java - Application stop suddenly when trying to login -
after creating inserting username , password signup.java, app stop when login (in emulator), , move signup page in (bluestack). not sure if data being entered in database when signing up.
dbmanager.java
package com.example.student_project; import com.example.student_project.*; import android.content.contentvalues; import android.content.context; import android.database.cursor; import android.database.sqlexception; import android.database.sqlite.sqlitedatabase; import android.database.sqlite.sqliteexception; import android.database.sqlite.sqliteopenhelper; public class dbmanager { public static final string key_rowid = "_id"; public static final string key_username = "username"; public static final string key_password = "password"; private static final string database_name= "login.db"; private static final int database_version = 4; private static final string database_table = "login_table"; private static dbhelper ourhelper; private final context ourcontext; private static sqlitedatabase ourdatabase; class dbhelper extends sqliteopenhelper { public dbhelper(context context) { super(context, database_name, null, database_version); // todo auto-generated constructor stub } @override public void oncreate(sqlitedatabase db) { // todo auto-generated method stub db.execsql("create table " + database_table + " ( " + key_rowid + " integer primary key autoincrement , " + key_username + " text not null , " + key_password + " text not null );" ); } @override public void onupgrade(sqlitedatabase db, int oldversion, int newversion) { // todo auto-generated method stub db.execsql("drop table if exists " + database_table); oncreate(db); } } public dbmanager(context c) { ourcontext = c; } public dbmanager open() throws sqlexception{ ourhelper = new dbhelper(ourcontext); try { ourdatabase = ourhelper.getwritabledatabase(); } catch(sqlexception ex) { ourdatabase = ourhelper.getreadabledatabase(); } return this; } public void close() { ourhelper.close(); } public long createentry(string username, string password) throws sqlexception { // todo auto-generated method stub contentvalues cv = new contentvalues(); cv.put(key_username, username); cv.put(key_password, password); return ourdatabase.insert(database_table, null, cv); } public static boolean verifyuser(string username , string password) { string columns[] = new string[2]; columns[0] = username; columns[1] = password; cursor c= null; int count=0; try { // todo auto-generated method stub c = ourdatabase.query(database_table, columns,null , null, null, null, null); count = c.getcount(); } catch (sqlexception e) { // todo: handle exception e.printstacktrace(); } { c.close(); } if(count>0) { return true; } else { return false; } } } mainactivity.java
package com.example.student_project; import com.example.student_project.*; import android.os.bundle; import android.app.activity; import android.content.intent; import android.text.inputfilter.lengthfilter; import android.util.log; import android.view.menu; import android.view.view; import android.view.view.onclicklistener; import android.widget.button; import android.widget.edittext; import android.widget.toast; public class mainactivity extends activity implements onclicklistener { private button btn_signup; private button btn_login; private edittext et_lusername; private edittext et_lpassword; @override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_main); log.i("mytag","this tag"); et_lusername = (edittext) findviewbyid(r.id.et_lusername); et_lpassword = (edittext) findviewbyid(r.id.et_lpassword); btn_signup = (button) findviewbyid(r.id.btn_signup); btn_login = (button) findviewbyid(r.id.btn_login); btn_login.setonclicklistener(this); btn_signup.setonclicklistener(this); } @override public boolean oncreateoptionsmenu(menu menu) { // inflate menu; adds items action bar if present. getmenuinflater().inflate(r.menu.main, menu); return true; } @override public void onclick(view v) { // todo auto-generated method stub switch(v.getid()) { case r.id.btn_login : { string un = et_lusername.gettext().tostring(); string pw = et_lusername.gettext().tostring(); boolean success = dbmanager.verifyuser(un,pw); if (success) { intent = new intent(mainactivity.this,adminmenu.class); startactivity(i); } else { toast.maketext(getapplicationcontext(), "wrong username or password",toast.length_long); } } case r.id.btn_signup: { intent = new intent(mainactivity.this,signup.class); startactivity(i); } } } } signup.java
