問(wèn)題描述

我有一個(gè)二維數(shù)組 QPushButton，當(dāng)用戶點(diǎn)擊按鈕時(shí)，如何獲取按鈕的索引?例如當(dāng)用戶點(diǎn)擊按鈕 a[2][3] 它會(huì)顯示 (2,3) ?

I have an 2D array QPushButton, how can I get index of the button when user clicks on its? such as When user clicks on the button a[2][3] it will show (2,3) ?

推薦答案

示例如下:

您可以為按鈕指定唯一的對(duì)象名稱.理想情況下，名稱應(yīng)該是有效的 C++ 標(biāo)識(shí)符.

You can give your buttons unique object names. The names should ideally be valid C++ identifiers.

// https://github.com/KubaO/stackoverflown/tree/master/questions/button-grid-22641306
#include <QtGui>
#if QT_VERSION_MAJOR >= 5
#include <QtWidgets>
#endif

struct Display : QLabel {
   Q_SLOT void onClicked() {
      auto const elements = sender()->objectName().split('_');
      auto const i = elements.at(1).toInt();
      auto const j = elements.at(2).toInt();
      setText(QString{"(%1,%2)"}.arg(i).arg(j));
   }
   Q_OBJECT
};

int main(int argc, char *argv[])
{
   QApplication a{argc, argv};
   QWidget window;
   QGridLayout layout{&window};
   QVarLengthArray<QPushButton, 12> buttons(12);
   Display display;

   const int rows = 4, columns = 3;
   for (int i = 0; i < rows; ++ i)
      for (int j = 0; j < columns; ++j) {
         auto & button = buttons[i*columns+j];
         button.setText(QString{"(%1,%2)"}.arg(i).arg(j));
         button.setObjectName(QString{"buton_%1_%2"}.arg(i).arg(j));
         layout.addWidget(&button, i, j);
         display.connect(&button, SIGNAL(clicked()), SLOT(onClicked()));
      }
   layout.addWidget(&display, rows, 0, 1, columns);

   window.show();
   return a.exec();
}
#include "main.moc"

Qt 5 - 使用 Lambda

在 Qt 5 和 C++11 中，您應(yīng)該使用函子為每個(gè)按鈕即時(shí)生成自定義槽.例如:

Qt 5 - Using Lambdas

In Qt 5 and C++11, you should use functors to generate custom slot for each button, on the fly. For example:

// https://github.com/KubaO/stackoverflown/tree/master/questions/button-grid-22641306
#include <QtWidgets>

int main(int argc, char *argv[])
{
   QApplication a{argc, argv};
   QWidget window;
   QGridLayout layout{&window};
   QVarLengthArray<QPushButton, 12> buttons(12);
   QLabel display;

   const int rows = 4, columns = 3;
   for (int i = 0; i < rows; ++ i)
      for (int j = 0; j < columns; ++j) {
         auto text = QStringLiteral("(%1,%2)").arg(i).arg(j);
         auto & button = buttons[i*columns+j];
         button.setText(text);
         layout.addWidget(&button, i, j);
         QObject::connect(&button, &QPushButton::clicked, [&display, text] {
            display.setText(text);
         });
      }
   layout.addWidget(&display, rows, 0, 1, columns);

   window.show();
   return a.exec();
}

Qt 4/5 - 使用 QSignalMapper

QSignalMapper 非常適合您的需求.它允許您將 QObject* 映射到其他東西"，例如字符串.例如:

Qt 4/5 - Using QSignalMapper

QSignalMapper is pretty much designed for what you want. It lets you map a QObject* to "something else", like a string. For example:

#include <QtGui>
#if QT_VERSION_MAJOR >= 5
#include <QtWidgets>
#endif

int main(int argc, char *argv[])
{
   QApplication a{argc, argv};
   QSignalMapper mapper;
   QWidget window;
   QGridLayout layout{&window};
   QVarLengthArray<QPushButton, 12> buttons(12);
   QLabel display;

   const int rows = 4, columns = 3;
   for (int i = 0; i < rows; ++ i)
      for (int j = 0; j < columns; ++j) {
         auto text = QString{"(%1,%2)"}.arg(i).arg(j);
         auto & button = buttons[i*columns+j];
         button.setText(text);
         layout.addWidget(&button, i, j);
         mapper.connect(&button, SIGNAL(clicked()), SLOT(map()));
         mapper.setMapping(&button, text);
      }
   display.connect(&mapper, SIGNAL(mapped(QString)), SLOT(setText(QString)));
   layout.addWidget(&display, rows, 0, 1, columns);

   window.show();
   return a.exec();
}

Qt 4/5 - 使用屬性系統(tǒng)

您可以利用 QWidget 是 QObject 的事實(shí).QObjects 有一個(gè)屬性系統(tǒng)，因此您可以將每個(gè)按鈕的索引設(shè)置為一個(gè)屬性，然后在連接到 clicked() 信號(hào)的插槽中檢索它.例如:

Qt 4/5 - Using the Property System

You can leverage the fact that a QWidget is a QObject. QObjects have a property system, so you can set each button's index as a property, and then retrieve it in the slot connected to the clicked() signal. For example:

#include <QtGui>
#if QT_VERSION_MAJOR >= 5
#include <QtWidgets>
#endif

const char kIndex[] = "index";
struct Display : QLabel {
   Q_SLOT void onClicked() {
      setText(sender()->property(kIndex).toString());
   }
   Q_OBJECT
};

int main(int argc, char *argv[])
{
   QApplication a{argc, argv};
   QWidget window;
   QGridLayout layout{&window};
   QVarLengthArray<QPushButton, 12> buttons(12);
   Display display;

   const int rows = 4, columns = 3;
   for (int i = 0; i < rows; ++ i)
      for (int j = 0; j < columns; ++j) {
         auto index = QString{"(%1,%2)"}.arg(i).arg(j);
         auto & button = buttons[i*columns+j];
         button.setText(index);
         button.setProperty(kIndex, index);
         layout.addWidget(&button, i, j);
         display.connect(&button, SIGNAL(clicked()), SLOT(onClicked()));
      }
   layout.addWidget(&display, rows, 0, 1, columns);

   window.show();
   return a.exec();
}
#include "main.moc"

這篇關(guān)于獲取二維數(shù)組 QPushButton 上 QPushButton 的索引的文章就介紹到這了，希望我們推薦的答案對(duì)大家有所幫助，也希望大家多多支持html5模板網(wǎng)！