How to build Canvas App in Power Apps - Part II

Table of Content:

• Improve apps by making basic customizations in Power Apps
• Explore screens and controls in Power Apps
• Get started with functions in Power Apps

Improve apps by making basic customizations in Power Apps

In the previous module, you generated the Flooring Estimates app and started to explore its default design. While the default screens make a useful app out of the box, you'll often want to customize a generated app to suit your needs.

This unit explains basic changes for each screen in the app. You can do a lot more to customize an app, but the best way to start learning is to take a generated app and make common customizations. This will allow you to become familiar with the controls, layouts, and functions.

Browse screen

The Flooring Estimates app already shows an image and some text for each product, but the layout could be better.

To improve the layout, use the following procedure:

• On the Screens pane on the left, select BrowseGallery

The selection box around the gallery confirms your choice.

• On the right pane, open the Data pane by selecting the drop-down menu next to Layout.

• Select a different layout, such as the one that shows the image, the title, and the subtitle but not the body.

• Select the category of the item at the top of the gallery.

• Change ThisItem.Category to ThisItem.Name in the formula bar.
• Repeat the previous two steps but change the other Label control to show the price of each item

• Changing the layout of a gallery and the types of data that it shows is that simple, and you might find that it's fun, too.

Details screen

On the details screen, you want to change the order of the fields. The controls on this screen differ from the controls on the browse screen, so the process for changing them is also slightly different.

• On the Screens pane on the left, select DetailScreen1 > DetailForm1.
• On the right pane, select Edit fields.

• Drag the Name field to the top of the list of fields and then drag the Image field to the bottom.

Edit/create screen

On the screen where your users edit and create entries, you want to make it easier for them to enter information in a text box.

1. On the Screens pane on the left, select EditScreen1 > EditForm1.
2. On the right pane, select Edit fields.
3. Expand Overview. Select the drop-down arrow for the Control type and then select Edit multi-line text.
4. A multi-line edit control will simplify your user's ability to add more than a few words in this field.

A few basic steps can greatly improve the appearance and experience of using an app, and Power Apps Studio provides many options for customizing those apps.

Explore screens and controls in Power Apps

This unit examines the screens and other controls that define the behavior of apps that Microsoft Power Apps generates. All the details won't be covered; however, knowing more about how these apps work will help you build your own apps.

Controls in Power Apps

A control is a UI element that produces an action or shows information. Many controls in Power Apps are similar to controls that you've used in other apps: labels, text-input boxes, drop-down lists, navigation elements, and so on.

In addition to these typical controls, Power Apps has more specialized controls, which you can find on the Insert tab.

A few controls that can add interest and impact to your apps include:

• Galleries - These controls are layout containers that hold a set of controls that show records from a data source.
• Forms - These controls show details about your data and let you create and edit records.
• Media - These controls let you add background images, include a camera button (so that users can take pictures from the app), a barcode reader for quickly capturing identification information, and more.
• Charts - These controls let you add charts so that users can perform instant analysis while they're on the road.

To see what controls are available, select the Insert tab, and then select each option in turn.

Explore the browse screen

Each screen in the app has multiple controls, but one control takes up most of the screen space. The first screen in the app is the browse screen, which is named BrowseScreen1 by default.

Controls in the browse screen that you'll want to become familiar with include:

• BrowseGallery1 - This control takes up most of the screen and shows data from your data source.
• NextArrow1 - When this control is selected, it opens the details screen.
• IconNewItem1 - When this control is selected, it opens the edit/create screen.

Explore the details screen

The details screen is named DetailScreen1 by default. Some of its controls are as follows:

• DetailForm1 - This control contains other controls and contains a data card for each field of the record that is being displayed.
• DataCard1 - This is a card control. Each card represents a single field of the record. In this case, it shows a flooring category from the Flooring Estimates table, as shown in the previous unit.
• IconEdit1 - When this control is selected, it opens the edit/create screen so that the user can edit the current item.

Explore the edit/create screen

The third screen in the app is EditScreen1. Some of its controls include:

• EditForm1 - This control contains other controls and contains a data card for each field of the record that is being edited.
• DataCard8 - This is another card control that shows a flooring category from the Flooring Estimates table, as shown in the previous unit.
• IconAccept1 - When this control is selected, it saves the user's changes.

Get started with functions in Power Apps

When using Microsoft Power Apps, you don't have to write complicated application code the way that a traditional developer does. However, you must express logic in an app and control its navigation, filtering, sorting, and other functionalities. This is where formulas come in.

