在Qt中显示UTF字符

Question

我有一个简单的程序，我需要显示日文字符。它有点奇怪的行为（在我看来），有时它会显示字符，有时它会像方格一样显示。

我的程序逻辑是启动向量，包含字母InitAlphabet();，然后随机选择一个字符painter.drawStaticText(0, 0, alphabet[randomNumb]);。

你能告诉我为什么会这样吗？ 代码：

private:
    Ui::Widget *ui;
    QVector<QString> alphabet;
    QVector<QString> translation;
    int randomNumb;

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void Widget::InitAlphabet()
{
    alphabet.push_back("あ");
    alphabet.push_back("い");
    alphabet.push_back("う");
    alphabet.push_back("え");
    alphabet.push_back("お");
    alphabet.push_back("か");
    alphabet.push_back("き");
    alphabet.push_back("く");
    alphabet.push_back("け");
    alphabet.push_back("こ");
    alphabet.push_back("さ");
    alphabet.push_back("し");
    alphabet.push_back("す");
    alphabet.push_back("せ");
    alphabet.push_back("そ");
    alphabet.push_back("た");
    alphabet.push_back("ち");
    alphabet.push_back("つ");
    alphabet.push_back("て");
    alphabet.push_back("と");
    alphabet.push_back("な");
    alphabet.push_back("に");
    alphabet.push_back("ぬ");
    alphabet.push_back("ね");
    alphabet.push_back("の");
    alphabet.push_back("は");
    alphabet.push_back("ひ");
    alphabet.push_back("ふ");
    alphabet.push_back("へ");
    alphabet.push_back("ほ");
    alphabet.push_back("ま");
    alphabet.push_back("み");
    alphabet.push_back("む");
    alphabet.push_back("め");
    alphabet.push_back("も");
    alphabet.push_back("や");
    alphabet.push_back("ゆ");
    alphabet.push_back("よ");
    alphabet.push_back("ら");
    alphabet.push_back("り");
    alphabet.push_back("る");
    alphabet.push_back("れ");
    alphabet.push_back("ろ");
    alphabet.push_back("わ");
    alphabet.push_back("ん");
}

---

int Widget::getRandomNumber()
{
    return qrand() % alphabet.length();
}

void Widget::paintEvent(QPaintEvent *)
{
    QPainter painter(this);
    painter.drawStaticText(0, 0, alphabet[randomNumb]);
   // painter.drawStaticText(50, 50, translation[randomNumb]);
}

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