how to preview of image in QFileDialog by default

[yoll522]

hi,

I am using QFileDialog::getOpenFileNames() in my code

it is good to use in Windows 7
01.jpg

but I find a question in Windows XP, that is QFileDialog has no preview image,

like this photo
02.JPG

I must manually open the preview from red circle every time when I use QFileDialog::getOpenFileNames()

so I would like to ask is there any way to automatic open preview image?

thanks a lot

and, sorry for my bad English.

[anda_skoa]

The two versions of the operating system probably have different default file dialogs, which is what Qt is using for its static convenience methods.

You could experiement with creating a QFileDialog instance manually and providing a custom QFileIconProvder when on XP

Cheers,
_

[yoll522]

The two versions of the operating system probably have different default file dialogs, which is what Qt is using for its static convenience methods.

You could experiement with creating a QFileDialog instance manually and providing a custom QFileIconProvder when on XP

Cheers,
_

Hi, thank you your answer

today, I try to make FileDialog,

I use QFileSystemModel in QListView

QFileSystemModel *fileSystemModel = new QFileSystemModel();
    ui->listView_file->setModel(fileSystemModel);

QFileSystemModel *fileSystemModel = new QFileSystemModel();
    ui->listView_file->setModel(fileSystemModel);

To copy to clipboard, switch view to plain text mode 

this is a picture of my program
001.jpg

please help me again,

I would like to ask how to let it show preview image on QListView?

like QFileDialog have preview image
01.jpg


thank you very much

[anda_skoa]

Have you tried what I suggested?

Cheers,
_

[yoll522]

yes

but I going to look QFileIconProvider document, it have "icon" function,

it is to provide systematic image, like the following instructions

enum QFileIconProvider::IconType
QFileIconProvider::Computer	
QFileIconProvider::Desktop	
QFileIconProvider::Trashcan	
QFileIconProvider::Network	
QFileIconProvider::Drive	
QFileIconProvider::Folder	
QFileIconProvider::File

enum QFileIconProvider::IconType
QFileIconProvider::Computer	
QFileIconProvider::Desktop	
QFileIconProvider::Trashcan	
QFileIconProvider::Network	
QFileIconProvider::Drive	
QFileIconProvider::Folder	
QFileIconProvider::File

To copy to clipboard, switch view to plain text mode 

I try it to use, this is my code

QFileIconProvider fileIcon;
ui->pushButton->setIcon(fileIcon.icon(QFileInfo("1.jpg")));

but I got this answer
002.jpg

it also have no preview Image

maybe I was wrong about something

could you please guide me

thanks you very much

[anda_skoa]

My suggestion was to use a QFileDialog instance and set your own QFileIconProvider, i.e. one that implemens the icon(QFileInfo) function such that it creates a preview image of the file.

Of course you can implement your own file dialog as well, but that will be quite some work.

Cheers,
__

[yoll522]

My suggestion was to use a QFileDialog instance and set your own QFileIconProvider, i.e. one that implemens the icon(QFileInfo) function such that it creates a preview image of the file.

Of course you can implement your own file dialog as well, but that will be quite some work.

Cheers,
__

hi, I try to Inheritance QFileIconProvider and over write icon function, this is my code

class myFileIconProvider:public QFileIconProvider {
public:
    QIcon icon(const QFileInfo &info) const{
        if(!QFileInfo(info.filePath()).isDir())
        {
            //if the file is image
            if( info.suffix().compare("jpg",Qt::CaseInsensitive)==0 ||
                    info.suffix().compare("bmp",Qt::CaseInsensitive)==0 ||
                    info.suffix().compare("png",Qt::CaseInsensitive)==0 ||
                    info.suffix().compare("jpeg",Qt::CaseInsensitive)==0 )
            {
                //creat a preview image to QIcon
                QIcon myIcon(info.filePath());
                return myIcon;
            }
        }
        //if the file is not image, return default icon
        return QFileIconProvider::icon(info);
    }
};

class myFileIconProvider:public QFileIconProvider {
public:
    QIcon icon(const QFileInfo &info) const{
        if(!QFileInfo(info.filePath()).isDir())
        {
            //if the file is image
            if( info.suffix().compare("jpg",Qt::CaseInsensitive)==0 ||
                    info.suffix().compare("bmp",Qt::CaseInsensitive)==0 ||
                    info.suffix().compare("png",Qt::CaseInsensitive)==0 ||
                    info.suffix().compare("jpeg",Qt::CaseInsensitive)==0 )
            {
                //creat a preview image to QIcon
                QIcon myIcon(info.filePath());
                return myIcon;
            }
        }
        //if the file is not image, return default icon
        return QFileIconProvider::icon(info);
    }
};

