Question

我创建了一个登录页面和一个注册页面。注册到应用程序后，我无法使用这些值进行登录;无论我在注册期间输入的内容如何，我都无法使用凭据登录。请帮助

我的代码是

DBHelper.java

public class DBHelper extends SQLiteOpenHelper
{
     private SQLiteDatabase db;
     public static final String KEY_ROWID = "_id";
        public static final String KEY_FNAME = "firstname";
        public static final String KEY_LNAME = "lastname";
        public static final String KEY_GENDER = "gender";
        public static final String KEY_USER = "username";
        public static final String KEY_EMAIL = "email";



     DBHelper DB = null;
     private static final String DATABASE_NAME = "srikanth1.db";
     private static final int DATABASE_VERSION = 2;
        public static final String DATABASE_TABLE_NAME = "sri1";

        private static final String DATABASE_TABLE_CREATE =
                "CREATE TABLE " + DATABASE_TABLE_NAME + "(" +
                "_id INTEGER PRIMARY KEY AUTOINCREMENT,"+
                "firstname TEXT NOT NULL, lastname TEXT NOT NULL, gender TEXT NOT NULL, username TEXT NOT NULL, password TEXT NOT NULL, email TEXT NOT NULL);";
    public DBHelper(Context context) {

      super(context, DATABASE_NAME, null, DATABASE_VERSION);
      System.out.println("In constructor");
    }




    @Override
    public void onCreate(SQLiteDatabase db) {

     try{

      db.execSQL(DATABASE_TABLE_CREATE);



     }catch(Exception e){
      e.printStackTrace();
     }
    }






    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
     // TODO Auto-generated method stub

    }




    public Cursor rawQuery(String string, String[] strings) {
     // TODO Auto-generated method stub
     return null;
    }




    public void open() {

     getWritableDatabase(); 
    }


    public Cursor getDetails(String text) throws SQLException 
    {

        Cursor mCursor =
                db.query(true, DATABASE_TABLE_NAME, 
                  new String[]{KEY_ROWID, KEY_FNAME, KEY_LNAME, KEY_GENDER, KEY_USER, KEY_EMAIL}, 
                  KEY_USER + "=" + text, 
                  null, null, null, null, null);
        if (mCursor != null) 
        {
            mCursor.moveToFirst();
        }
        return mCursor;


    }


    }

Registration.java

public class Registration extends Activity implements OnClickListener, OnItemSelectedListener
{
    // Variable Declaration should be in onCreate()
     private Button mSubmit;
     private Button mCancel;

     private EditText mFname;
     private EditText mLname;
     private EditText mUsername;
     private EditText mPassword;
     private EditText mEmail;
     private Spinner mGender;
     private String Gen;

     protected DBHelper DB = new DBHelper(Registration.this);

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.register);

        //Assignment of UI fields to the variables
          mSubmit = (Button)findViewById(R.id.submit);
          mSubmit.setOnClickListener(this);

          mCancel = (Button)findViewById(R.id.cancel);
          mCancel.setOnClickListener(this);

          mFname = (EditText)findViewById(R.id.efname);
          mLname = (EditText)findViewById(R.id.elname);

          mUsername = (EditText)findViewById(R.id.reuname);
          mPassword = (EditText)findViewById(R.id.repass);
          mEmail = (EditText)findViewById(R.id.eemail);


          mGender = (Spinner)findViewById(R.id.spinner1);

          // Spinner method to read the on selected value
          ArrayAdapter<State> spinnerArrayAdapter = new ArrayAdapter<State>(this,
                       android.R.layout.simple_spinner_item, new State[] { 
                    new State("Male"), 
                    new State("Female")});
          mGender.setAdapter(spinnerArrayAdapter);
          mGender.setOnItemSelectedListener(this); 
         }



         public void onClick(View v) 
         {
            /* int id = v.getId();
             if (id == R.id.cancel) {
                  Intent i = new Intent(getBaseContext(), LoginActivity.class);
                   startActivity(i);
                } else if (id == R.id.submit) {
                    String fname = mFname.getText().toString();
                       String lname = mLname.getText().toString();

