Question

我是android studio和sq lite数据库的新手，我正在为像gmail中的登录这样的应用程序开发一个登录页面。在这里，我将用户电话号码作为主键。当用户输入他的电话号码时，如果已经存在，它将重定向到密码屏幕。我不知道如何检查电话号码是否已经存在。这是我的代码。

PhoneNumber.java

    package com.hernaezchristophergmail.projectitrack;


    import android.app.Activity;
    import android.content.Context;
    import android.content.Intent;
    import android.database.Cursor;
    import android.database.sqlite.SQLiteDatabase;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.Toast;




    public class PhoneNumber extends AppCompatActivity {

        EditText Pnum;
        Button Con;
        UserDBHelper userDBHelper;
        SQLiteDatabase sqLiteDatabase;
        Context context = this;

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

            Pnum = (EditText) findViewById(R.id.tbPnumber);
            Con = (Button) findViewById(R.id.btbCon);

            Con.setOnClickListener(new View.OnClickListener(){
                @Override

                    public void onClick(View v){
                    String pnumber = Pnum.getText().toString().trim();



                    String storedPassword = UserDBHelper.getSingleEntry(pnumber,sqLiteDatabase);
                  /*  if(pnumber.equals("")||pnumber1.equals("")){
                        Toast.makeText(PhoneNumber.this, "Please", Toast.LENGTH_LONG).show();
                        return;
                    }*/

                    if(!pnumber.equals(storedPassword)){
                        Toast.makeText(PhoneNumber.this, "Invalid Login details", Toast.LENGTH_LONG).show();
                        return;
                    }
                    else{
                        Intent intent = new Intent(PhoneNumber.this,PasswordScreen.class);
                                startActivity(intent);
                    }
                }
            });
        }

       /* public void add(View view){
            String pnumber = Pnum.getText().toString();

            Intent intent = new Intent(PhoneNumber.this, PasswordScreen.class);
            startActivity(intent);

        }
        */

        public void create(View view) {
            Intent intent = new Intent(PhoneNumber.this, SignUp.class);
            startActivity(intent);
        }

        @Override
        public void onBackPressed(){

        }
    }

UserDBHelper.java

    package com.hernaezchristophergmail.projectitrack;

    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;

    /**
     * Created by Christopher on 4/26/2016.
     */
    public class UserDBHelper extends SQLiteOpenHelper {

        private static final String DATABASE_NAME = "ITRACK_USER.DB";
        private static final int DATABASE_VERSION = 1;


        private static final String CREATEINFO_QUERY=
                "CREATE TABLE "+ UserContact.UserInformation.TABLE_NAME+"("+ UserContact.UserInformation.User_Password+" TEXT," +
                        UserContact.UserInformation.User_PhoneNumber+" TEXT," + UserContact.UserInformation.User_Firstame+" TEXT," + UserContact.UserInformation.User_LastName+" TEXT);";

        public UserDBHelper(Context context){

            super(context,DATABASE_NAME,null,DATABASE_VERSION);
            Log.e("DATABASE OPERATIONS","DATABASE CREATED / OPENED ...");

        }

        @Override
        public void onCreate(SQLiteDatabase db) {
            db.execSQL(CREATEINFO_QUERY);
            Log.e("DATABASE OPERATION", "TABLE CREATED ...");

        }


        public void saveInfo(String first,String last,String pnum, String pass, SQLiteDatabase db){
            ContentValues contentvalues = new ContentValues();
            contentvalues.put(UserContact.UserInformation.User_Firstame,first);
            contentvalues.put(UserContact.UserInformation.User_LastName,last);
            contentvalues.put(UserContact.UserInformation.User_PhoneNumber,pnum);
            contentvalues.put(UserContact.UserInformation.User_Password,pass);

            db.insert(UserContact.UserInformation.TABLE_NAME, null, contentvalues);
            Log.e ("Database Operation", "one row inserted . . .");
        }

        public static String getSingleEntry(String pnum, SQLiteDatabase sqLiteDatabase) {
            Cursor cursor = sqLiteDatabase.query(UserContact.UserInformation.TABLE_NAME, null, " User_PhoneNumber=?",
                    new String[] { pnum }, null, null, null);
            if (cursor.getCount() < 1) {
                cursor.close();
                return "NOT EXIST";
            }
            cursor.moveToFirst();
            String phonenum = cursor.getString(cursor.getColumnIndex("password"));
            cursor.close();
            return phonenum;
        }


        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

        }
    }

UserContact.java

public class UserContact {

    public static abstract class UserInformation{
        public static final String TABLE_NAME = "info";
        public static final String User_Password= "password";
        public static final String User_LastName = "last_name";
        public static final String User_Firstame = "first_name";
        public static final String User_PhoneNumber = "phone_number";
        public static final String PHOTOID = "photo_id";
    }
}

Answer 1

错误是什么？另外，请看一下。

public static String getSingleEntry(String pnum, SQLiteDatabase sqLiteDatabase) {
            Cursor cursor = sqLiteDatabase.query(UserContact.UserInformation.TABLE_NAME, null, " User_PhoneNumber=?",
                    new String[] { pnum }, null, null, null);
            if (cursor.getCount() < 1) {
                cursor.close();
                return "NOT EXIST";
            }
            cursor.moveToFirst();
            String phonenum = cursor.getString(cursor.getColumnIndex("password"));
            cursor.close();
            return phonenum; //RETURN YES / NO if exist not the actual password for security purpose.
        }

if(!pnumber.equals(storedPassword)){ //ALSO HERE, return YES/NO if exist or new, not the actual password.
                        Toast.makeText(PhoneNumber.this, "Invalid Login details", Toast.LENGTH_LONG).show();
                        return;
                    }

Answer 2

查询错误
的 1。您的表中从不存在错误的列名 User_PhoneNumber。写下查询

 Cursor cursor = sqLiteDatabase.query(UserContact.UserInformation.TABLE_NAME, null, UserContact.UserInformation.User_PhoneNumber+"=?",
                    new String[] { pnum }, null, null, null);

和的 2。错误的列名：）您正在读取密码而不是电话号码..写

String phonenum = cursor.getString(cursor.getColumnIndex(UserContact.UserInformation.User_PhoneNumber));

而不是

String phonenum = cursor.getString(cursor.getColumnIndex("password"));

Answer 3

以下方法将返回给定数字的名称。通过这种方式，您可以触发该号码是否可用。如果数字为其他，则返回true。

public Boolean numberExists(Context context, String phoneNumber) {
        String contactName = null;
        ContentResolver resolver = context.getContentResolver();
        Uri uri = Uri.withAppendedPath(ContactsContract.Contacts.CONTENT_FILTER_URI, Uri.encode(phoneNumber));
        Cursor cursor = resolver.query(uri, new String[]{ContactsContract.Contacts.DISPLAY_NAME}, null, null, null);
        try {

            if (cursor != null) {
                if (cursor.moveToFirst()) {
                    return true;
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (cursor != null && !cursor.isClosed()) {
                cursor.close();
            }
        }
        return false;
    }

我不知道如何验证电话号码是否已存在。我只是一个新手，我现在不知道该怎么做

3 个答案: