如何根據QSignalMapper獲取QList的索引

Question

我有QPushButton的QList和QSignalMapper來識別按下哪個按鈕。 所以我做了類似的事情（我的項目非常大，所以我只剪切了問題所需的行）

QList<QPushButton*> Buttons;
QList <QLabel*> LabelList1;
QList <QLabel*> LabelList2;
QList <QLabel*> LabelList3;
QList <QLabel*> LabelList4;
QSignalMapper *ButtonsMapper;
ButtonsMapper= new QSignalMapper(this);
connect(ButtonsMapper, SIGNAL(mapped(int)),this,SIGNAL(ButtonsClicked(int)));
connect(this, SIGNAL(ButtonsClicked(int)),this,SLOT(deleteButton(int)));

Buttons.append(new QPushButton(tr("0")));//first button 
LabelList1.append(new QLabel(tr("0")));
LabelList2.append(new QLabel(tr("0")));
LabelList3.append(new QLabel(tr("0")));
LabelList4.append(new QLabel(tr("0")));
QPushButton * pb1 = Buttons.last();//pointer to the last button
connect(pb1, SIGNAL(clicked()), ButtonsMapper, SLOT(map()));
ButtonsMapper->setMapping(pb1,0);

Buttons.append(new QPushButton(tr("1")));//second button
LabelList1.append(new QLabel(tr("1")));
LabelList2.append(new QLabel(tr("1")));
LabelList3.append(new QLabel(tr("1")));
LabelList4.append(new QLabel(tr("1"))); 
QPushButton * pb2 = Buttons.last();//pointer to the last button
connect(pb2, SIGNAL(clicked()), ButtonsMapper, SLOT(map()));
ButtonsMapper->setMapping(pb2,1);

並且按下了刪除按鈕的函數deleteButton 。 如果我做那樣的事情

void myclass::deleteButton(int i){ 
   delete (Buttons.takeAt(i));
   delete ( LabelList1.takeAt(i));
   delete ( LabelList2.takeAt(i));
   delete( LabelList3.takeAt(i));
   delete( LabelList4.takeAt(i));
    }

該函數可能導致index out of range錯誤，如果我刪除第一個按鈕，然后我按下第二個按鈕，函數Buttons.takeAt(i)指向不存在按鈕。

Answer 1

從理論上講，您可以保留指向信號映射器的指針，並在刪除后重新映射索引。

void myclass::deleteButton(int i){
    delete (Buttons.takeAt(i));
    for(int i = 0; i < Buttons.size(); ++i) {
        ButtonsMapper->setMapping(Buttons[i], i);
    }
}

Answer 2

我建議你對代碼進行一些修改：

QMap<QPushButton*,int> Buttons;
QSignalMapper *ButtonsMapper;
ButtonsMapper= new QSignalMapper(this);
connect(ButtonsMapper, SIGNAL(mapped(int)),this,SIGNAL(ButtonsClicked(int)));
connect(this, SIGNAL(ButtonsClicked(int)),this,SLOT(deleteButton(int)));

Buttons.insert (new QPushButton(tr("0")),0);//first button 
QPushButton * pb1 = Buttons.last();//pointer to the last button
connect(pb1, SIGNAL(clicked()), ButtonsMapper, SLOT(map()));
ButtonsMapper->setMapping(pb1,0);

Buttons.insert (new QPushButton(tr("1")),1);//second button 
QPushButton * pb2 = Buttons.last();//pointer to the last button
connect(pb2, SIGNAL(clicked()), ButtonsMapper, SLOT(map()));
ButtonsMapper->setMapping(pb2,1);

void myclass::deleteButton(int i){
    if (Buttons.contains(i))
    delete (Buttons[i]);  
}

Answer 3

您可以將QPushButton映射到QWidget *而不是將QPushButton映射到index（ int ）。

- ButtonsMapper->setMapping(pb1,0);
+ ButtonsMapper->setMapping(pb1, pb1);

然后插槽也會改變

void myclass::deleteButton(QWidget * widget){
    Buttons.removeOne(widget);
    delete widget;  
}