How to Fix the 'R.java: error <identifier> expected' Issue in Android Development

What causes the 'R.java: error <identifier> expected' issue in Android, and how can it be resolved?

// No code snippet is provided initially.

The 'R.java: error <identifier> expected' is a common compilation error encountered in Android development. It indicates that the compiler found an issue with one or more resource identifiers, preventing the generation of the R.java file, which is crucial for accessing resources within your app.

// Example of correctly formatted XML resource file:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!" />

</LinearLayout>

Causes

• Missing or incorrect XML syntax in layout files, manifest files, or other resource files.
• Invalid characters in resource names (e.g., using capital letters or special characters).
• Resource files that have not been saved, leading to inconsistencies during the build process.
• Comments or incorrect nesting within XML files that disrupt their structure.

Solutions

• Check XML files for syntax errors and ensure they follow proper formatting.
• Verify that resource names are all lowercase and contain only letters, numbers, or underscores.
• Clean and rebuild your project using Build -> Clean Project and then Build -> Rebuild Project.
• Make sure all resource files are saved and free from unsaved changes before building the project.

Mistake: Using capital letters or special characters in resource names.

Solution: Ensure that all resource names are in lowercase and only contain letters, numbers, or underscores.

Mistake: Forgetting to save changes in XML files before building the project.

Solution: Always save all XML and resource files before attempting to build the project.

Mistake: Having typos or mistakes in comments within XML files.

Solution: Avoid complex comments and ensure comments are correctly formatted.