Trying to Make My App Universal

Introduction

As mobile app developers, we’ve all been there - trying to create an app that can run on multiple devices with varying screen sizes and operating systems. In this article, we’ll explore the process of making a PhoneGap application universal, specifically focusing on how to handle different screen sizes and operating systems.

Understanding PhoneGap

PhoneGap is a popular framework for building cross-platform mobile apps using web technologies like HTML, CSS, and JavaScript. It allows developers to create apps that can run on multiple platforms, including iOS and Android, without the need for native code development.

To achieve this, PhoneGap uses a technique called " hybrid app development," where the app is built as a single web page application (SPA) that’s then packaged into a native container. This allows the app to leverage the best features of each platform while still maintaining a consistent user experience across devices.

In this article, we’ll dive deeper into PhoneGap’s architecture and explore strategies for making an app universal.

Configuring PhoneGap for Universal App Development

When building a PhoneGap application, it’s essential to configure the project correctly to ensure that your app is delivered as a single, unified build. Here’s how:

Step 1: Create a New PhoneGap Project

To start, create a new PhoneGap project using the command-line tool or by following the instructions in the PhoneGap documentation.

phonegap create MyApp

Navigate into the project directory and open the config.xml file to configure the app’s metadata.

Step 2: Set the Target Platform

In the config.xml file, set the target platform for your app by specifying the platforms you want to support. For example:

<platform name="ios">
    <config-name>iPhone</config-name>
    <config-name>iPad</config-name>
</platform>

<platform name="android">
    <config-name>Tablet</config-name>
    <config-name>Handset</config-name>
</platform>

Step 3: Configure the App’s Build

Next, configure the app’s build by specifying the build options for each platform. For example:

<build>
    <android>
        <manifest-additions>
            <add name="android:name" value="@{APP_NAME}" />
        </manifest-additions>
    </android>

    <ios>
        <preprocessor-definitions>
            <define name="UI_USER_INTERFACE_IDIOM" value="UIUserInterfaceIdiomPad" />
        </preprocessor-definitions>
    </ios>
</build>

In this example, we’re defining a custom APP_NAME variable for the Android build and setting the UI_USER_INTERFACE_IDIOM constant to UIUserInterfaceIdiomPad for the iOS build. This allows us to control the app’s behavior based on the device type.

Step 4: Update the AppDelegate.m File

In our example, we’ve updated the AppDelegate.m file to return a string that determines which HTML file to load based on the device type. Here’s the updated code:

+ (NSString*) startPage {
    if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
        return @"index.html";
    } else {
        return @"mobile/index.html";
    }
}

Step 5: Update the Targeted Device Family

Finally, update the targeted device family in the Info.plist file to match the configuration we’ve defined:

<key>UIUserInterfaceIdiom</key>
<string>UIUserInterfaceIdiomPad</string>

<key>UISupportedInterfaceOrientations</key>
<array>
    <string>UIInterfaceOrientationLandscapeLeft</string>
    <string>UIInterfaceOrientationLandscapeRight</string>
</array>

By following these steps, we’ve set up our PhoneGap project for universal app development. In the next section, we’ll explore how to handle different screen sizes and operating systems.

Handling Different Screen Sizes

When building a PhoneGap application, it’s essential to handle different screen sizes and resolutions to ensure that your app adapts seamlessly across devices.

Step 1: Use Relative Units

One way to handle different screen sizes is by using relative units in our CSS styles. This allows us to define layouts that scale dynamically based on the device’s screen size.

body {
    font-size: 16px;
    line-height: 24px;
}

.container {
    max-width: 600px;
    margin: 40px auto;
}

In this example, we’ve defined a container class that uses relative units to set the maximum width and padding. This ensures that the container’s size scales dynamically based on the device’s screen size.

Step 2: Use Responsive Images

Another way to handle different screen sizes is by using responsive images. This allows us to define multiple versions of an image with different sizes and resolutions, depending on the device’s screen size.

<img src="image-small.jpg" alt="" width="100px" height="100px">
<img src="image-medium.jpg" alt="" width="200px" height="200px">
<img src="image-large.jpg" alt="" width="300px" height="300px">

In this example, we’ve defined three versions of an image with different sizes and resolutions. The src attribute specifies the original image file, while the width and height attributes specify the target size for each device type.

Step 3: Use CSS Media Queries

Finally, we can use CSS media queries to apply different styles based on the device’s screen size or orientation. This allows us to define complex layouts that adapt seamlessly across devices.

@media only screen and (max-width: 600px) {
    .container {
        max-width: 100%;
        margin: 20px auto;
    }
}

@media only screen and (orientation: landscape) {
    .image-container {
        width: 80%;
        height: 50%;
    }
}

In this example, we’ve defined two media queries that apply different styles based on the device’s screen size and orientation. The first query applies a maximum width and padding to the container, while the second query sets the image container’s width and height.

Conclusion

Creating an app universal with PhoneGap requires careful planning and configuration. By following these steps, we’ve demonstrated how to handle different screen sizes and operating systems using relative units, responsive images, and CSS media queries.

Remember, the key to building a universal app is to focus on adaptability and flexibility. By designing your app’s layout and user interface with multiple device types in mind, you can create an experience that scales seamlessly across platforms.

In our next article, we’ll explore more advanced topics in PhoneGap development, including data storage and offline support.

Last modified on 2023-05-20