QStandardItemModel中设置项目的背景颜色

如何根据内容显示不同的背景颜色？

参照ECMWF的Metview源码实现。

Qt的Model中不同类型的数据用role区分，Qt的宏ItemDataRole提供了一些角色：

 

 

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enum ItemDataRole {         DisplayRole = 0,         DecorationRole = 1,         EditRole = 2,         ToolTipRole = 3,         StatusTipRole = 4,         WhatsThisRole = 5,         // Metadata         FontRole = 6,         TextAlignmentRole = 7,         BackgroundColorRole = 8,         BackgroundRole = 8,         TextColorRole = 9,         ForegroundRole = 9,         CheckStateRole = 10,         // Accessibility         AccessibleTextRole = 11,         AccessibleDescriptionRole = 12,         // More general purpose         SizeHintRole = 13,         InitialSortOrderRole = 14,         // Internal UiLib roles. Start worrying when public roles go that high.         DisplayPropertyRole = 27,         DecorationPropertyRole = 28,         ToolTipPropertyRole = 29,         StatusTipPropertyRole = 30,         WhatsThisPropertyRole = 31,         // Reserved         UserRole = 32     };

 

也可以自定义角色，只要数值大于UserRole即可。

 

 

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enum ImageNavigtionModelRole{         CachedImageRole = Qt::UserRole + 100,         ImageMetaDataRole = Qt::UserRole +200 };

 

Qt的Model使用data函数、setData函数来获取和设置各种角色的具体数值。当我们需要修改背景颜色时，可以修改BackgroundColorRole角色的返回数据：

 

 

 

 

 

 

 

C++

 

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QVariant ImageNavigationModel::data(const QModelIndex &index, int role) const {     if(role == Qt::BackgroundRole)     {         QStandardItem* node = itemFromIndex(index.sibling(index.row(),0)); // 每行颜色均相同         QVariant cached_image_role = node->data(CachedImageRole);         if(!cached_image_role.isNull())         {             if(index.row()%2 == 0)                 return QColor("#FFE6BF");             else                 return QColor("#FFF2DE");         }         else         {             return QStandardItemModel::data(index, role);         }     }     return QStandardItemModel::data(index, role); }

 

这样就可以自定义数据的背景色。