如何在Qt中向主窗口添加按钮？

Question

我是qt编程的新手,所以如果你发现它是一个noob问题请不要介意.我在主窗口中添加了一个按钮,但是当我运行代码时,按钮不会显示.这是我的代码:

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtWidgets>

MainWindow::MainWindow(QWidget *parent)
{
QPushButton *train_button = new QPushButton(this);
train_button->setText(tr("something"));
train_button->move(600, 600);
train_button->show();
}

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow  
{  
Q_OBJECT

public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();

private:
Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H


MainWindow::~MainWindow()
{
delete ui;
}

我该怎么办？

Answer 1

在主窗口中,您应该使用中央小部件.你有两个选择:

设置中央小部件的按钮(不太好选择):

QPushButton *train_button = new QPushButton(this);
train_button->setText(tr("something"));
setCentralWidget(train_button);

添加一个小部件并将该按钮添加到该小部件并为centralWidget设置小部件:

QWidget * wdg = new QWidget(this);
QPushButton *train_button = new QPushButton(wdg);
train_button->setText(tr("something"));
setCentralWidget(wdg);

当然,您可以使用布局为您的centralWidget:

QWidget * wdg = new QWidget(this);
QVBoxLayout *vlay = new QVBoxLayout(wdg);
QPushButton *btn1 = new QPushButton("btn1");
vlay->addWidget(btn1);
QPushButton *btn2 = new QPushButton("btn2");
vlay->addWidget(btn2);
QPushButton *btn3 = new QPushButton("btn3");
vlay->addWidget(btn3);
wdg->setLayout(vlay);
setCentralWidget(wdg);