Form degli attributi¶
QField creates forms that are similar to QGIS, but with some differences. QGIS field widgets are supported on a best-effort basis and optimized for mobile use.
| Tipo di widget | Supporto | Note |
|---|---|---|
| Modifica testo | - HTML is not supported - Numeric input is enforced based on the field type. |
|
| Casella di controllo | ||
| Mappa valori | ||
| Nascosto | ||
| Allegato | This field is combined with camera integration. It is also able to open other files like pdf and doc (if you have an appropriate viewer) Attachment (photo settings) |
|
| Data/Ora | ||
| Intervallo | ||
| Riferimento alla relazione | ||
| Widget relazione | ||
| Relazione valore | ||
| Generatore UUID | ||
| Widget QML / HTML | ||
| Altri | Funding |
Attribute form configuration¶
In order to customize the attribute form, it is necessary to use the drag and drop designer in QGIS or to a use pre-written UI file. Like for QGIS you can make use of powerful expressions to populate the different fields. Additionally, to the ones available there are QFieldCloud specific variables, which can be utilized inside the attribute form.
Editabile¶
L'impostazione editabile sui campi è rispettata.
Ricorda l'ultimo valore¶
QField offers more fine-grained control over the last used values than QGIS, and uses its own settings instead of the QGIS ones.
Nascondi modulo all'inserimento di un elemento¶
L'impostazione Nascondi modulo all'inserimento di un elemento è direttamente applicata al form QField.
Designer trascina e rilascia¶
Gruppi e tab creati nel designer "trascina e rilascia" sono supportati.
In the "Attributes Form," you can structure your forms using various containers, such as tabs and groups, and enhance interactivity by incorporating expression-based conditional visibility. By enabling the Drag and Drop Designer, you gain the flexibility to re-order attribute fields, as well as gaining access to widgets that are not directly tied to specific fields (e.g., HTML/QML widgets).
Configura un widget relazione¶
Preparazione da Desktop
For detailed information on setting up layer relations in QGIS, please refer to the setting relations between multiple layers QGIS documentation. To further control the visibility and number of related items shown in QField, see the instructions for configuring Maximum items visibility for QField.
The relation widget shows all the referencing child features in a list. If enabled, it is possible to add, delete and open them.
The visual identification of the list entries is done via the Display Expression of the child layer.
Gestione chiavi¶
Since the parent primary key is used as foreign key in the referencing child features, the primary key must be safe to use (it must be unique) also after syncronizing back to the desktop. Therefore it is recommended to use UUIDs for primary keys. See [Working with Geopackages](../get-started/tutorials/advanced-setup-qfc/#working-with-geopackages for further information.
It is possible to already add children from a parent that is about to be added. This possibility will be blocked if there is no valid primary key on the parent or the constraints are violated. In case the adding of the parent feature is canceled after some children have been added already, the children are deleted as well.
Relazioni Molti-a-molti¶
On many-to-many relationships, according to the cardinality setting in the QGIS Vector Layer Properties, on adding, deleting or opening an entry in the list effects directly the child layer (on direct cardinality) or the linking table (on many-to-one cardinality).
The second case is usually used when there are additional relation information (e.g. percentage) in the linking table.
In case of the many-to-one cardinality on many-to-many relations the Display Expression needs to be set on the linking table.
Configuring Ordered Relations for QGIS and QField¶
The Ordered Relation Editor widget allows the reordering of linked child features based on a specific field.
1. Install the Plugin¶
Make sure you have installed the Ordered Relation Editor plugin from the official repository or through the "Plugin Manager" in QGIS.
2. Configure the Layout¶
Navigate to the Attributes Form section of your layer settings and set the layout editor to Drag and Drop Designer.
3. Set Up the Relation Editor Widget¶
In the Relation widget type dropdown, select Ordered Relation Editor. Then, configure the widget using the following settings:
-
Ordering Field: Specify the field in the child layer that will be used to determine the order of the features.
-
Description: Define an expression to be displayed for each child feature in the list.
-
Image Path (Optional): Provide a path to an image or icon to visually enhance the list. This is an expression that resolves dynamically.
Configuring an item threshold for Value Map Editor Widgets¶
To enhance the user experience within QField, it is possible to control the item threshold at which point the value map editor widgets switch to a toggle buttons interface. This feature allows users to quickly access items in QField when there are few and providing a more intuitive interface when dealing with a large number of items.
To activate the Toggle Button Interface:¶
-
Open Layer Properties by right-clicking on the desired layer and selecting 'Properties' from the menu.
-
Navigate to the QField tab located within the Layer Properties dialog.
-
Here, you will find an option to specify the quantity of items that will trigger the transition to a toggle button interface. Enter the preferred threshold value according to your needs.
Configuring the Attachment Widget¶
Preparazione da Desktop
The widget type Attachment is used with fields that store the path to files.
Può essere utilizzato per:
- mostrare e scattare foto o aggiungere immagini dalla galleria
- ascoltare e registrare clip audio
- mostrare e registrare video
- mostrare link a file esterni come PDF o documenti
The path should be set to relative. The pictures, audios, videos, pdf's and documents are stored then in a sub-directory of the project, where the link stored in the textfield is pointing to.
Note
QGIS 3.30 o versioni successive sono necessarie per la funzionalità audio e video
In QField the attachments are displayed. By clicking the icons symbol the camera or audio record is started to update the pictures, videos or audios with a new media.
On synchronization the sub-directory with the pictures, videos audios, pdf's and documents has to be copied as well.
The option hyperlink on the attachment widget will disable the camera functionality and enable a hyperlink to open a document (pdf, doc, ...).
Percorso dell'allegato configurabile¶
Preparazione da Desktop
QFieldSync offre la possibilità di configurare il percorso degli allegati.
- Vai a Plugin QFieldSync >Proprietà Layer
Usa le espressioni per specificare il percorso degli allegati. Per impostazione predefinita, le immagini vengono salvate nella cartella "DCIM", le registrazioni audio vengono salvate nella cartella "audio" e i video vengono salvati in "video" con un timestamp come nome.
Configurare un Widget di Relazione dei Valori¶
Preparazione da Desktop
Il widget Value Relation offre i valori di una tabella correlata in una casella combinata. Puoi selezionare layer, colonna chiave e colonna valore. Sono disponibili diverse opzioni per modificare i comportamenti standard: consenti valore nullo, ordina per valore e consenti selezioni multiple. Il widget visualizzerà un menu a tendina o a selezione multipla degli elementi di riferimento.
Group Values in the Value Relation Widget¶
You can organize and optimize the appearance of your Value Relation widgets by grouping related items together. This feature allows you to categorize the values in a dropdown list or in a table view based on the content of a chosen column.
For example, if you have a list of cities, you can group them by their respective states. This makes it easier for users to navigate and find the values they need, especially in lists with a large number of items.
Configurazione¶
Grouping is configured within the Value Relation widget's settings using the following options:
- Group column: Choose the column from the layer that will be used to organize the items. The values from this column will act as group title.
- Display group name: Check this box to display the group title as distinct header within the widget. This creates a clear separation between the different groups, making the list easier to navigate.
Configurare la Visibilità Condizionale¶
Preparazione da Desktop
Groups can be hidden based on an expression. This is useful when certain attributes are only required under certain conditions. As an example imagine mapping trees. Some of them might have a disease and you have a list of possible deseases. To not clutter the form with many fields, make a group and configure a visibility expression for a group "diseases". Add a field "disease" with the data type boolean. Only when the checkbox is checked, the list of diseases will be available to you.
In QField it will look like in the video below.
Definire Vincoli¶
Preparazione da Desktop
Attribute fields can have constraints attached. Constraints are rules in the form of expressions. Before a feature can be saved all constraints need to be met. A description can be added that is shown if a constraint is not satisfied.
Casi di uso comune¶
Non puoi inserire un valore di elevazione superiore alla montagna più alta di questo paese.
"elevation" < 5000
è chiesto di inserire un idenfificatore.
"identifier" IS NOT NULL
Definire i valori predefiniti¶
Preparazione da Desktop
Fields can have default values configured. Default values are inserted into the attribute form when digitizing a new feature. They are visible and can be modified as long as the field is editable.
Working with expressions¶
When creating expressions for projects intended to be used with QField, it is recommended to use layer names rather than layer IDs. This recommendation stems from the fact that during the project conversion process via QFieldSync, the resulting layers may receive different IDs, which can lead to incorrect expression evaluations. By using layer names, you ensure that expressions are evaluated consistently and accurately across different project states.
Variabili aggiuntive¶
For more information regarding storing information related to your position in object attributes, refer to the deticated GNSS documentation.
Per gli utenti di QFieldCloud, due variabili possono essere utilizzate nelle espressioni che includono i valori predefiniti degli attributi dei moduli:
- @cloud_username che restituisce il nome dell'utente QFieldCloud attualmente connesso.
- @cloud_useremail che restituisce l'indirizzo email dell'utente QFieldCloud attualmente connesso.
Casi di uso comune¶
Inserisci le informazioni di posizionamento come variabile:
@position_horizontal_accuracy
Inserisci l'ora e la data corrente:
now()
Inserisci la lunghezza della linea digitalizzata:
length($geometry)
Configura le variabili globali sul dispositivo e inseriscili.
@operator_name
Se vuoi assegnare un codice di regione basato sulla zona dove la nuova feature è inserita, puoi farlo utilizzando una espressione di aggregazione:
aggregate( layer:='regions', aggregate:='max', expression:="code", filter:=intersects( $geometry, geometry( @parent ) ) )
To transform the coordinates received from \@position_coordinate to the coordinate system of your project:
x(transform(@position_coordinate, 'EPSG:4326', @project_crs ))
y(transform(@position_coordinate, 'EPSG:4326', @project_crs ))
::: {#snapping_results} If you want to use the snapping results after drawing a line, you can use the [\@snapping_results]{.title-ref} variable. The following code extracts the value of the attribute [id]{.title-ref} of the snapping match of the first point of a line. :::
with_variable(
'first_snapped_point',
array_first( @snapping_results ),
attribute(
get_feature_by_id(
@first_snapped_point['layer'],
@first_snapped_point['feature_id']
),
'id'
)
)
Ricerca nei widget mappa valori e riferimento alla relazione¶
It is possible to search values in a value relation or relation reference widget using the magnifying glass next to the field.
Note
Define the display expression for the concerned layers, this will be used for searching for features. This is configured under Vector Layer Properties > Display
Configurare Valore Completamento Automatico¶
Preparazione da Desktop
The "Use completer" checkbox must be checked to be able to use the auto-complete in the value relation.
Here is a video showing how it works on QField
Definisci i widget QML¶
I widget QML personalizzati possono essere utili per integrare azioni avanzate nei form. In questo esempio definiamo aggiungi un pulsante che apre una mappa e un'app di navigazione di terze parti. Ciò è utile per aprire, ad esempio, le navigazioni turn-by-turn sull'app nativa del dispositivo per l'utente.
import QtQuick 2.0
import QtQuick.Controls 2.0
Button {
width: 200
height: width/5
text: "Open in Maps"
onClicked: {
Qt.openUrlExternally(expression.evaluate("'geo:0,0?q=' || $y || ',' || $x"));
}
}
L'URI geo sopra è adattato per funzionare con Android. Per Apple Maps l'URI può essere cambiato in 'geo:' || $y || ',' || $x.
