java - Add line to XML using attribute as identifier -

my xml file looks like:

<?xml version="1.0" encoding="utf-8"?> <test1> <task uuid="92f7f685-c370-4e55-9026-020e3cdcede0" status="1000">     <task_status>200</task_status>     </task> <task uuid="92f7f685-c370-4e55-9026-020e3cdcede0" status="     <task_status>200</task_status> </task> </test1> 

this file stored in private app directory. want edit file , store in it's "newer" version in same directory.

i have method write , read xml files:

private void writetofile(string data, string filename) {     try {         string utf8 = "utf-8";         int buffer_size = 8192;         fileoutputstream fileoutputstream = openfileoutput(filename, context.mode_private);         bufferedwriter bufferedwriter = new bufferedwriter(new outputstreamwriter(fileoutputstream, utf8), buffer_size);         bufferedwriter.write(data);         bufferedwriter.close();     } catch (ioexception e) {         log.e("writetofile: ", "datei-erstellung fehlgeschlagen: " + e.tostring());     } }  //datei lesen von datei im privatem app-verzeichnis private string readfromfile(string filename) {     string ret = "";     string utf8 = "utf-8";     int buffer_size = 8192;      try {         inputstream inputstream = openfileinput(filename);          if (inputstream != null) {             bufferedreader bufferedreader1 = new bufferedreader(new inputstreamreader(inputstream, utf8), buffer_size);             string receivestring;             stringbuilder stringbuilder = new stringbuilder();             while ((receivestring = bufferedreader1.readline()) != null) {                 stringbuilder.append(receivestring);             }             inputstream.close();             ret = stringbuilder.tostring();         }     } catch (filenotfoundexception e) {         log.e("readfromfile: ", "datei nicht gefunden: " + e.tostring());         e.printstacktrace();     } catch (ioexception e) {         log.e("readfromfile: ", "kann datei nicht lesen: " + e.tostring());         e.printstacktrace();     }     return ret; } 

how can add new tag <task_note>? want put in right task, have use uuid attribute identify have put tag.

the xmlpullparser reading know, doesn't help.

so, how can then?

edit:

i error:

  07-28 11:16:22.676  17703-17703/de.exampleapp w/system.err﹕ javax.xml.xpath.xpathexpressionexception: java.net.malformedurlexception: protocol not found: 000273e060e87000c0001323fa21427120150602153306.kx_task 07-28 11:16:22.676  17703-17703/de.exampleapp w/system.err﹕ @ org.apache.xpath.jaxp.xpathimpl.evaluate(xpathimpl.java:481) 07-28 11:16:22.676  17703-17703/de.example.app w/system.err﹕ @ de.example.app.taskslist.onactivityresult(taskslist.java:141) 

i here:

inputsource inputsource = new inputsource(filename);              string uuid = taskitems.get(position).get("uuid");             xpath xpath = xpathfactory.newinstance().newxpath();             try {                 node tasknode = (node) xpath.evaluate("//task[@uuid='" + uuid + "']", inputsource, xpathconstants.node);                 document document = tasknode.getownerdocument();                 //füge neue zeile ein                 node notenode = document.createelement("task_note");                 notenode.settextcontent(taskitems.get(position).get("task_note"));                 tasknode.appendchild(notenode);                 //speichere datei                 source input = new domsource(document);                 result output = new streamresult(new file(filename));                 transformerfactory.newinstance().newtransformer().transform(input, output);             } catch (xpathexpressionexception e) {                 e.printstacktrace();             } catch (transformerexception e) {                 e.printstacktrace();             }          } 

you can use xpath , , other java xml standard libraries within android:

    // read file     inputsource inputstream = new inputsource(new fileinputstream(inputfilename));      // find task node     xpath xpath = xpathfactory.newinstance().newxpath();     node tasknode = (node)xpath.evaluate("//task[uuid='92f7f685-c370-4e55-9026-020e3cdcede0']", inputstream,             xpathconstants.node);     document document = tasknode.getownerdocument();     // insert new node     node notenode = document.createelement("task_note");     notenode.settextcontent("this note");     tasknode.appendchild(notenode);      // save file     source input = new domsource(document);     result output = new streamresult(new file(outputfilename));     transformerfactory.newinstance().newtransformer().transform(input, output);