iv_zxingimag  .setOnLongClickListener(new View.OnLongClickListener() {
    @Override
public boolean onLongClick(View viewm) {
        saveCurrentImage();
        return false;
    }
});

private void saveCurrentImage() {
    //獲取當前螢幕的大小
int width = getWindow().getDecorView().getRootView().getWidth();
    int 
 
height = getWindow().getDecorView().getRootView().getHeight();
    //生成相同大小的圖片
Bitmap temBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
    //找到當前頁面的根佈局
View view = getWindow().getDecorView().getRootView();
    //設定快取
view.setDrawingCacheEnabled(true);
    view.buildDrawingCache();
    //從快取中獲取當前螢幕的圖片,建立一個DrawingCache的拷貝，因為DrawingCache得到的點陣圖在禁用後會被回收
 
temBitmap = view.getDrawingCache();
    SimpleDateFormat df = new SimpleDateFormat("yyyymmddhhmmss");
    final String time = df.format(new Date());
    if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
        File file = new File(Environment.getExternalStorageDirectory
 
().getAbsolutePath() + "/screen", time + ".png");
        if (!file.exists()) {
            file.getParentFile().mkdirs();
            try {
                file.createNewFile();
            } catch (IOException e) {
                // TODO Auto-generated catch block
e.printStackTrace();
            }
        }
        FileOutputStream fos = null;
        try {
            fos = new FileOutputStream(file);
            temBitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);
            fos.flush();
            fos.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
e.printStackTrace();
        }
        new Thread(new Runnable() {
            @Override
public void run() {
                String path = Environment.getExternalStorageDirectory().getAbsolutePath() + "/screen/" + time + ".png";
                final Result result = parseQRcodeBitmap(path);
                runOnUiThread(new Runnable() {
                    public void run() {
                        if (null != result) {
                            Toast.makeText(TakewayActivity.this, result.toString(), Toast.LENGTH_SHORT).show();
                        } else {
                            Toast.makeText(TakewayActivity.this, "無法識別", Toast.LENGTH_LONG).show();
                        }
                    }
                });
            }
        }).start();
        //禁用DrawingCahce否則會影響效能 ,而且不禁止會導致每次截圖到儲存的是第一次截圖快取的點陣圖
view.setDrawingCacheEnabled(false);
    }
}
//解析二維碼圖片,返回結果封裝在Result物件中
private Result parseQRcodeBitmap(String bitmapPath) {
    //解析轉換型別UTF-8
Hashtable<DecodeHintType, String> hints = new Hashtable<DecodeHintType, String>();
    hints.put(DecodeHintType.CHARACTER_SET, "utf-8");
    //獲取到待解析的圖片
BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    Bitmap bitmap = BitmapFactory.decodeFile(bitmapPath, options);
    options.inSampleSize = options.outHeight / 400;
    if (options.inSampleSize <= 0) {
        options.inSampleSize = 1; //防止其值小於或等於0
}
    options.inJustDecodeBounds = false;
    bitmap = BitmapFactory.decodeFile(bitmapPath, options);
    //新建一個RGBLuminanceSource物件，將bitmap圖片傳給此物件
RGBLuminanceSource rgbLuminanceSource = new RGBLuminanceSource(bitmap);
    //將圖片轉換成二進位制圖片
BinaryBitmap binaryBitmap = new BinaryBitmap(new HybridBinarizer(rgbLuminanceSource));
    //初始化解析物件
QRCodeReader reader = new QRCodeReader();
    //開始解析
Result result = null;
    try {
        result = reader.decode(binaryBitmap, hints);
    } catch (Exception e) {
        // TODO: handle exception
}
    return result;
}

public class RGBLuminanceSource extends LuminanceSource {

    private byte bitmapPixels[];

    protected RGBLuminanceSource(Bitmap bitmap) {
        super(bitmap.getWidth(), bitmap.getHeight());

        // 首先，要取得該圖片的畫素陣列內容
int[] data = new int[bitmap.getWidth() * bitmap.getHeight()];
        this.bitmapPixels = new byte[bitmap.getWidth() * bitmap.getHeight()];
        bitmap.getPixels(data, 0, getWidth(), 0, 0, getWidth(), getHeight());

        // 將int陣列轉換為byte陣列，也就是取畫素值中藍色值部分作為辨析內容
for (int i = 0; i < data.length; i++) {
            this.bitmapPixels[i] = (byte) data[i];
        }
    }

    @Override
public byte[] getMatrix() {
        // 返回我們生成好的畫素資料
return bitmapPixels;
    }

    @Override
public byte[] getRow(int y, byte[] row) {
        // 這裡要得到指定行的畫素資料
System.arraycopy(bitmapPixels, y * getWidth(), row, 0, getWidth());
        return row;
    }
}