使用安卓自带sqlite数据库简单实用（增删查改）

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使用安卓自带的sqlite数据库操作数据库（eclipse）

先上图：

主界面是增加数据、更新数据、删除数据三个按钮，，查询功能的话，    在删除界面、更新界面  写的查询所有数据。

接下来主要是代码的展示：（代码里有必要的注释）

SQLiteDBUtil.java     数据库工具类

activity_main.xml     主界面

MainActivity.java      

AddActivity.java       增加数据界面

UpdateActivity.java  更新数据界面

DeleteActivity.java    删除数据界面

首先新建一个数据库工具类：

SQLiteDBUtil.java

package easy.practice_sql;

import android.content.Context;

import android.database.DatabaseErrorHandler ;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteDatabase.CursorFactory ;

import android.database.sqlite.SQLiteOpenHelper;

public class SQLiteDBUtil extends SQLiteOpenHelper {

      public static final String NAME = "practiceDataBases" ; //数据库名

      public static final int VERSION = 1; //版本号

      /**

      * content上下文对象 name数据库名称 factory数据库工厂 version版本

      *

      * @param context

      */

      public SQLiteDBUtil(Context context) {

            super (context, NAME , null , VERSION );

            // TODO Auto-generated constructor stub

     }

      //

      @Override

      public void onCreate(SQLiteDatabase db) {//执行创建数据表的sql语句

           String userSQL = "create table practice"

                      + "(id integer primary key autoincrement,"

                      + "name varchar(5),"

                      + "age integer)" ;

           db.execSQL(userSQL);

     }

      @Override

      public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

            // TODO Auto-generated method stub

     }

}

主布局就是三个按钮：

activity_main.xml

< LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android"

    xmlns:tools = "http://schemas.android.com/tools"

    android:layout_width = "match_parent"

    android:layout_height = "match_parent"

    android:orientation = "vertical"

    tools:context = ".MainActivity" >

    < Button

        android:id = "@+id/add"

        android:layout_width = "fill_parent"

        android:layout_height = "wrap_content"

        android:text = "添加数据" />

    < Button

        android:id = "@+id/update"

        android:layout_width = "fill_parent"

        android:layout_height = "wrap_content"

        android:text = "更新数据" />

    < Button

        android:id = "@+id/delete"

        android:layout_width = "fill_parent"

        android:layout_height = "wrap_content"

        android:text = "删除数据" />

</ LinearLayout >

MainActivity.java  

package easy.practice_sql;

import java.util.Date ;

import android.os.Bundle;

import android.app.Activity;

import android.content.Intent;

import android.database.Cursor ;

import android.database.sqlite.SQLiteDatabase ;

import android.view.Menu;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.EditText ;

import android.widget.TextView ;

import android.widget.Toast ;

//15893028654

public class MainActivity extends Activity implements OnClickListener {

      private Button add , update , delete ;

      protected void onCreate(Bundle savedInstanceState) {

            super .onCreate(savedInstanceState);

           setContentView(R.layout. activity_main );

           initView();

           initAction();

     }

      private void initView() {

            add = (Button) findViewById(R.id. add );

            update = (Button) findViewById(R.id. update );

            delete = (Button) findViewById(R.id. delete );

     }

      private void initAction() {

            add .setOnClickListener( this );

            update .setOnClickListener( this );

            delete .setOnClickListener( this );

     }

      @Override

      public void onClick(View v) {

            switch (v.getId()) {

            case R.id. add :

                startActivity( new Intent(getApplicationContext(), AddActivity. class ));

                 break ;

            case R.id. update :

                startActivity( new Intent(getApplicationContext(),

                           UpdateActivity. class ));

                 break ;

            case R.id. delete :

                startActivity( new Intent(getApplicationContext(),

                           DeleteActivity. class ));

                 break ;

            default :

                 break ;

           }

     }

      @Override

      public boolean onCreateOptionsMenu(Menu menu) {

            // Inflate the menu; this adds items to the action bar if it is present.

           getMenuInflater().inflate(R.menu. main , menu);

            return true ;

