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Interconnecting the ConverterController Class and the User Interface

The following sections show how to connect the Converter Controller user interface and the ConverterController class to each other.

In this section:

Create an Instance of the ConverterController Class
Connect the ConverterController Class to the Text Fields
Connect the Convert Button to the ConverterController convert Action Method

Create an Instance of the ConverterController Class

As the final step of defining a class in Interface Builder, you create an instance of the ConverterController class and connect its outlets and actions. To carry out this task, perform these steps:

1. Select ConverterController in the Classes pane in the MainMenu.nib window.

2. Choose Instantiate ConverterController from the Classes menu. The instance appears in the Instances pane as shown in Figure 1-20. Notice that the instance has a yellow badge with an exclamation point next to it. This means the instance contains unconnected outlets.

   
   

   Figure 1-20  A newly instantiated ConverterController instance

   

Connect the ConverterController Class to the Text Fields

By connecting it to specific objects in the interface, you initialize its outlets. ConverterController uses these outlets to get and set values in the user interface. Follow these steps to connect the ConverterController instance to the user interface:

1. In the Instances pane in the nib file window, Control-drag a connection from the ConverterController instance to the Exchange Rate text field.

2. Interface Builder displays the Connections pane of the inspector. Select the outlet that corresponds to the first field, rateField.

3. Click Connect, as shown in Figure 1-21.

   
   

   Figure 1-21  Connecting ConverterController to the rateField outlet

   

4. Following the same steps, connect ConverterController’s dollarField and amountField outlets to the appropriate text fields.

Connect the Convert Button to the ConverterController convert Action Method

Follow these steps to connect the user interface elements in the Currency Converter window to the methods of the ConverterController class:

1. Control-drag a connection from the Convert button to the ConverterController instance in the nib file window.

2. In the Connections pane in the nib file window, make sure the Target/Action pane is displayed.

3. Select convert() in the Actions in ConverterController list and click Connect.

4. Save the nib file.

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