                       String uname = mUsername.getText().toString();
                       String pass = mPassword.getText().toString();
                       String email = mEmail.getText().toString();


                       boolean invalid = false;

                       if(fname.equals(""))
                       {
                        invalid = true;
                        Toast.makeText(getApplicationContext(), "Enter your Firstname", Toast.LENGTH_SHORT).show();
                       }
                       else

                       if(lname.equals(""))
                       {
                        invalid = true;
                        Toast.makeText(getApplicationContext(), "Please enter your Lastname", Toast.LENGTH_SHORT).show();
                       }
                       else

                        if(uname.equals(""))
                        {
                         invalid = true;
                         Toast.makeText(getApplicationContext(), "Please enter your Username", Toast.LENGTH_SHORT).show();
                        }
                        else


                          if(pass.equals(""))
                         {
                          invalid = true;
                          Toast.makeText(getApplicationContext(), "Please enter your Password", Toast.LENGTH_SHORT).show();

                       }
                         else 
                          if(email.equals(""))
                       {
                        invalid = true;
                        Toast.makeText(getApplicationContext(), "Please enter your Email ID", Toast.LENGTH_SHORT).show();
                       }
                         else
                          if(invalid == false)
                          {
                           addEntry(fname, lname, Gen, uname, pass, email);
                           Intent i_register = new Intent(Registration.this, LoginActivity.class);
                           startActivity(i_register);
                           //finish();
                          }
                }*/

          switch(v.getId()){

          case R.id.cancel:
           Intent i = new Intent(getBaseContext(), LoginActivity.class);
           startActivity(i);
           //finish();
           break;

          case R.id.submit:


           String fname = mFname.getText().toString();
           String lname = mLname.getText().toString();

           String uname = mUsername.getText().toString();
           String pass = mPassword.getText().toString();
           String email = mEmail.getText().toString();


           boolean invalid = false;

           if(fname.equals(""))
           {
            invalid = true;
            Toast.makeText(getApplicationContext(), "Enter your Firstname", Toast.LENGTH_SHORT).show();
           }
           else

           if(lname.equals(""))
           {
            invalid = true;
            Toast.makeText(getApplicationContext(), "Please enter your Lastname", Toast.LENGTH_SHORT).show();
           }
           else

            if(uname.equals(""))
            {
             invalid = true;
             Toast.makeText(getApplicationContext(), "Please enter your Username", Toast.LENGTH_SHORT).show();
            }
            else


              if(pass.equals(""))
             {
              invalid = true;
              Toast.makeText(getApplicationContext(), "Please enter your Password", Toast.LENGTH_SHORT).show();

           }
             else 
              if(email.equals(""))
           {
            invalid = true;
            Toast.makeText(getApplicationContext(), "Please enter your Email ID", Toast.LENGTH_SHORT).show();
           }
             else
              if(invalid == false)
              {
               addEntry(fname, lname, Gen, uname, pass, email);
               Intent i_register = new Intent(Registration.this, LoginActivity.class);
               startActivity(i_register);
               //finish();
              }

              break;
              }
            }





         public void onDestroy()
         {
          super.onDestroy();
          DB.close();
         }



         private void addEntry(String fname, String lname, String Gen, String uname, String pass, String email) 
         {

          SQLiteDatabase db = DB.getWritableDatabase();

          ContentValues values = new ContentValues();
          values.put("firstname", fname);
          values.put("lastname", lname);
          values.put("gender", Gen);
          values.put("username", uname);
          values.put("password", pass);
          values.put("email", email);

          try
          {
           db.insert(DBHelper.DATABASE_TABLE_NAME, null, values);

           Toast.makeText(getApplicationContext(), "your details submitted Successfully...", Toast.LENGTH_SHORT).show();
          }
          catch(Exception e)
          {
           e.printStackTrace();
          }
         }


          public void onItemSelected(AdapterView<?> parent, View view, int position, long id) 
             {
              // Get the currently selected State object from the spinner
              State st = (State)mGender.getSelectedItem();

              // Show it via a toast
              toastState( "onItemSelected", st );
             } 


         public void toastState(String name, State st) 
         {
          if ( st != null )
             {
           Gen = st.name;
          //Toast.makeText(getBaseContext(), Gen, Toast.LENGTH_SHORT).show();

             }

         }


         public void onNothingSelected(AdapterView<?> arg0) {
          // TODO Auto-generated method stub

