ANDROID_MARS学习笔记_S01原始版_009

一、代码
1.xml
(1)activity_main.xml

 <?xml version="1.0" encoding="utf-8"?>

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

     android:orientation="vertical"

     android:layout_width="fill_parent"

     android:layout_height="fill_parent"

     >

 <Button

     android:id="@+id/createDatabase"

     android:layout_width="fill_parent"

     android:layout_height="wrap_content"

     android:text="createDatabase"

     />

 <Button

     android:id="@+id/updateDatabase"

     android:layout_width="fill_parent"

     android:layout_height="wrap_content"

     android:text="updateDatabase"

     />

 <Button

     android:id="@+id/insert"

     android:layout_width="fill_parent"

     android:layout_height="wrap_content"

     android:text="insert"/>

 <Button

     android:id="@+id/update"

     android:layout_width="fill_parent"

     android:layout_height="wrap_content"

     android:text="update"/>

 <Button

     android:id="@+id/query"

     android:layout_width="fill_parent"

     android:layout_height="wrap_content"

     android:text="query"/>

 </LinearLayout>

2.java
(1)MainActivity.java

 package com.example.s01_original_e16_sqlite;

 import android.app.Activity;

 import android.content.ContentValues;

 import android.database.Cursor;

 import android.database.sqlite.SQLiteDatabase;

 import android.database.sqlite.SQLiteOpenHelper;

 import android.os.Bundle;

 import android.util.Log;

 import android.view.View;

 import android.view.View.OnClickListener;

 import android.widget.Button;

 public class MainActivity extends Activity {

     /** Called when the activity is first created. */

     private Button createButton;

     private Button insertButton;

     private Button updateButton;

     private Button updateRecordButton;

     private Button queryButton;

     @Override

     public void onCreate(Bundle savedInstanceState) {

         super.onCreate(savedInstanceState);

         setContentView(R.layout.activity_main);

         createButton = (Button)findViewById(R.id.createDatabase);

         updateButton = (Button)findViewById(R.id.updateDatabase);

         insertButton = (Button)findViewById(R.id.insert);

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

         queryButton = (Button)findViewById(R.id.query);

         createButton.setOnClickListener(new CreateListener());

         updateButton.setOnClickListener(new UpdateListener());

         insertButton.setOnClickListener(new InsertListener());

         updateRecordButton.setOnClickListener(new UpdateRecordListener());

         queryButton.setOnClickListener(new QueryListener());

     }

     class CreateListener implements OnClickListener{

         @Override

         public void onClick(View v) {

             //创建一个DatabaseHelper对象

             DBHelper dbHelper = new DBHelper(MainActivity.this, "my_sqlite_db");

             //只有调用了DatabaseHelper对象的getReadableDatabase()方法，或者是getWritableDatabase()方法之后，才会创建，或打开一个数据库

             SQLiteDatabase db = dbHelper.getReadableDatabase();

         }

     }

     class UpdateListener implements OnClickListener{

         @Override

         public void onClick(View v) {

             DBHelper dbHelper = new DBHelper(MainActivity.this,"my_sqlite_db",2);

             SQLiteDatabase db = dbHelper.getReadableDatabase();

         }

     }

     class InsertListener implements OnClickListener{

         @Override

         public void onClick(View v) {

             //生成ContentValues对象

             ContentValues values = new ContentValues();

             //想该对象当中插入键值对，其中键是列名，值是希望插入到这一列的值，值必须和数据库当中的数据类型一致

             values.put("id", 1);

             values.put("name","zhangsan");

             DBHelper dbHelper = new DBHelper(MainActivity.this,"my_sqlite_db",2);

             SQLiteDatabase db = dbHelper.getWritableDatabase();

             //调用insert方法，就可以将数据插入到数据库当中

             db.insert("user", null, values);

         }

     }

     //更新操作就相当于执行SQL语句当中的update语句

     //UPDATE table_name SET XXCOL=XXX WHERE XXCOL=XX...

     class UpdateRecordListener implements OnClickListener{

         @Override

         public void onClick(View arg0) {

             // TODO Auto-generated method stub

             //得到一个可写的SQLiteDatabase对象

             DBHelper dbHelper = new DBHelper(MainActivity.this,"my_sqlite_db",2);

             SQLiteDatabase db = dbHelper.getWritableDatabase();

             ContentValues values = new ContentValues();

             values.put("name", "zhangsanfeng");

             //第一个参数是要更新的表名

             //第二个参数是一个ContentValeus对象

             //第三个参数是where子句

             db.update("user", values, "id=?", new String[]{"1"});

         }

     }

     class QueryListener implements OnClickListener{

         @Override

         public void onClick(View v) {

             System.out.println("aaa------------------");

             Log.d("myDebug", "myFirstDebugMsg");

             DBHelper dbHelper = new DBHelper(MainActivity.this,"my_sqlite_db",2);

             SQLiteDatabase db = dbHelper.getReadableDatabase();

             Cursor cursor = db.query("user", new String[]{"id","name"}, "id=?", new String[]{"1"}, null, null, null);

             while(cursor.moveToNext()){

                 String name = cursor.getString(cursor.getColumnIndex("name"));

                 System.out.println("query--->" + name);

             }

         }

     }

 }

(2)DBHelper.java

 package com.example.s01_original_e16_sqlite;

 import android.content.Context;

 import android.database.sqlite.SQLiteDatabase;

 import android.database.sqlite.SQLiteDatabase.CursorFactory;

 import android.database.sqlite.SQLiteOpenHelper;

 public class DBHelper extends SQLiteOpenHelper {

     private static final int VERSION = 1;

     //在SQLiteOepnHelper的子类当中，必须有该构造函数

     public DBHelper(Context context, String name, CursorFactory factory,

             int version) {

         //必须通过super调用父类当中的构造函数

         super(context, name, factory, version);

         // TODO Auto-generated constructor stub

     }

     public DBHelper(Context context,String name){

         this(context,name,VERSION);

     }

     public DBHelper(Context context,String name,int version){

         this(context, name,null,version);

     }

     //该函数是在第一次创建数据库的时候执行,实际上是在第一次得到SQLiteDatabse对象的时候，才会调用这个方法

     @Override

     public void onCreate(SQLiteDatabase db) {

         // TODO Auto-generated method stub

         System.out.println("create a Database");

         //execSQL函数用于执行SQL语句

         db.execSQL("create table user(id int,name varchar(20))");

     }

     @Override

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

         // TODO Auto-generated method stub

         System.out.println("update a Database");

     }

 }

巴特西

ANDROID_MARS学习笔记_S01原始版_009_SQLite

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