Flutter Flow Chart

A package that let you draw a flow chart diagram with different kind of customizable elements. Dashboards can be saved for later use.

Image

See online example here

Features

  • diamond, rectangle, oval, storage, parallelogram elements
  • elements can be customizable with background, border and text color, border thickness, text size and weight.
  • interactively connect elements
  • save/load dashboard

Usage

First create a Dashboard:

Dashboard dashboard = Dashboard();

then crete the FlowChart widget where you can react to the user interactions:

FlowChart(
    dashboard: dashboard,
    onDashboardTapped: ((context, position) {}),
    onDashboardLongtTapped: ((context, position) {}),
    onElementLongPressed: (context, element) {},
    onElementPressed: (context, element) {},
    onHandlerPressed: (context, position, handler, element) {},
    onHandlerLongPressed: (context, position, handler, element) {},
)

then use the dashboard variable to add, remove, resize etc. elements or load/save the dashboard.

In the example, the StarMenu package is used to easily interact with user inputs.

The Dashboard

The Dashboard object contains all the methods described below used to interact with the flow chart.

relevant methods description
setGridBackgroundParams set grid background parameters
setHandlerFeedbackOffset set the feedback offset to help on mobile device to see the end of arrow and not hiding behind the finger when moving it
setElementResizable set the element as resizable. A handle will be displayed on the bottom right and will disappear when finish resizing
addElement add a FlowElement to the dashboard
removeAllElements remove all elements
removeElementConnection remove the given handler connection of the given element
removeElementConnections remove all the connections from the given element
removeElementById remove all the elements with the given id from the dashboard
removeElement remove the given element
addNextById make a connection from the given sourceElement to the elements with the given id
saveDashboard save the dashboard into the given file path
loadDashboard clear the dashboard and load the new one

The FlowElement

The FlowElement defines the element kind with its position, size, colors and so on.

properties type description
position Offset The position of the FlowElement
size Size The size of the FlowElement
text String Element text
textColor Color Text color
textSize double Text size
textIsBold bool Makes text bold if true
kind ElementKind Element shape: enum {rectangle, diamond, storage, oval, parallelogram}
handlers List Connection handlers: enum {topCenter, bottomCenter, rightCenter, leftCenter}
handlerSize Size The size of element handlers
backgroundColor Size Background color of the element
borderColor Size Border color of the element
borderThickness Size Border thickness of the element
elevation Size Shadow elevation
next List Shadow elevation
relevant methods description
setIsResizing When setting to true, a handler will disply at the element bottom right to let the user to resize it. When finish it will disappear.
setText Set element text
setTextColor Set text color
setTextSize Set text size
setTextIsBold Set text bold
setBackgroundColor Set background color
setBorderColor Set border color
setBorderThickness Set border thickness
setElevation Set elevation
changePosition Change element position in the dashboard
changeSize Change element size

Examples

Add an element to Dashboard

Dashboard dashboard = Dashboard();

///////////////////////////////////
/// Define 2 elements
FlowElement element1 = FlowElement(
    /// position in the local dashboard coordinates
    position: const Offset(100, 100),
    /// element size
    size: const Size(100, 100),
    /// text to show
    text: 'diamond',
    /// rectangle, diamond, storage, oval or parallelogram element kind
    kind: ElementKind.diamond,
    /// which handler to make active
    handlers: [
        Handler.bottomCenter,
        Handler.topCenter,
        Handler.leftCenter,
        Handler.rightCenter,
    ]);
FlowElement element2 = FlowElement(
    position: const Offset(300, 100),
    size: const Size(100, 150),
    text: 'rect',
    kind: ElementKind.rectangle,
    handlers: [
        Handler.bottomCenter,
        Handler.topCenter,
        Handler.leftCenter,
        Handler.rightCenter,
    ]);
///////////////////////////////////
/// Add the element to Dashboard
dashboard.addElement(element);

///////////////////////////////////
/// Connect right handler of element1 
/// to the left handler of element2
dashboard.addNextById(
    element1,
    element2.id,
    ArrowParams(
        thickness: 1.5,
        color: Colors.Black,
        startArrowPosition: Alignment.centerRight,
        endArrowPosition: Alignment.centerLeft,
    ),
);

///////////////////////////////////
/// Save/load dashboard
Directory appDocDir =
    await path.getApplicationDocumentsDirectory();

dashboard.saveDashboard('${appDocDir.path}/FLOWCHART.json');

dashboard.loadDashboard('${appDocDir.path}/FLOWCHART.json');

Libraries

flutter_flow_chart