android studio数据存储建立SQLite数据库怎么实现增删查改
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今天就跟大家聊聊有关android studio数据存储建立SQLite数据库怎么实现增删查改,可能很多人都不太了解,为了让大家更加了解,小编给大家总结了以下内容,希望大家根据这篇文章可以有所收获。
实验目的:
分别使用sqlite3
工具和Android
代码的方式建立SQLite
数据库。在完成建立数据库的工作后,编程实现基本的数据库操作功能,包括数据的添加、删除和更新。
实验要求:
创建一个学生管理的应用,基本信息包含学生姓名,班级,学号。采用数据库存储这些信息。
应用应该至少包含信息录入和删除功能。
数据显示考虑采用ListView。
实验效果:
工程结构:
源代码:
DBAdapter.java
package com.example.shiyan6_sqlite;import android.annotation.SuppressLint;import android.content.ContentValues;import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteException;import android.database.sqlite.SQLiteOpenHelper;import android.database.sqlite.SQLiteDatabase.CursorFactory;public class DBAdapter { private static final String DB_NAME = "student.db"; private static final String DB_TABLE = "peopleinfo"; private static final int DB_VERSION = 1; public static final String KEY_ID = "_id"; public static final String KEY_NAME = "name"; public static final String KEY_BANJI = "banji"; public static final String KEY_XUEHAO = "xuehao"; private SQLiteDatabase db; private final Context context; private DBOpenHelper dbOpenHelper; public DBAdapter(Context _context) { context = _context; } public void close() { if(db !=null) { db.close(); db=null; } } public void open() throws SQLiteException { dbOpenHelper = new DBOpenHelper(context, DB_NAME, null, DB_VERSION); try { db = dbOpenHelper.getWritableDatabase(); } catch (SQLiteException ex) { db = dbOpenHelper.getReadableDatabase(); } } public long insert(People people) { ContentValues newValues = new ContentValues(); newValues.put(KEY_NAME, people.Name); newValues.put(KEY_BANJI, people.Banji); newValues.put(KEY_XUEHAO, people.Xuehao); return db.insert(DB_TABLE, null, newValues); } public People[] queryAllData() { Cursor results = db.query(DB_TABLE, new String[] { KEY_ID, KEY_NAME, KEY_BANJI, KEY_XUEHAO}, null, null, null, null, null); return ConvertToPeople(results); } public People[] queryOneData(long id) { Cursor results = db.query(DB_TABLE, new String[] { KEY_ID, KEY_NAME, KEY_BANJI, KEY_XUEHAO}, KEY_ID + "=" + id, null, null, null, null); return ConvertToPeople(results); } @SuppressLint("Range") private People[] ConvertToPeople(Cursor cursor){ int resultCounts = cursor.getCount(); if (resultCounts == 0 || !cursor.moveToFirst()){ return null; } People[] peoples = new People[resultCounts]; for (int i = 0 ; i<resultCounts; i++){ peoples[i] = new People(); peoples[i].ID = cursor.getInt(0); peoples[i].Name = cursor.getString(cursor.getColumnIndex(KEY_NAME)); peoples[i].Banji = cursor.getString(cursor.getColumnIndex(KEY_BANJI)); peoples[i].Xuehao = cursor.getString(cursor.getColumnIndex(KEY_XUEHAO)); cursor.moveToNext(); } return peoples; } public long deleteAllData() { return db.delete(DB_TABLE, null, null); } public long deleteOneData(long id) { return db.delete(DB_TABLE, KEY_ID + "=" + id, null); } public long updateOneData(long id , People people){ ContentValues updateValues = new ContentValues(); updateValues.put(KEY_NAME, people.Name); updateValues.put(KEY_BANJI, people.Banji); updateValues.put(KEY_XUEHAO, people.Xuehao); return db.update(DB_TABLE, updateValues, KEY_ID + "=" + id, null); } private static class DBOpenHelper extends SQLiteOpenHelper { public DBOpenHelper(Context context, String name, CursorFactory factory, int version) { super(context, name, factory, version); } private static final String DB_CREATE = "create table " + DB_TABLE + " (" + KEY_ID + " integer primary key autoincrement, " + KEY_NAME+ " text not null, " + KEY_BANJI+ " text not null," + KEY_XUEHAO + " text not null);"; @Override public void onCreate(SQLiteDatabase _db) { _db.execSQL(DB_CREATE); } @Override public void onUpgrade(SQLiteDatabase _db, int _oldVersion, int _newVersion) { _db.execSQL("DROP TABLE IF EXISTS " + DB_TABLE); onCreate(_db); } }}
