Android項(xiàng)目如何實(shí)現(xiàn)連接SQLite數(shù)據(jù)庫(kù)

package com.example.databaseHelper;

public class DatabaseStatic {

 public final static String DATABASE_NAME = "BookStore.db";
 public final static int DATABASE_VERSION = 1;

 public final static String TABLE_NAME = "book";
 public final static String BOOK_NAME = "bookName";
 public final static String ID = "_id";
 public final static String AUTHOR = "author";
 public final static String PRICE = "price";
 public final static String DATE = "sellData";
}

package com.example.databaseHelper;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
import android.widget.Toast;

/*
 * 在這個(gè)類(lèi)的構(gòu)造函數(shù)里面我們調(diào)用了父類(lèi)的構(gòu)造方法用來(lái)創(chuàng)建數(shù)據(jù)庫(kù)文 
 * 件，第二個(gè)構(gòu)造方法只是為了方便構(gòu)造（不用些那么多的參數(shù)）
 * 這個(gè)類(lèi)繼承了 SQLiteOpenHelper 類(lèi)，并且重寫(xiě)了父類(lèi)里面的 
onCreate方法和 onUpgrade方法，
 * onCreate方法當(dāng)數(shù)據(jù)庫(kù)文件不存在的時(shí)候會(huì)被調(diào)用來(lái)創(chuàng)建一個(gè)新的數(shù)
 * 據(jù)庫(kù)文件（不懂的小伙伴可以百度一下）
 */

public class MyHelper extends SQLiteOpenHelper{

 public static String CREATE_TABLE = "create table "+ DatabaseStatic.TABLE_NAME +"(" + 
   DatabaseStatic.BOOK_NAME + " varchar(30), " + 
   DatabaseStatic.ID + " Integer primary key autoincrement, " + 
   DatabaseStatic.AUTHOR + " varchar(20) not null, " + 
   DatabaseStatic.PRICE + " real)"; // 用于創(chuàng)建表的SQL語(yǔ)句
 private Context myContext = null;

 public MyHelper(Context context, String name,
   CursorFactory factory, int version) {
  super(context, DatabaseStatic.DATABASE_NAME, null, DatabaseStatic.DATABASE_VERSION);
 }

 public MyHelper(Context context)
 {
  super(context, DatabaseStatic.DATABASE_NAME, null, DatabaseStatic.DATABASE_VERSION);
  myContext = context;
 }

 @Override
 public void onCreate(SQLiteDatabase db) {
  Log.i("UseDatabase", "創(chuàng)建數(shù)據(jù)庫(kù)");
  Toast.makeText(myContext, "創(chuàng)建數(shù)據(jù)庫(kù)", Toast.LENGTH_SHORT).show();
  db.execSQL(CREATE_TABLE);
 }

 @Override
 public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {

 } 
}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:id="@+id/mainLayout"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:orientation="vertical"
 android:gravity="center_horizontal"
 tools:context=".MainActivity" >

 <Button
  android:id="@+id/buttonCreateDatabase"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:text="創(chuàng)建數(shù)據(jù)庫(kù)" />
 <Button 
  android:id="@+id/buttonInsertDatabase"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:text="插入數(shù)據(jù)"/>
 <Button 
  android:id="@+id/buttonUpdateDatabase"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:text="更新數(shù)據(jù)"/>
 <Button 
  android:id="@+id/buttonDeleteDatabase"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:text="刪除數(shù)據(jù)"/>
 <Button 
  android:id="@+id/buttonQueryDatabase"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:text="顯示數(shù)據(jù)庫(kù)中 Book表中的所有數(shù)據(jù)"/>

</LinearLayout>

import com.example.databaseHelper.DatabaseStatic;
import com.example.databaseHelper.MyHelper;

import android.os.Bundle;
import android.app.Activity;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.graphics.Color;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {

 private MyHelper myHelper = null;
 private Button button = null;
 private SQLiteDatabase database = null;
 private static int bookSum = 0;
 TextView textView = null;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);

  textView = new TextView(this);
  LinearLayout layout = (LinearLayout) findViewById(R.id.mainLayout);
  layout.addView(textView);
  button = (Button) findViewById(R.id.buttonCreateDatabase);
  button.setOnClickListener(listener);
  button = (Button) findViewById(R.id.buttonInsertDatabase);
  button.setOnClickListener(listener);
  button = (Button) findViewById(R.id.buttonUpdateDatabase);
  button.setOnClickListener(listener);
  button = (Button) findViewById(R.id.buttonDeleteDatabase);
  button.setOnClickListener(listener);
  button = (Button) findViewById(R.id.buttonQueryDatabase);
  button.setOnClickListener(listener);
 }

 private View.OnClickListener listener = new View.OnClickListener() {

  @Override
  public void onClick(View v) {
   switch(v.getId())
   {
   case R.id.buttonCreateDatabase:
    createDatabase();
    break;
   case R.id.buttonInsertDatabase:
    insertDatabase();
    break;
   case R.id.buttonUpdateDatabase:
    updateDatabase();
    break;
   case R.id.buttonDeleteDatabase:
    deleteDatabase();
    break;
   case R.id.buttonQueryDatabase:
    searchDatabase();
    break;
   }
  }
 };

 private void createDatabase() // 創(chuàng)建或者打開(kāi)數(shù)據(jù)庫(kù)
 {
  myHelper = new MyHelper(this); 

  /*
   * 調(diào)用getWritabelDatabase方法或者
   * getReadableDatabase方法時(shí)，如果數(shù)據(jù)庫(kù)文
   * 件中不存在（注意一個(gè)數(shù)據(jù)庫(kù)中可以存在多個(gè)表格），
   * 那么會(huì)回調(diào)MyHelper類(lèi)的onCreate方法新建一個(gè)數(shù)據(jù)庫(kù)文
   * 件并且在這個(gè)數(shù)據(jù)庫(kù)文件中新建一
   * 個(gè)book表格
   */
  myHelper.getWritableDatabase(); 
 }

 private void insertDatabase() // 向數(shù)據(jù)庫(kù)中插入新數(shù)據(jù)
 {
  if(myHelper == null)
  {
   myHelper = new MyHelper(this);
  }
  database = myHelper.getWritableDatabase();

  ContentValues cV = new ContentValues();
  cV.put(DatabaseStatic.BOOK_NAME, "C Language");
  cV.put(DatabaseStatic.ID, ++bookSum);
  cV.put(DatabaseStatic.AUTHOR, "zhidian");
  cV.put(DatabaseStatic.PRICE, 42.6);
  /*
   * 這個(gè)方法是留給不熟悉SQL語(yǔ)句的小伙伴用的，Android把
   * SQLite的插入語(yǔ)句封裝了起來(lái)，
   * 通過(guò) ContentValues 類(lèi)的對(duì)象來(lái)保存數(shù)據(jù)庫(kù)中的數(shù)據(jù)，
   * 于HashMap
   */
  database.insert(DatabaseStatic.TABLE_NAME, null, cV); 

  /*
   * 對(duì)應(yīng)的SQL語(yǔ)句：
   * database.execSQL("insert into " + DatabaseStatic.TABLENAME + " values(?, ?, ?, ?)",
   * new Object[]{"C Language", ++bookSum, "zhidian", 42.6});
   * 或者是這個(gè)：
   * database.execSQL("insert into " + DatabaseStatic.TABLENAME + "(" + 
   *  DatabaseStatic.BOOKNAME + ", " + DatabaseStatic.ID + ", " + 
   *  DatabaseStatic.AUTHOR + ", " + DatabaseStatic.PRICE + 
   *  ") values(?, ?, ?, ?)", new Object[]{"C Language", ++bookSum, "zhidian", 42.6});
   * 這里將 ？ 號(hào)理解成一個(gè)C語(yǔ)言里面的占位符，然后通過(guò) Object[] 數(shù)組中的內(nèi)容補(bǔ)全，下同
   * 參數(shù)中的 Object[] 數(shù)組是一個(gè)通用的數(shù)組，里面的數(shù)據(jù)可以轉(zhuǎn)換為任意類(lèi)型的數(shù)據(jù)，通過(guò)這個(gè)完成不同數(shù)據(jù)類(lèi)型變量之間的儲(chǔ)存
  */

  Toast.makeText(this, "插入數(shù)據(jù)成功", Toast.LENGTH_SHORT).show();
 }

 private void updateDatabase() // 更新數(shù)據(jù)
 {
  if(myHelper == null)
  {
   myHelper = new MyHelper(this);
  }
  database = myHelper.getWritableDatabase();

  ContentValues cV = new ContentValues();
  cV.put(DatabaseStatic.AUTHOR, "xiaoming");
  /*
   * 調(diào)用 update 方法，將書(shū)名為"C Language" 的書(shū)作者更新為 "xiaoming
   */
  database.update(DatabaseStatic.TABLE_NAME, cV, 
    DatabaseStatic.BOOK_NAME + "= ?", new String[]{"C Language"});
  /*
   * 對(duì)應(yīng)的SQL語(yǔ)句：
   * database.execSQL("update " + DatabaseStatic.TABLENAME + " set " + DatabaseStatic.AUTHOR + 
   *  "= ? where " + DatabaseStatic.BOOKNAME + " = ?", new String[]{"xiaoming", "C Language"});
   */