     }

}

AddActivity.java       增加数据界面

package easy.practice_sql;

import android.os.Bundle;

import android.app.Activity;

import android.content.Intent ;

import android.database.sqlite.SQLiteDatabase;

import android.view.Menu;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.EditText;

import android.widget.Toast;

public class AddActivity extends Activity implements OnClickListener {

      private EditText add_name , add_age ;

      private Button btn_add ;

      @Override

      protected void onCreate(Bundle savedInstanceState ) {

            super .onCreate( savedInstanceState );

           setContentView(R.layout. activity_add );

           initView();

           initAction();

     }

      private void initView() {

            add_name = (EditText) findViewById(R.id. add_name );

            add_age = (EditText) findViewById(R.id. add_age );

            btn_add = (Button) findViewById(R.id. btn_add );

     }

      private void initAction() {

            btn_add .setOnClickListener( this );

     }

      @Override

      public void onClick(View v) {

            switch (v.getId()) {

            case R.id. btn_add :

                 if ( "" .equals( add_name .getText().toString())

                           || "" .equals( add_age .getText().toString())) {

                      Toast. makeText (getApplicationContext(), "请您输入姓名和年龄哦" ,

                                 Toast. LENGTH_SHORT ).show();

                } else {

                      doInsert();

                }

                 break ;

            default :

                 break ;

           }

     }

      public void doInsert() {

           String getName = add_name .getText().toString();

            int getAge = Integer. valueOf (( add_age .getText().toString()));

            //获取数据库操作对象

           SQLiteDBUtil db = new SQLiteDBUtil(getApplicationContext());

           SQLiteDatabase sd = db.getWritableDatabase();

            //创建 sql 语句

           String sql = "insert into practice values(null,?,?)" ;

            //执行 sql 语句

           sd.execSQL(sql, new Object[] { getName, getAge });

            //关闭数据库

           db.close();

           Toast. makeText (getApplicationContext(), "添加数据成功！" , Toast. LENGTH_SHORT )

                      .show();

            add_name .setText( "" );

            add_age .setText( "" );

     }

      @Override

      public boolean onCreateOptionsMenu(Menu menu) {

            // Inflate the menu; this adds items to the action bar if it is present.

           getMenuInflater().inflate(R.menu. add , menu);

            return true ;

     }

}

UpdateActivity.java  更新数据界面

package easy.practice_sql;

import android.os.Bundle;

import android.app.Activity;

import android.content.Intent ;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

import android.view.Menu;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.EditText;

import android.widget.TextView;

import android.widget.Toast;

public class UpdateActivity extends Activity implements OnClickListener {

      private EditText id , update_name , update_age ;

      private TextView updatae_showAll ;

      private Button btn_update ;

      @Override

      protected void onCreate(Bundle savedInstanceState) {

            super .onCreate(savedInstanceState);

           setContentView(R.layout. activity_update );

           initView();

           initAction();

     }

      private void initView() {

            id = (EditText) findViewById(R.id. id );

            update_name = (EditText) findViewById(R.id. update_name );

            update_age = (EditText) findViewById(R.id. update_age );

            updatae_showAll = (TextView) findViewById(R.id. update_showAll );

            btn_update = (Button) findViewById(R.id. btn_update );

           doQuery();

     }

      private void initAction() {

            btn_update .setOnClickListener( this );

     }

      @Override

      public void onClick(View v) {

            switch (v.getId()) {

            case R.id. btn_update :

                doUpdate();

                 break ;

            default :

                 break ;

           }

     }

      public void doQuery() {

            // **************************************************************

            // 将所有的信息展示在文本框里

           String s = "" ;

           SQLiteDBUtil db = new SQLiteDBUtil(getApplicationContext());

           SQLiteDatabase sd = db.getReadableDatabase();

           String sql = "select * from practice" ;

           Cursor cursor = sd.rawQuery(sql, null );

            while (cursor.moveToNext()) {

                s = s + "id:" + cursor.getInt(0) + "\t姓名:" + cursor.getString(1)

