Question

我需要选择一个非常大的字符串的特定部分（从QR代码解码）以在Android中的TextView元素中设置为文本。

//*these are the parts of the string whose corresponding values I need as a text for my TextViews.*

String uid, name, gname, gender, house, street, ps, po, dist, subdist, state, pin, address, dob;

//*this 'string' object holds the decoded qr string*

String string = "uid="001" name="Akbar Shah" gender="M" yob="1989" gname="Jahangir Shah" co="S/O: Jahangir Shah" house="45/5" street="Huzurey Ala Street" vtc="Alibagh" po="Bagnan" dist="Faridabad" subdist="Alamgarh" state="Andhra" pc="6754674" dob="15/04/89"";

//*this is where I am using substring() to get a specific part of the string value*

uid = string.substring(string.indexOf("uid=")+5, string.indexOf("name=")-2);
name = string.substring(string.indexOf("name=")+6, string.indexOf("gender=")-2);
gname = string.substring(string.indexOf("gname=")+7, string.indexOf("co=")-2);
gender = string.substring(string.indexOf("gender=")+8, string.indexOf("yob=")-2);

house = string.substring(string.indexOf("house=")+7, string.indexOf("street=")-2);
street = string.substring(string.indexOf("street=")+8, string.indexOf("vtc=")-2);
ps = string.substring(string.indexOf("vtc=")+5, string.indexOf("po=")-2);
po = string.substring(string.indexOf("po=")+4, string.indexOf("dist=")-2);
dist = string.substring(string.indexOf("dist=")+6, string.indexOf("subdist=")-2);
subdist = string.substring(string.indexOf("subdist=")+9, string.indexOf("state=")-2);
state = string.substring(string.indexOf("state=")+7, string.indexOf("pc=")-2);
pin = string.substring(string.indexOf("pc=")+4, string.indexOf("dob=")-2);
dob = string.substring(string.indexOf("dob=")+5, string.indexOf("/>")-1);

//*this is where I have concatenated the whole address parts into one*
address = house+", "+street+", \nPS - "+ps+", \nPO - "+po+", \nDistrict - "+dist+", \nSub-Division - "+subdist+", \nState - "+state+", \nPin Code - "+pin;

 TextView tv_uid, tv_name, tv_gName, tv_gender, tv_address, tv_dob;

//*this is where  I then setText those substrings for appropriate TextViews*

                    tv_uid.setText(uid);
                    tv_name.setText(name);
                    tv_gName.setText(gname);
                    tv_gender.setText(gender);
                    tv_address.setText(address);
                    tv_dob.setText(dob);

我这样做的方法只有在解码的QR字符串格式保持不变的情况下才有效，即现在解码的字符串是这样的：

String string =“uid =”001“name =”Akbar Shah“gender =”M“yob =”1989“gname =”Jahangir Shah“co =”S / O：Jahangir Shah“house =”45/5 “street =”Huzurey Ala Street“vtc =”Alibagh“po =”Bagnan“dist =”Faridabad“subdist =”Alamgarh“state =”Andhra“pc =”6754674“dob =”15/04/89“”; < / p>

然后，如果字符串看起来像这样，我的提取方式将不起作用：

String string =“uid =”002“name =”Amar Tripathi“gender =”M“yob =”1990“vtc =”Alibagh“po =”Bagnan“dist =”Faridabad“state =”Andhra“pc = “6754674”dob =“15/04/89”“;

或者，像这样：

String string =“uid =”003“name =”Anthony Gonzalis“gender =”M“yob =”1985“gname =”Jahangir Shah“house =”45/5“street =”Huzurey Ala Street“lm = “在肉店后面”loc =“Galianwalabagh”vtc =“Alibagh”dist =“Faridabad”state =“Andhra”pc =“6754674”dob =“15/04/89”“;

正如您可能已经注意到的那样，substring（）不能普遍用于所有情况，因为最后两个字符串值中缺少一些部分。因此，如果我指定提取夹在gname和co之间的特定子字符串，除了第一种情况，在最后两种情况下，它将无法找到co，因此执行代码行返回错误。有没有更好的方法呢？

P.S。我可以从“”？

中提取所有字符串部分

E.g。 “001”是字符串的一部分，我只想从中获取双引号内的001部分。

Answer 1

你可以使用正则表达式，例如"\w*="([^"]*(?="))"。这将检查以下内容：

\w*匹配字词（如字母和数字）直到
=＆＃39; =＆＃39;到达时只匹配字符＆＃39; =＆＃39;，
[^"]*首先匹配^＆＃39;＆＃34;＆＃39; -character（代表开头＆＃39;＆＃34;＆＃39; -character）然后每个字符那不是＆＃39;＆＃34;＆＃39;直到

(?=")

像这样使用这个正则表达式：myString.replace("\w*="([^"]*(?="))", "\1")。这将仅用Name="myName"替换整个myName。

希望这有帮助

Answer 2

首先，我创建了一个DataAttributes类。

DataAttributes.java

public class DataAttributes {
    // declare xml attributes of QR code xml response
    public static final String
            DATA_TAG = "PrintLetterBarcodeData",
            UID_ATTR = "uid",
            NAME_ATTR = "name",
            GENDER_ATTR = "gender",
            GNAME_ATTR = "gname",
            HOUSE_ATTR = "house",
            STREET_ATTR = "street",
            LM_ATTR = "lm",
            LOC_ATTR = "loc",
            VTC_ATTR = "vtc",
            PO_ATTR = "po",
            DIST_ATTR = "dist",
            SUBDIST_ATTR = "subdist",
            STATE_ATTR = "state",
            PC_ATTR = "pc",
            DOB_ATTR = "dob";
}

正在扫描QR码并将其存储在字符串中。

在您要显示扫描数据的活动中，在我的情况下是QRActivity ...所以我用单个参数创建了一个方法 - ＆gt; QRActivity.java中的QRActivity类中的（String scanData）

在其中编写以下代码

    Log.d("QR Code",scanData);
    XmlPullParserFactory pullParserFactory;

    try {
        // init the parserfactory
        pullParserFactory = XmlPullParserFactory.newInstance();
        // get the parser
        XmlPullParser parser = pullParserFactory.newPullParser();

        parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
        parser.setInput(new StringReader(scanData));

        // parse the XML
        int eventType = parser.getEventType();
        while (eventType != XmlPullParser.END_DOCUMENT) {
            if(eventType == XmlPullParser.START_DOCUMENT) {
                Log.d("QR Code","Start document");
            } else if(eventType == XmlPullParser.START_TAG && DataAttributes.DATA_TAG.equals(parser.getName())) {
                // extract data from tag
                //uid
                uid = parser.getAttributeValue(null,DataAttributes.UID_ATTR);
                //name
                name = parser.getAttributeValue(null,DataAttributes.NAME_ATTR);
                //gender
                gender = parser.getAttributeValue(null,DataAttributes.GENDER_ATTR);
                // guardian name
                gname = parser.getAttributeValue(null,DataAttributes.GNAME_ATTR);
                // house number
                house = parser.getAttributeValue(null,DataAttributes.HOUSE_ATTR);
                // Street name
                street = parser.getAttributeValue(null,DataAttributes.STREET_ATTR);
                // landmark
                lm = parser.getAttributeValue(null,DataAttributes.LM_ATTR);
                // locality
                loc = parser.getAttributeValue(null,DataAttributes.LOC_ATTR);
                // village town city
                vtc = parser.getAttributeValue(null,DataAttributes.VTC_ATTR);
                // Post Office
                po = parser.getAttributeValue(null,DataAttributes.PO_ATTR);
                // district
                dist = parser.getAttributeValue(null,DataAttributes.DIST_ATTR);
                // sub-division
                subdist = parser.getAttributeValue(null,DataAttributes.SUBDIST_ATTR);
                // state
                state = parser.getAttributeValue(null,DataAttributes.STATE_ATTR);
                // Post Code
                pc = parser.getAttributeValue(null,DataAttributes.PC_ATTR);
                // Date of Birth
                dob = parser.getAttributeValue(null,DataAttributes.DOB_ATTR);


            } else if(eventType == XmlPullParser.END_TAG) {
                Log.d("QR Code","End tag "+parser.getName());

            } else if(eventType == XmlPullParser.TEXT) {
                Log.d("QR Code","Text "+parser.getText());

            }
            // update eventType
            eventType = parser.next();
        }

        // display the data on screen
        String na = "N/A";

            if (uid == null){
                        tv_uid.setText(na);
            }else {
                        tv_uid.setText(uid);
            }

            if (name == null){
                        tv_name.setText(na);
            }else {
                        tv_name.setText(name);
            }

            if (gender == null){
                        tv_gender.setText(na);
            }else {
                        tv_gender.setText(gender);
            }

            if (gname == null){
                tv_gName.setText(na);
            }else {
                tv_gName.setText(gname);
            }

            if (house == null){
                tv_house.setText(na);
            }else {
                tv_house.setText(house);
            }

            if (street == null){
                tv_street.setText(na);
            }else {
                tv_street.setText(street);
            }

            if (lm == null){
                tv_lm.setText(na);
            }else {
                tv_lm.setText(lm);
            }

            if (loc == null){
                tv_loc.setText(na);
            }else {
                tv_loc.setText(loc);
            }

            if (vtc == null){
                tv_vtc.setText(na);
            }else {
                tv_vtc.setText(vtc);
            }

            if (po == null){
                tv_po.setText(na);
            }else {
                tv_po.setText(po);
            }

            if (dist == null){
                tv_dist.setText(na);
            }else {
                tv_dist.setText(dist);
            }

            if (subdist == null){
                tv_subdist.setText(na);
            }else {
                tv_subdist.setText(subdist);
            }

            if (state == null){
                tv_state.setText(na);
            }else {
                tv_state.setText(state);
            }

            if (pc == null){
                tv_pc.setText(na);
            }else {
                tv_pc.setText(pc);
            }

            if (dob == null){
                tv_dob.setText(na);
            }else {
                tv_dob.setText(dob);
            }
    } catch (XmlPullParserException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

上面的代码是我如何使用XMLPullParserFactory将字符串分段为适当的部分然后单独显示它们的示例。

现在，您可以在“活动”中使用适合您的方法。我只是展示了实现XMLPullParserFactory以分割字符串的方式。

如何从QR解码字符串中提取非常具体的字符串部分？

2 个答案: