Simple QR Code Scanner and Generator App (Android)

This Android application allows users to both scan QR codes using their device's camera and generate QR codes from text input.

Overview

The MainActivity class provides the main functionality of the application. It includes the following features:

• Scanning QR Codes: Uses the zxing-android library to integrate a camera-based QR code scanning functionality.
• Generating QR Codes: Takes text input from the user and generates a corresponding QR code image.

Functionality

The main screen (activity_main.xml layout, not shown here) contains the following interactive elements:

• Text View (tv_scan_result): Displays the result of a successful QR code scan.
• Edit Text (et_qr_string): Allows the user to enter text to be encoded into a QR code.
• Image View (iv_qr_image): Displays the generated QR code image.
• Button (btn_scan_barcode): When clicked, it launches the camera activity for scanning a QR code.
• Button (btn_add_qrcode): When clicked, it takes the text from the EditText and generates a QR code, which is then displayed in the ImageView.

Scanning a QR Code

1. Click the "Scan Barcode" button.
2. This will open the camera interface provided by the CaptureActivity from the zxing-android library.
3. Point the camera at a QR code.
4. If the scan is successful, the decoded text from the QR code will be displayed in the TextView (tv_scan_result).

Generating a QR Code

1. Enter the desired text into the EditText (et_qr_string).
2. Click the "Generate QR Code" button.
3. A QR code representing the entered text will be generated and displayed in the ImageView (iv_qr_image).
4. If the EditText is empty when the "Generate QR Code" button is clicked, a toast message will inform the user that the text cannot be empty.

Dependencies

This application relies on the following external library:

• zxing-android: This library provides the necessary components for capturing (scanning) and encoding (generating) QR codes and barcodes. The specific dependencies are likely managed through Gradle in the project's build.gradle files (not shown here). You would typically see dependencies like:

  implementation 'com.journeyapps:zxing-android-embedded:3.x.x' // For the CaptureActivity
  implementation 'com.google.zxing:core:3.x.x' // For the core ZXing functionality

Getting Started (Conceptual)

To build and run this application, you would typically:

1. Set up an Android development environment with Android Studio.
2. Create a new Android project or open an existing one.
3. Add the necessary zxing-android library dependencies to your project's build.gradle files.
4. Create the layout file (activity_main.xml) with the described UI elements.
5. Copy this MainActivity.java file into your project's source code directory.
6. Build and run the application on an Android emulator or a physical Android device.

Notes

• This code snippet focuses on the MainActivity logic. The layout file (activity_main.xml) and the implementation details of the CaptureActivity and EncodingHandler (from the zxing-android library) are not included here.
• Error handling for camera permissions and potential exceptions during QR code generation could be further enhanced in a production application.
• The size of the generated QR code (350 pixels in this case) can be adjusted in the EncodingHandler.createQRCode() method.