The JsonTreeModel class provides a data model for a JSON document. More...

#include <jsontreemodel.h>

Inheritance diagram for JsonTreeModel:

Public Types
enum	ScalarColumnSearchMode { NoSearch, QuickSearch, ComprehensiveSearch }
	This enum controls how setJson() updates the model's column headers. More...

Public Member Functions
	JsonTreeModel (QObject *parent=nullptr)
	Constructs an empty JsonTreeModel with the given parent. More...

	~JsonTreeModel () override
	Destroys the JsonTreeModel and frees its memory. More...

QVariant	headerData (int section, Qt::Orientation orientation, int role=Qt::DisplayRole) const override

QModelIndex	index (int row, int column, const QModelIndex &parent=QModelIndex()) const override

QModelIndex	parent (const QModelIndex &index) const override

int	rowCount (const QModelIndex &parent=QModelIndex()) const override
	Returns the number of rows under the given parent. More...

int	columnCount (const QModelIndex &parent=QModelIndex()) const override
	Returns the number of columns in the model. More...

QVariant	data (const QModelIndex &index, int role=Qt::DisplayRole) const override
	Returns data under the given index for the specified role. More...

bool	setData (const QModelIndex &index, const QVariant &value, int role=Qt::EditRole) override

Qt::ItemFlags	flags (const QModelIndex &index) const override

void	setJson (const QJsonArray &array, ScalarColumnSearchMode searchMode=QuickSearch)
	Sets the whole model's internal data structure to the given JSON array. More...

void	setJson (const QJsonObject &object, ScalarColumnSearchMode searchMode=QuickSearch)
	Sets the whole model's internal data structure to the given JSON object. More...

QJsonValue	json (const QModelIndex &index=QModelIndex()) const
	Returns the JSON value under the given index. More...

void	setScalarColumns (const QStringList &columns)
	Sets the JSON objects' scalar members that are shown by the model. More...

QStringList	scalarColumns () const
	Returns the names of the JSON objects' scalar members that are shown by the model. More...

Detailed Description

The JsonTreeModel class provides a data model for a JSON document.

JsonTreeModel represents an arbitrary JSON document as a tree. It supports unlimited nesting of JSON arrays and JSON objects. For compactness, scalar members of JSON objects are placed under named columns.

Column 0 shows the structure of the JSON document. It contains array index numbers and object member names.
Column 1 shows the scalar elements of JSON arrays.
Columns 2 and above show the scalar members of JSON objects. The header text for these columns are the names of the object members, either discovered during the call to setJson(), or set manually via setScalarColumns(). These columns are called the named scalar columns.

For example, the following JSON document contains an array of similar objects which can be compacted into a table:

[
    {
        "First Name": "Hua",
        "Last Name": "Li",
        "Phone Number": "+86 21 51748525",
        "Country": "China"
    }, {
        "First Name": "Gildong",
        "Last Name": "Hong",
        "Phone Number": "+82 31 712 0045",
        "Country": "South Korea"
    }, {
        "First Name": "Tarou",
        "Last Name": "Yamada",
        "Phone Number": "+81 3 6264 4500",
        "Country": "Japan"
    }, {
        "First Name": "Jane",
        "Last Name": "Doe",
        "Phone Number": "+1 408 906 8400",
        "Country": "USA"
    }, {
        "First Name": "Erika",
        "Last Name": "Mustermann",
        "Phone Number": "+49 30 63923257",
        "Country": "Germany"
    }, {
        "First Name": "Pyotr",
        "Last Name": "Ivanov",
        "Phone Number": "+7 921 097 7252",
        "Country": "Russia"
    }, {
        "First Name": "Kari",
        "Last Name": "Nordmann",
        "Phone Number": "+47 21 08 04 20",
        "Country": "Norway"
    }
]

Note: Use QTableView::hideColumn() or QTreeView::hideColumn() to hide the empty Scalar column

Here is a more hierarchical example:

{
    "Server Properties": {
        "Server ID": "314159",
        "Client IP Addresses": [
            "192.168.0.10",
            "192.168.0.11",
            "192.168.0.12"
        ]
    },
    "Analog Inputs": [
        {
            "Channel Name": "Transducer X",
            "Analog Input Type": "Voltage",
            "Scale": 1,
            "Offset": 0,
            "High Resolution": false
        },
        {
            "Channel Name": "Sensor Y",
            "Analog Input Type": "Current",
            "Scale": 6.25,
            "Offset": -25,
            "High Resolution": true
        }
    ]
}

Member Enumeration Documentation

◆ ScalarColumnSearchMode

enum JsonTreeModel::ScalarColumnSearchMode

This enum controls how setJson() updates the model's column headers.

See also: setJson(), setScalarColumns()

Enumerator
NoSearch	setJson() leaves the model headers unchanged. The caller should manually update the column headers via setScalarColumns().
QuickSearch	setJson() does a quick scan on the new JSON document. The model scans every member of JSON objects, but only scans the first element of JSON arrays.
ComprehensiveSearch	setJson() does a full scan on the new JSON document. The model scans every member of JSON objects and JSON arrays. All scalar members will be found and displayed, but this could be expensive for large JSON documents.

Constructor & Destructor Documentation

◆ JsonTreeModel()

JsonTreeModel::JsonTreeModel ( QObject * parent = nullptr )

explicit

Constructs an empty JsonTreeModel with the given parent.

◆ ~JsonTreeModel()

JsonTreeModel::~JsonTreeModel ( )

inlineoverride

Destroys the JsonTreeModel and frees its memory.

Member Function Documentation

◆ columnCount()

int JsonTreeModel::columnCount ( const QModelIndex & parent = QModelIndex() ) const

override

Returns the number of columns in the model.

