PrintHand Printing Sample

Android sample application demonstrating how to integrate the PrintHand mobile printing SDK.

Features

• Share Intent – Print images, web pages, and arbitrary files via Android's standard share mechanism.
• Intent API – Discover printers, obtain printer information, and submit print jobs directly via the PrintHand Intent API.
• Printing SDK – Full SDK integration using the PrintHand background service for silent, programmatic printing.
• MIFARE Classic NFC – Read and write MIFARE Classic NFC tags (access control data, counters, secure storage).

MIFARE Classic NFC Support

The app includes MifareClassicHelper, a utility class for all core MIFARE Classic tag operations.

Supported Operations

Operation	Method	Description
Connect	connect(Tag)	Open a connection to a MIFARE Classic tag
Authenticate	authenticateSector(mfc, block, keyType, key)	Authenticate a sector with Key A or Key B
Read	readBlock(mfc, block)	Read 16 bytes from a block
Write	writeBlock(mfc, block, data)	Write 16 bytes to a block
Increment	increment(mfc, block, amount)	Add to a value block
Decrement	decrement(mfc, block, amount)	Subtract from a value block
Transfer	transfer(mfc, block)	Commit a staged increment/decrement
Restore	restore(mfc, block)	Load a value block into the transfer buffer
Close	closeQuietly(mfc)	Close the tag connection

Quick Start

// Must run on a background thread – not the UI thread.
MifareClassic mfc = MifareClassicHelper.connect(tag);
if (mfc == null) return; // not a MIFARE Classic tag

try {
    byte[] key = MifareClassicHelper.DEFAULT_KEY; // replace with your per-sector key
    int block = 4; // first data block of sector 1

    // Authenticate
    boolean ok = MifareClassicHelper.authenticateSector(
            mfc, block, MifareClassicHelper.KEY_TYPE_A, key);
    if (!ok) return;

    // Read
    byte[] data = MifareClassicHelper.readBlock(mfc, block);

    // Write
    byte[] payload = new byte[MifareClassicHelper.BLOCK_SIZE]; // 16 bytes
    System.arraycopy(data, 0, payload, 0, payload.length);     // modify as needed
    MifareClassicHelper.writeBlock(mfc, block, payload);

    // Value-block increment and commit
    MifareClassicHelper.increment(mfc, block, 1);
    MifareClassicHelper.transfer(mfc, block);
} catch (IOException e) {
    Log.e(TAG, "NFC I/O error", e);
} finally {
    MifareClassicHelper.closeQuietly(mfc);
}

Security Notes

• Replace the default key (FF FF FF FF FF FF) with unique per-sector keys in production.
• Derive sector keys from a master key and the tag UID (key diversification) so that compromising one tag does not expose others.
• All NFC I/O must run on a background thread.
• MIFARE Classic uses the proprietary Crypto-1 cipher, which has known weaknesses. Migrate to MIFARE DESFire EV2/EV3 or NTAG 424 DNA for high-security applications.

Integration

Add the PrintHand SDK to your build.gradle:

dependencies {
    implementation 'com.dynamixsoftware.intentapi:intentAPI:12'
    implementation 'com.dynamixsoftware.printingsdk:printingSDK:12'
}

License

See the upstream DynamixSoftware/PrintingSample repository for license information.