Qt login，自动识别焦点
代码说明：
#include "mainwindow.h" #include "ui_mainwindow.h" MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) { ui->setupUi(this); pushButton = new QPushButton(this); pushButton->setObjectName(QString::fromUtf8("pushButton")); pushButton->setGeometry(QRect(40, 180, 51, 27)); pushButton_2 = new QPushButton(this); pushButton_2->setObjectName(QString::fromUtf8("pushButton_2")); pushButton_2->setGeometry(QRect(40, 140, 51, 27)); pushButton_3 = new QPushButton(this); pushButton_3->setObjectName(QString::fromUtf8("pushButton_3")); pushButton_3->setGeometry(QRect(100, 140, 51, 27)); &
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