         }

        }

LoginActivity .java

public class LoginActivity extends Activity implements OnClickListener 
{

    Button mLogin;
     Button mRegister;

     EditText muname;
     EditText mpassword;

     DBHelper DB = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);


        mRegister = (Button)findViewById(R.id.register);
        mRegister.setOnClickListener(this);

        mLogin = (Button)findViewById(R.id.login);
        mLogin.setOnClickListener(this); 

    }


 public void onClick(View v) 
 {
 switch(v.getId())
 {

 case R.id.register:
  Intent i = new Intent(getBaseContext(), Registration.class);
  startActivity(i);
  break;

 case R.id.login:

  muname = (EditText)findViewById(R.id.Ledituname);
  mpassword = (EditText)findViewById(R.id.Leditpw);

  String username = muname.getText().toString();
  String password = mpassword.getText().toString();



  if(username.equals("") || username == null)
  {
   Toast.makeText(getApplicationContext(), "Please enter User Name", Toast.LENGTH_SHORT).show();
  }
  else if(password.equals("") || password == null)
  {
   Toast.makeText(getApplicationContext(), "Please enter your Password", Toast.LENGTH_SHORT).show();
  }
  else
  {
   boolean validLogin = validateLogin(username, password, getBaseContext());
   if(validLogin)
   {
    //System.out.println("In Valid");
    Intent in = new Intent(getBaseContext(), TabBar.class);
    //in.putExtra("UserName", muname.getText().toString());
    startActivity(in);
    //finish();
   }
  }
  break;

 }

 }


 private boolean validateLogin(String username, String password, Context baseContext) 
 {
  DB = new DBHelper(getBaseContext());
  SQLiteDatabase db = DB.getReadableDatabase();

  String[] columns = {"_id"};

  String selection = "username=? AND password=?";
  String[] selectionArgs = {username,password};

  Cursor cursor = null;
  try{

  cursor = db.query(DBHelper.DATABASE_TABLE_NAME, columns, selection, selectionArgs, null, null, null);
  startManagingCursor(cursor);
  }
  catch(Exception e)

  {
   e.printStackTrace();
  }
int numberOfRows = cursor.getCount();

  if(numberOfRows <= 0)
  {

   Toast.makeText(getApplicationContext(), "User Name and Password miss match..\nPlease Try Again", Toast.LENGTH_LONG).show();
   Intent intent = new Intent(getBaseContext(), LoginActivity.class);
   startActivity(intent);
   return false;
  }


  return true;

 }

 public void onDestroy()
 {
  super.onDestroy();
  DB.close();
 }
}

register.xml

<?xml version="1.0" encoding="utf-8"?>



    <ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/scrollView1" 
        android:layout_width="match_parent" 
        android:layout_height="wrap_content">

        <LinearLayout 

            android:id="@+id/linearLayout1" 
            android:layout_width="match_parent" 
            android:layout_height="match_parent"
            android:orientation="vertical">
    <TextView
        android:id="@+id/fname"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="First Name"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:textAppearance="?android:attr/textAppearanceLarge" />


    <EditText
        android:id="@+id/efname"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" 
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:singleLine="true">


        <requestFocus />
    </EditText>


    <TextView
        android:id="@+id/lname"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Last Name"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:textAppearance="?android:attr/textAppearanceLarge" />


    <EditText
        android:id="@+id/elname"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" 
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:singleLine="true"/>


    <TextView
        android:id="@+id/rgender"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Gender"
         android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:textAppearance="?android:attr/textAppearanceLarge" />


    <Spinner
        android:id="@+id/spinner1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"

        android:drawSelectorOnTop="true" />


    <TextView
        android:id="@+id/runame"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="User Name"
         android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:textAppearance="?android:attr/textAppearanceLarge" />


    <EditText
        android:id="@+id/reuname"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" 
         android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"/>


    <TextView
        android:id="@+id/rpass"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Password"
         android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:textAppearance="?android:attr/textAppearanceLarge" />


    <EditText
        android:id="@+id/repass"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="textPassword" 
         android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"/>


    <TextView
        android:id="@+id/email"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Email"
         android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:textAppearance="?android:attr/textAppearanceLarge" />


    <EditText
        android:id="@+id/eemail"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="textEmailAddress" 
         android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"/>





    <RelativeLayout
        android:id="@+id/relativeLayout1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

         <Button
        android:id="@+id/submit"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Submit" 
         android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"/>


    <Button
        android:id="@+id/cancel"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Cancel" 
        android:layout_toRightOf="@id/submit"/>

    </RelativeLayout>
</LinearLayout>
   </ScrollView>

Activity_login.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >


    <TextView
        android:id="@+id/Luname"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="User Name"

        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:textAppearance="?android:attr/textAppearanceLarge" />


    <EditText
        android:id="@+id/Ledituname"

        android:layout_width="match_parent"
        android:layout_height="wrap_content" 
        android:singleLine="true"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp">


        <requestFocus />
    </EditText>


    <TextView
        android:id="@+id/Lpass"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Password"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:textAppearance="?android:attr/textAppearanceLarge" />


    <EditText
        android:id="@+id/Leditpw"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="textPassword" 
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"/>


    <RelativeLayout
        android:id="@+id/relativeLayout1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <Button
        android:id="@+id/login"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:text="Login" />




    <Button
        android:id="@+id/register"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Register" 
        android:layout_toRightOf="@id/login"/>

    </RelativeLayout>

LogCatFile

06-26 07:07:17.980: E/AndroidRuntime(791): FATAL EXCEPTION: main
06-26 07:07:17.980: E/AndroidRuntime(791): Process: com.example.app, PID: 791
06-26 07:07:17.980: E/AndroidRuntime(791): java.lang.NullPointerException
06-26 07:07:17.980: E/AndroidRuntime(791):  at com.example.app.LoginActivity.validateLogin(LoginActivity.java:109)
06-26 07:07:17.980: E/AndroidRuntime(791):  at com.example.app.LoginActivity.onClick(LoginActivity.java:71)
06-26 07:07:17.980: E/AndroidRuntime(791):  at android.view.View.performClick(View.java:4438)
06-26 07:07:17.980: E/AndroidRuntime(791):  at android.view.View$PerformClick.run(View.java:18422)
06-26 07:07:17.980: E/AndroidRuntime(791):  at android.os.Handler.handleCallback(Handler.java:733)
06-26 07:07:17.980: E/AndroidRuntime(791):  at android.os.Handler.dispatchMessage(Handler.java:95)
06-26 07:07:17.980: E/AndroidRuntime(791):  at android.os.Looper.loop(Looper.java:136)
06-26 07:07:17.980: E/AndroidRuntime(791):  at android.app.ActivityThread.main(ActivityThread.java:5017)
06-26 07:07:17.980: E/AndroidRuntime(791):  at java.lang.reflect.Method.invokeNative(Native Method)
06-26 07:07:17.980: E/AndroidRuntime(791):  at java.lang.reflect.Method.invoke(Method.java:515)
06-26 07:07:17.980: E/AndroidRuntime(791):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
06-26 07:07:17.980: E/AndroidRuntime(791):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
06-26 07:07:17.980: E/AndroidRuntime(791):  at dalvik.system.NativeStart.main(Native Method)

Answer 1

替换它：

    DB = new DBHelper(getBaseContext());

到此，

    DB = new DBHelper(LoginActivity.this);

Answer 2

我检查了代码并且工作正常。附加我用于屏幕截图的代码。不确定您是否使用了正确的导入，我已将代码附加到导入。

enter image description here

代码如下，

activity_login.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >


    <TextView
        android:id="@+id/Luname"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="User Name"

        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:textAppearance="?android:attr/textAppearanceLarge" />


    <EditText
        android:id="@+id/Ledituname"

        android:layout_width="match_parent"
        android:layout_height="wrap_content" 
        android:singleLine="true"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp">


        <requestFocus />
    </EditText>


    <TextView
        android:id="@+id/Lpass"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Password"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:textAppearance="?android:attr/textAppearanceLarge" />


    <EditText
        android:id="@+id/Leditpw"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="textPassword" 
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"/>


    <RelativeLayout
        android:id="@+id/relativeLayout1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <Button
        android:id="@+id/login"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:text="Login" />




    <Button
        android:id="@+id/register"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Register" 
        android:layout_toRightOf="@id/login"/>

    </RelativeLayout>
</LinearLayout>

register.xml

<?xml version="1.0" encoding="utf-8"?>



    <ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/scrollView1" 
        android:layout_width="match_parent" 
        android:layout_height="wrap_content">