People.java
package com.example.shiyan6_sqlite;public class People { public int ID = -1; public String Name; public String Banji; public String Xuehao; @Override public String toString(){ String result = ""; result += "ID:" + this.ID + ","; result += "姓名:" + this.Name + ","; result += "班级:" + this.Banji + ", "; result += "学号:" + this.Xuehao; return result; }}MainActivity.javapackage com.example.shiyan6_sqlite;import androidx.appcompat.app.AppCompatActivity;import android.database.sqlite.SQLiteDatabase;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.TextView;public class MainActivity extends AppCompatActivity { EditText e_xm,e_nl,e_sg,e_id; TextView t_1; Button b_add,b_allsee,b_clearsee,b_alldel,b_delid,b_seeid,b_updid; DBAdapter dbAdapter; SQLiteDatabase db; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); e_xm=findViewById(R.id.e_xm); e_nl=findViewById(R.id.e_nl); e_sg=findViewById(R.id.e_sg); b_add=findViewById(R.id.b_add); b_allsee=findViewById(R.id.b_allsee); b_clearsee=findViewById(R.id.b_clearall); b_alldel=findViewById(R.id.b_delall); b_delid=findViewById(R.id.b_delid); b_seeid=findViewById(R.id.b_seeid); b_updid=findViewById(R.id.b_updid); e_id=findViewById(R.id.e_id); t_1=findViewById(R.id.t_1); dbAdapter=new DBAdapter(this); dbAdapter.open(); b_add.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { People t=new People(); t.Name=e_xm.getText().toString(); t.Banji=e_nl.getText().toString(); t.Xuehao=e_sg.getText().toString(); long colunm=dbAdapter.insert(t); if (colunm == -1 ){ t_1.setText("添加过程错误!"); } else { t_1.setText("成功添加数据,ID:"+String.valueOf(colunm)); } } }); b_allsee.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { People [] peoples =dbAdapter.queryAllData(); if (peoples == null){ t_1.setText("数据库中没有数据"); return; } String t="数据库:\n"; for(int i=0;i<peoples.length;++i){ t+=peoples[i].toString()+"\n"; } t_1.setText(t); } }); b_clearsee.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { t_1.setText(""); } }); b_alldel.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { dbAdapter.deleteAllData(); t_1.setText("已删除所有数据!"); } }); b_delid.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { int id=Integer.parseInt(e_id.getText().toString()); long result=dbAdapter.deleteOneData(id); String msg = "删除ID为"+e_id.getText().toString()+"的数据" + (result>0?"成功":"失败"); t_1.setText(msg); } }); b_seeid.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { int id=Integer.parseInt(e_id.getText().toString()); People people[]=dbAdapter.queryOneData(id); if(people==null){ t_1.setText("Id为"+id+"的记录不存在!"); } else{ t_1.setText("查询成功:\n"+people[0].toString()); } } }); b_updid.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { int id=Integer.parseInt(e_id.getText().toString()); People t=new People(); t.Name=e_xm.getText().toString(); t.Banji=e_nl.getText().toString(); t.Xuehao=e_sg.getText().toString(); long n=dbAdapter.updateOneData(id,t); if (n<0){ t_1.setText("更新过程错误!"); } else { t_1.setText("成功更新数据,"+String.valueOf(n)+"条"); } } }); } @Override protected void onStop() { super.onStop(); dbAdapter.close(); }}
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