dzy Viewer

A lightweight Android app designed to open .dzy files, which are ZIP-like archives containing index.html, styles.css, and assets, displaying them in a WebView.

How It Works

1. Handling File Opening

• The app registers an intent filter in AndroidManifest.xml to handle .dzy files from both file:// and content:// URIs.
• When a user selects a .dzy file, the system sends the file URI to MainActivity.java.

2. Extracting .dzy Archive

• Since .dzy is a ZIP-like format, the app extracts its contents into the app's private storage.
• The extraction process:
  • Reads the .dzy file using a ZipInputStream.
  • Extracts index.html, styles.css, and other assets into a temporary directory.
  • Ensures security by restricting access to extracted files.

3. Loading in WebView

• After extraction, the WebView loads index.html from the extracted directory.
• JavaScript and CSS are enabled for proper rendering.
• If the file fails to load, the app displays a custom error page.

4. Error Handling

• If the .dzy file is corrupted, missing index.html, or unreadable, a custom error page is shown using loadData() in WebView.

5. App Hiding Mechanism

• The app does not appear in the app drawer by modifying the AndroidManifest.xml to remove the launcher intent filter.
• It can only be accessed when opening a .dzy file from another app.

Technologies Used

• Java (No AppCompat or AndroidX)
• Android WebView for displaying extracted HTML content
• ZipInputStream for extracting .dzy archives
• Intent Filters for handling file opening

Security Considerations

• Files are extracted into private storage (getCacheDir() or getFilesDir()).
• No external storage permissions are required.
• Auto-clearing data prevents leftover extracted files.