javascript - 我正在尝试配置一个简单的 DbHelper，但在执行相同操作时出现错误

Question

当我尝试在手机上调试应用程序时，就会发生此错误......

我不知道问题出在哪里？

错误是:MY LOGCAT WINDOW

My DatabaseHelper class

package com.example.adityasinh.healthassitance;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

public class DatabaseHelper extends SQLiteOpenHelper {


    private static final int DATABASE_VERSION =1;
    private static final String DATABASE_NAME ="contact.db";
    private static final String TABLE_NAME ="contacts";

    SQLiteDatabase db;

    private static final String CREATE_QUERY =
            "CREATE TABLE "
                    + Contact.NewUserInfo.TABLE_NAME+" ("
                    + Contact.NewUserInfo.First_Name+" TEXT NOT NULL,"
                    + Contact.NewUserInfo.Last_Name+" TEXT NOT NULL,"
                    + Contact.NewUserInfo.Gender+" TEXT NOT NULL,"
                    + Contact.NewUserInfo.Age+" TEXT NOT NULL,"
                    + Contact.NewUserInfo.Mob_No+" TEXT NOT NULL,"
                    + Contact.NewUserInfo.Pass1+" TEXT NOT NULL,"
                    + Contact.NewUserInfo.Pass2+" TEXT NOT NULL,"
                    + Contact.NewUserInfo.Emailid+" TEXT NOT NULL );";




    public DatabaseHelper(Context context)
    {
        super(context,DATABASE_NAME,null,DATABASE_VERSION);
        Log.e("DATABASE OPERATIONS","DB created / opened........");
    }

    public void insertContact(String first_name, String last_name, String gender, String age, String mob, String emailid, String pass1,String pass2,SQLiteDatabase db)
    {
        db=this.getWritableDatabase();
        ContentValues values = new ContentValues();
        ContentValues contentValues = new ContentValues();
        contentValues.put(Contact.NewUserInfo.First_Name,first_name);
        contentValues.put(Contact.NewUserInfo.Last_Name,last_name);
        contentValues.put(Contact.NewUserInfo.Gender,gender);
        contentValues.put(Contact.NewUserInfo.Age,age);
        contentValues.put(Contact.NewUserInfo.Mob_No,mob);
        contentValues.put(Contact.NewUserInfo.Emailid,emailid);
        contentValues.put(Contact.NewUserInfo.Pass1,pass1);
        contentValues.put(Contact.NewUserInfo.Pass2,pass2);
       // db.insert(Contact.NewUserInfo.TABLE_NAME, null, contentValues);
        Log.e("DATABASE OPERATIONS", "One Row Inserted...");



        db.insert(TABLE_NAME, null, values);
        db.close();

    }

    public String searchPass(String Emailid){

        db = this.getReadableDatabase();
        String query = "Select email and password from"+TABLE_NAME;
        Cursor cursor = db.rawQuery (query , null );
        cursor.getInt(0);
        String a,b;
        b="Not Found";
        if(cursor.moveToFirst())
        {
            do{
                a=cursor.getString(0);

                if(a.equals(Emailid))
                {
                    b=cursor.getString(1);
                    break;
                }

            }while(cursor.moveToNext());
        }

        return b;

    }




    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL(CREATE_QUERY);
        Log.e("DATABASE OPERATIONS","Table created......");
        this.db = db;



    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        String query = "DROP TABLE IF EXITS"+TABLE_NAME;
        db.execSQL(query);
        this.onCreate(db);

    }


}

My Contact class

package com.example.adityasinh.healthassitance;


public class Contact {

    public static abstract class NewUserInfo
    {
        public static final String First_Name = "first_name";
        public static final String Last_Name = "last_name";
        public static final String Gender = "gender";
        public static final String Age = "age";
        public static final String Mob_No ="mob_no";
        public static final String Emailid ="emailid";
        public static final String Pass1 ="pass1";
        public static final String Pass2 ="pass2";

        public static final String TABLE_NAME = "contacts";


    }
}

My SignupActivity class

package com.example.adityasinh.healthassitance;

import android.app.Activity;
import android.content.ContentValues;
import android.content.Context;
import android.content.Intent;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class SignupActivity extends Activity{

    Context context= this;
    SQLiteDatabase sqLiteDatabase;
    DatabaseHelper databaseHelper;

