遍历本地文件
qt 提供了很多种便利类来实现本地的文件系统管理，比如QDirModel和QFileSystemModel，qml中又提供了FolderListModel 。需要包含Qt.labs.folderlistmodel 2.0
笔者的环境没有安装Qt.labs.folderlistmodel 2.0 所以只能在QDirModel和 QFileSystemModel来选择，缺点是pro 文件中要添加QT += widgets， 因为该模块实现需要依赖widgets。
对于 QDirModel和 QFileSystemModel的选择
在QDirModel文档中说明
此类已过时。它提供了保持旧的源代码工作。我们强烈建议不要在新代码中使用它。
所以最终选择了QFileSystemModel
核心代码
本文章代码参考了git上一个demo，但是添加了一些代码，主要是可以返回上一级
参考代码的git地址 ： https://github.com/junyius1/filesystembrowser
main.cpp
#include <QApplication>
#include <QQmlApplicationEngine>
#include <QtQml>
#include <QFileSystemModel>
#include <QDateTime>
#include <QDesktopServices>
#include <QUrl>
#include <QDirModel>
#include <QQuickView>
static inline QString permissionString(const QFileInfo &fi)
{
const QFile::Permissions permissions = fi.permissions();
QString result = QLatin1String("----------");
if (fi.isSymLink())
result[0] = QLatin1Char('l');
else if (fi.isDir())
result[0] = QLatin1Char('d');
if (permissions & QFileDevice::ReadUser)
result[1] = QLatin1Char('r');
if (permissions & QFileDevice::WriteUser)
result[2] = QLatin1Char('w');
if (permissions & QFileDevice::ExeUser)
result[3] = QLatin1Char('x');
if (permissions & QFileDevice::ReadGroup)
result[4] = QLatin1Char('r');
if (permissions & QFileDevice::WriteGroup)
result[5] = QLatin1Char('w');
if (permissions & QFileDevice::ExeGroup)
result[6] = QLatin1Char('x');
if (permissions & QFileDevice::ReadOther)
result[7] = QLatin1Char('r');
if (permissions & QFileDevice::WriteOther)
result[8] = QLatin1Char('w');
if (permissions & QFileDevice::ExeOther)
result[9] = QLatin1Char('x');
return result;
}
static inline QString sizeString(const QFileInfo &fi)
{
if (!fi.isFile())
return QString();
const qint64 size = fi.size();
if (size > 1024 * 1024 * 10)
return QString::number(size / (1024 * 1024)) + QLatin1Char('M');
if (size > 1024 * 10)
return QString::number(size / 1024) + QLatin1Char('K');
return QString::number(size);
}
class DisplayFileSystemModel : public QFileSystemModel {
Q_OBJECT
public:
explicit DisplayFileSystemModel(QObject *parent = nullptr)
: QFileSystemModel(parent) {
}
public Q_SLOTS:
void onRootPathChanged(const QString &newPath)
{
qDebug()<< "=====" << "onRootPathChanged==="<<newPath;
}
public:
enum Roles {
SizeRole = Qt::UserRole + 4,
DisplayableFilePermissionsRole = Qt::UserRole + 5,
LastModifiedRole = Qt::UserRole + 6,
UrlStringRole = Qt::UserRole + 7,
//NameRole = Qt::UserRole + 8
};
Q_ENUM(Roles)
QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override
{
if (index.isValid() && role >= SizeRole) {
switch (role) {
case SizeRole:
return QVariant(sizeString(fileInfo(index)));
case DisplayableFilePermissionsRole:
return QVariant(permissionString(fileInfo(index)));
case LastModifiedRole:
return QVariant(fileInfo(index).lastModified().toString(Qt::SystemLocaleShortDate));
case UrlStringRole:
return QVariant(QUrl::fromLocalFile(filePath(index)).toString());
default:
break;
}
}
return QFileSystemModel::data(index, role);
}
QHash<int,QByteArray> roleNames() const override
{
QHash<int, QByteArray> result = QFileSystemModel::roleNames();
result.insert(SizeRole, QByteArrayLiteral("size"));
result.insert(DisplayableFilePermissionsRole, QByteArrayLiteral("displayableFilePermissions"));