        <LinearLayout 

            android:id="@+id/linearLayout1" 
            android:layout_width="match_parent" 
            android:layout_height="match_parent"
            android:orientation="vertical">
    <TextView
        android:id="@+id/fname"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="First Name"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:textAppearance="?android:attr/textAppearanceLarge" />


    <EditText
        android:id="@+id/efname"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" 
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:singleLine="true">


        <requestFocus />
    </EditText>


    <TextView
        android:id="@+id/lname"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Last Name"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:textAppearance="?android:attr/textAppearanceLarge" />


    <EditText
        android:id="@+id/elname"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" 
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:singleLine="true"/>


    <TextView
        android:id="@+id/rgender"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Gender"
         android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:textAppearance="?android:attr/textAppearanceLarge" />


    <Spinner
        android:id="@+id/spinner1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"

        android:drawSelectorOnTop="true" />


    <TextView
        android:id="@+id/runame"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="User Name"
         android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:textAppearance="?android:attr/textAppearanceLarge" />


    <EditText
        android:id="@+id/reuname"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" 
         android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"/>


    <TextView
        android:id="@+id/rpass"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Password"
         android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:textAppearance="?android:attr/textAppearanceLarge" />


    <EditText
        android:id="@+id/repass"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="textPassword" 
         android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"/>


    <TextView
        android:id="@+id/email"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Email"
         android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:textAppearance="?android:attr/textAppearanceLarge" />


    <EditText
        android:id="@+id/eemail"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="textEmailAddress" 
         android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"/>





    <RelativeLayout
        android:id="@+id/relativeLayout1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

         <Button
        android:id="@+id/submit"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Submit" 
         android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"/>


    <Button
        android:id="@+id/cancel"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Cancel" 
        android:layout_toRightOf="@id/submit"/>

    </RelativeLayout>
</LinearLayout>
   </ScrollView>

DBHelper.java

package com.example.test;

import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class DBHelper extends SQLiteOpenHelper {
    private SQLiteDatabase db;
    public static final String KEY_ROWID = "_id";
    public static final String KEY_FNAME = "firstname";
    public static final String KEY_LNAME = "lastname";
    public static final String KEY_GENDER = "gender";
    public static final String KEY_USER = "username";
    public static final String KEY_EMAIL = "email";

    DBHelper DB = null;
    private static final String DATABASE_NAME = "srikanth1.db";
    private static final int DATABASE_VERSION = 2;
    public static final String DATABASE_TABLE_NAME = "sri1";

    private static final String DATABASE_TABLE_CREATE = "CREATE TABLE "
            + DATABASE_TABLE_NAME
            + "("
            + "_id INTEGER PRIMARY KEY AUTOINCREMENT,"
            + "firstname TEXT NOT NULL, lastname TEXT NOT NULL, gender TEXT NOT NULL, username TEXT NOT NULL, password TEXT NOT NULL, email TEXT NOT NULL);";

    public DBHelper(Context context) {

        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        System.out.println("In constructor");
    }

    @Override
    public void onCreate(SQLiteDatabase db) {

        try {

            db.execSQL(DATABASE_TABLE_CREATE);

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub

    }

    public Cursor rawQuery(String string, String[] strings) {
        // TODO Auto-generated method stub
        return null;
    }

    public void open() {

        getWritableDatabase();
    }

    public Cursor getDetails(String text) throws SQLException {

        Cursor mCursor = db.query(true, DATABASE_TABLE_NAME, new String[] {
                KEY_ROWID, KEY_FNAME, KEY_LNAME, KEY_GENDER, KEY_USER,
                KEY_EMAIL }, KEY_USER + "=" + text, null, null, null, null,
                null);
        if (mCursor != null) {
            mCursor.moveToFirst();
        }
        return mCursor;

    }

}

Registration.java

package com.example.test;

import android.app.Activity;
import android.content.ContentValues;
import android.content.Intent;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.Toast;

public class Registration extends Activity implements OnClickListener,
        OnItemSelectedListener {
    // Variable Declaration should be in onCreate()
    private Button mSubmit;
    private Button mCancel;

    private EditText mFname;
    private EditText mLname;
    private EditText mUsername;
    private EditText mPassword;
    private EditText mEmail;
    private Spinner mGender;
    private String Gen;

    protected DBHelper DB = new DBHelper(Registration.this);

