List all the enum object ?

[sonichy]

I want to list all the enum object:

for(enum &i : QStyle::StandardPixmap){
//for(int i=0; i<20; i++){
    ui->listWidget->addItem(new QListWidgetItem(QIcon(style()->standardPixmap(i)), "QStyle::SP_ArrowBack"));
}

[mrjj]

hi
Use F2 to look at its definition.

enum StandardPixmap {
SP_TitleBarMenuButton,
...

Its a plain enum and hence it cannot provide the name for you only the value.

So you can grap list and make a map with enum, Text or
simply make a switch case.

This is as old an issue as C++ itself.
Tons on the net about it.
https://stackoverflow.com/questions/5093460/how-to-convert-an-enum-type-variable-to-a-string

[JonB]

@mrjj
His code is not actually attempting to get the names of the enum values. It needs to know the upper limit of the QStyle::StandardPixmap values, which seems to be QStyle::SP_LineEditClearButton at present.... If that's what he means by his question.

[mrjj]

@JNBarchan
Ah, good catch. I was fooled by the "QStyle::SP_ArrowBack" text.
F2 is still his friend :)

[JonB]

@mrjj
If he's waiting for C++ to tell him the upper "bound" of the enum, I think he's out of luck, unless you know better.

[JonB]

@mrjj said in List all the enum object ?:

@JNBarchan
Ah, good catch. I was fooled by the "QStyle::SP_ArrowBack" text.

Actually, looking at it, I suspect upon reconsideration that actually your interpretation was correct, and it's the second, "name-of-enum-value" argument to QListWidgetItem() he's interested in. I was confused by the commenting out of the for loop. Who knows here... !

[mrjj]

@JNBarchan
Old type enums cannot do anything of that sort and even the new c++ 11 one , only gave it
type safety / type specifier and still no way to get a string version of it.
There might be a template way to make be accepted in for (item : container) construct but
good old for loop seems most appropriate.

[kshegunov]

http://doc.qt.io/qt-5/qmetaenum.html

[mrjj]

Ah, thanks @kshegunov , its flagged with
Q_ENUM(StandardPixmap)
so one can use Qt meta system.

[kshegunov]

Yes, sorry for being so cryptic, here you go:

QMetaEnum standardPixmap = QMetaEnum::fromType<QStyle::StandardPixmap>();
for (qint32 i = 0, count = standardPixmap.keyCount(); i < count; i++)
    qDebug() << standardPixmap.key(i) << endl;

[goldenhawking]

It's difficult for C++ to do this. Enum is treated as a value-item, for example, int when the source code is compiled.
Yee, kshegunov's answer with Qt meta system is good, a string map will be pre-compiled in moc step.

[goldenhawking]

@goldenhawking said in List all the enum object ?:

meta

-Qt's meta compiler makes c++ a "Dynamic" like language , it's very important feature.

[sonichy]

QMetaEnum metaEnum = QMetaEnum::fromType<QStyle::StandardPixmap>();
for (qint32 i = 0, count = metaEnum.keyCount(); i < count; i++) {
    QStyle::StandardPixmap SP = (QStyle::StandardPixmap)metaEnum.keyToValue(metaEnum.key(i));
    QListWidgetItem *LWI = new QListWidgetItem(QIcon(style()->standardPixmap(SP)), metaEnum.key(i));
    LWI->setSizeHint(QSize(100,100));
    ui->listWidget->addItem(LWI);
}