java - trying to write to read and write to a text file in eclipse -
i trying write , read text file name students having kinds of hassles new android programming trying out first time. have looked @ code here , there try , figure out doing wrong cant find 1 specific thing help, question has been asked couple of times, sorry asking again. please see different .xml , .java files below. actual question able write data textfile , main screen click on textfield take edit screen, edit specific field , save text file (this has not been done yet still struggling figure out why writing , reading textfile not working, hope poor attempt @ coding shed light on matter. please don't crucify me bad coding super new android
/////////////////////////////add screen.java/////////////////////////////// public class addnew extends activity { private static final string newline = system.getproperty("line.separator"); textview txttext; edittext modules; edittext types; @override protected void oncreate(bundle savedinstancestate){ super.oncreate(savedinstancestate); setcontentview(r.layout.add); txttext = (textview)findviewbyid(r.id.textview1); modules = (edittext)findviewbyid(r.id.etmod); types = (edittext)findviewbyid(r.id.ettype); button backman = (button)findviewbyid(r.id.btnbackmain); backman.setonclicklistener(new onclicklistener(){ public void onclick(view v){ //this code go startactivity(new intent(addnew.this, mainactivity.class)); } }); //end button //get day, month & year date picker datepicker mydpicker = (datepicker)findviewbyid(r.id.dpdate); integer year = mydpicker.getyear(); integer month = mydpicker.getmonth(); integer day = mydpicker.getdayofmonth(); stringbuilder sb = new stringbuilder(); sb.append(year.tostring()).append("-").append(month.tostring()).append ("-").append(day.tostring()); final string dobstr=sb.tostring(); txttext.settext("test"); button save = (button)findviewbyid(r.id.btnsaveadded); save.setonclicklistener(new onclicklistener(){ public void onclick(view v){ //this code go try { writetofile(modules.gettext().tostring(), types.gettext().tostring(),dobstr); } catch (ioexception e) { // todo auto-generated catch block e.printstacktrace(); } } private void writetofile(string mod, string astype, string dobdate) throws ioexception { // todo auto-generated method stub //string texttofile; stringbuilder sbtext = new stringbuilder(); sbtext.append(mod + "," + dobstr + "," + astype); //texttofile=sbtext.tostring(); string filename = "student"; printwriter printwriter = null; file file = new file(filename); try { if (!file.exists()) file.createnewfile(); printwriter = new printwriter(new fileoutputstream(filename, true)); printwriter.write(newline ); //+texttofile); } catch (ioexception ioex) { ioex.printstacktrace(); } { if (printwriter != null) { printwriter.flush(); printwriter.close(); } } } }); //end button
} }
`public class mainactivity extends activity { textview fdisplay; textview ftest; int numitems=0; //use later keep track of number of items. string intext; //use variable information read in textfile.
@override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_main); button but1=(button)findviewbyid(r.id.btnadd); but1.setonclicklistener(new onclicklistener(){ public void onclick(view v){ //this code go startactivity(new intent(mainactivity.this, addnew.class)); } }); //end but1 button but2 = (button)findviewbyid(r.id.btneditcur); but2.setonclicklistener(new onclicklistener(){ public void onclick(view v){ //this code go startactivity(new intent(mainactivity.this, editcur.class)); } }); //end of button 2 fdisplay = (textview)findviewbyid(r.id.tvassign1); try { readfromfile(); } catch (filenotfoundexception e) { // todo auto-generated catch block e.printstacktrace(); } catch (ioexception e) { // todo auto-generated catch block e.printstacktrace(); } } private void readfromfile() throws ioexception { // todo auto-generated method stub // string ret=""; bufferedreader br; filereader fr = null; try { fr = new filereader("student"); br = new bufferedreader(fr); string line = br.readline(); while (null != line) { fdisplay.append(line); fdisplay.append("\n"); line = br.readline(); } } catch (ioexception e) { // todo auto-generated catch block e.printstacktrace(); } { if (null != fr) { try { fr.close(); } catch (ioexception e) { // ignore } } } } } `
for writting on file have used this
string filename; string content; filename = "path_and_file"; content = "content on file" bufferedwriter out = new bufferedwriter(new filewriter(filename)); out.write(mystring.tostring()); out.flush(); out.close(); and reading have function:
public static string readfileasstring() { string result = ""; string filename; filename = "path_and_file"; file file = new file(filename); if ( file.exists() ) { fileinputstream fis = null; try { fis = new fileinputstream(file); char current; while (fis.available() > 0) { current = (char) fis.read(); result = result + string.valueof(current); } } catch (exception e) { // system.out.println("debug exception string :"+ e.tostring()); } { if (fis != null) { try { fis.close(); } catch (ioexception ignored) { }} else {// system.out.println("debug exception string null"); } } return result; } else { return "default content"; } } 
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