本文共 2354 字,大约阅读时间需要 7 分钟。
方法不统一,会有很多很多方法,我的只是其中的一种呢
首先先在布局文件里写入四个按钮 分别是 增删改查
实现是点击按钮触发onClick完成的
接下来结束创建数据库类
数据库类继承SQLiteOpenHelper
public class PersonSql extends SQLiteOpenHelper { //构造方法 public PersonSql(@Nullable Context context, @Nullable String name, @Nullable SQLiteDatabase.CursorFactory factory, int version) { super(context, name, factory, version); } //创建数据库的时候执行,且只会执行一次 @Override public void onCreate(SQLiteDatabase db) { //创建数据库的同时创建表 //person数表名 db.execSQL("create table person (id integer primary key autoincrement , " + "name varchar(100)," + "age integer )"); } //更新数据库版本的时候执行 @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { }}
//剩下的就是主线程啦
public class MainActivity extends AppCompatActivity { SQLiteDatabase db; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //创建数据库 PersonSql personSql = new PersonSql(this, "day99.db", null, 1); db = personSql.getReadableDatabase(); } //增 public void add(View view) { ContentValues contentValues = new ContentValues(); contentValues.put("name","阿萨德"); contentValues.put("age",33); db.insert("person",null,contentValues); } //删 public void del(View view) { db.delete("person","id = ?",new String[]{ "2"}); } //改 public void update(View view) { ContentValues contentValues = new ContentValues(); contentValues.put("name","请求"); contentValues.put("age",22); db.update("person",contentValues,"id = ?",new String[]{ "4"}); } //查 public void query(View view) { Cursor cursor = db.query("person", null, null, null, null, null, null); while (cursor.moveToNext()) { String id = cursor.getString(cursor.getColumnIndex("id")); String name = cursor.getString(cursor.getColumnIndex("name")); String age = cursor.getString(cursor.getColumnIndex("age")); Toast.makeText(this, id + "---" + "---" + name + "---" + age, Toast.LENGTH_SHORT).show(); } }}
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