Qt QGridLayout如何调整小部件的宽度和高度

Question

我正在尝试在QDialog窗口中调整LineEdit和PushButton宽度。 LineEdit应该比按钮宽20倍，所以它足够长以显示整个路径。下面是我的代码，我尝试了几种方法，但它们都有类似的布局（见截图）。我想让Option窗口至少宽2倍，以使LineEdit足够宽。我该怎么做？

这是我的代码：

  this->setWindowTitle(tr("Options"));

  QGridLayout* logLayout = new QGridLayout;

  QLineEdit _logPathLE = new QLineEdit;
  logLayout->addWidget(_logPathLE, 0, 0);
  logLayout->setColumnStretch(0, 20);  // 1st: try with setStretch
  //_logPathLE->setSizePolicy(QSizePolicy::MinimumExpanding, QSizePolicy::Preferred);  // 2nd try with setSizePolicy
  //logLayout->addWidget(logLocation, 0, 0, 0, 20);  // 3rd: try with span multiple columns

  QPushButton* browseFolder = new QPushButton(tr("..."));
  logLayout->addWidget(browseFolder, 0, 1);
  logLayout->setColumnStretch(1, 1);
  //browseFolder->setSizePolicy(QSizePolicy::MinimumExpanding, QSizePolicy::Preferred);
  //logLayout->addWidget(browseFolder, 0, 20, 0, 1);

  QGroupBox* optGroupBox = new QGroupBox(tr("Log location"));
  optGroupBox->setLayout(logLayout);

  QDialogButtonBox* btns = new QDialogButtonBox(QDialogButtonBox::Ok | QDialogButtonBox::Cancel);
  connect(btns, SIGNAL(accepted()), this, SLOT(accept()));
  connect(btns, SIGNAL(rejected()), this, SLOT(reject()));

  QVBoxLayout* options = new QVBoxLayout;
  options->addWidget(optGroupBox);
  options->addWidget(btns);

  this->setLayout(options);