Views without Controllers

Introduction

Views can be created without controllers with an optional style sheet. These views can be used as building blocks to create a GUI.  After you have defined your controller-less views, the application can either require in these views using markup or can dynamically generate these views in the controller code.

XML Markup

In XML markup, use the Require tag to add controller-less views into another view.  Assign the src attribute to the name of the view file minus the .xml extension and the type to view.  Define the id attribute to access each instance of the controller-less view in the controller.

For instance, a button view could be reused repeatedly in a view-controller to construct a dialog box. For example, the following view can be defined without a controller:

This view can be inserted into another view multiple times by using the Require tag and assigning it an unique ID. For example,

Then, the controller can use $.button1, $.button2 and $.button3 to access each instance of the foo view.

Controller Code

Starting with Alloy 1.4.0, you can dynamically create views in the controller code.  Each component in the controller-less view needs to be assigned an id attribute.  Using the Require or Widgetelements to include external views in the controller-less view does not work using this procedure, that is, you can include the external views, but the styles cannot be updated with the updateViews method.

To create a view without a corresponding controller:

1. Use the Alloy.createController() method to create a controller from the controller-less view.  Pass a string with the name of the view minus the .xml extension as the only argument to the method
2. Use the updateViews() method with the created controller.  Pass a  style dictionary as the only argument to the method.  The style dictionary contains key-value pairs, where the key is the id of the view component and the value is another dictionary containing key-value pairs of attributes you want to set for the view component.
3. Use the getView() method to retrieve the view of the controller object.
4. Use the add() method to add the view to a view component in the controller.  Pass the instance of the controller-less view to the method.  The view component that wants to add the controller-less view should call the method.

For example, the following view defines an image with a label below it:

The controller code creates an instance of the controller-less view and adds the instance to main view in the controller.

Prior to Alloy 1.4.0, to dynamically generate a view with a controller:

1. Create a new instance of the controller using the Alloy.createController() method. Pass a string with the name of the view as the only argument to the method.
2. Modify the properties.
3. Use the getView() method to retrieve the view of the controller object.
4. Use the add() method to add the view to a view component in the controller.  Pass the instance of the controller-less view to the method.  The view component that wants to add the controller-less view should call the method.