android - copy database from assets to phone and access that -
i creating database in sqlitebrowser. copy database file manually converting .sqlite format , copy assets->databases->(file) . , try access it, not able so.
my database code
public class data extends sqliteopenhelper { sqlitedatabase databaseobject; static string db_path = "/data/data/vishesh.goswami.ithinkk/databases/"; static string db_name = "project_db.sqlite"; sqlitedatabase db; private context mcontext=null; static int l=1; static string database_name="project_db.sqlite"; string getquestion=null; data(context context) { super(context, database_name, null, l); this.mcontext=context; } public void createdatabase() throws ioexception { boolean mdatabaseexist = checkdatabase(); if (!mdatabaseexist) { this.getreadabledatabase(); try { copydatabase(); } catch (ioexception mioexception) { mioexception.printstacktrace(); throw new error("error copying database"); } { this.close(); } } } /** method checks whether database exists or not **/ private boolean checkdatabase() { try { final string mpath = db_path + db_name; db=sqlitedatabase.opendatabase(mpath, null,sqlitedatabase.open_readonly); // file file = new file(mpath); //if (file.exists()) // return true; // else // return false; } catch (sqliteexception e) { e.printstacktrace(); return false; } if(db!=null){ db.close(); } return db!=null?true :false; } /** * method copy database /assets directory application * package /databases directory **/ private void copydatabase() throws ioexception { try { inputstream minputstream = mcontext.getassets().open(db_name); string outfilename = db_path + db_name; outputstream moutputstream = new fileoutputstream(outfilename); byte[] buffer = new byte[1024]; int length; while ((length = minputstream.read(buffer)) > 0) { moutputstream.write(buffer, 0, length); } moutputstream.flush(); moutputstream.close(); minputstream.close(); } catch (exception e) { e.printstacktrace(); } } /** method open database operations **/ public boolean opendatabase() throws sqlexception { string mpath = db_path + db_name; databaseobject = sqlitedatabase.opendatabase(mpath, null, sqlitedatabase.open_readwrite); return databaseobject!=null; } /** method close database connection , released occupied memory **/ @override public synchronized void close() { if (databaseobject != null) databaseobject.close(); sqlitedatabase.releasememory(); super.close(); } @override public void oncreate(sqlitedatabase arg0) { string query="create table if not exists data (id integer primary key autoincrement, " + "question text , option1 text ,option2 text ,option3 text,option4 text )"; my testactivity code is
public class testactivity extends activity { data object,projectobject; sqlitedatabase mydatabase; textview t; @override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_test); object =new data(this); object.open(); t=(textview) findviewbyid(r.id.textview1); t.settext("ques."+ " " + object.fetchquestion(1)); projectobject = new data(this); try{ projectobject.createdatabase(); } catch(ioexception e) { toast.maketext(getbasecontext(),"it not worked11"+e.getmessage(), toast.length_short ).show(); } try{ projectobject.opendatabase(); mydatabase=projectobject.getreadabledatabase(); projectobject.close(); } catch(exception e){ toast.maketext(getbasecontext(),"it not worked2222"+e.getmessage(), toast.length_short ).show(); } object.close1(); } but app stops : unfortunately showing unable fetch database. using icecream sandwich 4.0.4 appreciated. logcat :
07-22 17:32:18.583: d/jdwp(21577): sendbufferedrequest : len=0x45 07-22 17:32:18.800: d/activitythread(21577): bind_application handled : 0 / appbinddata{appinfo=applicationinfo{418495f0 vishesh.goswami.ithinkk}} 07-22 17:32:19.248: d/androidruntime(21577): shutting down vm 07-22 17:32:19.249: w/dalvikvm(21577): threadid=1: thread exiting uncaught exception (group=0x40f3d258) 07-22 17:32:19.289: e/androidruntime(21577): fatal exception: main 07-22 17:32:19.289: e/androidruntime(21577): java.lang.runtimeexception: unable start activity componentinfo{vishesh.goswami.ithinkk/vishesh.goswami.ithinkk.testactivity}: java.lang.nullpointerexception 07-22 17:32:19.289: e/androidruntime(21577): @ android.app.activitythread.performlaunchactivity(activitythread.java:2077) 07-22 17:32:19.289: e/androidruntime(21577): @ android.app.activitythread.handlelaunchactivity(activitythread.java:2104) 07-22 17:32:19.289: e/androidruntime(21577): @ android.app.activitythread.access$600(activitythread.java:134) 07-22 17:32:19.289: e/androidruntime(21577): @ android.app.activitythread$h.handlemessage(activitythread.java:1247) 07-22 17:32:19.289: e/androidruntime(21577): @ android.os.handler.dispatchmessage(handler.java:99) 07-22 17:32:19.289: e/androidruntime(21577): @ android.os.looper.loop(looper.java:154) 07-22 17:32:19.289: e/androidruntime(21577): @ android.app.activitythread.main(activitythread.java:4624) 07-22 17:32:19.289: e/androidruntime(21577): @ java.lang.reflect.method.invokenative(native method) 07-22 17:32:19.289: e/androidruntime(21577): @ java.lang.reflect.method.invoke(method.java:511) 07-22 17:32:19.289: e/androidruntime(21577): @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:809) 07-22 17:32:19.289: e/androidruntime(21577): @ com.android.internal.os.zygoteinit.main(zygoteinit.java:576) 07-22 17:32:19.289: e/androidruntime(21577): @ dalvik.system.nativestart.main(native method) 07-22 17:32:19.289: e/androidruntime(21577): caused by: java.lang.nullpointerexception 07-22 17:32:19.289: e/androidruntime(21577): @ vishesh.goswami.ithinkk.data.oncreate(data.java:127) 07-22 17:32:19.289: e/androidruntime(21577): @ android.database.sqlite.sqliteopenhelper.getwritabledatabase(sqliteopenhelper.java:165) 07-22 17:32:19.289: e/androidruntime(21577): @ vishesh.goswami.ithinkk.data.open(data.java:149) 07-22 17:32:19.289: e/androidruntime(21577): @ vishesh.goswami.ithinkk.testactivity.oncreate(testactivity.java:22) 07-22 17:32:19.289: e/androidruntime(21577): @ android.app.activity.performcreate(activity.java:4479) 07-22 17:32:19.289: e/androidruntime(21577): @ android.app.instrumentation.callactivityoncreate(instrumentation.java:1050) 07-22 17:32:19.289: e/androidruntime(21577): @ android.app.activitythread.performlaunchactivity(activitythread.java:2041) 07-22 17:32:19.289: e/androidruntime(21577): ... 11 more
try following link may because helpful me
edit
try databasehelper class user jaydeep has used in answer database not copying assets
public class databasehelper extends sqliteopenhelper{ private context mycontext; private string db_path = "/data/data/gr.peos/databases/"; //private string db_path = mycontext.getapplicationcontext().getpackagename()+"/databases/"; private static string db_name = "blib.sqlite";//the extension may .sqlite or .db public sqlitedatabase mydatabase; /*private string db_path = "/data/data/" + mycontext.getapplicationcontext().getpackagename() + "/databases/";*/ public databasehelper(context context) throws ioexception { super(context,db_name,null,1); this.mycontext=context; boolean dbexist = checkdatabase(); if(dbexist) { //system.out.println("database exists"); opendatabase(); } else { system.out.println("database doesn't exist"); createdatabase(); } } public void createdatabase() throws ioexception{ boolean dbexist = checkdatabase(); if(dbexist) { //system.out.println(" database exists."); } else{ this.getreadabledatabase(); try{ copydatabase(); } catch(ioexception e){ throw new error("error copying database"); } } } private boolean checkdatabase() { //sqlitedatabase checkdb = null; boolean checkdb = false; try{ string mypath = db_path + db_name; file dbfile = new file(mypath); //checkdb = sqlitedatabase.opendatabase(mypath,null,sqlitedatabase.open_readwrite); checkdb = dbfile.exists(); } catch(sqliteexception e){ system.out.println("database doesn't exist"); } return checkdb; } private void copydatabase() throws ioexception { //open local db input stream inputstream myinput = mycontext.getassets().open(db_name); // path created empty db string outfilename = db_path + db_name; //open empty db output stream outputstream myoutput = new fileoutputstream("/data/data/gr.peos/databases/blib.sqlite"); // transfer byte inputfile outputfile byte[] buffer = new byte[1024]; int length; while ((length = myinput.read(buffer))>0) { myoutput.write(buffer,0,length); } //close streams myoutput.flush(); myoutput.close(); myinput.close(); } public void opendatabase() throws sqlexception { //open database string mypath = db_path + db_name; mydatabase = sqlitedatabase.opendatabase(mypath, null, sqlitedatabase.open_readwrite); } public synchronized void close(){ if(mydatabase != null){ mydatabase.close(); } super.close(); } also, note there difference in approach , approach used jaydeep. also, before accessing database using open() method, need call createdatabase() method. maybe can resolve issue.
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