產生和解碼二維條碼(QRCode)與一維條碼

Ref : http://www.unood.me/2013/07/android-qrcodecode39.html

有的應用程式需要將一段字符加密為一個二維條碼，我們可以用一個現成的開源程式碼來幫我們搞定二維碼，這個框架就是Google 自家的Zxing，它已經封裝好了對一維碼、二維碼的編碼和解碼的功能。

ZXing是一個用Java實作而且OpenSource專門用來判斷條碼的library，所以如果要自行開發相關判斷條碼功能的話，可以直接呼叫ZXing幫忙處理。為了不要依賴外部軟體，我將會介紹直接在你app內嵌Zxing條碼掃描、解碼功能的相關API。

在本篇中，以快速實現效果為準，並不會從原始碼編譯開始(因為那又要用到類似make的工具ant) ，這個ant我自己玩了幾個小時也沒玩出名堂，每次編都出現詭異的錯誤。
所以我會建議各位新手直接下載github上面做好的.jar檔案，直接匯入eclipse，直接開始使用。
然後我用的是2.2版的，最新的3.0不知道為什麼會出現VerifyError的錯誤，傻眼...

package com.example.qrcode_and_barcode;
	import java.util.HashMap;
	import android.app.Activity;
	import android.graphics.Bitmap;
	import android.graphics.drawable.BitmapDrawable;
	import android.os.Bundle;
	import android.widget.ImageView;
	import android.widget.TextView;
	import com.google.zxing.BarcodeFormat;
	import com.google.zxing.BinaryBitmap;
	import com.google.zxing.ChecksumException;
	import com.google.zxing.EncodeHintType;
	import com.google.zxing.FormatException;
	import com.google.zxing.LuminanceSource;
	import com.google.zxing.MultiFormatReader;
	import com.google.zxing.MultiFormatWriter;
	import com.google.zxing.NotFoundException;
	import com.google.zxing.RGBLuminanceSource;
	import com.google.zxing.Reader;
	import com.google.zxing.Result;
	import com.google.zxing.WriterException;
	import com.google.zxing.common.BitMatrix;
	import com.google.zxing.common.HybridBinarizer;
	public class MainActivity extends Activity
	{
	ImageView qrcode;
	ImageView barcode;
	TextView bar;
	TextView qr;
	@Override
	protected void onCreate(Bundle savedInstanceState)
	{
	super.onCreate(savedInstanceState);
	setContentView(R.layout.activity_main);
	qrcode = (ImageView) findViewById(R.id.qrcode);
	barcode = (ImageView) findViewById(R.id.barcode);
	qr = (TextView) findViewById(R.id.qr);
	bar = (TextView) findViewById(R.id.bar);
	try
	{
	String _要編碼的內容 = "0123456789";
	qrcode.setImageBitmap(encodeAsBitmap(_要編碼的內容, BarcodeFormat.QR_CODE, 300, 150));
	barcode.setImageBitmap(encodeAsBitmap(_要編碼的內容, BarcodeFormat.CODE_39, 400, 70));
	String barString = decode(getBitmapFromImageView(barcode));
	String qrString = decode(getBitmapFromImageView(qrcode));
	qr.setText(qrString);
	bar.setText(barString);
	}
	catch (WriterException e)
	{
	// TODO 自動產生的 catch 區塊
	e.printStackTrace();
	}
	}
	private Bitmap getBitmapFromImageView(ImageView v)
	{
	final BitmapDrawable bitmapDrawable = (BitmapDrawable) v.getDrawable();
	return bitmapDrawable.getBitmap();
	}
	private String decode(Bitmap bMap)
	{
	String contents = null;
	int w = bMap.getWidth();
	int h = bMap.getHeight();
	int[] intArray = new int[w * h];
	//copy pixel data from the Bitmap into the 'intArray' array
	bMap.getPixels(intArray, 0, bMap.getWidth(), 0, 0, bMap.getWidth(), bMap.getHeight());
	LuminanceSource source = new RGBLuminanceSource(bMap.getWidth(), bMap.getHeight(), intArray);
	BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
	// use this otherwise ChecksumException
	Reader reader = new MultiFormatReader();
	try
	{
	Result result = reader.decode(bitmap);
	contents = result.getText();
	}
	catch (NotFoundException e)
	{
	e.printStackTrace();
	}
	catch (ChecksumException e)
	{
	e.printStackTrace();
	}
	catch (FormatException e)
	{
	e.printStackTrace();
	}
	return contents;
	}
	public static Bitmap encodeAsBitmap(String contents, BarcodeFormat format, int desiredWidth, int desiredHeight) throws WriterException
	{
	if (contents.length() == 0) return null;
	final int WHITE = 0xFFFFFFFF;
	final int BLACK = 0xFF000000;
	HashMap<EncodeHintType, String> hints = null;
	String encoding = null;
	for (int i = 0; i < contents.length(); i++)
	{
	if (contents.charAt(i) > 0xFF)
	{
	encoding = "UTF-8";
	break;
	}
	}
	if (encoding != null)
	{
	hints = new HashMap<EncodeHintType, String>(2);
	hints.put(EncodeHintType.CHARACTER_SET, encoding);
	}
	MultiFormatWriter writer = new MultiFormatWriter();
	BitMatrix result = writer.encode(contents, format, desiredWidth, desiredHeight, hints);
	int width = result.getWidth();
	int height = result.getHeight();
	int[] pixels = new int[width * height];
	for (int y = 0; y < height; y++)
	{
	int offset = y * width;
	for (int x = 0; x < width; x++)
	{
	pixels[offset + x] = result.get(x, y) ? BLACK : WHITE;
	}
	}
	Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
	bitmap.setPixels(pixels, 0, width, 0, 0, width, height);
	return bitmap;
	}
	}