android - SQLite disk IO exception and can't open database exception -

i have gone through other similar questions did not answer.

in android app i'm opening pre-built database. in assets folder , copied using sqliteopenhelper, if not present. class:

import java.io.fileoutputstream; import java.io.ioexception; import java.io.inputstream; import java.io.outputstream;  import android.content.context; import android.database.sqlexception; import android.database.sqlite.sqlitedatabase; import android.database.sqlite.sqliteopenhelper;  public class externaldbopenhelper extends sqliteopenhelper {  public static string db_path; public static string db_name; public sqlitedatabase database; public final context context;  public sqlitedatabase getdb() {     return database; }  public externaldbopenhelper(context context, string databasename) {     super(context, databasename, null, 1);     this.context = context;      string packagename = context.getpackagename();     db_path = string.format("//data//data//%s//databases//", packagename);     db_name = databasename;     opendatabase(); }  public void createdatabase() {     boolean dbexist = checkdatabase();     if (!dbexist) {         this.getreadabledatabase();         try {             copydatabase();         } catch (ioexception e) {             // log.e(this.getclass().tostring(), "copying error");             //throw new error("error copying database!");         }     } else {         // log.i(this.getclass().tostring(), "database exists");     } }  private boolean checkdatabase() {     sqlitedatabase checkdb = null;     try {         string path = db_path + db_name;         checkdb = sqlitedatabase.opendatabase(path, null,                 sqlitedatabase.open_readonly);      } catch (sqlexception e) {         // log.e(this.getclass().tostring(), "error while checking db");     }      if (checkdb != null) {         checkdb.close();     }     return checkdb != null; }  private void copydatabase() throws ioexception {      inputstream externaldbstream = context.getassets().open(db_name);      string outfilename = db_path + db_name;      outputstream localdbstream = new fileoutputstream(outfilename);      byte[] buffer = new byte[1024];     int bytesread;     while ((bytesread = externaldbstream.read(buffer)) > 0) {         localdbstream.write(buffer, 0, bytesread);     }      localdbstream.close();     externaldbstream.close();  }  public sqlitedatabase opendatabase() throws sqlexception {     string path = db_path + db_name;     if (database == null) {         createdatabase();         database = sqlitedatabase.opendatabase(path, null,                 sqlitedatabase.open_readwrite); //caused line     }     return database; }  @override public synchronized void close() {     if (database != null) {         database.close();     }     super.close(); }  @override public void oncreate(sqlitedatabase db) { }  @override public void onupgrade(sqlitedatabase db, int oldversion, int newversion) { } } 

and in activity:

private static final string db_name = "mydb.sqlite"; private sqlitedatabase database; private externaldbopenhelper dbopenhelper;  //in oncreate() dbopenhelper = new externaldbopenhelper(this,db_name); database = dbopenhelper.opendatabase(); 

in app repeatedly query database using cursor , rawquery. open database open_readonly never modify it. so wasn't closing before. added now:

@override protected void ondestroy() {     dbopenhelper.close();     super.ondestroy();  } 

was problem? had never experienced sqlite disk io exception , can't open database exception before(without dbopenhelper.close();. reported once each in crash report). both times apps crashed on launch , caused line

database = sqlitedatabase.opendatabase(path, null, sqlitedatabase.open_readwrite);

in opendatabase() in theexternaldbopenhelper class.

i'm unable reproduce errors. 2 devices reported have device names "other" , blank.

