SQLite 사용법

* MainActivity.java

public class MainActivity extends AppCompatActivity {

    EditText editText;
    EditText editText2;
    TextView textView;

    SQLiteDatabase database;

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

        editText = findViewById(R.id.editText);
        editText2 = findViewById(R.id.editText2);
        textView = findViewById(R.id.textView);

        Button button = findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String databaseName = editText.getText().toString();
                createDatabase(databaseName);
            }
        });

        Button button2 = findViewById(R.id.button2);
        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String tableName = editText2.getText().toString();
                createTable(tableName);
            }
        });

        Button button3 = findViewById(R.id.button3);
        button3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                insertRecord();
            }
        });

        Button button4 = findViewById(R.id.button4);
        button4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                excuteQuery();
            }
        });
    }

    public void createDatabase(String databaseName) {
        println("createDatabase 호출됨");

        try {
            database = openOrCreateDatabase(databaseName + ".db", MODE_PRIVATE, null);
            println("데이터베이스 생성됨 : " + databaseName);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void createTable(String tableName) {
        println("createTable 호출됨");

        try {
            if (database == null) {
                println("데이터베이스를 먼저 열어주세요.");
                return;
            }

            String sql = "create table if not exists " + tableName + "(_id integer PRIMARY KEY autoincrement, name text, age integer, mobile text)";
            database.execSQL(sql);
            println("테이블 생성됨 : " + tableName);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void insertRecord() {
        println("insertRecord 호출됨");

        try {
            if (database == null) {
                println("데이터베이스를 먼저 열어주세요.");
                return;
            }

            String tableName = editText2.getText().toString();
            if (tableName == null) {
                println("테이블 이름을 입력하세요.");
                return;
            }

            String sql = "insert into " + tableName + "(name, age, mobile) values ('홍길동', '20', '010-1000-1000')";
            database.execSQL(sql);
            println("레코드 추가함");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void excuteQuery() {
        println("excuteQuery 호출됨");

        if (database == null) {
            println("테이터베이스를 먼저 열어주세요.");
        }

        String tableName = editText2.getText().toString();
        if (tableName == null) {
            println("테이블 이름을 입력하세요.");
        }

        try {
            String sql = "select _id, name, age, mobile from " + tableName;
            Cursor cursor = database.rawQuery(sql, null);

            int i = 1;
            while (cursor.moveToNext()) {


                int id = cursor.getInt(0);
                String name = cursor.getString(1);
                int age = cursor.getInt(2);
                String mobile = cursor.getString(3);

                println("레코드 #" + i + " : " + id + ", " + name + ", " + age + ", " + mobile);
                i++;
            }

            cursor.close();
        } catch (Exception e ) {
            e.printStackTrace();
        }
    }

    public void println(String data) {
        textView.append(data + "\n");
    }

}

* activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <EditText
            android:id="@+id/editText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:ems="10"
            android:inputType="textPersonName" />

        <Button
            android:id="@+id/button"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="데이터베이스 만들기" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <EditText
            android:id="@+id/editText2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:ems="10"
            android:inputType="textPersonName" />

        <Button
            android:id="@+id/button2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="테이블 만들기" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <Button
            android:id="@+id/button3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="레코드 추가" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <Button
            android:id="@+id/button4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="레코드 조회" />
    </LinearLayout>

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical" >

            <TextView
                android:id="@+id/textView"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />

        </LinearLayout>

    </ScrollView>

</LinearLayout>

* SQLite 다운로드

https://sqlitebrowser.org/dl/