To copy to clipboard, switch view to plain text mode 

myFileIconProvider fileIconProvider;
QFileSystemModel fileSystemModel;
fileSystemModel.setIconProvider(&fileIconProvider);
 
ui->listView_file->setModel(fileSystemModel);

myFileIconProvider fileIconProvider;
QFileSystemModel fileSystemModel;
fileSystemModel.setIconProvider(&fileIconProvider);

ui->listView_file->setModel(fileSystemModel);

To copy to clipboard, switch view to plain text mode 

0000.jpg

it look good, but some problem in program

if the file is too much, then the ui->listView_file (QListView) will delay for a few second,

I think maybe icon function draw the QIcon was slowly,

if I go into a folder has 20 image, than the program will delay 2-3 second ˇ_ˇ

anyway, I am very grateful for your help

[anda_skoa]

Hmm.

Another option might be a class derived from QFileSystemModel or a QIdentityProxyModel subclass on top of a normal QFileSystemModel.

When an icon for a file (Qt:ecorationRole) is requested, a cache lookup could check if there is already a thumbnail for the given file.
if not, return a standard icon and trigger an asynchronous creation of the thumbail and notify the view when it is ready.

Cheers,
_

[yoll522]

Hmm.

Another option might be a class derived from QFileSystemModel or a QIdentityProxyModel subclass on top of a normal QFileSystemModel.

When an icon for a file (Qt:ecorationRole) is requested, a cache lookup could check if there is already a thumbnail for the given file.
if not, return a standard icon and trigger an asynchronous creation of the thumbail and notify the view when it is ready.

Cheers,
_

I try to create myFileSystemModel class, but I don't know how to load thumbnail from system

I use QPixmapCache and use "fine" function, but it seem to be looking the cache from program, not system.

so, if my program restart, the thumbnail will be reload,

could you please give me more tips, thank you.

this is my code:

class cMyFileSystemModel : public QFileSystemModel{
public:
    QVariant data (const QModelIndex & index, int role = Qt::DisplayRole) const{
        if(role == Qt::DecorationRole){
            QFileInfo fileInfo = this->fileInfo(index);
 
            if( fileInfo.suffix().compare("jpg",Qt::CaseInsensitive)==0 ||
                fileInfo.suffix().compare("bmp",Qt::CaseInsensitive)==0 ||
                fileInfo.suffix().compare("png",Qt::CaseInsensitive)==0 ||
                fileInfo.suffix().compare("jpeg",Qt::CaseInsensitive)==0 )
            {
 
                QPixmap pm;
                if (!QPixmapCache::find(fileInfo.filePath(), &pm)) {
 
                    pm.load(fileInfo.filePath());
                    QPixmapCache::insert(fileInfo.filePath(), pm);
                    QIcon myIcon(pm);
                    return myIcon;
                }
 
                }else{
                    QIcon myIcon(pm);
                    return myIcon;
                }
            }
 
        }
        return QFileSystemModel::data(index,role);
    }
 
};

class cMyFileSystemModel : public QFileSystemModel{
public:
    QVariant data (const QModelIndex & index, int role = Qt::DisplayRole) const{
        if(role == Qt::DecorationRole){
            QFileInfo fileInfo = this->fileInfo(index);

            if( fileInfo.suffix().compare("jpg",Qt::CaseInsensitive)==0 ||
                fileInfo.suffix().compare("bmp",Qt::CaseInsensitive)==0 ||
                fileInfo.suffix().compare("png",Qt::CaseInsensitive)==0 ||
                fileInfo.suffix().compare("jpeg",Qt::CaseInsensitive)==0 )
            {

                QPixmap pm;
                if (!QPixmapCache::find(fileInfo.filePath(), &pm)) {

                    pm.load(fileInfo.filePath());
                    QPixmapCache::insert(fileInfo.filePath(), pm);
                    QIcon myIcon(pm);
                    return myIcon;
                }

                }else{
                    QIcon myIcon(pm);
                    return myIcon;
                }
            }

        }
        return QFileSystemModel::data(index,role);
    }

};

To copy to clipboard, switch view to plain text mode 

[anda_skoa]

I use QPixmapCache and use "fine" function, but it seem to be looking the cache from program, not system.

I am not sure what you mean. "The QPixmapCache class provides an application-wide cache for pixmaps."

so, if my program restart, the thumbnail will be reload,

Your code doesn't show any persitance handling, i.e. no saving to disk or initializing the cache from disk.
Maybe you forgot that and you are starting with an empty cache on each startup?

Cheers,
_