UI设计流程图

UI设计界面

• 主界面
  

• 控制条
  

• 播放列表
  

• 画面显示
  

• 标题栏
  

• 设置界面
  

• 提示框
  

点击播放功能实现

槽函数实现：
connect(ui->ctrlBarWind, &CtrlBar::SigPlayOrPause, this, &MainWind::OnPlayOrPause);

ctrbar.h

class CtrlBar : public QWidget
{
    Q_OBJECT

public:
    explicit CtrlBar(QWidget *parent = 0);
    ~CtrlBar();
signals:
    void SigPlayOrPause();      // 先实现这个

private slots:
    void on_playOrPauseBtn_clicked();

    void on_stopBtn_clicked();

private:
    Ui::CtrlBar *ui;
};

ctrbar.cpp

CtrlBar::CtrlBar(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::CtrlBar)
{
    ui->setupUi(this);
}

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

void CtrlBar::on_playOrPauseBtn_clicked()
{
    qDebug() << "on_playOrPauseBtn_clicked";
    emit SigPlayOrPause();      // 发送信号
}

mainwid.h

class MainWind : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWind(QWidget *parent = 0);
    ~MainWind();
    int InitSignalsAndSlots();
    void OnPlayOrPause();
private:
    Ui::MainWind *ui;
    IjkMediaPlayer *mp_ = NULL;
};

mainwind.cpp

MainWind::MainWind(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWind)
{
    ui->setupUi(this);

    // 初始化信号槽相关的
    InitSignalsAndSlots();
}

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

int MainWind::InitSignalsAndSlots()
{
    connect(ui->ctrlBarWind, &CtrlBar::SigPlayOrPause, this, &MainWind::OnPlayOrPause);
}

int MainWind::message_loop(void *arg)
{
    IjkMediaPlayer *mp = (IjkMediaPlayer *)arg;
  
    while (1) {
        AVMessage msg;
        int retval = mp->ijkmp_get_msg(&msg, 1);    
        if (retval < 0)
            break;
        switch (msg.what) {
              
        case FFP_MSG_PREPARED:
            mp->ijkmp_start();
            break;
        default:
          break;
        }
        msg_free_res(&msg);
}
      
void MainWind::OnPlayOrPause()
{
    int ret = 0;
    // 1. 先检测mp是否已经创建
    if(!mp_) {
        mp_ = new IjkMediaPlayer();
        //1.1 创建
        ret = mp_->ijkmp_create(std::bind(&MainWind::message_loop, this, std::placeholders::_1));
        if(ret <0) {
            delete mp_;
            mp_ = NULL;
            return;
        }
        // 1.2 设置url
        mp_->ijkmp_set_data_source("m1.mp3");
        // 1.3 准备工作
        ret = mp_->ijkmp_prepare_async();
        if(ret <0) {
            delete mp_;
            mp_ = NULL;
            return;
        }
    } else {
        // 已经准备好了，则暂停或者恢复播放
    }
}