If you've used Microsoft Excel functions, you should recognize the approach that Power Apps takes. This unit shows a couple of basic formulas for text formatting and then describes three of the formulas that Power Apps includes when it generates an app. With this information, you'll have a better idea of what formulas can do, and then you can also start to write your own.

Get started with formulas and properties

The previous unit explored controls in all three screens of an app that Power Apps generated. In this section, you’ll use the properties of the label control to format the price in the gallery.

By default, the price appears as a plain number without a currency symbol. Suppose that you want to add a dollar sign and change the text color based on the item's cost (for example, red if it's more than $5 but green otherwise). The following graphic shows the expected result.

By default, Power Apps pulls in a price value for each item. This value is set as the Text property of the label that shows the price.

 Note - Be sure to complete the steps in unit 1 of this module as the description field is changed to price as reflected in the next steps.

• In BrowseScreen1, select the price of the first item.

• In the drop-down list of properties, select Text.
• To add the currency symbol for US dollars, set the Text property to this formula:

Text(ThisItem.Price, "$ ##.00")

Note - If your formula returns an error, then please note that the language setting of your Power Apps environment can affect some separators and operators. For example, the above formula is expressed in a language and region that uses dot or period as the decimal separator, such as Japan or the United Kingdom. However, this same formula in a language and region where a comma is used for the decimal separator, such as France or Spain, the formula will need to be: Text(ThisItem.Price; "$ ##,00")

The property selection operator (dot or period) in ThisItem.Price is always the same, no matter what the decimal separator is, but notice that the decimal separator and the chaining operation separator changed to a comma and semicolon respectively. Internally the formula doesn't change, all that changes is how it's displayed and edited by the author. See Formula separators and chaining operator for more information.

The Text function specifies how to format the number. The formula is like an Excel function, but Power Apps formulas refer to controls and other app elements instead of cells in a workbook.

If you select a control and then open the property drop-down list, a list of properties that are relevant to the control appears. For example, the following is a partial list of the properties for a Label control. Some properties are relevant across a wide range of controls, but others are relevant only for a specific control.

To conditionally format the price's color, select the price Label and choose the Color property and set it to this formula:

If(ThisItem.Price > 5, Color.Red, Color.Green)

Formulas included in the generated app

Power Apps uses a couple of formulas in every app that it generates. Both examples are from the browse screen and work with the OnSelect property. This property defines what happens when a user selects a control.

• The first formula is associated with the IconNewItem1 control +. Select this control to open the edit/create a screen where you can create an item. To view the formula, select the + and then select it in the formula bar. The formula is as follows:

NewForm(EditForm1);Navigate(EditScreen1, ScreenTransition.None)

The formula instantiates an edit page on the edit/create screen so that users can create an item. A value of ScreenTransition.None means that there's no transition, such as a fade, between screens.

• The second formula is associated with the IconSortUpDown1 control. Select this control to sort the items in the gallery. The formula is as follows:

UpdateContext({SortDescending1: !SortDescending1})

The formula uses UpdateContext to update a variable called SortDescending1. The exclamation "!" symbol in the formula is a shortcut for the Not function. The value of the variable switches back and forth as you select the control. This variable tells the gallery on this screen how to sort the items.

The app contains many other formulas, so take some time to select controls and determine what formulas are set for various properties.

For more information about these and other functions, refer to formula reference for Power Apps page.

For additional information on customizing a canvas app, refer to the Use the UI and controls in a canvas app in Power Apps learning path and the Use basic formulas to make a better canvas app in Power Apps learning path.

Summary

This module showed you how to customize an app by adding controls, formatting, and logic in Power Apps.

Additionally, you were able to:

• Change the layout of a gallery.
• Change the data that a control shows.
• Change the order in which fields appear.
• Change the control with which a user provides information.
• Format a number as a price and coloring prices based on their values.

This article is part of Microsoft Certified: Power Platform App Maker Associate and will be one of many in the series of articles on my journey to become Microsoft Power Platform Architect:

1. PL – 900 – Power Platform Fundamentals
2. PL – 100 - Microsoft Power Platform App Maker
3. PL – 200 - Microsoft Power Platform Functional Consultant
4. PL – 400 - Microsoft Power Platform Developer
5. PL – 600 - Microsoft Power Platform Solution Architect

Until next time,

Nikola Basta