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.register);

        // Assignment of UI fields to the variables
        mSubmit = (Button) findViewById(R.id.submit);
        mSubmit.setOnClickListener(this);

        mCancel = (Button) findViewById(R.id.cancel);
        mCancel.setOnClickListener(this);

        mFname = (EditText) findViewById(R.id.efname);
        mLname = (EditText) findViewById(R.id.elname);

        mUsername = (EditText) findViewById(R.id.reuname);
        mPassword = (EditText) findViewById(R.id.repass);
        mEmail = (EditText) findViewById(R.id.eemail);

        mGender = (Spinner) findViewById(R.id.spinner1);

        // Spinner method to read the on selected value
        ArrayAdapter<State> spinnerArrayAdapter = new ArrayAdapter<State>(this,
                android.R.layout.simple_spinner_item, new State[] {
                        new State("Male"), new State("Female") });
        mGender.setAdapter(spinnerArrayAdapter);
        mGender.setOnItemSelectedListener(this);
    }

    @Override
    public void onClick(View v) {
        /*
         * int id = v.getId(); if (id == R.id.cancel) { Intent i = new
         * Intent(getBaseContext(), LoginActivity.class); startActivity(i); }
         * else if (id == R.id.submit) { String fname =
         * mFname.getText().toString(); String lname =
         * mLname.getText().toString();
         * 
         * String uname = mUsername.getText().toString(); String pass =
         * mPassword.getText().toString(); String email =
         * mEmail.getText().toString();
         * 
         * 
         * boolean invalid = false;
         * 
         * if(fname.equals("")) { invalid = true;
         * Toast.makeText(getApplicationContext(), "Enter your Firstname",
         * Toast.LENGTH_SHORT).show(); } else
         * 
         * if(lname.equals("")) { invalid = true;
         * Toast.makeText(getApplicationContext(), "Please enter your Lastname",
         * Toast.LENGTH_SHORT).show(); } else
         * 
         * if(uname.equals("")) { invalid = true;
         * Toast.makeText(getApplicationContext(), "Please enter your Username",
         * Toast.LENGTH_SHORT).show(); } else
         * 
         * 
         * if(pass.equals("")) { invalid = true;
         * Toast.makeText(getApplicationContext(), "Please enter your Password",
         * Toast.LENGTH_SHORT).show();
         * 
         * } else if(email.equals("")) { invalid = true;
         * Toast.makeText(getApplicationContext(), "Please enter your Email ID",
         * Toast.LENGTH_SHORT).show(); } else if(invalid == false) {
         * addEntry(fname, lname, Gen, uname, pass, email); Intent i_register =
         * new Intent(Registration.this, LoginActivity.class);
         * startActivity(i_register); //finish(); } }
         */

        switch (v.getId()) {

        case R.id.cancel:
            Intent i = new Intent(getBaseContext(), LoginActivity.class);
            startActivity(i);
            // finish();
            break;

        case R.id.submit:

            String fname = mFname.getText().toString();
            String lname = mLname.getText().toString();

            String uname = mUsername.getText().toString();
            String pass = mPassword.getText().toString();
            String email = mEmail.getText().toString();

            boolean invalid = false;

            if (fname.equals("")) {
                invalid = true;
                Toast.makeText(getApplicationContext(), "Enter your Firstname",
                        Toast.LENGTH_SHORT).show();
            } else

            if (lname.equals("")) {
                invalid = true;
                Toast.makeText(getApplicationContext(),
                        "Please enter your Lastname", Toast.LENGTH_SHORT)
                        .show();
            } else

            if (uname.equals("")) {
                invalid = true;
                Toast.makeText(getApplicationContext(),
                        "Please enter your Username", Toast.LENGTH_SHORT)
                        .show();
            } else

            if (pass.equals("")) {
                invalid = true;
                Toast.makeText(getApplicationContext(),
                        "Please enter your Password", Toast.LENGTH_SHORT)
                        .show();

