QLineEdit 按回车/失去焦点

server/2025/1/15 12:04:33/

1、目的

因为QLineEdit在写值时回车和失去焦点都会发出editingFinished，现在自定义控件回车或失去焦点并且值有改变才会处理一次，并能够处理的int或double型数据去除多余的0。

2、方法

处理回车应该重写控件事件keyPressEvent函数，失去焦点应该重写focusOutEvent函数，并再回车时调用clearFocus从而触发失去焦点事件；至于去掉多余0就很简单了，只需将字符串传成int或double再转成字符串。

3、效果

在这里插入图片描述

4、源代码

a.头文件

#ifndef CUSTOMLINEEDIT_H
#define CUSTOMLINEEDIT_H#include <QKeyEvent>
#include <QLineEdit>class CustomLineEdit : public QLineEdit {Q_OBJECTpublic:enum NumericType {IntType = 0,DoubleType,};CustomLineEdit(NumericType numerciType, QWidget *parent = Q_NULLPTR);CustomLineEdit(NumericType numerciType, QString initText,QWidget *parent = Q_NULLPTR);signals:void editFinishedAndChanged();  // 编辑完成并改变值protected:void keyPressEvent(QKeyEvent *event) Q_DECL_OVERRIDE;void focusOutEvent(QFocusEvent *event) Q_DECL_OVERRIDE;private:void dealData();QString removeSurplusZeros(const QString &value);private:QString pre_Text_;                    // 前一个值NumericType numeric_Type_ = IntType;  // 控件数据
};#endif  // CUSTOMLINEEDIT_H

b.头文件

#include "customlineedit.h"CustomLineEdit::CustomLineEdit(NumericType numerciType, QWidget *parent): CustomLineEdit(numerciType, "", parent) {}CustomLineEdit::CustomLineEdit(NumericType numerciType, QString initText,QWidget *parent): QLineEdit(initText, parent),numeric_Type_(numerciType),pre_Text_(initText) {}void CustomLineEdit::keyPressEvent(QKeyEvent *event) {// 处理回车if (event->key() == Qt::Key_Enter || event->key() == Qt::Key_Return) {clearFocus();  // 按回车后让控件失去焦点，触发失去焦点focusOutEvent}QLineEdit::keyPressEvent(event);
}void CustomLineEdit::focusOutEvent(QFocusEvent *event) {// 处理失去焦点dealData();QLineEdit::focusOutEvent(event);
}void CustomLineEdit::dealData() {if (text().isEmpty()) {setText(pre_Text_);} else {setText(removeSurplusZeros(text()));}if (pre_Text_ != text()) {emit editFinishedAndChanged();pre_Text_ = text();}
}QString CustomLineEdit::removeSurplusZeros(const QString &value) {// 移除多余0，并判断范围是否超出则返回QString retValue;switch (numeric_Type_) {case IntType: {bool ok;int num = value.toInt(&ok);if (!ok) {// 转换失败，返回原字符串retValue = value;} else {retValue = QString::number(num);}} break;case DoubleType: {bool ok;double num = value.toDouble(&ok);if (!ok) {// 转换失败，返回原字符串retValue = value;} else {// 这注意double转QString的精度问题retValue = QString::number(num, 'g', 10);}} break;default: {retValue = value;} break;}return retValue;
}