Android的SQLite的增删查改

原创作品，允许转载，转载时请务必声明作者信息和本声明。http://www.cnblogs.com/zhu520/p/8343675.html

本人小白，那个大神看到有问题可指出，谢谢。。。。

一：sqlite概念：是一个软件库，实现了自给自足(这意味着不需要任何外部的依赖)，无服务器的，零配置的，事务性(完全兼容 ACID 的)的sql数据库引擎,SQLite 是非常小的，是轻量级的，完全配置时小于 400KiB，省略可选功能配置时小于250KiB。支持多种开发语言，C, C++, PHP, Perl, Java, C#,Python, Ruby等

注意，SQLite 是不区分大小写的，但也有一些命令是大小写敏感的，比如 GLOB 和 glob 在 SQLite 的语句中有不同的含义。

对于Android，在应用程序中以编程方式创建的SQLite数据库始终存储在/data/data/项目名称/databases文件夹中

SQL 能做什么？

SQL 面向数据库执行查询

SQL 可从数据库取回数据

SQL 可在数据库中插入新的记录

SQL 可更新数据库中的数据

SQL 可从数据库删除记录

SQL 可创建新数据库

SQL 可在数据库中创建新表

SQL 可在数据库中创建存储过程

SQL 可在数据库中创建视图

SQL 可以设置表、存储过程和视图的权限

二：创建一个Android 工程后继承SQLiteOpenHelper它主要用于新建数据库，新建数据表和跟新数据库

package zhu.com.sqlite_curd;

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

/**
 * Created by Pearl on 2018/1/25.
 */

public class CasualCreatClass  extends SQLiteOpenHelper {

    /**构造方法
     * (Context context, String name, CursorFactory factory,int version)
     * 数据库创建的构造方法  数据库名称  sql_table.db ，版本号为1
     * @param context 上下文对象
     * @param /name 数据库名称 secb.db
     * @param /factory  游标工厂
     * @param /version 数据库版本
     */
    public CasualCreatClass(Context context) {
        super(context, "sql_table.db", null, 1);
    }

    /**数据库第一次被使用时创建数据库
     * 初始化数据库的表结构
     */
    @Override
    public void onCreate(SQLiteDatabase sqLiteDatabase) {
        //执行有更新行为的sql语句
        sqLiteDatabase.execSQL("CREATE Table man (manId integer primary key autoincrement, name varchar(20), age integer)");
    }

    /**数据库版本升级时调用
     * 数据库版本发生改变时才会被调用,数据库在升级时才会被调用;
     * @param sqLiteDatabase 操作数据库
     * @param i 旧版本
     * @param i1 新版本
     */
    @Override
    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
        sqLiteDatabase.execSQL("drop table if exists man");
        onCreate(sqLiteDatabase);
    }
}

类中的构造方法用于创建数据库和初始版本号；

onCreate方法用于初始化数据库的表结构，这里新建了一个man表，里面有manId(主键)，name，age；

onUpgrade方法用于数据库版本升级时调用，此时可以用测试类去测试一下看看新建语法有没有问题，看看有没有新建数据库：

在清单文件中application节点上方添加四行代码（第三行要写自己应用的包名）

三：源码

1）：activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    tools:context="zhu.com.sqlite_curd.MainActivity">
    <!--市-->
    <LinearLayout

        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:background="@android:drawable/edit_text"
        android:addStatesFromChildren="true"
        >
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="?android:attr/textColorSecondary"
            android:text="城市名："
            android:id="@+id/tvCity"
            />
        <EditText
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:singleLine="true"
            android:background="@null"
            android:id="@+id/etCity"
            />
    </LinearLayout>
    <!--编码-->
    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:background="@android:drawable/edit_text"
        android:addStatesFromChildren="true"
        >
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="?android:attr/textColorSecondary"
            android:text="市区号"
            android:id="@+id/tvCode"
            />
        <EditText
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:singleLine="true"
            android:background="@null"
            android:id="@+id/etCode"
            />
    </LinearLayout>

    <!--增加，修改，查询-->
    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:addStatesFromChildren="true"
        >
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="增加"
            android:id="@+id/bt_add"
            />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="修改"
            android:id="@+id/bt_modify"
            />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="查询"
            android:id="@+id/bt_query"
            />
    </LinearLayout>

    <!--把数据显示到这里来-->
    <ListView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:padding="5dip"
        android:id="@+id/listView"
        />

</LinearLayout>

2）:listview.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:padding="5dip"
  android:id="@+id/linear"
  >
      <ImageView
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:gravity="left"
          android:id="@+id/imCity"
      />
      <TextView
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:gravity="left"
          android:id="@+id/tvCity"
          />
      <TextView
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_alignParentRight="true"
          android:gravity="right"
          android:id="@+id/btRemove"
          />
</RelativeLayout>

