSelectionBehavior(QAbstractItemView::SelectRows);
this->horizontalHeader()->setStretchLastSection(true);
this->horizontalHeader()->setHighlightSections(false);
this->verticalHeader()->setVisible(false);
this->setShowGrid(false);
this->setEditTriggers(QAbstractItemView::NoEditTriggers);
this->setSelectionMode(QAbstractItemView::ExtendedSelection);

model = new TableModel();
this->setModel(model);
this->initHeader();
model->setModalDatas(&grid_data_list);
progressbar_delegate = new ProgressBarDelegate();
this->setItemDelegate(progressbar_delegate);

connect(model, &TableModel::updateCount, this, &TableView::updateCount);

this->initHeader();
}

TableView::~TableView(void)
{
if(progressbar_delegate) {
delete progressbar_delegate;
progressbar_delegate = NULL;
}

if(model) {
delete model;
model = NULL;
}
grid_data_list.clear();
}

void TableView::addRow(QStringList rowList)
{
grid_data_list.append(rowList);
model->refrushModel();
}

void TableView::remove()
{
QModelIndexList model_index_list = this->selectedIndexes();
int model_count = model_index_list.count();
if(model_count <= 0)
return;

QList list_row;
for(int i=model_count-1; i>=0; i--)
{
QModelIndex model_index = model_index_list.at(i);
int row = model_index.row();
if(!list_row.contains(row))
list_row.append(row);
}

if(list_row.isEmpty())
return;

qSort(list_row);

for(int i=list_row.count()-1; i>=0; i--)
{
grid_data_list.removeAt(list_row.at(i));
}

model->refrushModel();
}

void TableView::clear()
{
grid_data_list.clear();
model->refrushModel();
}

int TableView::rowCount()
{
return model->rowCount(QModelIndex());
}

void TableView::initHeader()
{
QStringList header;
header << tr("name") << tr("size") << tr("progress") << tr("speed") << tr("left time") << tr("state");
model->setHorizontalHeaderList(header);
}

void TableView::changeValue()
{
//这里以10行尾列进行更新
int row_count = this->rowCount();
if(row_count < 10)
return;

for(int i=0; i<10; i++)
{
QStringList file_list = grid_data_list.at(i);
int progress = rand()0;
QStringList row_list;
row_list << file_list.at(0) << file_list.at(1) << QString::number(progress) << file_list.at(3) << file_list.at(4) << file_list.at(5);
grid_data_list.replace(i, row_list);
}

model->refrushModel();
}

完整的工程（源码）下载地址：http://download.csdn.net/detail/u011012932/6829783。