  Toast.makeText(this, "數(shù)據(jù)更新成功", Toast.LENGTH_SHORT).show();
 }

 private void deleteDatabase() // 數(shù)據(jù)庫(kù)中刪除數(shù)據(jù)
 {
  if(myHelper == null)
  {
   myHelper = new MyHelper(this);
  }
  database = myHelper.getWritableDatabase();

  /*
   * 調(diào)用 delete 方法刪除數(shù)據(jù)庫(kù)中的數(shù)據(jù)
   * 對(duì)應(yīng)的SQL語(yǔ)句：
   * database.execSQL("delete from " + 
   * DatabaseStatic.TABLE_NAME + " where " + 
   * DatabaseStatic.BOOK_NAME + " = ?", new 
   * String[]{"C Language"});
   */
  database.delete(DatabaseStatic.TABLE_NAME, DatabaseStatic.BOOK_NAME + " = ? ",
    new String[]{"C Language"});

  Toast.makeText(this, "數(shù)據(jù)刪除成功", Toast.LENGTH_SHORT).show();
 }

 private void searchDatabase() // 查詢(xún)數(shù)據(jù)庫(kù)中的數(shù)據(jù)
 {
  if(myHelper == null)
  {
   myHelper = new MyHelper(this);
  }
  database = myHelper.getWritableDatabase();
  /*
   * 調(diào)用database的query方法，第一個(gè)參數(shù)是要查詢(xún)的表名，
   * 后面的參數(shù)是一些查詢(xún)的約束條件，對(duì)應(yīng)于SQL語(yǔ)句的一些參
   * 數(shù)， 這里全為null代表查詢(xún)表格中所有的數(shù)據(jù)
   * 查詢(xún)的結(jié)果返回一個(gè) Cursor對(duì)象
   * 對(duì)應(yīng)的SQL語(yǔ)句：
   * Cursor cursor = database.rawQuery("select * from book", null);
   */
  Cursor cursor = database.query(DatabaseStatic.TABLE_NAME, null, null, null, null, null, null);

  StringBuilder str = new StringBuilder();
  if(cursor.moveToFirst()) // 顯示數(shù)據(jù)庫(kù)的內(nèi)容
  {
   for(; !cursor.isAfterLast(); cursor.moveToNext()) // 獲取查詢(xún)游標(biāo)中的數(shù)據(jù)
   {
    str.append(cursor.getString(cursor.getColumnIndex(DatabaseStatic.ID)) + " ");
    str.append(cursor.getString(cursor.getColumnIndex(DatabaseStatic.BOOK_NAME)) + " ");
    str.append(cursor.getString(cursor.getColumnIndex(DatabaseStatic.AUTHOR)) + " ");
    str.append(cursor.getString(cursor.getColumnIndex(DatabaseStatic.PRICE)) + "\n");
   }
  }
  cursor.close(); // 記得關(guān)閉游標(biāo)對(duì)象
  if(str.toString().equals(""))
  {
   str.append("數(shù)據(jù)庫(kù)為空！");
   textView.setTextColor(Color.RED);
  }
  else 
  {
   textView.setTextColor(Color.BLACK);
  }
  textView.setText(str.toString());
 }

 @Override
 public boolean onCreateOptionsMenu(Menu menu) {
  getMenuInflater().inflate(R.menu.main, menu);
  return true;
 }
}

create table 表名(參數(shù)1 數(shù)據(jù)類(lèi)型 約數(shù)條件, 參數(shù)2 數(shù)據(jù)類(lèi)型 約束條件…) 

insert into 表名(參數(shù)1, 參數(shù)2…) values(參數(shù)1的值, 參數(shù)2的值…) 

insert into 表名 values(參數(shù)1的值, 參數(shù)2的值) 

insert into person(_id, name, sex, age) values(1, “指點(diǎn)”, “男”, 19) 
insert into person values(1, “指點(diǎn)”, “男”, 19)

update 表名 set 參數(shù)1 = 值, 參數(shù)2 = 值… where 條件1 and 條件2 or 條件3… 

delete from 表名 where 條件1 and 條件2 or 條件3… 

delete from person where _id > 0 and name = “指點(diǎn)”

select 參數(shù)1, 參數(shù)2… from 表名 where 條件1 and 條件2… 

select _id, name, sex from person where name = “指點(diǎn)” or _id = 1