3):CityBean\

package zhu.com.sqlite_curd;
/**
 * 普通JavaBean
 *
 */
public class CityBean {
    public static final String ID = "_id";
    public static final String CITY = "city";
    public static final String CODE = "code";

    private String id;
    private String city;
    private String code;

    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getCity() {
        return city;
    }
    public void setCity(String city) {
        this.city = city;
    }
    public String getCode() {
        return code;
    }
    public void setCode(String code) {
        this.code = code;
    }

}

4):SQLiteHelper

package zhu.com.sqlite_curd;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
/**
 * 实现对表的创建、更新、变更列名操作
 * @author ytm0220@163.com
 *
 */
public class SQLiteHelper extends SQLiteOpenHelper {
    public static final String TB_NAME = "citys";

    public SQLiteHelper(Context context, String name, CursorFactory factory,
            int version) {
        super(context, name, factory, version);
    }

    /**
     * 创建新表
     */
    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE IF NOT EXISTS " +
                TB_NAME + "(" +
                CityBean.ID + " integer primary key," +
                CityBean.CITY + " varchar," +
                CityBean.CODE + " integer"+
                ")");
    }

    /**
     * 当检测与前一次创建数据库版本不一样时，先删除表再创建新表
     */
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + TB_NAME);
        onCreate(db);
    }

    /**
     * 变更列名
     * @param db
     * @param oldColumn
     * @param newColumn
     * @param typeColumn
     */
    public void updateColumn(SQLiteDatabase db, String oldColumn, String newColumn, String typeColumn){
        try{
            db.execSQL("ALTER TABLE " +
                    TB_NAME + " CHANGE " +
                    oldColumn + " "+ newColumn +
                    " " + typeColumn
            );
        }catch(Exception e){
            e.printStackTrace();
        }
    }

}

5):MainActivity

package zhu.com.sqlite_curd;

import android.app.Activity;
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.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;

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

public class MainActivity extends Activity {
    private static String DB_NAME = "mycity.db";
    private static int DB_VERSION = 1;
    private static int POSTION;
    private ListView listview;
    private Cursor cursor;
    private SQLiteDatabase db;
    private SQLiteHelper dbHelper;
    private ListAdapter listAdapter;

    private EditText etCity;
    private EditText etCode;
    private Button bt_add;
    private Button bt_modify;
    private Button bt_query;

    private List<CityBean> cityList = new ArrayList<CityBean>();
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        etCity = (EditText) findViewById(R.id.etCity);
        etCode = (EditText) findViewById(R.id.etCode);
        bt_add = (Button) findViewById(R.id.bt_add);
        bt_modify = (Button) findViewById(R.id.bt_modify);
        bt_query = (Button) findViewById(R.id.bt_query);

        try{
            /* 初始化并创建数据库 */
            dbHelper = new SQLiteHelper(this, DB_NAME, null, DB_VERSION);
            /* 创建表 */
            db = dbHelper.getWritableDatabase();    //调用SQLiteHelper.OnCreate()
            /* 查询表，得到cursor对象 */
            cursor = db.query(SQLiteHelper.TB_NAME, null, null, null, null, null, CityBean.CODE + " DESC");
            cursor.moveToFirst();
            while(!cursor.isAfterLast() && (cursor.getString(1) != null)){
                CityBean city = new CityBean();
                city.setId(cursor.getString(0));
                city.setCity(cursor.getString(1));
                city.setCode(cursor.getString(2));
                cityList.add(city);
                cursor.moveToNext();
            }
        }catch(IllegalArgumentException e){
            //当用SimpleCursorAdapter装载数据时，表ID列必须是_id，否则报错column '_id' does not exist
            e.printStackTrace();
            //当版本变更时会调用SQLiteHelper.onUpgrade()方法重建表 注：表以前数据将丢失
            ++ DB_VERSION;
            dbHelper.onUpgrade(db, --DB_VERSION, DB_VERSION);
//            dbHelper.updateColumn(db, SQLiteHelper.ID, "_"+SQLiteHelper.ID, "integer");
        }
        listview = (ListView)findViewById(R.id.listView);
        listAdapter = new ListAdapter();
        listview.setAdapter(listAdapter);
        listview.setOnItemClickListener(new ListView.OnItemClickListener(){
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int postion,
                                    long arg3) {
                setSelectedValues(postion);
            }
        });