                           + "\t年龄:" + cursor.getInt(2) + "\n" ;

           }

           db.close();

           cursor.close();

            updatae_showAll .setText(s);

            // **************************************************************

     }

      public void doUpdate() {

           String getName = update_name .getText().toString();

           String getAge = update_age .getText().toString();

           String getId = id .getText().toString();

            int age = Integer. valueOf (getAge);

            int id = Integer. valueOf (getId);

           SQLiteDBUtil db = new SQLiteDBUtil(getApplicationContext());

           SQLiteDatabase sd = db.getWritableDatabase();

           String sql = "update practice set name= ?" + " ,age= ? where id=?" ;

           sd.execSQL(sql, new Object[] { getName, age, id });

            // 这里进行关闭

           db.close();

           Toast. makeText (getApplicationContext(), "修改成功了哦！" , Toast. LENGTH_SHORT )

                      .show();

     }

      @Override

      public boolean onCreateOptionsMenu(Menu menu) {

            // Inflate the menu; this adds items to the action bar if it is present.

           getMenuInflater().inflate(R.menu. update , menu);

            return true ;

     }

}

DeleteActivity.java    删除数据界面

package easy.practice_sql;

import android.os.Bundle;

import android.app.Activity;

import android.content.Intent ;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

import android.view.Menu;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.EditText;

import android.widget.TextView;

import android.widget.Toast;

public class DeleteActivity extends Activity implements OnClickListener {

      private EditText text ;

      private TextView showAll ;

      private Button btn_delete ;

      @Override

      protected void onCreate(Bundle savedInstanceState) {

            super .onCreate(savedInstanceState);

           setContentView(R.layout. activity_delete );

           initView();

           initAction();

     }

      private void initView() {

            text = (EditText) findViewById(R.id. text );

            btn_delete = (Button) findViewById(R.id. btn_delete );

            showAll = (TextView) findViewById(R.id. showAll );

            // 显示所有的信息

           doQuery();

     }

      private void initAction() {

            btn_delete .setOnClickListener( this );

     }

      @Override

      public void onClick(View v) {

            switch (v.getId()) {

            case R.id. btn_delete :

                String getText = text .getText().toString();

                 if (! "" .equals(getText)) { // 如果文本框里用户输入了信息，就进行操作。（这里只考虑用户输入所要删除的id，数据库里都有

                      doDelete(getText);

                } else {

                      Toast. makeText (getApplicationContext(), "请输入所要删除的姓名" ,

                                 Toast. LENGTH_SHORT ).show();

                }

                 break ;

            default :

                 break ;

           }

     }

      public void doDelete(String name) {

           SQLiteDBUtil db = new SQLiteDBUtil(getApplicationContext());

           SQLiteDatabase sd = db.getWritableDatabase();

            // 在这里，若是有字符串的话，，前后需要加单引号

           String sql = "delete from practice where name = " + "'" + name + "'" ;

           sd.execSQL(sql);

            // 这里进行关闭

           db.close();

           Toast. makeText (getApplicationContext(), "删除成功" ,

                      Toast. LENGTH_SHORT ).show();

     }

      public void doQuery() {

            // **************************************************************

            // 将所有的信息展示在文本框里

           String s = "" ;

           SQLiteDBUtil db = new SQLiteDBUtil(getApplicationContext());

           SQLiteDatabase sd = db.getReadableDatabase();

           String sql = "select * from practice" ;

           Cursor cursor = sd.rawQuery(sql, null );

            while (cursor.moveToNext()) {

                s = s + "id:" + cursor.getInt(0) + "\t姓名:" + cursor.getString(1)

                           + "\t年龄:" + cursor.getInt(2) + "\n" ;

           }

           db.close();

           cursor.close();

            showAll .setText(s);

            // **************************************************************

     }

      @Override

      public boolean onCreateOptionsMenu(Menu menu) {

            // Inflate the menu; this adds items to the action bar if it is present.

           getMenuInflater().inflate(R.menu. delete , menu);

            return true ;

     }

}