c++ - 从未命名的 QGraphicsTextItem 中获取文本

Question

我和我的一个 friend 目前正在尝试使用 Qt 在 C++ 中制作游戏。我们当前的问题是，我们需要从按钮 mousePressEvent 上的 QGraphicsTextItem 获取文本。在游戏菜单中，可以选择有多少玩家，因此我们在 for 循环中放置了一个 QGraphicsTextItem，以便所有用户都可以输入他们的名字。由于 for 循环，我们没有每个文本项对象的名称，因此我们可以存储这些名称。我们已经设法使用 QMap 将所有内存地址存储到对象，但我们不知道如何获取其文本。我们甚至不知道这是否是最好的方法。

GameInfo.h

class GameInfo {
public:
    GameInfo();
    int players;

    QStringList names = (QStringList() // Default player names. This array should be overwritten by the custom names
        << "Player 1"
        << "Player 2"
        << "Player 3"
        << "Player 4"
        << "Player 5"
        << "Player 6"
        << "Player 7");

    QMap<int, QGraphicsTextItem**> textBoxMap; // This is where we store all the addresses
};

Game.cpp

    QGraphicsRectItem * overviewBox = new QGraphicsRectItem();
    overviewBox->setRect(0, 0, 782, 686);
    scene->addItem(overviewBox);

    int faceNo = 0;

// Create the player selection section
    for(int i = 1; i <= players; i++) { // "players" is defined another place in the code, and is an integer between 1 and 6
        Container * selContainer = new Container();
        selContainer->Selection(i, faceNo);
        selContainer->setPos(50, 70 + 110 * (i - 1));
        scene->addItem(selContainer);
        Container * ovContainer = new Container(overviewBox);
        ovContainer->Overview(i, faceNo);
        ovContainer->setPos(0, 0 + 110 * (i - 1));

        info->textBoxMap.insert(i, &selContainer->textBox->playerText); // This is where we save the addresses
    }

Selection.cpp

extern Game * game;

Container::Container(QGraphicsItem * parent): QGraphicsRectItem(parent) {

}

void Container::Selection(int nPlayers, int sPiceNo, QGraphicsItem *parent) {

    QString numName = QString::number(nPlayers);

    setRect(0, 0, 672, 110);
    this->setPen(Qt::NoPen); // Removes border

    int posY = this->rect().height() / 2;

    QSignalMapper * signalMapper = new QSignalMapper(this);

    arrowL = new Arrow(0, posY - 32, 0, this);
    piece = new Piece(sPiceNo, 96, posY - 32, 1, 1, this);
    arrowR = new Arrow(192, posY - 32, 1, this);
    textBox = new TextBox(game->info->names[nPlayers - 1], true, this);
    textBox->setPos(288, posY - 32);
    lockBtn = new Button("Lock", 96, 32, this);
    connect(lockBtn, SIGNAL(clicked()), signalMapper, SLOT(map()));
    signalMapper->setMapping(lockBtn, nPlayers);
    connect(signalMapper, SIGNAL(mapped(int)), this, SLOT(lock(int)));
    lockBtn->setPos(640, posY - 16);

}


void Container::Overview(int ovPlayers, int ovPiceNo, QGraphicsItem * parent) {
    // Some code...
}

void Container::lock(int nPlayer) {
    qDebug() << game->info->textBoxMap[nPlayer];
    qDebug() << game->info->names[nPlayer - 1];

    game->info->names[nPlayer - 1] = **game->info->textBoxMap[nPlayer].toPlainText(); // This line causes an error
}

由于最后一行而发生的错误如下所示:

error: no match for 'operator=' (operand types are 'QString' and 'QGraphicsTextItem')
 game->info->names[nPlayer - 1] = **game->info->textBoxMap[nPlayer];
                                ^

TextBox.cpp

TextBox::TextBox(QString text, bool editable, QGraphicsItem * parent): QGraphicsRectItem(parent) {
    this->editable = editable;

// Draw the textbox
    setRect(0, 0, 320, 64);
    if(!editable) {
        this->setPen(Qt::NoPen); // Removes border
    }
    else if(editable) {
        QBrush brush;
        brush.setStyle(Qt::SolidPattern);
        brush.setColor(QColor(255, 255, 255, 255));
        setBrush(brush);
    }

// Draw the text
    playerText = new QGraphicsTextItem(text, this);
    int fontId = QFontDatabase::addApplicationFont(":/fonts/built_titling_bd.ttf");

    QString family = QFontDatabase::applicationFontFamilies(fontId).at(0);
    QFont built(family, 25);
    playerText->setFont(built);
    int xPos = 0;
    int yPos = rect().height() / 2 - playerText->boundingRect().height() / 2;
    playerText->setPos(xPos,yPos);
}

我的问题是如何从 QGraphicsTextItem 中获取文本？

Answer 1

在尝试开发游戏之前，您应该尝试更多地了解 C++。 (拥有公共(public)变量违反了 OO 和 C++ 范式)

但这就是您要寻找的: http://doc.qt.io/qt-5/qgraphicstextitem.html#toPlainText

编辑:

如果您无法调试某行代码，我只能建议尝试将您的代码分开，以便在一行中进行最少的调用。我没有尝试过下面的代码，但是你应该如何尝试调试你的代码:

    void Container::lock(int nPlayer)
    {
       qDebug() << game->info->textBoxMap[nPlayer];
       qDebug() << game->info->names[nPlayer - 1];
       QGraphicsTextItem **value = game->info->textBoxMap.value(nPlayer, nullptr);
       game->info->names[nPlayer - 1] =(*value)->toPlainText();
    }