package com.example.student_project; import com.example.student_project.*; import android.os.bundle; import android.app.activity; import android.app.dialog; import android.content.intent; import android.view.menu; import android.view.view; import android.view.view.onclicklistener; import android.widget.button; import android.widget.edittext; import android.widget.textview; import android.widget.toast; public class signup extends activity implements onclicklistener { private button btn_add; private edittext et_username; private edittext et_password; private edittext et_confirmpassword; @override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.signup); et_username = (edittext) findviewbyid(r.id.et_username); et_password = (edittext) findviewbyid(r.id.et_password); et_confirmpassword = (edittext) findviewbyid(r.id.et_confirmpassword); btn_add = (button) findviewbyid(r.id.btn_add); btn_add.setonclicklistener(this); } @override public boolean oncreateoptionsmenu(menu menu) { // inflate menu; adds items action bar if present. getmenuinflater().inflate(r.menu.main, menu); return true; } @override public void onclick(view v) { // todo auto-generated method stub switch(v.getid()) { case r.id.btn_add : boolean diditwork = true; try { string username = et_username.gettext().tostring(); string password = et_password.gettext().tostring(); string cpassword = et_confirmpassword.gettext().tostring(); if(password.equalsignorecase(cpassword)) { dbmanager empty = new dbmanager(signup.this); empty.open(); empty.createentry(username,password); empty.close(); intent addintent = new intent(signup.this,mainactivity.class); startactivity(addintent); } else { toast.maketext(getapplicationcontext(), "passwords not match", toast.length_long); } } catch (exception e) { diditwork = false; dialog d = new dialog(this); string error = e.tostring(); d.settitle("dang"); textview tv = new textview(this); tv.settext(error); d.setcontentview(tv); d.show(); } /* { if(diditwork) { dialog d = new dialog(this); d.settitle("hech ya"); textview tv = new textview(this); tv.settext("success"); d.setcontentview(tv); d.show(); } } */ } } } admin.java
package com.example.student_project; import android.os.bundle; import android.app.activity; import android.content.intent; import android.view.menu; import android.view.view; import android.view.view.onclicklistener; import android.widget.button; import android.widget.edittext; public class adminmenu extends activity { @override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.admin_menu); } @override public boolean oncreateoptionsmenu(menu menu) { // inflate menu; adds items action bar if present. getmenuinflater().inflate(r.menu.main, menu); return true; } } logcat error
w/activitymanager( 293): unbind failed: not find connection android.os.binderproxy@410ce000 i/choreographer( 1994): skipped 55 frames! application may doing work on main thread. d/androidruntime( 1994): shutting down vm w/dalvikvm( 1994): threadid=1: thread exiting uncaught exception (group=0x40a71930) e/androidruntime( 1994): fatal exception: main e/androidruntime( 1994): java.lang.nullpointerexception e/androidruntime( 1994): @ com.example.student_project.dbmanager.verifyuser(dbmanager.java:110) e/androidruntime( 1994): @ com.example.student_project.mainactivity.onclick(mainactivity.java:61) e/androidruntime( 1994): @ android.view.view.performclick(view.java:4204) e/androidruntime( 1994): @ android.view.view$performclick.run(view.java:17355) e/androidruntime( 1994): @ android.os.handler.handlecallback(handler.java:725) e/androidruntime( 1994): @ android.os.handler.dispatchmessage(handler.java:92) e/androidruntime( 1994): @ android.os.looper.loop(looper.java:137) e/androidruntime( 1994): @ android.app.activitythread.main(activitythread.java:5041) e/androidruntime( 1994): @ java.lang.reflect.method.invokenative(native method) e/androidruntime( 1994): @ java.lang.reflect.method.invoke(method.java:511) e/androidruntime( 1994): @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:793) e/androidruntime( 1994): @ com.android.internal.os.zygoteinit.main(zygoteinit.java:560) e/androidruntime( 1994): @ dalvik.system.nativestart.main(native method) w/activitymanager( 293): force finishing activity com.example.student_project/.mainactivity w/windowmanager( 293): failure taking screenshot (246x410) layer 21020
it because cursor c null..and u have'nt caught nullpointerexception in catch block in verifyuser()..change sqlexception in catch exception catch exceptions..
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