C++ 如何将 int 转换为 QString？
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How to convert int to QString?
提问by Ahmad
Is there a QStringfunction which takes an intand outputs it as a QString?
是否有一个QString函数接受一个int并将其输出为 a QString？
回答by Georg Fritzsche
回答by Kamil Klimek
And if you want to put it into string within some text context, forget about +operator.
Simply do:
如果您想将其放入某个文本上下文中的字符串中，请忘记+运算符。简单地做：
// Qt 5 + C++11
auto i = 13;
auto printable = QStringLiteral("My magic number is %1. That's all!").arg(i);
// Qt 5
int i = 13;
QString printable = QStringLiteral("My magic number is %1. That's all!").arg(i);
// Qt 4
int i = 13;
QString printable = QString::fromLatin1("My magic number is %1. That's all!").arg(i);
回答by Gabriel de Grimouard
Moreover to convert whatever you want, you can use QVariant.
For an intto a QStringyou get:
此外，要转换您想要的任何内容，您可以使用QVariant. 对于 aint到 aQString你得到：
QVariant(3).toString();
A floatto a stringor a stringto a float:
Afloat到 astring或 astring到 a float：
QVariant(3.2).toString();
QVariant("5.2").toFloat();
回答by Matthew Kraus
Yet another option is to use QTextStreamand the <<operator in much the same way as you would use coutin C++:
另一种选择是以与在 C++ 中使用的方式大致相同的方式使用QTextStream和<<运算符cout：
QPoint point(5,1);
QString str;
QTextStream(&str) << "Mouse click: (" << point.x() << ", " << point.y() << ").";
// OUTPUT:
// Mouse click: (5, 1).
Because operator <<()has been overloaded, you can use it for multiple types, not just int. QString::arg()is overloaded, for example arg(int a1, int a2), but there is no arg(int a1, QString a2), so using QTextStream()and operator <<is convenient when formatting longer strings with mixed types.
由于运算符<<()已重载，因此您可以将其用于多种类型，而不仅仅是int. QString::arg()例如arg(int a1, int a2)，被重载，但没有arg(int a1, QString a2)，因此在使用混合类型格式化较长的字符串时，使用QTextStream()and 运算符<<很方便。
Caution:You might be tempted to use the sprintf()facility to mimic C style printf()statements, but it is recommended to use QTextStreamor arg()because they support Unicode strings.
注意：您可能想使用该sprintf()工具来模拟 C 风格的printf()语句，但建议使用QTextStream或arg()因为它们支持 Unicode strings。
回答by Narek
I always use QString::setNum().
我总是使用QString::setNum().
int i = 10;
double d = 10.75;
QString str;
str.setNum(i);
str.setNum(d);
setNum()is overloaded in many ways. See QStringclass reference.
setNum()在很多方面都超载了。请参阅QString类参考。
回答by liaK
In it's simplest form, use the answer of Georg Fritzsche
以最简单的形式，使用Georg Fritzsche的答案
For a bit advanced, you can use this,
对于有点高级，你可以使用这个，
QString QString::arg ( int a, int fieldWidth = 0, int base = 10, const QChar & fillChar = QLatin1Char( ' ' ) ) const
Get the documentation and an example here..
在此处获取文档和示例..
回答by Morgan
Just for completeness, you can use the standard library and do QString qstr = QString::fromStdString(std::to_string(42));
为了完整起见，您可以使用标准库并执行 QString qstr = QString::fromStdString(std::to_string(42));
回答by André
If you need locale-aware number formatting, use QLocale::toString instead.
如果您需要识别区域设置的数字格式，请改用 QLocale::toString。
