The wavelet linux Android SQLite database realizes user login registration, easy to understand!

Read a lot of other people wrote the Android SQLite data operation code, are floating clouds, blind! It is not easy to understand, I think I write well, and the Android project is also used, so in the blog park to save and share a bit!

A Sqlitehelper class is an automatic overload of adding and deleting functions, and the other is a class of its own definition, using the context to pass values. I use fragment, with activity words getactivity () Remove!

Realize the user login registration Function!

http://www.cnblogs.com/xiaobo-Linux/(wavelet) Zhao Archive QQ463431476

 Public classMysqlitehelperextendsSqliteopenhelper {//Custom Access SQLite     PublicMysqlitehelper (Context context) {Super(Context, "userdb.db",NULL, 3); //TODO auto-generated Constructor stub} @Override Public voidonCreate (Sqlitedatabase db) {//TODO auto-generated Method Stub//http://www.cnblogs.com/xiaobo-linux/(wavelet) Zhao Archive QQ463431476 db.execsql ("CREATE table users (ID int primary key, name text,pwd text)"); } @Override Public voidOnupgrade (Sqlitedatabase db,intOldversion,intnewversion) {        //TODO auto-generated Method Stub            } }

 Public classUserloginextendsActivityImplementsonclicklistener{PrivateMysqlitehelper Helper;         Button sign;              Button reg;       String name;       String MyPwd; PrivateEditText User; PrivateEditText pwd; http://www.cnblogs.com/xiaobo-Linux/(wavelet) Zhao Archive QQ463431476 Public voidonCreate (Bundle savedinstancestate) {Super. OnCreate (savedinstancestate); //Set the status bar colorGetWindow (). Addflags (WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);          GetWindow (). Setstatusbarcolor (Getresources (). GetColor (R.color.statusbar)); //Set Actionbar colorActionBar ActionBar =Getactionbar (); Actionbar.setbackgrounddrawable (NewColordrawable (Color.parsecolor ("#0099CC")));              Setcontentview (R.layout.login); Findviewbyid (R.id.button1). Setonclicklistener ( This); Findviewbyid (R.id.button2). Setonclicklistener ( This); User=(EditText) Findviewbyid (R.ID.EDITTEXT1); PWD=(EditText) Findviewbyid (R.ID.EDITTEXT2); }        Public voidInsert () {helper=NewMysqlitehelper (Getapplicationcontext ()); Sqlitedatabase DB=helper.getwritabledatabase (); //Check If the user name is duplicatedString SQL1 = "SELECT * from Users"; Cursor Cursor= Db.rawquery (SQL1,NULL);  while(Cursor.movetonext ()) {//first column IDName = cursor.getstring (1);//gets the value of the 2nd column, starting with the index of the first column 0MyPwd = cursor.getstring (2);//gets the value of the 3rd column               }           if((User.gettext (). toString (). Equals (name)) {Toast.maketext ( This, "This user already exists, please re-register", Toast.length_short). Show (); }         Else{String sql2= "INSERT into users (NAME,PWD) VALUES ('" +user.gettext (). ToString () + "', '" +pwd.gettext (). ToString () + "')";               Db.execsql (SQL2); Toast.maketext ( This, "Registered successfully! ", Toast.length_short). Show (); }      }    Public voidSelect () {helper=NewMysqlitehelper (Getapplicationcontext ()); Sqlitedatabase DB=helper.getwritabledatabase (); String SQL= "SELECT * from Users"; Cursor Cursor= Db.rawquery (SQL,NULL);  while(Cursor.movetonext ()) {//first column IDName = cursor.getstring (1);//gets the value of the 2nd column, starting with the index of the first column 0MyPwd = cursor.getstring (2);//gets the value of the 3rd column               }            if((User.gettext (). toString (). Equals (name)) &&(Pwd.gettext (). toString (). Equals (MyPwd))) {Toast.maketext ( This, "User authentication succeeded", Toast.length_short). Show (); Intent mainactivity=NewIntent (); Mainactivity. SetClass ( This, Mainactivity.class);  This. StartActivity (mainactivity); Finish ();//Exit         }         Else{Toast.maketext ( This, "The account or password is wrong, please re-enter", Toast.length_short). Show ();                } cursor.close ();                Db.close (); //Toast.maketext (This, "database has been closed", Toast.length_short). Show (); } @Override Public voidOnClick (View v) {//TODO auto-generated Method Stub       Switch(V.getid ()) { CaseR.id.button1:select ();  Break;  CaseR.id.button2:insert ();  Break; } }     

http://www.cnblogs.com/xiaobo-Linux/(wavelet) Zhao Archive QQ463431476

The effect is as follows:

The wavelet linux Android SQLite database realizes user login registration, easy to understand!