Qt C++ - 在 QSplashScreen 内对齐 QProgressBar

Question

我通过子类化 QSplashScreen 将 QProgressBar 放入 QSplashScreen 中。它覆盖了drawContents() 方法。

我以为我已经正确设置了几何图形，但它同时呈现在屏幕的顶部和底部。我不知道为什么。也许还有另一种对齐方式。数字是正确的，因为图像是 380x284，所以 19 高度的进度条应该向下 265 像素。

对于糟糕的图片，抱歉，启动画面没有显示打印屏幕按钮。目前它只是一个 1 色的白色闪屏，但正如您所见，顶部和底部的进度条（它们都是相同的颜色，是来自相机的照明）。

http://i.imgur.com/p1LoJ.jpg

另一个问题是 QSplashScreen 的 showMessage() 方法。我希望消息显示在进度条上方，右对齐...如果有人有任何想法如何做到这一点。

splashscreen.cpp

#include "splashscreen.h"

SplashScreen::SplashScreen(QApplication *app, QWidget *parent) :
    QSplashScreen(parent)
{
    this->app = app;

    this->setPixmap(QPixmap(":/images/splashscreen.png"));
    this->setCursor(Qt::BusyCursor);

    // if I dont make it a child, it *only* renders at the top
    progress = new QProgressBar(this); 
    progress->setGeometry(0, 265, 380, 19); // puts it at bottom
    progress->setAlignment(Qt::AlignHCenter | Qt::AlignVCenter);
    progress->setValue(0);
    progress->setMaximum(100);
    progress->setEnabled(true);

    this->showMessage("Hello", Qt::AlignBottom);

    connect(progress, SIGNAL(valueChanged(int)), this, SLOT(progressBarUpdated(int)));
}

void SplashScreen::drawContents(QPainter *painter)
{
    QSplashScreen::drawContents(painter);
    this->progress->render(painter);
}

void SplashScreen::progressBarUpdated(int value)
{
    this->repaint();
    this->app->processEvents();
}

splashscreen.h

#ifndef SPLASHSCREEN_H
#define SPLASHSCREEN_H

#include <QSplashScreen>
#include <QProgressBar>
#include <QApplication>

class SplashScreen : public QSplashScreen
{
    Q_OBJECT
public:
    explicit SplashScreen(QApplication *app, QWidget *parent = 0);
    QProgressBar *progress;
    QWidget *spacer;
    QApplication *app;

public slots:
    void progressBarUpdated(int value);

protected:
    void drawContents(QPainter *painter);

};

#endif // SPLASHSCREEN_H

main.cpp

#include <QtGui/QApplication>
#include <time.h>

#include "splashscreen.h"
#include "mainwindow.h"

int main(int argc, char *argv[])
{
    srand(time(0));
    QApplication a(argc, argv);

    SplashScreen *splash = new SplashScreen(&a);
    splash->show();

    // snip.. loading a ton of stuff into memory at startup 
    // if you're testing this you might have to sleep/timer here iono

    MainWindow w;
    splash->finish(&w);
    w.show();

    return app.exec();
}

Answer 1

您可以直接绘制进度，无需创建 QProgressBar。例如：

sp.h:

#ifndef SPLASHSCREEN_H
#define SPLASHSCREEN_H

#include <QSplashScreen>
#include <QApplication>

class SplashScreen : public QSplashScreen
{
    Q_OBJECT
public:
    explicit SplashScreen(QApplication *app, QWidget *parent = 0);
    int m_progress;
    QApplication *app;

public slots:
    void setProgress(int value)
    {
      m_progress = value;
      if (m_progress > 100)
        m_progress = 100;
      if (m_progress < 0)
        m_progress = 0;
      update();
    }

protected:
    void drawContents(QPainter *painter);

};

#endif // SPLASHSCREEN_H

sp.cpp

#include "sp.h"

SplashScreen::SplashScreen(QApplication *aApp, QWidget *parent) :
    QSplashScreen(parent), app(aApp), m_progress(0)

{
    this->setPixmap(QPixmap(":/images/splashscreen.png"));
    this->setCursor(Qt::BusyCursor);

    this->showMessage("Hello", Qt::AlignBottom);
}

void SplashScreen::drawContents(QPainter *painter)
{
  QSplashScreen::drawContents(painter);

  // Set style for progressbar...
  QStyleOptionProgressBarV2 pbstyle;
  pbstyle.initFrom(this);
  pbstyle.state = QStyle::State_Enabled;
  pbstyle.textVisible = false;
  pbstyle.minimum = 0;
  pbstyle.maximum = 100;
  pbstyle.progress = m_progress;
  pbstyle.invertedAppearance = false;
  pbstyle.rect = QRect(0, 265, 380, 19); // Where is it.

  // Draw it...
  style()->drawControl(QStyle::CE_ProgressBar, &pbstyle, painter, this);
}

也许这对你有帮助。