正在更新 Qtimer 的交流值

Question

我正在使用mini2440的qt工具。我为 i2c adc 做了一个 gui 具有 starti2c 和 stopi2c。一切正常：按下starti2c按钮时它会读取信号值，但我希望更新此值。我知道Qtimer可以使用，但是我该怎么做呢？这是代码：

---

# include <termio.h>
# include <time.h>
# include <string.h>
# include <sys/time.h>
HelloForm::HelloForm(QWidget* parent, const char* name, WFlags fl):
HelloBaseForm(parent, name, fl)
{
connect(PushButton1,SIGNAL(clicked()),this,SLOT(starti2c()));
connect(PushButton2,SIGNAL(clicked()),this,SLOT(stopi2c()));
}
HelloForm::~HelloForm()  
{
}
//*********************Code for getting i2c**************************// 
  char HelloForm::geti2c()
{
  char buf[100];                              
  char buff[100];     
  char valuee;
  int m1;   
  char con_buff[10];
  int fd=open("/dev/i2c/0",O_RDWR);
  if (fd<0)
  {
   Message->setText(" NOT ABLE TO OPEN THE DRIVER ");
   }
   else
  {
  Message->setText(" I2C IS WORKING ");
}
    int  io,wbyte,rbyte,i;
   //********i2cdetect and read************
   buf[0]=0x48;    
  buf[1]=0x00;   
  buf[2]=0x91;  
  io=ioctl(fd,I2C_SLAVE,0x48); 
  if(io<0)
{
Message->setText(" ");
 Message->setText("error ioctl");
 }
 else
 {
 wbyte=write(fd,buf,3); 
                   // write all three control word to arm 
 usleep(1*1000);
 }
 if(wbyte!=3)
{
Message->setText("error write");
Message->setText(QString::number(wbyte));
rbyte=read(fd,buff,10);    
//ADC->setText(buff);
sscanf(buff,"%c",&valuee);             
m1=int(valuee);     
return(m1);
}

void HelloForm::starti2c()
{

while(1)
{   
float adc_val=0;
adc_val=geti2c();
adc_val=(adc_val*5)/255.00;
usleep(1*1000);   
ADC->setText(QString::number(adc_val));   
  }
  }
//***********stop********//
void HelloForm::stopi2c()
{                        
   ADC->setText(" ");
Message->setText("Stopped");
}        

---

Answer 1

希望这能让你开始 - 它创建一个每 1000 毫秒超时一次的计时器。 计时器的超时信号连接到 PushButton1 连接到的同一插槽 - starti2c。

QTimer *timer = new QTimer(this);
connect(timer, SIGNAL(timeout()), this, SLOT(starti2c()));
timer->start(1000);

该代码应放置在您拥有 2 个连接语句的位置下方。