การทำระบบ Login ด้วย SQLite

git clone https://github.com/Devahoy/android-login-example.git
git checkout part1

git clone git@github.com:Devahoy/android-login-example.git
git checkout part1

package com.devahoy.sample.login;

public interface UserManagerHelper {

    public static final String DATABASE_NAME = "ahoy_login";
    public static final int DATABASE_VERSION = 1;

    /**
     * ทำการเซฟข้อมูล User ลงฐานข้อมูล
     * @param user
     * @return หากบันทึกสำเร็จจะส่งค่า row ID กลับมา ถ้ามี error จะส่ง -1
     */
    public long registerUser(User user);

    /**
     * ทำการเช็ค User ว่าล็อคอินด้วย username และ password <br />
     * ถูกต้องตรงกับในฐานข้อมูลหรือไม่ (มันก็คือการ query sqlite นั่นเอง) <br />
     * หาก query ด้วย username, password แล้วมีข้อมูล แสดงว่า ล็อคอินถูกต้อง
     * @param user
     * @return - หากตรง ก็ส่งค่าเป็น user นั้นๆกลับไป หากไม่ตรงก็ส่ง null
     */
    public User checkUserLogin(User user);

    /**
     * สำหรับเปลี่ยน password โดยทำการ query หาข้อมูล username, password ก่อน <br />
     * จากนั้นถึง update โดยเปลี่ยน password ใหม่แทน
     * @param user
     * @return - ส่งค่า จำนวนแถวที่มีการ update
     */
    public int changePassword(User user);

}

package com.devahoy.sample.login.model;

import android.provider.BaseColumns;

public class User {

    public static final String TABLE = "user";

    public class Column {
        public static final String ID = BaseColumns._ID;
        public static final String USERNAME = "username";
        public static final String PASSWORD = "password";
    }

    private int id;
    private String username;
    private String password;

    // Constructor
    public User(String username, String password) {
        this.username = username;
        this.password = password;
    }

    public User() {

    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }
    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}

package com.devahoy.sample.login;

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

public class UserManager extends SQLiteOpenHelper implements UserManagerHelper {

    public UserManager(Context context) {
        super(context, UserManagerHelper.DATABASE_NAME, null, UserManagerHelper.DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {

    }

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

    }

    @Override
    public long registerUser(User user) {
        return 0;
    }

    @Override
    public User checkUserLogin(User user) {
        return null;
    }

    @Override
    public int changePassword(User user) {
        return 0;
    }
}

public class UserManager extends SQLiteOpenHelper implements UserManagerHelper {
    public static final String TAG = UserManager.class.getSimpleName();
    private SQLiteDatabase mDatabase;

...
}

@Override
public void onCreate(SQLiteDatabase db) {
    String CREATE_TABLE_USER = String.format("CREATE TABLE %s " +
                    "(%s INTEGER PRIMARY KEY AUTOINCREMENT, %s TEXT, %s TEXT)" ,
            User.TABLE,
            User.Column.ID,
            User.Column.USERNAME,
            User.Column.PASSWORD
    );

    db.execSQL(CREATE_TABLE_USER);

    Log.i(TAG, CREATE_TABLE_USER);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    String DROP_USER = "DROP TABLE IF EXISTS " + UserManagerHelper.DATABASE_VERSION;

    db.execSQL(DROP_USER);

    Log.i(TAG, DROP_USER);
    onCreate(mDatabase);
}

@Override
public long registerUser(User user) {

    mDatabase = this.getWritableDatabase();

    ContentValues values = new ContentValues();
    values.put(User.Column.USERNAME, user.getUsername());
    values.put(User.Column.PASSWORD, user.getPassword());

    long result = mDatabase.insert(User.TABLE, null, values);
    mDatabase.close();

    return result;
}

@Override
public User checkUserLogin(User user) {

    mDatabase = this.getReadableDatabase();

    Cursor cursor = mDatabase.query(User.TABLE,
            null,
            User.Column.USERNAME + " = ? AND " +
                    User.Column.PASSWORD + " = ?",
            new String[]{user.getUsername(), user.getPassword()},
            null,
            null,
            null);

    User currentUser = new User();

    if (cursor != null) {
        if (cursor.moveToFirst()) {
            currentUser.setId((int) cursor.getLong(0));
            currentUser.setUsername(cursor.getString(1));
            currentUser.setPassword(cursor.getString(2));
            mDatabase.close();
            return currentUser;
        }
    }

    return null;
}

@Override
public int changePassword(User user) {

    mDatabase = this.getWritableDatabase();

    ContentValues values = new ContentValues();
    values.put(User.Column.USERNAME, user.getUsername());
    values.put(User.Column.PASSWORD, user.getPassword());

    int row = mDatabase.update(User.TABLE,
            values,
            User.Column.ID + " = ?",
            new String[] {String.valueOf(user.getId())});

    mDatabase.close();
    return row;
}

package com.devahoy.sample.login;

import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import com.devahoy.sample.login.model.User;
import com.devahoy.sample.login.utils.UserManager;


public class LoginActivity extends ActionBarActivity {

    private Button mLogin;
    private EditText mUsername;
    private EditText mPassword;
    private TextView mRegister;
    private Context mContext;

    private UserManager mManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_login);

        mManager = new UserManager(this);

        mContext = this;

        mLogin = (Button) findViewById(R.id.button_login);
        mUsername = (EditText) findViewById(R.id.username);
        mPassword = (EditText) findViewById(R.id.password);
        mRegister = (TextView) findViewById(R.id.register);

        mLogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                checkLogin();
            }
        });

        mRegister.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(mContext, RegisterActivity.class);
                startActivity(intent);
            }
        });
    }

    private void checkLogin() {
        String username = mUsername.getText().toString().trim().toLowerCase();
        String password = mPassword.getText().toString().trim();