            } else if (email.equals("")) {
                invalid = true;
                Toast.makeText(getApplicationContext(),
                        "Please enter your Email ID", Toast.LENGTH_SHORT)
                        .show();
            } else if (invalid == false) {
                addEntry(fname, lname, Gen, uname, pass, email);
                Intent i_register = new Intent(Registration.this,
                        LoginActivity.class);
                startActivity(i_register);
                // finish();
            }

            break;
        }
    }

    public void onDestroy() {
        super.onDestroy();
        DB.close();
    }

    private void addEntry(String fname, String lname, String Gen, String uname,
            String pass, String email) {

        SQLiteDatabase db = DB.getWritableDatabase();

        ContentValues values = new ContentValues();
        values.put("firstname", fname);
        values.put("lastname", lname);
        values.put("gender", Gen);
        values.put("username", uname);
        values.put("password", pass);
        values.put("email", email);

        try {
            db.insert(DBHelper.DATABASE_TABLE_NAME, null, values);

            Toast.makeText(getApplicationContext(),
                    "your details submitted Successfully...",
                    Toast.LENGTH_SHORT).show();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void onItemSelected(AdapterView<?> parent, View view, int position,
            long id) {
        // Get the currently selected State object from the spinner
        State st = (State) mGender.getSelectedItem();

        // Show it via a toast
        toastState("onItemSelected", st);
    }

    public void toastState(String name, State st) {
        if (st != null) {
            Gen = st.name;
            // Toast.makeText(getBaseContext(), Gen, Toast.LENGTH_SHORT).show();

        }

    }

    public void onNothingSelected(AdapterView<?> arg0) {
        // TODO Auto-generated method stub

    }

}

LoginActivity.java

package com.example.test;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class LoginActivity extends Activity implements OnClickListener {

    Button mLogin;
    Button mRegister;

    EditText muname;
    EditText mpassword;

    DBHelper DB = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);

        mRegister = (Button) findViewById(R.id.register);
        mRegister.setOnClickListener(this);

        mLogin = (Button) findViewById(R.id.login);
        mLogin.setOnClickListener(this);

    }

    public void onClick(View v) {
        switch (v.getId()) {

        case R.id.register:
            Intent i = new Intent(getBaseContext(), Registration.class);
            startActivity(i);
            break;

        case R.id.login:

            muname = (EditText) findViewById(R.id.Ledituname);
            mpassword = (EditText) findViewById(R.id.Leditpw);

            String username = muname.getText().toString();
            String password = mpassword.getText().toString();

            if (username.equals("") || username == null) {
                Toast.makeText(getApplicationContext(),
                        "Please enter User Name", Toast.LENGTH_SHORT).show();
            } else if (password.equals("") || password == null) {
                Toast.makeText(getApplicationContext(),
                        "Please enter your Password", Toast.LENGTH_SHORT)
                        .show();
            } else {
                boolean validLogin = validateLogin(username, password,
                        getBaseContext());
                if (validLogin) {
                    // System.out.println("In Valid");
                    //Intent in = new Intent(getBaseContext(), TabBar.class);
                    // in.putExtra("UserName", muname.getText().toString());
                    //startActivity(in);

                    Toast.makeText(getApplicationContext(),
                            "Success Valid Login", Toast.LENGTH_SHORT)
                            .show();

                    // finish();
                }
            }
            break;

        }

    }

    private boolean validateLogin(String username, String password,
            Context baseContext) {
        DB = new DBHelper(getBaseContext());
        SQLiteDatabase db = DB.getReadableDatabase();

        String[] columns = { "_id" };

        String selection = "username=? AND password=?";
        String[] selectionArgs = { username, password };

        Cursor cursor = null;
        try {

            cursor = db.query(DBHelper.DATABASE_TABLE_NAME, columns, selection,
                    selectionArgs, null, null, null);
            startManagingCursor(cursor);
        } catch (Exception e)

        {
            e.printStackTrace();
        }
        int numberOfRows = cursor.getCount();

        if (numberOfRows <= 0) {

            Toast.makeText(getApplicationContext(),
                    "User Name and Password miss match..\nPlease Try Again",
                    Toast.LENGTH_LONG).show();
            Intent intent = new Intent(getBaseContext(), LoginActivity.class);
            startActivity(intent);
            return false;
        }

        return true;

    }

    public void onDestroy() {
        super.onDestroy();
        DB.close();
    }
}

State.java

package com.example.test;

public class State {

    public String name;

    public State(String name)
    {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }


    @Override
    public String toString()
    {
        return name;
    }
}

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