本篇内容主要讲解“Qt中树形控件Tree Widget的使用方法有哪些”，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习“Qt中树形控件Tree Widget的使用方法有哪些”吧!
Tree Widget在项目控件组（Item Widgets）里面可以找到。这种控件其实有时还是很有用处的，我主要利用的是带有复选框的树形控件。结果如图所示;
当选中顶层的树形节点时，子节点全部被选中；当取消选择顶层树形节点时，子节点的选中状态将全部被取消，二当选中子节点是，父节点显示部分选中的状态。
几个主要的函数：
setCheckState设置复选框；
ItemIsUserCheckable 项目上是否有复选框
ItemIsEnabled 项目上是否没有被禁用（Enabled可用/Disabled禁用）
ItemIsSelectable 项目是否可以选中
代码：
在mainwindow.h中插入一下代码：
void init(); void updateParentItem(QTreeWidgetItem *item); public slots: void treeItemChanged(QTreeWidgetItem* item,int column);在mainwindow构造函数中添加：
init(); connect(ui->treeWidget,SIGNAL(itemChanged(QTreeWidgetItem*,int)),this,SLOT(treeItemChanged(QTreeWidgetItem*,int)));init函数的实现;
QTreeWidgetItem* group1=new QTreeWidgetItem(ui->treeWidget); group1->setText(0,"group1"); group1->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable); group1->setCheckState(0,Qt::Unchecked); QTreeWidgetItem* subItem11=new QTreeWidgetItem(group1); subItem11->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable); subItem11->setText(0,"subItem11"); subItem11->setCheckState(0,Qt::Unchecked); QTreeWidgetItem* subItem12=new QTreeWidgetItem(group1); subItem12->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable); subItem12->setText(0,"subItem12"); subItem12->setCheckState(0,Qt::Unchecked); QTreeWidgetItem* subItem13=new QTreeWidgetItem(group1); subItem13->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable); subItem13->setText(0,"subItem11"); subItem13->setCheckState(0,Qt::Unchecked); QTreeWidgetItem* subItem14=new QTreeWidgetItem(group1); subItem14->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable); subItem14->setText(0,"subItem12"); subItem14->setCheckState(0,Qt::Unchecked); QTreeWidgetItem* group2=new QTreeWidgetItem(ui->treeWidget); group2->setText(0,"group2"); group2->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable); group2->setCheckState(0,Qt::Unchecked); QTreeWidgetItem* subItem1=new QTreeWidgetItem(group2); subItem1->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable); subItem1->setText(0,"subItem11"); subItem1->setCheckState(0,Qt::Unchecked); QTreeWidgetItem* subItem2=new QTreeWidgetItem(group2); subItem2->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable); subItem2->setText(0,"subItem12"); subItem2->setCheckState(0,Qt::Unchecked); QTreeWidgetItem* subItem3=new QTreeWidgetItem(group2); subItem3->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable); subItem3->setText(0,"subItem11"); subItem3->setCheckState(0,Qt::Unchecked); QTreeWidgetItem* subItem4=new QTreeWidgetItem(group2); subItem4->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable); subItem4->setText(0,"subItem12"); subItem4->setCheckState(0,Qt::Unchecked); QTreeWidgetItem* group3=new QTreeWidgetItem(ui->treeWidget); group3->setText(0,"group3"); group3->setFlags(Qt::ItemIsAutoTristate|Qt::ItemIsEnabled|Qt::ItemIsSelectable); group3->setCheckState(0,Qt::Unchecked); QTreeWidgetItem* subItem111=new QTreeWidgetItem(group3); subItem111->setFlags(Qt::ItemIsAutoTristate|Qt::ItemIsEnabled|Qt::ItemIsSelectable); subItem111->setText(0,"subItem111"); subItem111->setCheckState(0,Qt::Unchecked); QTreeWidgetItem* subItem112=new QTreeWidgetItem(group3); subItem112->setFlags(Qt::ItemIsAutoTristate|Qt::ItemIsEnabled|Qt::ItemIsSelectable); subItem112->setText(0,"subItem112"); subItem112->setCheckState(0,Qt::Unchecked);treeItemChanged函数的实现;
QString itemText=item->text(0); //选中 if(Qt::Checked ==item->checkState(0))//全选check打勾 { QTreeWidgetItem* parent=item->parent();//定义一个节点 int count=item->childCount();//子节点的数目 if(count>0) { for(int i=0;i<count;i++) { //子节点也选中 item->child(i)->setCheckState(0,Qt::Checked); } } else { //是子节点 updateParentItem(item); } } else if(Qt::Unchecked==item->checkState(0))//存在未选中 { int count=item->childCount(); if(count>0) { for(int i=0;i<count;i++) { item->child(i)->setCheckState(0,Qt::Unchecked); } } else { updateParentItem(item); } }updateParentItem 函数的实现;
QTreeWidgetItem* parent=item->parent(); if(parent==NULL) { return; } int selectedCount =0; int childCount =parent->childCount(); for(int i=0;i<childCount;i++) { QTreeWidgetItem* childItem=parent->child(i); if(childItem->checkState(0)==Qt::Checked) { selectedCount++; } } if(selectedCount<=0) { parent->setCheckState(0,Qt::Unchecked); } else if(selectedCount>0&&selectedCount<childCount) { //部分选中状态 parent->setCheckState(0,Qt::PartiallyChecked); } else if(selectedCount==childCount) { parent->setCheckState(0,Qt::Checked); }到此，相信大家对“Qt中树形控件Tree Widget的使用方法有哪些”有了更深的了解，不妨来实际操作一番吧！这里是编程网网站，更多相关内容可以进入相关频道进行查询，关注我们，继续学习！
