SQLite数据库创建，增删查改

来源：互联网发布：od矩阵的作用编辑：程序博客网时间：2024/05/17 06:13

转载请注明出处：http://blog.csdn.net/mr_leixiansheng/article/details/53584005

步骤：

1、新建自己的数据库类继承SQLiteOpenHelper并重写（设置数据库要包含的类别）

2、主程序中实现数据库的创建，和增删查改

1、创建类

package com.example.administrator.sqlite;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;import android.widget.Toast;/** * Created by Administrator on 2016/12/12. */public class MyDatabaseHelper extends SQLiteOpenHelper {    private static final String CREATE_BOOK = "create table book ("            + "id integer primary key autoincrement, "            + "name text, "            + "age integer)";    private Context context;    public MyDatabaseHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {        super(context, name, factory, version);        this.context = context;    }    @Override    public void onCreate(SQLiteDatabase sqLiteDatabase) {        sqLiteDatabase.execSQL(CREATE_BOOK);        Toast.makeText(context, "数据库创建成功",Toast.LENGTH_SHORT).show();    }    @Override    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {    }}

2、实现对数据库的操作

package com.example.administrator.sqlite;import android.content.ContentValues;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.util.Log;import android.view.View;import android.widget.Button;import android.widget.Toast;import java.util.zip.CRC32;public class MainActivity extends AppCompatActivity implements View.OnClickListener {    private MyDatabaseHelper dbHelper;    //新建,增删改查    private Button create,insert,delete,change,query;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        //创建book.db数据库对象，版本号1        dbHelper = new MyDatabaseHelper(this, "book.db", null, 1);        //获取元素ID        create = (Button) findViewById(R.id.create);        insert = (Button) findViewById(R.id.insert);        delete = (Button) findViewById(R.id.delete);        change = (Button) findViewById(R.id.change);        query = (Button) findViewById(R.id.query);        //设置按键点击监听        create.setOnClickListener(this);        insert.setOnClickListener(this);        delete.setOnClickListener(this);        change.setOnClickListener(this);        query.setOnClickListener(this);    }    @Override    public void onClick(View view) {        switch (view.getId()) {            case R.id.create:                dbHelper.getWritableDatabase();                break;            case R.id.insert:                insertData();                Toast.makeText(this, "添加成功", Toast.LENGTH_SHORT).show();                break;            case R.id.delete:                deletData();                Toast.makeText(this, "删除成功", Toast.LENGTH_SHORT).show();                break;            case R.id.change:                changeDate();                Toast.makeText(this, "更改成功", Toast.LENGTH_SHORT).show();                break;            case R.id.query:                queryData();                Toast.makeText(this, "浏览", Toast.LENGTH_SHORT).show();                break;            default:                break;        }    }    private void queryData() {        SQLiteDatabase db = dbHelper.getWritableDatabase();        Cursor cursor = db.query("book", null, null, null, null, null, null);        //遍历        while (cursor.moveToNext()) {            String name = cursor.getString(cursor.getColumnIndex("name"));            int age = cursor.getInt(cursor.getColumnIndex("age"));            Log.i("MainActivity", name);            Log.i("MainActivity", String.valueOf(age));        }        cursor.close();    }    private void deleteData() {        SQLiteDatabase db = dbHelper.getWritableDatabase();        db.delete("book","name = ?",new String[] {"小明"});    }    private void changeDate() {        SQLiteDatabase db = dbHelper.getWritableDatabase();        ContentValues values = new ContentValues();        values.put("name", "小黄");        db.update("book",values, "name = ?",new String[] {"小红"});    }    private void insertData() {        SQLiteDatabase db = dbHelper.getWritableDatabase();        ContentValues values = new ContentValues();        values.put("name", "小明");        values.put("age", 5);        db.insert("book", null, values);        values.clear();        values.put("name", "小红");        values.put("age", 10);        db.insert("book", null, values);    }}

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