Dasturlash II 15-hafta mavzu: qt muhitida multimediyali fayllar bilan ishlash

#include
#include
#include
#include
#include

2. 
   Keyin, QMediaPlayer ko`rsatgichi bo`ladigan player o`zgaruvchisini qo`shamiz. Undan so`ng, keyinroq aniqlanadigan funksiyalarni e’lon qilamiz:
   

private:
Ui::MainWindow *ui;
QMediaPlayer* player;
public:
void stateChanged(QMediaPlayer::State state);
void positionChanged(qint64 position);

3. 
   Keyin mainwindow.cpp ni ochamiz va player ni yuklaymiz:
   

MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
player = new QMediaPlayer(this);
player->setVolume(ui->volume->value());
connect(player, &QMediaPlayer::stateChanged, this,
&MainWindow::stateChanged);
connect(player, &QMediaPlayer::positionChanged, this,
&MainWindow::positionChanged);
}
QMediaPlayer sinfi bizning dasturimiz tomonidan yuklangan audio fayllarni qo`yish uchun mo`ljallangan asosiy sinf. Shunday qilib, biz qo`yilayotgan audio fayl holatini va uning joriy pozitsiyasini bilishimiz kerak. Bunday ma’lumotlarni uning stateChanged() va positionChanged() signallarini bizning slot funksiyamizga yuborish orqali olishimiz mumkin.

4. 
   stateChanged() bizga audio faylning joriy qo`yilish holati haqidagi ma’lumotlarni olishga imkon beradi. Keyin biz Push Button tugmasini mos ravishda qo`shamiz va o`chirib qo`yamiz.
   

void MainWindow::stateChanged(QMediaPlayer::State state)
{
if (state == QMediaPlayer::PlayingState)
{
ui->playButton->setEnabled(false);
ui->pauseButton->setEnabled(true);
ui->stopButton->setEnabled(true);
}
else if (state == QMediaPlayer::PausedState)
{
ui->playButton->setEnabled(true);
ui->pauseButton->setEnabled(false);
ui->stopButton->setEnabled(true);
}
else if (state == QMediaPlayer::StoppedState)
{
ui->playButton->setEnabled(true);
ui->pauseButton->setEnabled(false);
ui->stopButton->setEnabled(false);
}
}

5. 
   Xuddi positionChanged() va slot funksiyalari kabi, ulardan vaqt chizig`i (timeline)ni bo`laklash uchun, vaqtni hisoblash oynasi sifatida o`rnatamiz:
   

void MainWindow::positionChanged(qint64 position)
{
if (ui->progressbar->maximum() != player->duration())
ui->progressbar->setMaximum(player->duration());
ui->progressbar->setValue(position);
int seconds = (position/1000) % 60;
int minutes = (position/60000) % 60;
int hours = (position/3600000) % 24;
QTime time(hours, minutes,seconds);
ui->durationDisplay->setText(time.toString());
}

6. 
   Endi mainwindow.h ni ochamiz va har bir tugma vidjetiga o`ng tugmani bosgan holda, Go to slot... buyrug`ini tanlaymiz va clicked() signalini belgilaymiz. Bu orqali biz muayyan tugma uchun, u bosilganida bajariluvchi ishlarga xos kodlarni tarkibiga oluvchi slotlarni tuzib chiqamiz:
   

void MainWindow::on_playButton_clicked()
{
player->play();
}
void MainWindow::on_pauseButton_clicked()
{
player->pause();
}
void MainWindow::on_stopButton_clicked()
{
player->stop();
}

7. 
   Shundan so`ng, Horizontal Slider ga o`ng tugmani bosamiz va Go to slot... buyrug`ini va sliderMoved() signalni tanlab, OK tugmasini bosamiz:
   

8. 
   sliderMoved() signali foydalanuvchi audio qo`yilishi pozitsiyasini o`zgartirish uchun uning ustiga bosganida ishga tushadi. Aytaylik, biz bu pozitsiyaning media playerga uzatilishini va unga audio faylning ovozini yoki qo`yilish pozitsiyasini o`zgartirish haqida xabar yuborishini istaymiz. Bunda audio faylning ovoz balandligi qiymatini 0 qilib qo`yishdan ehtiyot bo`lish kerak. Quyidagi kodni ko`rib chiqamiz:
   

void MainWindow::on_volume_sliderMoved(int position)
{
player->setVolume(position);
}
void MainWindow::on_progressbar_sliderMoved(int position)
{
player->setPosition(position);
}

9. 
   Endi oldingi loyihamizdagi kabi, File meyular qatorini va uning tarkibida Open File menyusini yaratamiz va unga harakat (action) qo`shamiz.
   
10.