android.database.sqlite.sqlitecantopendatabaseexception in android.database.sqlite.sqlitedatabase.dbopen:  java.lang.runtimeexception: unable start activity        componentinfo{com.technicosa.unjumble/com.technicosa.unjumble.mainactivity}: android.database.sqlite.sqlitecantopendatabaseexception: unable open database file @ android.app.activitythread.performlaunchactivity(activitythread.java:1956) @ android.app.activitythread.handlelaunchactivity(activitythread.java:1981) @ android.app.activitythread.access$600(activitythread.java:123) @ android.app.activitythread$h.handlemessage(activitythread.java:1147) @ android.os.handler.dispatchmessage(handler.java:99) @ android.os.looper.loop(looper.java:137) @ android.app.activitythread.main(activitythread.java:4424) @ java.lang.reflect.method.invokenative(native method) @ java.lang.reflect.method.invoke(method.java:511) @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:784) @ com.android.internal.os.zygoteinit.main(zygoteinit.java:551) @ dalvik.system.nativestart.main(native method) caused by: android.database.sqlite.sqlitecantopendatabaseexception: unable open database file @ android.database.sqlite.sqlitedatabase.dbopen(native method) @ android.database.sqlite.sqlitedatabase.opendatabase(sqlitedatabase.java:1013) @ android.database.sqlite.sqlitedatabase.opendatabase(sqlitedatabase.java:986) @ android.database.sqlite.sqlitedatabase.opendatabase(sqlitedatabase.java:1024) @ android.database.sqlite.sqlitedatabase.opendatabase(sqlitedatabase.java:986) @ android.database.sqlite.sqlitedatabase.opendatabase(sqlitedatabase.java:962) @ com.technicosa.unjumble.dbhelper.externaldbopenhelper.opendatabase(externaldbopenhelper.java:90) @ com.technicosa.unjumble.dbhelper.externaldbopenhelper.<init>(externaldbopenhelper.java:33) @ com.technicosa.unjumble.mainactivity.oncreate(mainactivity.java:131) @ android.app.activity.performcreate(activity.java:4465) @ android.app.instrumentation.callactivityoncreate(instrumentation.java:1049) @ android.app.activitythread.performlaunchactivity(activitythread.java:1920) ... 11 more 

look @ this working charm

public class smartopenhelper extends sqliteopenhelper {      private context context;     private sqlitedatabase mydatabase;     private string db_sql;     private smartversionhandler smartversionhandler;      smartopenhelper(context context, string dbname, int dbversion, string dbsqlname, smartversionhandler smartversionhandler) throws ioexception {         super(context, dbname, null, dbversion);         this.context = context;         this.db_sql = dbsqlname;         this.smartversionhandler = smartversionhandler;     }      @override     public void oncreate(sqlitedatabase db) {         try {             bufferedinputstream instream = new bufferedinputstream(context.getassets().open(db_sql));             string sql = "";             int character = -2;             {                 character = instream.read();                 if ((character != -1) && (character != -2))                     sql += (char) character;                 else                     break;             } while (true);             system.out.println("oncreate db sql = " + sql.split("\n"));             string[] arrsql = sql.split("\n");              (int = 0; < arrsql.length; i++) {                 db.execsql(arrsql[i]);             }          } catch (ioexception e) {             e.printstacktrace();         }         if (this.smartversionhandler != null) {             this.smartversionhandler.oninstalling(smartapplication.ref_smart_application);         }     }      @override     public void onupgrade(sqlitedatabase db, int oldversion, int newversion) {          try {             bufferedinputstream instream = new bufferedinputstream(context.getassets().open(db_sql));             string sql = "";             int character = -2;             {                 character = instream.read();                 if ((character != -1) && (character != -2))                     sql += (char) character;                 else                     break;             } while (true);              system.out.println("onupgrade db sql = " + sql.split("\n"));             string[] arrsql = sql.split("\n");             (int = 0; < arrsql.length; i++) {                 db.execsql(arrsql[i]);             }          } catch (ioexception e) {             e.printstacktrace();         }         if (this.smartversionhandler != null) {             this.smartversionhandler.onupgrading(oldversion, newversion, smartapplication.ref_smart_application);         }     }      public sqlitedatabase getopendatabase() {         return mydatabase;     }      public synchronized void close() {         if (mydatabase != null) {             mydatabase.close();         }         super.close();     }  }