Question

我是qt的新手所以我对sizepolicy和小部件的不了解。我有一个垂直框布局，我首先添加了一个Qlabel，然后是一个QTreeWidget，然后再添加一个Qlabel。现在的问题是QTreeWidget在垂直方向占据了整个空间，然后在QTreeWidget之后留下了一个非常大的空间，虽然目前只有行存在，但是添加了QLabel。我希望第二个Qlabel在两行可见之后立即添加，现在当添加更多行时，它会向下移动。有人可以建议我怎么做吗？

Answer 1

我认为这就是你的意思： UI具有布局：Label，QTreeWidget，Label，Spacer （Spacer很重要因为其他Qt可能只是扩展标签以填充窗口。）重要提示：在Designer TreeWidget中，需要关闭优先级，垂直滚动条。

UI示例：

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>MainWindow</class>
 <widget class="QMainWindow" name="MainWindow">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>517</width>
    <height>568</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>MainWindow</string>
  </property>
  <widget class="QWidget" name="centralWidget">
   <layout class="QVBoxLayout" name="verticalLayout">
    <item>
     <widget class="QLabel" name="label">
      <property name="text">
       <string>TextLabel</string>
      </property>
     </widget>
    </item>
    <item>
     <widget class="my_tree" name="treeView">
      <property name="sizePolicy">
       <sizepolicy hsizetype="Expanding" vsizetype="Preferred">
        <horstretch>0</horstretch>
        <verstretch>0</verstretch>
       </sizepolicy>
      </property>
      <property name="verticalScrollBarPolicy">
       <enum>Qt::ScrollBarAlwaysOff</enum>
      </property>
      <property name="horizontalScrollBarPolicy">
       <enum>Qt::ScrollBarAsNeeded</enum>
      </property>
     </widget>
    </item>
    <item>
     <widget class="QLabel" name="label_2">
      <property name="text">
       <string>TextLabel</string>
      </property>
     </widget>
    </item>
    <item>
     <spacer name="verticalSpacer">
      <property name="orientation">
       <enum>Qt::Vertical</enum>
      </property>
      <property name="sizeHint" stdset="0">
       <size>
        <width>20</width>
        <height>40</height>
       </size>
      </property>
     </spacer>
    </item>
   </layout>
  </widget>
  <widget class="QMenuBar" name="menuBar">
   <property name="geometry">
    <rect>
     <x>0</x>
     <y>0</y>
     <width>517</width>
     <height>21</height>
    </rect>
   </property>
  </widget>
  <widget class="QToolBar" name="mainToolBar">
   <attribute name="toolBarArea">
    <enum>TopToolBarArea</enum>
   </attribute>
   <attribute name="toolBarBreak">
    <bool>false</bool>
   </attribute>
  </widget>
  <widget class="QStatusBar" name="statusBar"/>
 </widget>
 <layoutdefault spacing="6" margin="11"/>
 <customwidgets>
  <customwidget>
   <class>my_tree</class>
   <extends>QTreeView</extends>
   <header>my_tree.h</header>
  </customwidget>
 </customwidgets>
 <resources/>
 <connections/>
</ui>

重载的QTreeView（在你的情况下是QTreeWidget）用于获取想要的sizehints：编辑 - 这是一个uggly头只定义我称为my_tree.h -

    #ifndef MY_TREE_H
#define MY_TREE_H
#include <QHeaderView>
#include <QTreeView>

class my_tree: public QTreeView
{
    Q_OBJECT
public:
    my_tree(QWidget* parent):QTreeView(parent)
    {
        // Important: if something is shown/hidden we need a new size
        connect(this,SIGNAL(expanded( const QModelIndex & )),SLOT(onExpandCollapsed()));
        connect(this,SIGNAL(collapsed( const QModelIndex & )),SLOT(onExpandCollapsed()));
    };

    // QWidget interface
public:
    QSize sizeHint() const {return my_size(); };
    QSize minimumSizeHint() const { return my_size(); };

private:
    QSize my_size() const
    {   //QSize tst(sizeHintForColumn(0) + 2 * frameWidth(), sizeHintForRow(0) + 2 * frameWidth());

        int neededHight= 2 * frameWidth()+ this->header()->height();

        QModelIndex root = this->rootIndex();

        QAbstractItemModel* m = this->model();

        //if(this->rootIsDecorated())
        {
            neededHight += recursiveHeightHint(root,m);
        }
        QSize temp = QTreeView::sizeHint();
        temp.setHeight(neededHight);
        return QSize(1,neededHight);
    }

    // we need the size of all visible items -> isExpanded
    // the root item is usually shown as a non-Valid index -> !i.isValid()
    int recursiveHeightHint(QModelIndex i,QAbstractItemModel* m) const
    {
        int temp=sizeHintForIndex(i).height();
        if(this->isExpanded(i) || !i.isValid())
        {
        if(m->hasChildren(i))
        {
            int numRows = m->rowCount(i);
            for(int count =0;count<numRows;count++)
                temp+=recursiveHeightHint(m->index(count,0,i),m);
        }
        }
        return temp;
    }

private slots:
    void onExpandCollapsed(){updateGeometry();}
};

#endif // MY_TREE_H

PS：在Designer中首先放置基本Widget，然后将其定义为自行设计的占位符。

我使用此条目来获得此解决方案：

QListWidget adjust size to content

设置QtreeWidget高度

1 个答案: