Simple Model View (SMV) is a Unity package meant to be a very simple implementation of a Model View-type system for simpliflying UI plumbing.

It creates a simple paradigm for:

• synchronizing a state value and multiple UI elements
• getting update events when a state value is changed either via UI element or via code.

Developed under Unity 2018.2

Clone this project and copy the Assets/SimpleModelView folder into your Unity project.

When you load the ExampleComplex scene, you'll be prompted to load TextMeshPro into the project - that's fine. However the transform for the example RotationSpeed_TextMeshProWorldSpace gets messed up, but don't worry about that for demo purposes.

You'll need to either:

• remove the two source files that use TextMeshPro (SMVViewTextMeshProUGUI and SMVViewTextMeshProWV) and ignore the warnings in the example scene
• or, get TextMeshPro and add it to your project

SMV uses a user-defined mapping to link a value with a UI element. The user specifies one or more mappings to use in a project

Each mapping is represented by a single value stored in an SMVControl (somewhat analogous to a controller in MVC paradigm), and by one or more SMVView components that each create a link to a UI element. This way, several UI elements (via SMVView) can be mapped to a single value (SMVControl) - for example if you have a Slider UI element and want a Text element to show its value, or if you have both desktop and VR UI's for your program with different UI elements. If the value in the SMVControl changes, either from code or UI interaction, all mapped UI elements will also be updated, and the new value is accessible via code.

The SMVView types SMVViewInputFieldFloat and SMVViewInputFieldInt will only accept float and integer values, respectively, and will discard invalid input strings when input by the user, and then restore the prior valid state.

using SMView;

It doesn't matter where you add it. In the examples, it's in a game object called SMV.

Access the members of the SMV singleton by accessing its instance: SMV.Instance

Edit the members of the SVMmapping enum in the script SMVmappings_USER_DEFINED. Give a descriptive name to each mapping you want.

For each UI element that you want to map, add the appropriate SMVView componenent, and assign the mapping it should use in the dropdown. For example, if you want to map a Slider, add an SMVViewSlider component to your slider, and choose the mapping it should use.

1. Automatically when a mapped UI element is changed.

2. Manually when your code calls SMV.Instance.SetValue(<mapping enum>) with the enum corresponding to the mapping you want to change.

From your code, simply call SMV.Instance.GetValueXYZ(<mapping enum>), where XYZ is the data type for the mapping.

Each SMVView type automatically handles value-change events for the UI element it belongs to. When an event is received, it updates the SMVControl that it is mapped to, which in turn updates any other SMVView objects that are a part of the mapping. The SMVControl then generates its own update that can be optionally handled by the user's code by supplying a listener to the SMV.OnUpdateEvent event in the editor (see below).

Load the sample scene ExampleBasic.

The SMV GameObject in the top of the scene holds the SMV singleton.

This example uses a single mapping (RotationSpeed) from those defined in SMVmappings_USER_DEFINED.cs. The other mappings are used in the ExampleComplex scene. Any mappings that aren't used by your UI elements are ignored.

In the scene under Canvas | Panel | SMV-mapped-items there are 3 UI elements. Look at each of them and you'll see each has an SMVView* component attached. They're all set to the RotationSpeed mapping.

When any of the UI elements are changed, the SMV system handles updating each of the other mapped elements (after validation in the case of SMVViewInputFieldFloat), and updates the state for the mapped SMVControl.

From the code in ExampleMainBasic component, you can see how the value of the mapping is accessed. A property is used to simplify access:

public float RotationSpeed
{
    set { SMV.Instance.SetValue(SMVmapping.RotationSpeed, value);  }
    get { return SMV.Instance.GetValueFloat(SMVmapping.RotationSpeed); }
}

Whenever RotationSpeed is assigned a value, the mapped UI elements are updated.

Load the sample scene ExampleComplex.

Besides showing examples of all the possible SMVView* types, this example shows how to receive change events for all mapped UI elements in one place.

When a mapping's value is changed (either from code or UI), an event is generated that can be handled by providing a listener for the SMV.OnUpdateEvent (set in the editor like for other UI event listeners).

In the listener, you can filter the event by mapping, and handle it (or ignore it) as you please. This provides an easy, single spot for handling value changes both from code and from UI.

For example, see the ExampleComplex script in the ExampleComplex scene:

public void OnSVMUpdate(SMVmapping mapping)
{
    //Log when we get an event for demo purposes, but skip the TimeLabel update since they're each frame
    if(mapping != SMVmapping.TimeLabel)
        Debug.Log("*** OnSVMUpdate called with mapping " + mapping.ToString());

    switch ((int)mapping)
    {
        case (int)SMVmapping.RotatingTextCount:
            SetupRotatingTextObjects();
            break;
        case (int)SMVmapping.TextColor:
            UpdateRotatingTextColor();
            break;
        default:
			//ignore this mapping
            break;
    }
}   

If you make some fixes or additions, submit a pull request! And thanks!

Michael Stauffer, Univ. of Pennsylvania, Philadelphia PA. [email protected]

This project is licensed under the MIT License - see the LICENSE file for details