A Step-by-Step Guide to Implementing App Widgets on iOS (Part 1)

App Widgets are a great way to give users quick access to important information or functionality on their iOS devices. With the release of iOS 14 and Apple introduced support for customizable widgets, making it easier than ever for developers to create their own. In this guide, we'll walk through the steps of implementing an App Widget on iOS, including setting it up, configuring its appearance and functionality, and testing it. This topic will be split into several posts, so stay tuned. For the official document, here the Apple Documentation.

Step 1: Setting up the App Widget

The first step to implementing an App Widget on iOS is to create a new target in Xcode. Here's how to do it:

1. Open your project in Xcode and go to File > New > Target.
2. Select Widget Extension from the list of available templates and click Next.

1. Give product name for the Widget (e.g., MyWidget) and click Finish (Just untick for all tickable fields right now).

This will create an MyWidget directory under Your Project in Project Navigator. You can see your widget preview by open MyWidget.swiftand wait the preview loaded.

Step 2: Configuring the Widget Appearance

Now that we've created the basic structure of our App Widget, let's focus on its appearance. There are several ways to configure the widget's appearance, including its size, layout, and style.

Widget Size and Layout

The size of your widget can have a big impact on its usability and aesthetics. In iOS 14 and later, you can choose from three different widget sizes: small, medium, large, extra large. Each size has its own recommended layout and content guidelines, so it's important to choose the right size for your specific use case. Here the Human Interface Guidelines WidgetKit from Apple.

I want to add an Image to the default WidgetView. To configure the layout of your widget, you can use SwiftUI. SwiftUI provides a declarative syntax for building user interface.

Here's an example of how to create a simple widget view using SwiftUI:

struct MyWidgetEntryView : View {
    var entry: Provider.Entry

    var body: some View {
        VStack{
            Text(entry.date, style: .time)
            Image(systemName: "magnifyingglass.circle.fill").resizable()
                .aspectRatio(contentMode: .fit)
                .frame(width:80, height: 80)
        }.padding()
    }

}

This creates a widget view with a Text and an Image vertically with VStack. I added VStack and Image from default View that only show Text from current time. The .padding() modifier adds some space around the label to make it look more visually appealing.

Best Practices for Widget Layout

When designing your widget layout, it's important to follow best practices to ensure that it's both aesthetically pleasing and functional. Here are some tips to keep in mind:

• Keep your layout simple and easy to understand.
• Use clear and legible fonts and colors.
• Minimize the amount of text and other visual elements to ensure that the widget is easy to read and use.
• Use SwiftUI's or UIKit's layout

Step 3: Implementing Widget Functionality

Once you've configured the appearance of your App Widget, you'll need to add functionality to make it truly useful. Here's how to do it:

Interacting with Data Sources

To interact with data sources, you'll need to use a widget extension to access the data from your app. Here are the steps involved:

1. Add a widget extension target to your Xcode project.
2. Configure the extension to access the relevant data sources in your app.
3. Use the data to update your widget's appearance.

Using Deep Link URLs to Add Functionality

To access the relevant data sources in the App, I'm using a deep link URL to open a specific screen in your app when the user taps the widget. Here's how to do it:

1. Create a deep link URL for the screen you want to open in your app. For the example, this can be done using the URLComponents and URLQueryItem classes in Swift.

var components = URLComponents()
components.scheme = "myapp"
components.host = "screen"
let queryItem = URLQueryItem(name: "id", value: "1234")
components.queryItems = [queryItem]
let deepLinkURL = components.url!` 
```

In this example, the deep link URL opens a screen with the ID "1234" in an app with the scheme "myapp".

2.  Implement the `openURL(_:)` method in your widget's view to open the deep link URL when the widget is tapped.

```swift
struct MyWidgetEntryView : View {
    var entry: Provider.Entry

    var body: some View {
        VStack{
            Text(entry.date, style: .time)
            Link(destination: URL(string: "myapp://screen?id=1234")!){
                Image(systemName: "magnifyingglass.circle.fill").resizable()
                    .aspectRatio(contentMode: .fit)
                    .frame(width:80, height: 80)
            }

        }.padding()
    }
}
```

In this example, the I wrapped the `Image` with `Link`. When a user taps this `Link`, the app will open and do something to this URL. That why we need to setup the deep link on the App. 

3.  Handle the deep link URL in your app's `AppDelegate` to open the correct screen.

```swift
`func application(_ app: UIApplication, open url: URL, options: [UIApplication.OpenURLOptionsKey : Any] = [:]) -> Bool {
    guard let components = URLComponents(url: url, resolvingAgainstBaseURL: true),
          let id = components.queryItems?.first(where: { $0.name == "id" })?.value else {
        return false
    }
    // Open the correct screen based on the ID
    return true
}` 
```

In this example, the `application(_:open:options:)` method in the `AppDelegate` extracts the ID from the query parameters in the deep link URL and opens the correct screen in the app.

This is the example Widget with a working deep link:



### Step 4: Testing the App Widget

Testing your App Widget is crucial to ensure it works as expected before releasing it to users. Here are some tips on how to test your widget thoroughly:

#### Simulating the Widget in Xcode

1.  Open your project in Xcode and select the scheme for your widget target from the dropdown menu in the top left corner of the window.
2.  Click the "Run" button in the toolbar to build and run your widget in the simulator.

Xcode's simulator allows you to test your widget in various sizes and configurations, so make sure to test your widget in all possible configurations to ensure it looks and functions correctly.
{% embed https://youtube.com/shorts/nm_kNhdnCbs?feature=share %}


#### Testing on a Physical Device

While testing on the simulator is helpful, testing on an actual device is the best way to ensure your widget works as expected. Here's how to test your widget on a physical device:

1.  Connect your device to your computer and select it as the target device in Xcode.
2.  Build and run your widget on the device.

Testing on a device allows you to see how your widget looks and behaves in the real world, and can help you identify any issues that may not have been apparent in the simulator.

#### Troubleshooting Common Issues

During testing, you may encounter some common issues with your widget, such as layout problems or functionality bugs. Here's how to troubleshoot these issues:

##### Layout Problems

If your widget's layout isn't displaying as expected, you can use Xcode's debugging tools to identify the source of the problem. For example, you can use the "Debug View Hierarchy" tool to inspect the layout of your widget and identify any layout issues.

##### Functionality Bugs

If your widget's functionality isn't working as expected, you can use Xcode's debugging tools to identify the source of the problem. For example, you can use the "Debug Navigator" tool to step through your code and identify any logic errors that may be causing the issue.

**Conclusion:** Implementing an App Widget on iOS can be a great way to improve the user experience of your app and give users quick access to important information and functionality. By following the steps outlined in this guide, you can create a high-quality App Widget that looks great and functions well. Good luck!