Atmiya Institute of Technology & Science, Rajkot Department of MCA

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1 Atmiya Institute of Technology & Science, Rajkot Department of MCA Chapter 10 Application Preference (/data/data/<package name>/shared_prefs/<preferences filename>.xml) Private Preference (Data sharing within activity) Sting Data SharedPreference sp = getpreferences(mode_private); SharedPreference.Edit e = sp.edit(); e.putint( Sce,10); e.putstring( Name, abc ); e.commit(); Retrieving Data SharedPreference sp = getpreferences(mode_private); int sce = sp.getint( Sce,null); String name = sp.getstring( Name,null); Shared Preference (Data sharing between multiple activities of application) Sting Data (In Activity1.java) SharedPreference sp = getsharedpreferences( game,0); SharedPreference.Edit e = sp.edit(); e.putint( Sce,10); e.putstring( Name, abc ); e.commit(); Intent i = new Intent(getApplicationContext(), Activity2.class); startactivity(i); Retrieving Data (In Activity2.java) SharedPreference sp = getsharedpreferences( game,0); int sce = sp.getint( Sce,null); String name = sp.getstring( Name,null); Prepared By : Hetal Thaker, Assistant Profess, AITS, Rajkot Page 1

2 Reading and Writing data to file Writing data to file FileOutputStream fos; String strfilecontents = Some text to write to the file. ; fos = openfileoutput( Filename.txt, MODE_PRIVATE); fos.write(strfilecontents.getbytes()); fos.close(); FileOutputStream fout = null; OutputStreamWriter osw = null; fout = openfileoutput("test.txt", Context.MODE_PRIVATE); osw = new OutputStreamWriter(fOut); osw.write("good mning!!! MCA-5"); osw.write("hi"); osw.close(); fout.close(); catch(exception e) e.printstacktrace(system.err); Appending data to file FileOutputStream fos; String strfilecontents = Me text to write to the file. ; fos = openfileoutput( Filename.txt, MODE_APPEND); fos.write(strfilecontents.getbytes()); fos.close(); Reading data to file FileInputStream fin = null; InputStreamReader isr = null; char[] b = new char[1024]; String data = null; Prepared By : Hetal Thaker, Assistant Profess, AITS, Rajkot Page 2

3 fin = openfileinput("test.txt"); isr = new InputStreamReader(fIn); isr.read(b); data = new String(b); TextView tv = (TextView) findviewbyid(r.id.textview1); tv.settext(data); isr.close(); fin.close(); catch(ioexception e) e.printstacktrace(system.err); Creating, deleting database and table with SQLite Database. Creating and Deleteing Database: SQLiteDatabase db; db = openorcreatedatabase( mca.db,sqlitedatabase.create_if_necessary,null); deletedatabase( mca.db ); Creating Table: String s = CREATE TABLE stud (id INTEGER PRIMARY KEY AUTOINCREMENT, firstname TEXT, lastname TEXT); ; db.execsql(s); Insert, Update and Delete operation with SQLite Database. Insert Operation: ContentValues cv = new ContentValues(); cv.put( firstname, abc ); cv.put( lastname, def ); db.insert( stud, null,cv); db.execsql( insert into tbl_auths(firstname, lastname) values ( abc, def ); ); Update Operation: ContentValues values = new ContentValues(); Prepared By : Hetal Thaker, Assistant Profess, AITS, Rajkot Page 3

4 values.put( firstname, aaa ); db.update( tbl_auths, values, lastname=?, new String*+, def -); db.execsql( update tbl_auths set firstname= aaa where lastname= def ; ); Delete Operation: db.delete( tbl_auths, firstname=?, new String*+, aaa -); db.execsql( delete from tbl_auths where firstname= aaa' ); Querying SQLite Database SELECT * FROM tbl_books; Curs c = mdatabase.query( tbl_books,null,null,null,null,null,null); Or Curs c = db.rawquery( select * from tbl_books ); SELECT * tbl_books WHERE id=9; Curs c = mdatabase.query( tbl_books, null, id=?, new String*+, 9 -, null, null, null); SELECT title, id FROM tbl_books ORDER BY title ASC; String ascolumnstoreturn*+ =, title, id -; String strstorder = title ASC ; Curs c = mdatabase.query( tbl_books, ascolumnstoreturn, null, null, null, null, strstorder); Retrieving data from curs c.movetofirst(); while(c.movetonext()) String s= c.getstring(c.getcolumnindex( fname )); c.getcount(); (Count no. of rows) c.getcolumncount(); (Count no. of columns) Prepared By : Hetal Thaker, Assistant Profess, AITS, Rajkot Page 4

5 Fetching data from multiple table SQLiteQueryBuilder querybuilder = new SQLiteQueryBuilder(); querybuilder.settables( tbl_books, tbl_auths ); querybuilder.appendwhere( tbl_books.authid=tbl_auths.id ); String ascolumnstoreturn[] = tbl_books.title, tbl_books.id, tbl_auths.firstname, tbl_auths.lastname, tbl_books.authid -; String strstorder = title ASC ; Curs c = querybuilder.query(mdatabase, ascolumnstoreturn, null, null, null, null,strstorder); String sqlunionexample = SELECT title AS Name, tbl_books AS OriginalTable from tbl_books WHERE Name LIKE? UNION SELECT (firstname lastname) AS Name, tbl_auths AS OriginalTable from tbl_auths WHERE Name LIKE? ORDER BY Name ASC; ; Curs c = mdatabase.rawquery(sqlunionexample, new String*+, %ow%, %ow% -); Wking with transactions mdatabase.begintransaction(); // Insert some recds, updated others, delete a few // Do whatever you need to do as a unit, then commit it mdatabase.settransactionsuccessful(); catch (Exception e) // Transaction failed. Failed! Do something here. // It s up to you. finally mdatabase.endtransaction(); Prepared By : Hetal Thaker, Assistant Profess, AITS, Rajkot Page 5