如何在這樣的QLineEdit中製作額外的圖標？

Question

我想實現一個「乾淨」的按鈕，像Qt Creator中下面的截圖，按鈕住在QLineEdit的，而不是單一部件

我應該在哪裏開始？

Answer 1

見提議的解決方案 http://blog.qt.digia.com/blog/2007/06/06/lineedit-with-a-clear-button/

由於原鏈接這篇博客已不存在，我提供了一個新的代碼片段。

主要想法是將QToolButton添加到QLineEdit並正確定位。

LineEdit::LineEdit(QWidget *parent) 
    : QLineEdit(parent) 
{ 
    int height = sizeHint().height(); 
    int btnSize = sizeHint().height() - 5; 

    clearButton = new QToolButton(this); 
    QPixmap pixmap(":clear.png"); 
    clearButton->setIcon(QIcon(pixmap)); 
    clearButton->setCursor(Qt::ArrowCursor); 
    clearButton->setStyleSheet("QToolButton { border: none; padding: 2px}"); 
    clearButton->setFixedSize(btnSize, btnSize); 
    clearButton->hide(); 

    int frameWidth = style()->pixelMetric(QStyle::PM_DefaultFrameWidth); 
    setStyleSheet(QString("QLineEdit { padding-right: %1px }") 
               .arg(btnSize - frameWidth)); 
    setMinimumHeight(height); 

    connect(clearButton, SIGNAL(clicked()), this, SLOT(clear())); 
    connect(this, SIGNAL(textChanged(const QString&)), 
      this, SLOT(updateCloseButton(const QString&))); 
} 

void LineEdit::resizeEvent(QResizeEvent *) 
{ 
    int frameWidth = style()->pixelMetric(QStyle::PM_DefaultFrameWidth); 
    clearButton->move(width() - clearButton->width() - frameWidth, 0); 
} 

void LineEdit::updateCloseButton(const QString& text) 
{ 
    clearButton->setVisible(!text.isEmpty()); 
} 

另外，由於Qt的5.2，可以使用QLineEdit內置方法setClearButtonEnabled。 http://doc.qt.io/qt-5/qlineedit.html#clearButtonEnabled-prop