Question

我对QMediaPlayer的工作原理有一些根本的误解。我认为如果我一个接一个地播放两个音轨，那么应该只播放最后一个。但是有时候顺序是错误的，我听到的是第一首曲目，而不是第二首曲目（单击了第一和第三按钮）。但是在放袋里，我总是看到正确的顺序。您会如何建议我解决这个问题？

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) {
  ui->setupUi(this);
  player = new QMediaPlayer(this);

  connect(player, &QMediaPlayer::mediaStatusChanged, this, [this](auto status) {
    QMediaPlayer *ptr = qobject_cast<QMediaPlayer *>(sender());
    qDebug() << "mediaStatusChanged: " << status << " currentMedia:" << ptr->currentMedia().request().url().fileName();
  });
  connect(player, &QMediaPlayer::stateChanged, this, [this](auto status) {
    QMediaPlayer *ptr = qobject_cast<QMediaPlayer *>(sender());
    qDebug() << "stateChanged: " << status << " currentMedia:" << ptr->currentMedia().request().url().fileName();
  });
}

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

void MainWindow::on_pushButton_clicked() {
  qDebug() << "     pushButton clicked";
  QString trackPath1 = QDir::currentPath() + "/track1.mp3";
  QString trackPath2 = QDir::currentPath() + "/track2.mp3";

  player->setMedia((QUrl::fromLocalFile(trackPath1)));
  player->play();

  player->stop();

  player->setMedia((QUrl::fromLocalFile(trackPath2)));
  player->play();
}

调试输出：

     pushButton clicked
mediaStatusChanged:  QMediaPlayer::LoadingMedia  currentMedia: "track1.mp3"
stateChanged:  QMediaPlayer::PlayingState  currentMedia: "track1.mp3"
stateChanged:  QMediaPlayer::StoppedState  currentMedia: "track1.mp3"
stateChanged:  QMediaPlayer::PlayingState  currentMedia: "track2.mp3"
mediaStatusChanged:  QMediaPlayer::BufferedMedia  currentMedia: "track2.mp3"
mediaStatusChanged:  QMediaPlayer::EndOfMedia  currentMedia: "track2.mp3"
stateChanged:  QMediaPlayer::StoppedState  currentMedia: "track2.mp3"
     pushButton clicked
mediaStatusChanged:  QMediaPlayer::LoadingMedia  currentMedia: "track1.mp3"
stateChanged:  QMediaPlayer::PlayingState  currentMedia: "track1.mp3"
stateChanged:  QMediaPlayer::StoppedState  currentMedia: "track1.mp3"
stateChanged:  QMediaPlayer::PlayingState  currentMedia: "track2.mp3"
mediaStatusChanged:  QMediaPlayer::StalledMedia  currentMedia: "track2.mp3"
mediaStatusChanged:  QMediaPlayer::BufferedMedia  currentMedia: "track2.mp3"
mediaStatusChanged:  QMediaPlayer::EndOfMedia  currentMedia: "track2.mp3"
stateChanged:  QMediaPlayer::StoppedState  currentMedia: "track2.mp3"
     pushButton clicked
mediaStatusChanged:  QMediaPlayer::LoadingMedia  currentMedia: "track1.mp3"
stateChanged:  QMediaPlayer::PlayingState  currentMedia: "track1.mp3"
stateChanged:  QMediaPlayer::StoppedState  currentMedia: "track1.mp3"
stateChanged:  QMediaPlayer::PlayingState  currentMedia: "track2.mp3"
mediaStatusChanged:  QMediaPlayer::StalledMedia  currentMedia: "track2.mp3"
mediaStatusChanged:  QMediaPlayer::BufferedMedia  currentMedia: "track2.mp3"
mediaStatusChanged:  QMediaPlayer::EndOfMedia  currentMedia: "track2.mp3"
stateChanged:  QMediaPlayer::StoppedState  currentMedia: "track2.mp3"

QMediaPlayer播放曲目顺序错误

0 个答案: