Add a Behavior

It’s time to business logic behavior. You’ll start by working on the user interface created from Add Screen guide.

Events and business logic add behavior to your application. In this tutorial, we will add a event to respond to a release event on the qsButton widget. We will add logic to transition to screen1. On Screen1, we will add an event on the Exit button. We will add logic to transition back to screen0.

Add a Release Event for qsButton

Enable the release event

1. In the Screen designer or Screen Tree pane, select qsButton to activate its properties in the Object Editor.

In the Object editor under Events section, enable Released. Alternatively, you can click Project->Event Manager to display the Event Manager.

Upon MHC generate, the following event callback code will be generated:

le_gen_screen_Screen0.h

// event handlers
// !!THESE MUST BE IMPLEMENTED IN THE APPLICATION CODE!!
void event_Screen0_qsButton_OnReleased(leButtonWidget* btn);

le_gen_screen_Screen0.c

Screen0_qsButton->fn->setReleasedEventCallback(Screen0_qsButton, event_Screen0_qsButton_OnReleased); |

app_Screen0.c - We recommend users create a separate applicaton file for each screen. Event handlers defined in le_gen_screen_Screen0.h should be implemented in your app_Screen0.c file. Implemented the following code in your app_Screen0.c file.

// event handlers
void event_Screen0_qsButton_OnReleased(leButtonWidget* btn)
{
    legato_showScreen(screenID_Screen1);                    // transition to screen1
}

Add a On Show Event for screen1

Enable the On Show event

1. In the Screen designer select screen1 to activate its properties in the Object Editor.

In the Object editor under Events section, enable On Show.

Upon MHC generate, the following event callback code will be generated:

le_gen_screen_Screen1.h

// Screen Events:
void Screen1_OnShow(); // called when this screen is shown);

le_gen_screen_Screen1.c

Screen1_OnShow(); // raise event |

app_Screen1.c - We recommend users create a separate applicaton file for each screen. Event handlers defined in le_gen_screen_Screen1.h should be implemented in your app_Screen1.c file. Implement the following code in your app_Screen1.c file.

// event handlers
void Screen1_OnShow()
{
    // Add business logic to respond to the OnShow event

}

Click File -> Save to finalize your new event addition.

Add a Release Event for ButtonWidget0 Button

Enable the release event

1. In the Screen designer or Screen Tree pane, select ExitButton to activate its properties in the Object Editor.

In the Object editor under Events section, enable Released. Alternatively, you can click Project -> Event Manager to display the Event Manager.

Upon MHC generate, the following event callback code will be generated:

le_gen_screen_Screen1.h

// event handlers
// !!THESE MUST BE IMPLEMENTED IN THE APPLICATION CODE!!
void event_Screen1_ExitButton_OnReleased(leButtonWidget* btn);

le_gen_screen_Screen1.c

Screen1_ExitButton->fn->setReleasedEventCallback(Screen1_ExitButton, event_Screen1_ExitButton_OnReleased);

app_Screen1.c - We recommend users create a separate applicaton file for each screen. Event handlers defined in le_gen_screen_Screen0.h should be implemented in your app_Screen0.c file. Implemented the following code in your app_Screen1.c file.

// event handlers
void event_Screen1_ExitButton_OnReleased(leButtonWidget* btn)
{
    legato_showScreen(screenID_Screen0);                    // transition to screen0
}

Click File -> Save to finalize your new event addition.

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Next Step

In this tutorial, you learned how to use the Event Manager window to enable composer to generate qsButton and cancel button released event code. You learn to enable an onShow event for screen1. These events allow you to control your applications behavior. At this point, you’re ready build and run your application. This tutorial series is complete.

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If you are new to MPLAB® Harmony, you should probably start with these tutorials:

• MPLAB® Harmony v3 software framework
• MPLAB® Harmony v3 Configurator Overview
• Create a New MPLAB® Harmony v3 Project

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