Solving the Mysterious com.airbnb.lottie.parser.moshi.JsonDataException: A Step-by-Step Guide

In the world of mobile app development, errors can be a frustrating and daunting obstacle. One such error that has been puzzling developers is the “com.airbnb.lottie.parser.moshi.JsonDataException: Expected a double but was END_ARRAY at path $.layers[0].shapes[0].it[1].c.k[3]” exception. In this article, we will delve into the world of Lottie animations, JSON parsing, and Moshi to understand the root cause of this error and provide a comprehensive guide to resolving it.

Understanding the Error Message

Before we dive into the solution, let’s break down the error message to understand what’s happening:

com.airbnb.lottie.parser.moshi.JsonDataException: 
Expected a double but was END_ARRAY at path $.layers[0].shapes[0].it[1].c.k[3]

This error message is telling us that:

• Lottie parser is throwing a JsonDataException
• The parser was expecting a double value but found an END_ARRAY instead
• The error occurred at the path $.layers[0].shapes[0].it[1].c.k[3]

What is Lottie?

Lottie is an open-source animation library developed by Airbnb that allows you to easily add animations to your mobile app. It uses JSON files to define the animation and provides a lot of flexibility and customization options. Lottie is widely used in many popular apps, including Instagram, Facebook, and TikTok.

What is Moshi?

Moshi is a modern JSON library for Android and Java that provides a simple and efficient way to parse JSON data. Moshi is used by Lottie to parse the JSON animation files. Moshi is known for its performance, flexibility, and ease of use.

Cause of the Error

The “com.airbnb.lottie.parser.moshi.JsonDataException: Expected a double but was END_ARRAY at path $.layers[0].shapes[0].it[1].c.k[3]” error typically occurs when the JSON animation file is malformed or contains invalid data. This can happen due to various reasons, such as:

• Incorrectly formatted JSON data
• Missing or duplicate keys
• Invalid or missing values
• Corrupted JSON file

Solution: Step-by-Step Guide

Now that we understand the error and its causes, let’s move on to the solution. Follow these steps to resolve the “com.airbnb.lottie.parser.moshi.JsonDataException: Expected a double but was END_ARRAY at path $.layers[0].shapes[0].it[1].c.k[3]” error:

Step 1: Check the JSON File

Open the JSON animation file and check for any syntax errors or formatting issues. You can use online tools like JSONLint or JSLint to validate the JSON data.

{
  "layers": [
    {
      "shapes": [
        {
          "it": [
            {
              "c": {
                "k": [10, 20, 30, 40] // Check if the values are correct
              }
            }
          ]
        }
      ]
    }
  ]
}

Step 2: Verify the Data Types

Check the data types of the values in the JSON file. In this case, the error message is indicating that the parser was expecting a double value but found an END_ARRAY instead. Make sure that the value is a double and not an array.

{
  "layers": [
    {
      "shapes": [
        {
          "it": [
            {
              "c": {
                "k": 10.5 // Instead of [10, 20, 30, 40]
              }
            }
          ]
        }
      ]
    }
  ]
}

Step 3: Check for Duplicate Keys

Duplicate keys in the JSON file can also cause parsing errors. Make sure to remove any duplicate keys and rename them to unique names.

{
  "layers": [
    {
      "shapes": [
        {
          "it": [
            {
              "c": {
                "k1": 10.5,
                "k2": 20.5 // Instead of having multiple "k" keys
              }
            }
          ]
        }
      ]
    }
  ]
}

Step 4: Validate the JSON File

Use online tools or Moshi’s built-in validation feature to validate the JSON file. This will help you catch any syntax errors or formatting issues.

Moshi moshi = new Moshi.Builder().build();
JsonAdapter<LottieAnimation> adapter = moshi.adapter(LottieAnimation.class);

try {
  LottieAnimation animation = adapter.fromJson(jsonData);
} catch (JsonDataException e) {
  Log.e("Error", e.getMessage());
}

Step 5: Update the Lottie Dependency

Make sure that you are using the latest version of the Lottie library. Sometimes, updating the dependency can resolve parsing issues.

dependencies {
  implementation 'com.airbnb.android:lottie:4.2.2'
}

Conclusion

In conclusion, the “com.airbnb.lottie.parser.moshi.JsonDataException: Expected a double but was END_ARRAY at path $.layers[0].shapes[0].it[1].c.k[3]” error can be resolved by following these steps: checking the JSON file for syntax errors, verifying the data types, checking for duplicate keys, validating the JSON file, and updating the Lottie dependency. By following this guide, you should be able to resolve the error and get your Lottie animations up and running.

Additional Resources

For further learning and troubleshooting, here are some additional resources:

• Lottie Android Documentation
• Moshi GitHub Repository
• JSONLint Online Tool

Error Message	Cause	Solution
com.airbnb.lottie.parser.moshi.JsonDataException: Expected a double but was END_ARRAY at path $.layers[0].shapes[0].it[1].c.k[3]	Malformed JSON data, incorrect data types, duplicate keys, or corrupted JSON file	Check the JSON file for syntax errors, verify data types, check for duplicate keys, validate the JSON file, and update the Lottie dependency

By following this comprehensive guide, you should be able to resolve the “com.airbnb.lottie.parser.moshi.JsonDataException: Expected a double but was END_ARRAY at path $.layers[0].shapes[0].it[1].c.k[3]” error and get your Lottie animations working smoothly. Remember to stay calm, be patient, and troubleshoot step-by-step to resolve the error.

Frequently Asked Questions

If you’ve encountered the error “com.airbnb.lottie.parser.moshi.JsonDataException: Expected a double but was END_ARRAY at path $.layers[0].shapes[0].it[1].c.k[3]” and are scratching your head, don’t worry, we’ve got you covered! Check out these frequently asked questions to get to the bottom of this pesky error.