我正在嘗試配置一個簡單的DbHelper，並在執行相同操作時遇到錯誤

Question

每當我嘗試在手機上調試應用程序時，就會發生此錯誤...

我不知道是什么問題？

錯誤是： 我的LOGCAT窗口

我的DatabaseHelper類

 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); } } 

我的聯系方式

 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"; } } 

我的SignupActivity類

 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(); } } } } 

還有我的LoginActivity類

 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

兩件事情：

您兩次打開一個可寫的Databse：

• 在SignupActivity的onSignUpClick函數中
• 在您的DatabaseHelper（insertContact）中

無需在onSignupClick中打開數據庫！ 您不能同時使用2個可寫數據庫。

您的insertContact函數中有一個錯誤：

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();

}