Android SQLite数据库操作示例

• 构造函数，调用父类SQLiteOpenHelper的构造函数。这个方法需要四个参数：上下文环境，数据库名字，一个可选的游标工厂（通常是NULL），一个代表你正在使用的数据库模型版本的整数。
• onCreate（）方法，它需要一个SQLiteDatabase对象作为参数，根据需要对这个对象填充表和初始化数据。
• onUpgrade（）方法，它需要三个参数，一个SQLiteDatabase对象，一个旧的版本号和一个新的版本号，这样你就可以清楚如何把一个数据库从旧的模型转变为新的模型。

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

public class MyDBHelper extends SQLiteOpenHelper {
	private static final String COLUMN_ID = "_id";
	public static final String TABLE_NAME = "category";
	private static final String DATABASE_NAME = "category.db";
	private static final int DATABASE_VERSION = 1;

	private static final String DATABASE_CREATE = "CREATE TABLE IF NOT EXISTS " + TABLE_NAME + "(" + COLUMN_ID
			+ " INTEGER PRIMARY KEY AUTOINCREMENT, " + " fid TEXT, token TEXT, cid TEXT, cname TEXT)";

	public CategoryDBHelper(Context context) {
		super(context, DATABASE_NAME, null, DATABASE_VERSION);
	}

	@Override
	public void onCreate(SQLiteDatabase db) {
		db.execSQL(DATABASE_CREATE);
	}

	@Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
		db.execSQL("DROP TABLE IF EXISTS" + TABLE_NAME);
		onCreate(db);
	}
}

增删改查数据库

public class CategoryDBManager {
	private MyDBHelper myDBHelper;

	private static CategoryDBManager categoryDBManager = null;

	private CategoryDBManager(Context context) {
		myDBHelper = new MyDBHelper(context);
	}

	/**
	 * 单例模式
	 */
	public static CategoryDBManager getInstance(Context context) {
		if (categoryDBManager == null) {
			synchronized (CategoryDBManager.class) {
				if (categoryDBManager == null) {
					categoryDBManager = new CategoryDBManager(context);
				}
			}
		}

		return categoryDBManager;
	}

	public SQLiteDatabase getDB() {
		SQLiteDatabase db = myDBHelper.getWritableDatabase();

		while (db.isDbLockedByCurrentThread()) {
		}
		return db;
	}

	public void insertLists(String token, String fid, List<PlateCategoryData> lists) {
		// 打开可写数据库
		SQLiteDatabase db = getDB();

		for (PlateCategoryData pd : lists) {
			// 执行SQL语句，替换占位符
			db.execSQL("insert into " + MyDBHelper.TABLE_NAME + "(cid, cname, fid, token) values(?, ?, ?, ?)",
					new Object[] { pd.getId(), pd.getName(), fid, token });
		}

		// 释放资源
		db.close();
	}

	public ArrayList<PlateCategoryData> getLists(String fid, String token) {
		ArrayList<PlateCategoryData> datas = new ArrayList<PlateCategoryData>();
		SQLiteDatabase db = getDB();
		// 执行原始查询，得到cursor
		String querySql = "select cid, cname from " + MyDBHelper.TABLE_NAME + " where fid = ? and token = ?";
		Cursor cursor = db.rawQuery(querySql, new String[] { fid, token });

		// 移动cursor到第一个数据（无数据返回false）
		if (cursor.moveToFirst()) {
			// while判断是否有下一条数据
			do {
				PlateCategoryData pd = new PlateCategoryData(cursor.getString(cursor.getColumnIndex("cid")),
						cursor.getString(cursor.getColumnIndex("cname")));
				datas.add(pd);
			} while (cursor.moveToNext());
		}

		cursor.close();
		db.close();

		return datas;
	}

	public void updateLists(String fid, String token, ArrayList<PlateCategoryData> datas) {
		SQLiteDatabase db = getDB();

		for (PlateCategoryData pd : datas) {
			String sql = "update " + MyDBHelper.TABLE_NAME
					+ " set cid = ?, cname = ? where fid = ? and token = ?";
			db.execSQL(sql, new Object[] { pd.getId(), pd.getName(), fid, token });
		}

		db.close();
	}

	public void deleteLists(String fid, String token) {
		SQLiteDatabase db = getDB();

		db.execSQL("delete from " + MyDBHelper.TABLE_NAME + " where fid = ? and token = ?", new Object[] { fid,
				token });

		db.close();
	}

	public void closeDB() {
		SQLiteDatabase db = getDB();

		if (db.isOpen()) {
			myDBHelper.close();
			db.close();
		}
	}
}

参考链接