This number is the same for the entire model; the parent is irrelevant.

Column 0 shows the structure of the JSON document. It contains array index numbers and object member names.
Column 1 shows the scalar elements of JSON arrays.
Columns 2 and above are the named scalar columns, corresponding to scalarColumns().

See also: rowCount(), scalarColumns()

◆ data()

QVariant JsonTreeModel::data	(	const QModelIndex &	index,
		int	role = `Qt::DisplayRole`
	)		const

override

Returns data under the given index for the specified role.

Only valid when role is Qt::DisplayRole or Qt::EditRole.

If index.column() is 0, then this function returns the array index or object member name that corresponds to index.row(). This differs from json(), which returns the full JSON value if index.column() is 0.

Note: This function is designed for interfacing with Qt item views. To access data, use json().

See also: setData(), json()

◆ flags()

Qt::ItemFlags JsonTreeModel::flags ( const QModelIndex & index ) const

override

◆ headerData()

QVariant JsonTreeModel::headerData	(	int	section,
		Qt::Orientation	orientation,
		int	role = `Qt::DisplayRole`
	)		const

override

Horizontal headers show the text of scalarColumns() for the third column onwards. Vertical headers show the text of column 0.

◆ index()

QModelIndex JsonTreeModel::index	(	int	row,
		int	column,
		const QModelIndex &	parent = `QModelIndex()`
	)		const

override

◆ json()

QJsonValue JsonTreeModel::json ( const QModelIndex & index = QModelIndex() ) const

Returns the JSON value under the given index.

If the index is invalid, then this function returns the entire JSON document stored in the model.

If index.column() is 0, then this function returns the full JSON value at index.row(); the value could be a JSON object or JSON array. If index.column() is non-zero, this function returns a single scalar value.

Example:

Index (6, 2) returns the string "Kari".
Index (6, 1) returns an undefined QJsonValue.
Index (6, 0) returns the following object:
{
"First Name": "Kari",
"Last Name": "Nordmann",
"Phone Number": "+47 21 08 04 20",
"Country": "Norway"
}
Invalid indices return the whole document:
[
{
"First Name": "Hua",
"Last Name": "Li",
"Phone Number": "+86 21 51748525",
"Country": "China"
}, {
"First Name": "Gildong",
"Last Name": "Hong",
"Phone Number": "+82 31 712 0045",
"Country": "South Korea"
}, {
"First Name": "Tarou",
"Last Name": "Yamada",
"Phone Number": "+81 3 6264 4500",
"Country": "Japan"
}, {
"First Name": "Jane",
"Last Name": "Doe",
"Phone Number": "+1 408 906 8400",
"Country": "USA"
}, {
"First Name": "Erika",
"Last Name": "Mustermann",
"Phone Number": "+49 30 63923257",
"Country": "Germany"
}, {
"First Name": "Pyotr",
"Last Name": "Ivanov",
"Phone Number": "+7 921 097 7252",
"Country": "Russia"
}, {
"First Name": "Kari",
"Last Name": "Nordmann",
"Phone Number": "+47 21 08 04 20",
"Country": "Norway"
}
]

See also: setJson(), data()

◆ parent()

QModelIndex JsonTreeModel::parent ( const QModelIndex & index ) const

override

◆ rowCount()

int JsonTreeModel::rowCount ( const QModelIndex & parent = QModelIndex() ) const

override

Returns the number of rows under the given parent.

If the parent represents a JSON array, then the row count equals the number of array elements. If the parent represents a JSON object, then the row count equals the number of child arrays and child objects combined.

See also: columnCount()

◆ scalarColumns()

QStringList JsonTreeModel::scalarColumns ( ) const

inline

Returns the names of the JSON objects' scalar members that are shown by the model.

See also: setScalarColumns()

◆ setData()

bool JsonTreeModel::setData	(	const QModelIndex &	index,
		const QVariant &	value,
		int	role = `Qt::EditRole`
	)

override

◆ setJson() [1/2]

void JsonTreeModel::setJson	(	const QJsonArray &	array,
		ScalarColumnSearchMode	searchMode = `QuickSearch`
	)

Sets the whole model's internal data structure to the given JSON array.

If searchMode is QuickSearch (default) or ComprehensiveSearch, this function also updates the column headers.

See also: json(), setData()

◆ setJson() [2/2]

void JsonTreeModel::setJson	(	const QJsonObject &	object,
		ScalarColumnSearchMode	searchMode = `QuickSearch`
	)

Sets the whole model's internal data structure to the given JSON object.

If searchMode is QuickSearch (default) or ComprehensiveSearch, this function also updates the column headers.

See also: json(), setData()

◆ setScalarColumns()

void JsonTreeModel::setScalarColumns ( const QStringList & columns )

Sets the JSON objects' scalar members that are shown by the model.

The model's named scalar columns are set to the list of specified columns, in the listed order.

If a scalar member of a JSON object is named after one of these columns, it is shown under that column. Otherwise, the member is hidden.

See also: scalarColumns(), setJson()

The documentation for this class was generated from the following files:

src/jsontreemodel.h
src/jsontreemodel.cpp

Public Types

Public Member Functions

Detailed Description

Member Enumeration Documentation

◆ ScalarColumnSearchMode

Constructor & Destructor Documentation

◆ JsonTreeModel()

◆ ~JsonTreeModel()

Member Function Documentation

◆ columnCount()

◆ data()

◆ flags()

◆ headerData()

◆ index()

◆ json()

◆ parent()

◆ rowCount()

◆ scalarColumns()

◆ setData()

◆ setJson() [1/2]

◆ setJson() [2/2]

◆ setScalarColumns()