android用sqllite数据库实现古诗的增、删、改、查，写一个完整的简单示例，写清文件名

好的，以下是一个简单的 Android SQLite 数据库示例，实现了对古诗的增、删、改、查操作。主要分为两个部分：数据库操作类 `PoemDBHelper` 和具体的增删改查操作实现。

1. `PoemDBHelper.java` 文件：

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

public class PoemDBHelper extends SQLiteOpenHelper {
    // 数据库名称和版本号
    private static final String DB_NAME = "poem.db";
    private static final int DB_VERSION = 1;

    // 表名和列名常量
    public static final String TABLE_NAME = "poem";
    public static final String COLUMN_ID = "_id";
    public static final String COLUMN_TITLE = "title";
    public static final String COLUMN_AUTHOR = "author";
    public static final String COLUMN_CONTENT = "content";

    // 创建表的 SQL 语句
    private static final String CREATE_TABLE_SQL = "CREATE TABLE " + TABLE_NAME + " ("
            + COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
            + COLUMN_TITLE + " TEXT, "
            + COLUMN_AUTHOR + " TEXT, "
            + COLUMN_CONTENT + " TEXT)";

    public PoemDBHelper(Context context) {
        super(context, DB_NAME, null, DB_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        // 创建表
        db.execSQL(CREATE_TABLE_SQL);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // 数据库升级时调用
        // 这里我们简单处理，直接删除表并重新创建
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
        onCreate(db);
    }
}

2. 具体的增删改查操作实现：

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

import java.util.ArrayList;
import java.util.List;

public class PoemDAO {
    private PoemDBHelper dbHelper;

    public PoemDAO(Context context) {
        dbHelper = new PoemDBHelper(context);
    }

    // 增加古诗
    public void addPoem(Poem poem) {
        SQLiteDatabase db = dbHelper.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(PoemDBHelper.COLUMN_TITLE, poem.getTitle());
        values.put(PoemDBHelper.COLUMN_AUTHOR, poem.getAuthor());
        values.put(PoemDBHelper.COLUMN_CONTENT, poem.getContent());
        db.insert(PoemDBHelper.TABLE_NAME, null, values);
        db.close();
    }

    // 删除古诗
    public void deletePoem(Poem poem) {
        SQLiteDatabase db = dbHelper.getWritableDatabase();
        db.delete(PoemDBHelper.TABLE_NAME, PoemDBHelper.COLUMN_ID + "=?", new String[]{String.valueOf(poem.getId())});
        db.close();
    }

    // 修改古诗
    public void updatePoem(Poem poem) {
        SQLiteDatabase db = dbHelper.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(PoemDBHelper.COLUMN_TITLE, poem.getTitle());
        values.put(PoemDBHelper.COLUMN_AUTHOR, poem.getAuthor());
        values.put(PoemDBHelper.COLUMN_CONTENT, poem.getContent());
        db.update(PoemDBHelper.TABLE_NAME, values, PoemDBHelper.COLUMN_ID + "=?", new String[]{String.valueOf(poem.getId())});
        db.close();
    }

    // 查找所有古诗
    public List<Poem> getAllPoems() {
        List<Poem> poems = new ArrayList<>();
        SQLiteDatabase db = dbHelper.getReadableDatabase();
        Cursor cursor = db.query(PoemDBHelper.TABLE_NAME, null, null, null, null, null, null);
        while (cursor.moveToNext()) {
            int id = cursor.getInt(cursor.getColumnIndex(PoemDBHelper.COLUMN_ID));
            String title = cursor.getString(cursor.getColumnIndex(PoemDBHelper.COLUMN_TITLE));
            String author = cursor.getString(cursor.getColumnIndex(PoemDBHelper.COLUMN_AUTHOR));
            String content = cursor.getString(cursor.getColumnIndex(PoemDBHelper.COLUMN_CONTENT));
            poems.add(new Poem(id, title, author, content));
        }
        cursor.close();
        db.close();
        return poems;
    }

    // 根据标题查找古诗
    public List<Poem> getPoemsByTitle(String title) {
        List<Poem> poems = new ArrayList<>();
        SQLiteDatabase db = dbHelper.getReadableDatabase();
        Cursor cursor = db.query(PoemDBHelper.TABLE_NAME, null, PoemDBHelper.COLUMN_TITLE + " like ?", new String[]{"%" + title + "%"}, null, null, null);
        while (cursor.moveToNext()) {
            int id = cursor.getInt(cursor.getColumnIndex(PoemDBHelper.COLUMN_ID));
            String poemTitle = cursor.getString(cursor.getColumnIndex(PoemDBHelper.COLUMN_TITLE));
            String author = cursor.getString(cursor.getColumnIndex(PoemDBHelper.COLUMN_AUTHOR));
            String content = cursor.getString(cursor.getColumnIndex(PoemDBHelper.COLUMN_CONTENT));
            poems.add(new Poem(id, poemTitle, author, content));
        }
        cursor.close();
        db.close();
        return poems;
    }
}

3. `Poem.java` 文件，表示古诗实体类：

public class Poem {
    private int id;
    private String title;
    private String author;
    private String content;

    public Poem(int id, String title, String author, String content) {
        this.id = id;
        this.title = title;
        this.author = author;
        this.content = content;
    }

    public Poem(String title, String author, String content) {
        this.title = title;
        this.author = author;
        this.content = content;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }
}

4. `MainActivity.java` 文件，测试代码：

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.util.Log;

import java.util.List;

public class MainActivity extends AppCompatActivity {

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

        PoemDAO dao = new PoemDAO(this);

        // 添加古诗
        dao.addPoem(new Poem("静夜思", "李白", "床前明月光，疑是地上霜。举头望明月，低头思故乡。"));

        // 查询所有古诗
        List<Poem> poems = dao.getAllPoems();
        for (Poem poem : poems) {
            Log.i("MainActivity", "id: " + poem.getId() + ", title: " + poem.getTitle() + ", author: " + poem.getAuthor() + ", content: " + poem.getContent());
        }

        // 修改古诗
        Poem poemToUpdate = poems.get(0);
        poemToUpdate.setTitle("静夜思（改）");
        dao.updatePoem(poemToUpdate);

        // 查询所有古诗
        poems = dao.getAllPoems();
        for (Poem poem : poems) {
            Log.i("MainActivity", "id: " + poem.getId() + ", title: " + poem.getTitle() + ", author: " + poem.getAuthor() + ", content: " + poem.getContent());
        }

        // 根据标题查询古诗
        List<Poem> poemsByTitle = dao.getPoemsByTitle("夜思");
        for (Poem poem : poemsByTitle) {
            Log.i("MainActivity", "id: " + poem.getId() + ", title: " + poem.getTitle() + ", author: " + poem.getAuthor() + ", content: " + poem.getContent());
        }

        // 删除古诗
        Poem poemToDelete = poems.get(0);
        dao.deletePoem(poemToDelete);

        // 查询所有古诗
        poems = dao.getAllPoems();
        for (Poem poem : poems) {
            Log.i("MainActivity", "id: " + poem.getId() + ", title: " + poem.getTitle() + ", author: " + poem.getAuthor() + ", content: " + poem.getContent());
        }
    }
}

注意，由于我们使用了 SQLiteOpenHelper 类，因此需要在 AndroidManifest.xml 中添加以下权限：

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

同时，我们需要在 `<application>` 标签下添加以下代码，以便在应用启动时进行数据库初始化：

<meta-data
    android:name="android.database.sqlite.SQLiteDatabase"
    android:value="PoemDBHelper.getWritableDatabase()" />

好了，这就是一个简单的 Android SQLite 数据库示例啦！