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Using QSettings in QML with also json and XML support

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(Lildeimos -)
croozeus (Talk | contribs)
m (Croozeus - - Usage: Added appropriate code highlights)
Line 32: Line 32:
  
 
Start copying {{Icode|setting.cpp}} and {{Icode|setting.h}} into your project source directory. In the {{Icode|main.cpp}} file include the .h:
 
Start copying {{Icode|setting.cpp}} and {{Icode|setting.h}} into your project source directory. In the {{Icode|main.cpp}} file include the .h:
<code>
+
<code cpp>
 
#include "setting.h"
 
#include "setting.h"
 
</code>
 
</code>
 
the register the context property
 
the register the context property
<code>
+
<code cpp>
 
Settings settings(appName, fileName);
 
Settings settings(appName, fileName);
 
viewer.rootContext()->setContextProperty("settings", &settings);
 
viewer.rootContext()->setContextProperty("settings", &settings);
 
</code>
 
</code>
 
fileName will be create as follow:
 
fileName will be create as follow:
<code>
+
<code cpp>
 
QDesktopServices::storageLocation( QDesktopServices::DataLocation ) + "/" + appName + "/" + fileName;
 
QDesktopServices::storageLocation( QDesktopServices::DataLocation ) + "/" + appName + "/" + fileName;
 
</code>
 
</code>
Line 57: Line 57:
  
 
so to write a new value or overwrite the existing just put in your qml this
 
so to write a new value or overwrite the existing just put in your qml this
<code>
+
<code javascript>
 
settings.setValue("main/user", "Marco");
 
settings.setValue("main/user", "Marco");
 
</code>
 
</code>
  
 
to get a value:
 
to get a value:
<code>
+
<code javascript>
 
var user;
 
var user;
 
user = settings.getValue("main/user");
 
user = settings.getValue("main/user");
 
</code>
 
</code>
 
if you want to have a default value if there is not yet a setting named "main/user", do:
 
if you want to have a default value if there is not yet a setting named "main/user", do:
<code>
+
<code javascript>
 
var user;
 
var user;
 
user = settings.getValue("main/user", "Marco");
 
user = settings.getValue("main/user", "Marco");
Line 89: Line 89:
 
==== appendToArray ====
 
==== appendToArray ====
 
to make this in your qml just use:
 
to make this in your qml just use:
<code>
+
<code javascript>
 
settings.appendToArray( "main/user", { "name": "Marco" , "location": "Italy" });
 
settings.appendToArray( "main/user", { "name": "Marco" , "location": "Italy" });
 
settings.appendToArray( "main/user", { "name": "Marco2" , "location": "Italy2" });
 
settings.appendToArray( "main/user", { "name": "Marco2" , "location": "Italy2" });
Line 96: Line 96:
 
==== removeArray ====
 
==== removeArray ====
 
to remove the whole array:
 
to remove the whole array:
<code>
+
<code javascript>
 
settings.removeArray( "main/user");
 
settings.removeArray( "main/user");
 
</code>
 
</code>
Line 102: Line 102:
 
==== removeArrayEntry ====
 
==== removeArrayEntry ====
 
to remove a single entry of the array:
 
to remove a single entry of the array:
<code>
+
<code javascript>
 
settings.removeArrayEntry( "main/user", 1);
 
settings.removeArrayEntry( "main/user", 1);
 
</code>
 
</code>
Line 108: Line 108:
 
==== getIndexOfValueInArray ====
 
==== getIndexOfValueInArray ====
 
this will get the first array index of "Marco2" inside the array "main/user" checking it in the "name" field.
 
this will get the first array index of "Marco2" inside the array "main/user" checking it in the "name" field.
<code>
+
<code javascript>
 
var i = settings.getIndexOfValueInArray("main/user", "name", "Marco2");
 
var i = settings.getIndexOfValueInArray("main/user", "name", "Marco2");
 
</code>
 
</code>
  
 
so if it is needed to remove "Marco2" from the array, just do:
 
so if it is needed to remove "Marco2" from the array, just do:
<code>
+
<code javascript>
 
settings.removeArrayEntry( "main/user", settings.getIndexOfValueInArray("main/user", "name", "Marco2") );
 
settings.removeArrayEntry( "main/user", settings.getIndexOfValueInArray("main/user", "name", "Marco2") );
 
</code>
 
</code>
Line 120: Line 120:
 
==== checkValueArray ====
 
==== checkValueArray ====
 
this will return true or false whenever "Marco" is in the array "main/user"
 
this will return true or false whenever "Marco" is in the array "main/user"
<code>
+
<code javascript>
 
var b = settings.checkValueArray("main/user", "name", "Marco");
 
var b = settings.checkValueArray("main/user", "name", "Marco");
 
</code>
 
</code>
Line 126: Line 126:
 
==== getArrayJson ====
 
==== getArrayJson ====
 
this function will retrieve the array in a json string format. It is possible to use the eval() function for example to fill a [http://doc.qt.nokia.com/4.7-snapshot/qml-listmodel.html ListModel]:
 
this function will retrieve the array in a json string format. It is possible to use the eval() function for example to fill a [http://doc.qt.nokia.com/4.7-snapshot/qml-listmodel.html ListModel]:
<code>
+
<code javascript>
 
var users = eval ( settings.getArrayJson("main/users") );
 
var users = eval ( settings.getArrayJson("main/users") );
 
listModel.clear();
 
listModel.clear();
Line 144: Line 144:
 
this function is useful to fill a [http://doc.qt.nokia.com/4.7-snapshot/qml-xmllistmodel.html XmlListModel]. The returned xml format is like:
 
this function is useful to fill a [http://doc.qt.nokia.com/4.7-snapshot/qml-xmllistmodel.html XmlListModel]. The returned xml format is like:
  
<code>
+
<code xml>
 
<xml>
 
<xml>
 
   <item>
 
   <item>
Line 160: Line 160:
  
 
so, for example:
 
so, for example:
<code>
+
<code javascript>
 
XmlListModel {
 
XmlListModel {
 
     id: xmlListModel
 
     id: xmlListModel

Revision as of 21:00, 13 May 2012

This article explains how to use settings in QML

Article Metadata
Tested with
SDK: Nokia Qt SDK 1.2.1
Devices(s): all
Compatibility
Platform(s): all
Device(s): all
Article
Keywords: QSettings
Created: lildeimos (09 May 2012)
Last edited: croozeus (13 May 2012)

Contents

Introduction

This class is used as a context property in QML applications as an easy way to store and get user settings. It supports storing arrays. These can also retrieved in json or xml format.

Usage

Start copying setting.cpp and setting.h into your project source directory. In the main.cpp file include the .h:

#include "setting.h"

the register the context property

Settings settings(appName, fileName);
viewer.rootContext()->setContextProperty("settings", &settings);

fileName will be create as follow:

QDesktopServices::storageLocation( QDesktopServices::DataLocation ) + "/" + appName + "/" + fileName;

In your QML sources you will now be able to use the property settings in ini format as explained below.

single settings

The ini format is mostly like as:

[main]
user=Marco
location=Italy
...

so to write a new value or overwrite the existing just put in your qml this

settings.setValue("main/user", "Marco");

to get a value:

var user;
user = settings.getValue("main/user");

if you want to have a default value if there is not yet a setting named "main/user", do:

var user;
user = settings.getValue("main/user", "Marco");

if "main/user" exist it will return that value, else will return "Marco".


array settings

The ini format for arrays is mostly like as:

[main]
user/size=2
user/1/name=Marco
user/1/location=Italy
user/2/name=Marco2
user/2/location=Italy2
...

appendToArray

to make this in your qml just use:

settings.appendToArray( "main/user", { "name": "Marco" , "location": "Italy" });
settings.appendToArray( "main/user", { "name": "Marco2" , "location": "Italy2" });

removeArray

to remove the whole array:

settings.removeArray( "main/user");

removeArrayEntry

to remove a single entry of the array:

settings.removeArrayEntry( "main/user", 1);

getIndexOfValueInArray

this will get the first array index of "Marco2" inside the array "main/user" checking it in the "name" field.

var i = settings.getIndexOfValueInArray("main/user", "name", "Marco2");

so if it is needed to remove "Marco2" from the array, just do:

settings.removeArrayEntry( "main/user", settings.getIndexOfValueInArray("main/user", "name", "Marco2") );


checkValueArray

this will return true or false whenever "Marco" is in the array "main/user"

var b = settings.checkValueArray("main/user", "name", "Marco");

getArrayJson

this function will retrieve the array in a json string format. It is possible to use the eval() function for example to fill a ListModel:

var users = eval ( settings.getArrayJson("main/users") );
listModel.clear();
for (var i=0; i<users.length; i++)
{
listModel.append( {
"name": users[i].name,
"location": users[i].location
} );
}

getArray

this function is like getArrayJson but it returns the values in a QList< QVariantMap > ready to be use without the need to use eval() function.

getArrayXml

this function is useful to fill a XmlListModel. The returned xml format is like:

<xml>
<item>
<name>Marco</name>
<location>Italy</location>
</item>
 
<item>
<name>Marco2</name>
<location>Italy2</location>
</item>
...
</xml>

so, for example:

XmlListModel {
id: xmlListModel
xml: getArrayXml("main/users")
query: "/xml/item"
 
XmlRole { name: "name"; query: "name/string()" }
XmlRole { name: "location"; query: "location/string()" }
}

will fill xmlListModel with the stored array.

Download

File:Settings-v1.0.zip

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