More ways to use the Navigate function

Completed

There are many ways to set up navigation in your app, other than simply using the OnSelect property of a button or icon control. This unit introduces you to three common techniques: the OnSuccess property of a Form control, the OnTimerEnd property of a Timer control, and the OnChange property a Dropdown control.

OnSuccess navigation

For designers, a user experience consideration is providing some feedback to users who submit changes to data. Power Apps provides tools to give this feedback. If you insert a Success screen in your app, you'll want to land users on it only when Power Apps records updated data with success. So how do you do that?

First, find the Success screen in New screen > Templates. Then add it to your app.

Next, find your form and go to the OnSuccess property. It's important to send users to the Success screen only if Power Apps correctly writes their data. In the OnSuccess property, you can add a Navigate function with the name of your Success screen, such as:

Navigate(‘Success Screen’, ScreenTransition.Fade)

Then, you'll want your users to be able to go back to another screen. A good technique (other than making a selectable button or icon) is to add a Timer control.

OnTimerEnd navigation

Using a Timer control is a way to help move your users through your app. When the time runs out, the Navigate function moves to the designated screen. In our example, the Timer control would let the user see the success message for a few seconds and then go back to the catalog screen.

The Timer control is visible when you add it to your app, and it's set to a duration of 60,000 milliseconds (60 seconds). The AutoStart property is turned off, so you need to start it by creating a trigger. In the default mode, with a few adjustments, you can make it behave as you want. You'll practice these adjustments in the next unit's exercise, but here's a summary of the steps:

1. Insert a Timer control.

2. Set the AutoStart property to true.

3. Set the Duration property to 4000 (four seconds).

4. Set the OnTimerEnd property to Navigate('<yourScreenName>').

5. Set the Visible property to false.

With AutoStart set as true, the Timer control starts when the user lands on the screen in preview or play mode. In four seconds, the Navigate function fires and sends the user to another screen.

OnChange navigation

Another good navigation technique is to add a menu to your app as a Dropdown control. You can add dropdown functionality to a single screen and then copy it to other screens of your app.

A Dropdown control uses a table of data (data type: Table). In the Items property, you can add any table of data that you want. If you have just two screens for navigation, you can put a table in the Items property of your Dropdown control like this:

["","Catalog", "Admin"]

The square brackets indicate a table of data, and the code means exactly the same thing as this example:

Table({Value: ""},{Value: "Catalog"},{Value: "Admin"})

The square brackets provide a simpler way to enter the same data.

You added an empty text string ("") as your first value in the table. You assign that as the Default property.

With the Items property defined, you can then change the OnChange property of the Dropdown control.

Tip

Be careful to update the correct property of your Dropdown control. It's easy to make the mistake of updating the OnSelect property. Remember that you initiate the OnSelect property when you select the control, not when you change the control. Make sure that you update the OnChange property in an instance like this one.

The most efficient way to update the OnChange property for a Dropdown control is to use a Switch function, and to refer to the control by using the Self function. But you could also use an If function. Switch and If are both ways to evaluate a condition and then perform an action.

In the Contoso Coffee Machines app, for example, the Dropdown control would have the following code as the OnChange property:

Switch(Self.SelectedText.Value,
"Catalog",Navigate('Catalog Screen',ScreenTransition.Cover),
"Admin",Navigate('Admin Screen',ScreenTransition.Cover)
);
Reset(Self)

The Switch statement evaluates a particular value to see if it matches one of the results, and then it performs an action. In the preceding example, Self.SelectedText.Value is the value selected in the Dropdown control. If this value is Catalog, the Switch function executes the navigation to the catalog screen. If the value is Admin, the Switch function executes the navigation to the admin screen.

Switch executes only a single condition that depends on the matched value. So it's ideal when you have many possible courses of action based on a single value.

Finally, you use the Reset function to reset the Dropdown control to the Default value of "" (empty string).

If you didn't quite understand all of that information, don't worry. We'll walk through it again in the next unit's exercise.