result.insert(LastModifiedRole, QByteArrayLiteral("lastModified"));
//result.insert(NameRole,QByteArrayLiteral("name"));
return result;
}
public:
Q_INVOKABLE bool _isDir(const QModelIndex &index)
{
return isDir(index);
}
Q_INVOKABLE QModelIndex parentIndex(const QModelIndex &index)
{
return parent(index);
}
};
int main(int argc, char ** argv)
{
QApplication app(argc, argv);
QQuickView view;
QFileSystemModel *fsm = new DisplayFileSystemModel(&view);
// QFileSystemModel *fsm = new QFileSystemModel(&view);
QObject::connect(fsm, SIGNAL(rootPathChanged(const QString)), fsm,
SLOT(onRootPathChanged(const QString)));
QModelIndex lIndex = fsm->setRootPath(QDir::homePath());
// fsm->setResolveSymlinks(true);
view.rootContext()->setContextProperty("rootPathIndex", lIndex);
view.rootContext()->setContextProperty("fileSystemModel", fsm);
view.setSource(QUrl(QStringLiteral("qrc:/main.qml")));
view.show();
return app.exec();
}
#include "main.moc"
main.qml
import QtQuick 2.2
import QtQml.Models 2.2
import QtQuick.Controls 2.3
Rectangle
{
id:root
width: 500
height: 800
Button
{
id:back
y:460
z:100
text: "back"
onClicked:
{
console.log("back clicked")
view.setParentModel();
}
}
ListView {
id: view
width: 300
height: 400
function getParentModel()
{
return view.model.parentIndex
}
function setParentModel()
{
console.log(view.model.indexArray.length)
if(view.model.indexArray.length === 1)
return
view.model.indexArray.pop();
view.model.testIndex= fileSystemModel.parentIndex(view.model.rootIndex)
view.model.rootIndex = view.model.testIndex
console.log(view.model.indexArray.length,view.model.indexArray)
//方法2
// view.model.testIndex= view.model.indexArray[viewmodel.indexArray.length-1]
// viewmodel.rootIndex = viewmodel.indexArray[viewmodel.indexArray.length-1]
// view.model.rootIndex = view.model.testIndex
}
model: DelegateModel {
property var testIndex
property var parentIndex
property var indexArray: new Array; //方法2
model: fileSystemModel
rootIndex:{
view.model.testIndex = rootPathIndex
//方法2
view.model.indexArray.push(rootPathIndex);
console.log("set rootIndex==",view.model.indexArray.length ,view.model.testIndex)
//return rootPathIndex
}
onRootIndexChanged:{
view.model.rootIndex = view.model.testIndex
console.log("set onRootIndexChanged==",view.model.testIndex)
}
delegate: Rectangle {
width: 200; height: 65
Image{
id:img
source:fileSystemModel._isDir(view.model.modelIndex(index))? "qrc:/dir.png":"qrc:/listenItem.png"
}
Text{
text: fileName
anchors.verticalCenter: img.verticalCenter
anchors.left: img.right
anchors.leftMargin: 10
}
MouseArea {
anchors.fill: parent
onClicked: {
if (model.hasModelChildren){
console.log("clicked",view.model.testIndex);
view.model.testIndex= view.model.modelIndex(index)
view.model.rootIndex = view.model.modelIndex(index)
//方法2
view.model.indexArray.push(view.model.testIndex);
console.log("clikced ", view.model.indexArray.length)
}
}
}
}
}
}
}
上述代码实现了两种方法来返回上一层，最早是使用了一个array来记录各层级节点，
后来找到了获得父节点的方法，所以用了最新获得父节点的方式来实现。代码中有些还是不太明白，等有时间了再自信琢磨琢磨。
尤其是：
onRootIndexChanged:{
view.model.rootIndex = view.model.testIndex
console.log("set onRootIndexChanged==",view.model.testIndex)
}
既然rootIndex Changed了，为什么还需要给rootIndex赋值呢？导致多次打印。
效果如下
