no reaction at the first touch on the new form from doubleclick on a listview

mkdh

I have a ListVew and button on my widget.
there are two different reaction:
condition 1. (OK)
When I press the button , the new form(MyDesign) will be generated.
And I can get reaction from the first pressing button on the generated form(MyDesign) .
condition 2.(NOT OK)
When I doubleclick the item on a listview , the new form(MyDesign) will be generated.
But there are no reaction from the first pressing button on the new form(MyDesign).

(the slot of btnOK and lvwFile are both on_btnOK_clicked())
Why?
How to correct it?

    btnOK=new MainButton(this);
    btnOK->setFocusPolicy(Qt::NoFocus);
    connect(btnOK, SIGNAL(onClicked()), this, SLOT(on_btnOK_clicked()));
    ui->lvwFile->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    ui->lvwFile->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    ui->lvwFile->setHorizontalScrollMode(QAbstractItemView::ScrollPerPixel);
    ui->lvwFile->setVerticalScrollMode(QAbstractItemView::ScrollPerPixel);
    QScroller::grabGesture(ui->lvwFile,QScroller::LeftMouseButtonGesture);
    connect(ui->lvwFile, SIGNAL(clicked(QModelIndex)), this, SLOT(lvwFile_Clicked()));
    connect(ui->lvwFile, SIGNAL(onPressed()), this, SLOT(Delete_Clicked()));
    connect(ui->lvwFile, SIGNAL(doubleClicked(QModelIndex)), this, SLOT(on_btnOK_clicked()));


void diaOpenFileByListView::on_btnOK_clicked()
{
    lvwFile_Clicked();
    strPath=ui->lblPath->text();
    if(strPath.isNull()==false && strPath!=""){
        MyDesign *formDesign=new MyDesign(this);
        formDesign->setGeometry(0,0,this->width(),this->height());
        formDesign->filePath=strPath;
        formDesign->exec();
        //this->close();
        //delete ui;
        BindLV();
    }
}

mkdh

what different between clicked and doubleClicked?

In doubleClicked case,
I can't press the button before touching the screen on my new widget.
connect(ui->lvwFile, SIGNAL(doubleClicked(QModelIndex)), this, SLOT(on_btnOK_clicked()));

In clicked case,
I can press the button before touching the screen on my new widget.
connect(ui->lvwFile, SIGNAL(clicked(QModelIndex)), this, SLOT(on_btnOK_clicked()));

But, I want to use doubleClicked....