        User user = new User(username, password);

        User validateUser = mManager.checkUserLogin(user);

        if (null == validateUser) {
            String message = getString(R.string.login_error_message);
            Toast.makeText(mContext, message, Toast.LENGTH_SHORT).show();
        } else {
            Intent intent = new Intent(mContext, MainActivity.class);
            intent.putExtra(User.Column.USERNAME, validateUser.getUsername());
            intent.putExtra(User.Column.ID, validateUser.getId());
            startActivity(intent);
            finish();
        }
    }
}

User user = new User(username, password);
long rowId = mManager.registerUser(user);

if (rowId == -1) {

} else {

}

package com.devahoy.sample.login;

import android.content.Context;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import com.devahoy.sample.login.model.User;
import com.devahoy.sample.login.utils.UserManager;

public class RegisterActivity extends ActionBarActivity {

    private EditText mUsername;
    private EditText mPassword;
    private EditText mConfirmPassword;
    private Button mRegister;

    private Context mContext;
    private UserManager mManager;

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

        mManager = new UserManager(this);
        mContext = this;

        mUsername = (EditText) findViewById(R.id.username);
        mPassword = (EditText) findViewById(R.id.password);
        mConfirmPassword = (EditText) findViewById(R.id.confirm_password);
        mRegister = (Button) findViewById(R.id.button_register);

        mRegister.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                String username = mUsername.getText().toString().trim().toLowerCase();
                String password = mPassword.getText().toString();
                String confirmPassword = mConfirmPassword.getText().toString();

                if (password.equals(confirmPassword)) {
                    User user = new User(username, password);
                    long rowId = mManager.registerUser(user);

                    if (rowId == -1) {
                        String message = getString(R.string.register_error_message);
                        Toast.makeText(mContext, message, Toast.LENGTH_SHORT).show();
                    } else {
                        String message = getString(R.string.register_success);
                        Toast.makeText(mContext, message, Toast.LENGTH_SHORT).show();
                        finish();
                    }

                } else {
                    String message = getString(R.string.register_password_error);
                    Toast.makeText(mContext, message, Toast.LENGTH_SHORT).show();
                }

            }
        });
    }
}

<?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">

    <ImageView
        android:layout_width="150dp"
        android:layout_height="150dp"
        android:src="@drawable/ic_launcher"
        android:id="@+id/logo"
        android:layout_gravity="center"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/say_hi"
        android:textSize="24sp"
        android:layout_marginTop="16dp"
        android:layout_gravity="center"/>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/welcome_message"
        android:id="@+id/welcome"
        android:textSize="32sp"
        android:layout_gravity="center"/>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/change_password"
        android:id="@+id/change_password"
        android:layout_marginTop="32dp"
        android:layout_gravity="center"/>
</LinearLayout>

package com.devahoy.sample.login;

import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.text.TextUtils;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import com.devahoy.sample.login.model.User;
import com.devahoy.sample.login.utils.UserManager;

public class MainActivity extends ActionBarActivity {

    Button mChangePassword;
    TextView mUsername;
    private UserManager mManager;
    User mUser;

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

        mManager = new UserManager(this);
        mUser = new User();

        mChangePassword = (Button) findViewById(R.id.change_password);
        mUsername = (TextView) findViewById(R.id.say_hi);

        Bundle args = getIntent().getExtras();

        if (null == args) {
            Toast.makeText(this, getString(R.string.welcome_error_message),
                    Toast.LENGTH_SHORT).show();
            finish();
        } else {
            mUsername.setText(getString(R.string.say_hi) + " " +
                    args.getString(User.Column.USERNAME));

            mUser.setId(args.getInt(User.Column.ID));
            mUser.setUsername(args.getString(User.Column.USERNAME));
        }

        mChangePassword.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                showDialogPassword();
            }
        });
    }

    private void showDialogPassword() {

    }

    private void goToLogin() {
        Intent intent = new Intent(this, LoginActivity.class);
        startActivity(intent);
        finish();
    }
}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
    <EditText
        android:id="@+id/password"
        android:inputType="textPassword"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="4dp"
        android:layout_marginLeft="4dp"
        android:layout_marginRight="4dp"
        android:layout_marginBottom="16dp"
        android:hint="@string/new_password"/>
</LinearLayout>

    AlertDialog.Builder builder =
            new AlertDialog.Builder(MainActivity.this);
    LayoutInflater inflater = getLayoutInflater();
    View view = inflater.inflate(R.layout.dialog, null);

    final EditText newPassword = (EditText) view.findViewById(R.id.password);
    builder.setView(view);

    builder.setPositiveButton(getString(android.R.string.ok),
            new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            String password = newPassword.getText().toString();
            if(!TextUtils.isEmpty(password)) {
                mUser.setPassword(password);
                mManager.changePassword(mUser);
                Toast.makeText(getApplicationContext(),
                        getString(R.string.change_password_message),
                        Toast.LENGTH_SHORT).show();
                goToLogin();
            }
        }
    });
    builder.setNegativeButton(getString(android.R.string.cancel), null);
    builder.show();