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

    public void onSignUpClick(View v)
    {




        if(v.getId()==R.id.Bsignupbutton)
        {









            EditText first_name= (EditText) findViewById(R.id.firstname);
            EditText last_name=(EditText) findViewById(R.id.lastname);
            EditText gender=(EditText) findViewById(R.id.gender);
            EditText age=(EditText) findViewById(R.id.age);
            EditText mobileno=(EditText) findViewById(R.id.mobileno);
            EditText emailid=(EditText) findViewById(R.id.emailid1);
            EditText pass1=(EditText) findViewById(R.id.pass1);
            EditText pass2=(EditText) findViewById(R.id.pass2);

            String firstnamestr= first_name.getText().toString();
            String lastnamestr= last_name.getText().toString();
            String genderstr= gender.getText().toString();
            String agestr= age.getText().toString();
            String mobilenostr= mobileno.getText().toString();
            String emailidstr= emailid.getText().toString();
            String pass1str= pass1.getText().toString();
            String pass2str= pass2.getText().toString();





            if(!pass1str.equals(pass2str))
            {
                Toast pass = Toast.makeText(SignupActivity.this,"Password Don't Match",Toast.LENGTH_SHORT);
                pass.show();
            }
            else {

                ////insert details in DB

                databaseHelper=new DatabaseHelper(context);
                sqLiteDatabase= databaseHelper.getWritableDatabase();
                databaseHelper.insertContact(firstnamestr , lastnamestr , genderstr , agestr , mobilenostr , emailidstr , pass1str , pass2str , sqLiteDatabase);

                ContentValues contentValues = new ContentValues();
                contentValues.put(Contact.NewUserInfo.First_Name,firstnamestr);
                contentValues.put(Contact.NewUserInfo.Last_Name,lastnamestr);
                contentValues.put(Contact.NewUserInfo.Gender,genderstr);
                contentValues.put(Contact.NewUserInfo.Age,agestr);
                contentValues.put(Contact.NewUserInfo.Mob_No,mobilenostr);
                contentValues.put(Contact.NewUserInfo.Emailid,emailidstr);
               //contentValues.put(Contact.NewUserInfo,Pass1,pass1str);
                //contentValues.put(Contact.NewUserInfo,Pass2,pass2str);


                Toast.makeText(getBaseContext(),"Data Saved",Toast.LENGTH_LONG).show();

                databaseHelper.close();




            }


        }

    }
}

And my LoginActivity class

package com.example.adityasinh.healthassitance;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class LoginActivity extends AppCompatActivity {


    DatabaseHelper helper=new DatabaseHelper(this);

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

    public void onButtonClick(View v)
    {

        if(v.getId()==R.id.Blogin)
        {


            EditText a = (EditText) findViewById(R.id.emailid1);
            String str= a.getText().toString();
            EditText b = (EditText) findViewById(R.id.password);
            String pass1= b.getText().toString();

            String password= helper.searchPass(str);
           if(pass1.equals(password))
            {
                Intent i = new Intent(LoginActivity.this,DisplayActivity.class);

                startActivity(i);

            }
            else {

                     Toast temp  = Toast.makeText(LoginActivity.this,"UserName And Password Don't Match",Toast.LENGTH_SHORT);
                     temp.show();
                }

        }
        if(v.getId()==R.id.Bsignup)
        {

            Intent i = new Intent(LoginActivity.this,SignupActivity.class);
            startActivity(i);
        }

    }
}

Answer 1

有两件事:

您打开一个可写数据库两次:

• 在 SignupActivity 的 onSignUpClick 函数中
• 在您的 DatabaseHelper (insertContact) 中

不需要在onSignupClick中打开数据库!您不能同时使用 2 个可写数据库。

您的 insertContact 函数中有错误:

public void insertContact(String first_name, String last_name, String gender, String age, String mob, String emailid, String pass1,String pass2,SQLiteDatabase db)
{
    db=this.getWritableDatabase();
    ContentValues values = new ContentValues(); // <- why?
    ContentValues contentValues = new ContentValues();
    contentValues.put(Contact.NewUserInfo.First_Name,first_name);
    contentValues.put(Contact.NewUserInfo.Last_Name,last_name);
    contentValues.put(Contact.NewUserInfo.Gender,gender);
    contentValues.put(Contact.NewUserInfo.Age,age);
    contentValues.put(Contact.NewUserInfo.Mob_No,mob);
    contentValues.put(Contact.NewUserInfo.Emailid,emailid);
    contentValues.put(Contact.NewUserInfo.Pass1,pass1);
    contentValues.put(Contact.NewUserInfo.Pass2,pass2);
   // db.insert(Contact.NewUserInfo.TABLE_NAME, null, contentValues);
    Log.e("DATABASE OPERATIONS", "One Row Inserted...");



    db.insert(TABLE_NAME, null, values); // <- this is the empty ContentValues. Should be contentValues instead of values
    db.close();

}