안드로이드 SQLiteOpenHelper, SQLiteDatabase, Cursor를 사용 회원가입과 로그인

안녕하세요 알통몬입니다. 공감 및 댓글은 포스팅 하는데 아주아주 큰 힘이 됩니다!! 포스팅 내용이 찾아주신 분들께 도움이 되길 바라며 더 깔끔하고 좋은 포스팅을 만들어 나가겠습니다^^

안녕하세요 부르곰입니다.

예전 포스팅에서 안드로이드 SQLite 사용법에 대해 포스팅한적이 있는데요.

설명이라든가 여러가지가 좀 어렵게 포스팅한 거 같아서 쉽고 간단한게 다시 포스팅하려고 합니다.

가장 먼저 SQLiteOpenHelper 를 상속받은 클래스를 만들어 데이터베이스와 테이블 생성을 위한 코드를

작성합니다.

import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; import android.widget.Toast; public class MembershipOpenHelper extends SQLiteOpenHelper { Context context; public MembershipOpenHelper(Context context) { super(context, "member.db", null, 1); this.context = context; } @Override public void onCreate(SQLiteDatabase db) { try { String sql = "create table membership (" + "email varchar(40) not null primary key," + "pwd varchar(72) not null" + ");"; db.execSQL(sql); Toast.makeText(context, "[membership] 테이블 생성", Toast.LENGTH_SHORT).show(); } catch (Exception e) { e.printStackTrace(); } } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { } }

그리고 세 개의 액티비티와 세 개의 xml 을 준비했습니다.

1. LoginActivity, JoinActivity, MainActivity

2. activity_login, activity_join, activity_main

바로 코드입니다.

먼저 LoginActivity 와 xml

import android.content.Intent; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.os.Bundle; import android.support.annotation.Nullable; import android.support.v7.app.AppCompatActivity; import android.util.Log; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.Toast; public class LoginActivity extends AppCompatActivity { MembershipOpenHelper openHelper; EditText emailEt, pwdEt; SQLiteDatabase db; Button loginBtn, joinBtn; @Override protected void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_login); openHelper = new MembershipOpenHelper(this); db = openHelper.getWritableDatabase(); emailEt = (EditText) findViewById(R.id.emailEt); pwdEt = (EditText) findViewById(R.id.pwdEt); loginBtn = (Button) findViewById(R.id.loginBtn); joinBtn = (Button) findViewById(R.id.joinBtn); loginBtn.setOnClickListener(listener); joinBtn.setOnClickListener(listener); } View.OnClickListener listener = new View.OnClickListener() { @Override public void onClick(View v) { switch (v.getId()) { case R.id.joinBtn: startActivity(new Intent(LoginActivity.this, JoinActivity.class)); finish(); break; case R.id.loginBtn: String email = emailEt.getText().toString(); String pwd = pwdEt.getText().toString(); String sql = "select * from membership where email = '"+email+"' and pwd = '"+pwd+"'"; Cursor cursor = db.rawQuery(sql, null); while (cursor.moveToNext()) { String no = cursor.getString(0); String rest_id = cursor.getString(1); Log.d("select ", "no : " + no + "\nrest_id : " + rest_id); } if(cursor.getCount() == 1) { // 해당 이메일과 아이디가 있으면 1개의 row를 가져오겠죠? Toast.makeText(LoginActivity.this, email+ "님 환영합니다", Toast.LENGTH_SHORT).show(); Intent intent = new Intent(LoginActivity.this, MainActivity.class); intent.putExtra("email", email); intent.putExtra("pwd", pwd); startActivity(intent); finish(); } else { // 없다면 아무 값도 가져오지 않으므로 count 가 0 이겠죠? Toast.makeText(LoginActivity.this, "이메일 또는 비밀번호가 틀렸습니다.", Toast.LENGTH_SHORT).show(); } cursor.close(); break; } } }; }

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="center"> <EditText android:id="@+id/emailEt" android:layout_width="match_parent" android:layout_height="wrap_content" android:ems="10" android:inputType="textEmailAddress" /> <EditText android:id="@+id/pwdEt" android:layout_width="match_parent" android:layout_height="wrap_content" android:ems="10" android:inputType="textPassword" /> <Button android:id="@+id/loginBtn" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="Log In" /> <Button android:id="@+id/joinBtn" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="Membership" /> </LinearLayout>

두 번째 JoinActivity와 xml

import android.content.Intent; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.os.Bundle; import android.support.annotation.Nullable; import android.support.v7.app.AppCompatActivity; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.Toast; public class JoinActivity extends AppCompatActivity { MembershipOpenHelper openHelper; SQLiteDatabase db; EditText emailEt, pwdEt; Button joinBtn; @Override protected void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_join); openHelper = new MembershipOpenHelper(this); db = openHelper.getWritableDatabase(); emailEt = (EditText) findViewById(R.id.emailEt2); pwdEt = (EditText) findViewById(R.id.pwdEt2); joinBtn = (Button) findViewById(R.id.joinBtn2); joinBtn.setOnClickListener(listener); } View.OnClickListener listener = new View.OnClickListener() { @Override public void onClick(View v) { switch (v.getId()) { case R.id.joinBtn2: String email = emailEt.getText().toString(); String pwd = pwdEt.getText().toString(); String sql = "select * from membership where email = '"+email+"'"; Cursor cursor = db.rawQuery(sql, null); if(cursor.getCount() == 1) { // 해당 이메일과 아이디가 있으면 1개의 row를 가져오겠죠? Toast.makeText(JoinActivity.this, "이미 존재하는 이메일입니다.", Toast.LENGTH_SHORT).show(); startActivity(new Intent(JoinActivity.this, MainActivity.class)); finish(); } else { // 없다면 아무 값도 가져오지 않으므로 count 가 0 이겠죠? String sql2 ="insert into membership(email, pwd) values('"+email+"','"+pwd+"')"; db.execSQL(sql2); Toast.makeText(JoinActivity.this, "회원가입을 축하합니다.", Toast.LENGTH_SHORT).show(); startActivity(new Intent(JoinActivity.this, LoginActivity.class)); } cursor.close(); break; } } }; }
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="center"> <EditText android:id="@+id/emailEt2" android:layout_width="match_parent" android:layout_height="wrap_content" android:ems="10" android:inputType="textEmailAddress" /> <EditText android:id="@+id/pwdEt2" android:layout_width="match_parent" android:layout_height="wrap_content" android:ems="10" android:inputType="textPassword" /> <Button android:id="@+id/joinBtn2" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="Button" /> </LinearLayout>

마지막으로

MainActivty 와 xml 가입한 아이디와 비밀번호로 로그인되었는지 확인하기 위해 만들었습니다 ㅎㅎ

import android.content.Intent; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.widget.TextView; public class MainActivity extends AppCompatActivity { TextView emailTv, pwdTv; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Intent intent = getIntent(); String email = intent.getStringExtra("email"); String pwd = intent.getStringExtra("pwd"); emailTv = (TextView) findViewById(R.id.emailTv); pwdTv = (TextView) findViewById(R.id.pwdTv); emailTv.setText(email); pwdTv.setText(pwd); } }
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:gravity="center"> <TextView android:id="@+id/emailTv" android:layout_width="match_parent" android:layout_height="48dp" android:gravity="center"/> <TextView android:id="@+id/pwdTv" android:layout_width="match_parent" android:layout_height="48dp" android:gravity="center"/> </LinearLayout>

이상입니다.

궁금하신 점이나, 프로젝트가 필요하신 분들은 공감 후 댓글 달아주시면 메일로 보내드리겠습니다~~