qtmplayer/mainwindow.cpp

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

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    initMainWindow(); // 初始化主界面
    mplayerInit(); // 初始化 mplayer
}

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

void MainWindow::initMainWindow()
{
    // 设置主窗体属性
    setWindowTitle("音乐播放器");

    // 设置子组件背景透明
    ui->song_list_widget->setAttribute(Qt::WA_TranslucentBackground);
    ui->label_artist->setAttribute(Qt::WA_TranslucentBackground);
    ui->label_song_list->setAttribute(Qt::WA_TranslucentBackground);
    ui->label_song_name->setAttribute(Qt::WA_TranslucentBackground);
    ui->label_meta_album->setAttribute(Qt::WA_TranslucentBackground);
    ui->contrl_widget->setAttribute(Qt::WA_TranslucentBackground);
    ui->widget_show->setAttribute(Qt::WA_TranslucentBackground);
    ui->volume_widget->setAttribute(Qt::WA_TranslucentBackground);
    ui->widget_3->setAttribute(Qt::WA_TranslucentBackground);
    ui->time_left_label->setAttribute(Qt::WA_TranslucentBackground);
    ui->time_right_label->setAttribute(Qt::WA_TranslucentBackground);
    ui->time_widget->setAttribute(Qt::WA_TranslucentBackground);

    // 设置滑块属性
    ui->time_slider->setStyleSheet("QSlider::groove:horizontal { background-color: white; }"
                                   "QSlider::handle:horizontal { background-color: blue; width: 20px;}");
    ui->volume_slider->setStyleSheet("QSlider::groove:horizontal { background-color: gray; }"
                                     "QSlider::handle:horizontal { background-color: yellow; width: 20px;}");
    ui->volume_slider->setMinimum(0); // 最小音量 0
    ui->volume_slider->setMaximum(100); // 最大音量 100
    // 当前音量从 mplayer 属性获取

    //    QSlider* slider = new QSlider(Qt::Horizontal);
    //    slider->setMinimum(0);      // 设置最小值
    //    slider->setMaximum(100);    // 设置最大值
    //    slider->setValue(50);       // 设置当前值
    //    slider->setSingleStep(1);   // 设置步长

}

void MainWindow::mplayerInit()
{
    // 创建一个无名管道
    int fd[2];
    pipe(fd);

    // 创建有名管道
    mkfifo("fifo_cmd",0666);

    // 创建 子进程启动 mplayer
    pid_t pid = fork();
    if(pid == 0) // 子进程
    {
        // 重定向标准输出
        dup2(fd[1],1);
        // 使用 exec 启动 mplayer
//        execlp("mplayer","mplayer","-idle","-slave","-quiet","/home/flykhan/qtmplayer/song/StopLove.mp3",NULL);
        execlp("mplayer","mplayer","-idle","-slave","-quiet","-input","file=fifo_cmd","/home/flykhan/qtmplayer/song/StopLove.mp3",NULL);
        _exit(-1); // 异常退出
    }
    else if(pid>0) // 父进程
    {
        // 打开管道
        // 以写的方式打开(阻塞到某进程 以读的方式打开)
        int fifo_fd = open("fifo_cmd",O_WRONLY);
        if(fifo_fd < 0){
            perror("open");
//            return 0;
            _exit(-1);
        }
    }
}