        /* 插入表数据并ListView显示更新 */
        bt_add.setOnClickListener(new Button.OnClickListener(){
            @Override
            public void onClick(View arg0) {
                if(etCity.getText().length() > 1 && etCode.getText().length() >1){
                    ContentValues values = new ContentValues();
                    values.put(CityBean.CITY, etCity.getText().toString().trim());
                    values.put(CityBean.CODE, etCode.getText().toString().trim());
                    //插入数据 用ContentValues对象也即HashMap操作,并返回ID号
                    Long cityID = db.insert(SQLiteHelper.TB_NAME, CityBean.ID, values);
                    CityBean city = new CityBean();
                    city.setId(""+cityID);
                    city.setCity(etCity.getText().toString().trim());
                    city.setCode(etCode.getText().toString().trim());
                    cityList.add(city);
                    listview.setAdapter(new ListAdapter());
                    resetForm();
                }
            }
        });

        /* 查询表，模糊条件查询 */
        bt_query.setOnClickListener(new Button.OnClickListener(){
            @Override
            public void onClick(View view) {
                cityList.removeAll(cityList);
                String sql = null;
                String sqlCity = etCity.getText().length() > 0 ? CityBean.CITY + " like '%" + etCity.getText().toString().trim() + "%'" : "";
                String sqlCode = etCode.getText().length() > 0 ? CityBean.CITY + " like '%" + etCity.getText().toString().trim() + "%'" : "";
                if( (!"".equals(sqlCity)) && (!"".equals(sqlCode)) ){
                    sql = sqlCity + " and" + sqlCode;
                }else if(!"".equals(sqlCity)){
                    sql = sqlCity;
                }else if(!"".equals(sqlCode)){
                    sql = sqlCode;
                }
                cursor = db.query(true, SQLiteHelper.TB_NAME,
                        new String[]{CityBean.ID, CityBean.CITY, CityBean.CODE},
                        sql,
                        null, null, null, null, null);
                cursor.moveToFirst();
                while(!cursor.isAfterLast() && (cursor.getString(1) != null)){
                    CityBean city = new CityBean();
                    city.setId(cursor.getString(0));
                    city.setCity(cursor.getString(1));
                    city.setCode(cursor.getString(2));
                    cityList.add(city);
                    cursor.moveToNext();
                }
                listview.setAdapter(new ListAdapter());
                resetForm();
            }
        });

        /* 修改表数据 */
        bt_modify.setOnClickListener(new Button.OnClickListener(){
            @Override
            public void onClick(View arg0) {
                ContentValues values = new ContentValues();
                values.put(CityBean.CITY, etCity.getText().toString().trim());
                values.put(CityBean.CODE, etCode.getText().toString().trim());
                db.update(SQLiteHelper.TB_NAME, values, CityBean.ID + "=" + cityList.get(POSTION).getId(), null);
                cityList.get(POSTION).setCity(etCity.getText().toString().trim());
                cityList.get(POSTION).setCode(etCode.getText().toString().trim());
                listview.setAdapter(new ListAdapter());
                resetForm();
            }
        });
    }

    /* 设置选中ListView的值 */
    public void setSelectedValues(int postion){
        POSTION = postion;
        etCity.setText(cityList.get(postion).getCity());
        etCode.setText(cityList.get(postion).getCode());
    }

    /* 重值form */
    public void resetForm(){
        etCity.setText("");
        etCode.setText("");
    }

    @Override
    protected void onDestroy() {
        db.delete(SQLiteHelper.TB_NAME, null, null);
        super.onDestroy();
    }

    private class ListAdapter extends BaseAdapter {
        public ListAdapter(){
            super();
        }
        @Override
        public int getCount() {
            return cityList.size();
        }

        @Override
        public Object getItem(int postion) {
            return postion;
        }

        @Override
        public long getItemId(int postion) {
            return postion;
        }

        @Override
        public View getView(final int postion, View view, ViewGroup parent) {
            view = getLayoutInflater().inflate(R.layout.listview, null);
            TextView tv = (TextView) view.findViewById(R.id.tvCity);
            tv.setText("" + cityList.get(postion).getCity());
            TextView bu = (TextView) view.findViewById(R.id.btRemove);
            bu.setText("删除");//R.string.delete
            bu.setId(Integer.parseInt(cityList.get(postion).getId()));

            /* 删除表数据 */
            bu.setOnClickListener(new Button.OnClickListener(){
                @Override
                public void onClick(View view) {
                    try{
                        db.delete(SQLiteHelper.TB_NAME, CityBean.ID + "=" + view.getId(), null);
                        cityList.remove(postion);
                        listview.setAdapter(new ListAdapter());
                    }catch(Exception e){
                        e.printStackTrace();
                    }
                }
            });
            return view;
        }
    }
}

6):运行效果

7：源码下载（放心这次是百度云）密码: ryv4