tr（“\ 302 \ 261”）在Qt中的含义是什么？

Question

我正在关注http://doc.qt.io/qt-5/qtwidgets-widgets-calculator-example.html的Qt计算器示例。我遇到了下面的代码。

for (int i = 0; i < NumDigitButtons; ++i) {
    digitButtons[i] = createButton(QString::number(i), SLOT(digitClicked()));
}

Button *pointButton = createButton(tr("."), SLOT(pointClicked()));
Button *changeSignButton = createButton(tr("\302\261"), SLOT(changeSignClicked()));

Button *backspaceButton = createButton(tr("Backspace"), SLOT(backspaceClicked()));
Button *clearButton = createButton(tr("Clear"), SLOT(clear()));
Button *clearAllButton = createButton(tr("Clear All"), SLOT(clearAll()));

Button *clearMemoryButton = createButton(tr("MC"), SLOT(clearMemory()));
Button *readMemoryButton = createButton(tr("MR"), SLOT(readMemory()));
Button *setMemoryButton = createButton(tr("MS"), SLOT(setMemory()));
Button *addToMemoryButton = createButton(tr("M+"), SLOT(addToMemory()));

Button *divisionButton = createButton(tr("\303\267"), SLOT(multiplicativeOperatorClicked()));
Button *timesButton = createButton(tr("\303\227"), SLOT(multiplicativeOperatorClicked()));
Button *minusButton = createButton(tr("-"), SLOT(additiveOperatorClicked()));
Button *plusButton = createButton(tr("+"), SLOT(additiveOperatorClicked()));

Button *squareRootButton = createButton(tr("Sqrt"), SLOT(unaryOperatorClicked()));
Button *powerButton = createButton(tr("x\302\262"), SLOT(unaryOperatorClicked()));
Button *reciprocalButton = createButton(tr("1/x"), SLOT(unaryOperatorClicked()));
Button *equalButton = createButton(tr("="), SLOT(equalClicked()));

但是，我无法理解tr("\302\261")，tr("\303\267")，tr("x\302\262")mean来自下面的行。

Button *changeSignButton = createButton(tr("\302\261"), SLOT(changeSignClicked()));
Button *divisionButton = createButton(tr("\303\267"), SLOT(multiplicativeOperatorClicked()));
Button *powerButton = createButton(tr("x\302\262"), SLOT(unaryOperatorClicked()));

当我删除\303\267时，我发现÷符号消失了。所以我猜它与分裂按钮有某种关系。

我不知道\ 303 \ 267如何与分裂有关。我搜索了Qt文档页面，一无所获。

我的问题是：

在这个例子中，tr("\302\261")，tr("\303\267")和tr("x\302\262")是什么意思？

Answer 1

tr()函数用于（可选）将给定字符串转换为其他语言。来自this answer available on Qt forum：

如果您希望应用程序具有多种语言支持，请将代码中的每个用户可见字符串包装在tr（）函数中。然后Qt将在不同的语言环境中使用适当的翻译字符串。当然Qt实际上不会为你翻译，你（或你的翻译家伙）必须用QtLinguist来做。

传递给tr()函数的字符串是UTF-8字符的八进制代码。如你所知，\303\267是÷。 \302\261是±，x\302\262意味着x的力量为2（x后跟上标两个字符）。