Android数据库SQLite的简单示例.docx

1、Android数据库SQLite的简单示例Android数据库SQLite的使用示例Android 提供了三种数据存储方式，第一种是文件存储;第二种是SharedPreferences存储;第三种就是数据库SQLiteDatabase存储。文件存储我就不用多说了，而SharedPreferences可以存取简单的数据(int,double,float.etc)，它经常用于数据缓存，因为它读取存储简单。详细可以参见本系列。Android高手进阶教程(七)之-Android 中Preferences的使用! 今天我们将讲一下SQLiteDatabase的使用。而掌握SqliteDatabase，将

2、会我们接下来掌握ContentProvider打下良好的基石。为了让大家更好的掌握，我们手把手完成该节的Demo。 第一步：新建一个Android工程，命名为SQLiteDatabaseDemo. 第二步:创建一个新的类BooksDB.java这个类要继承于android.database.sqlite.SQLiteOpenHelper抽象类，我们要实现其中两个方法：onCreate(),onUpdate.具体代码如下： 01package com.android.tutor; 02import android.content.ContentValues; 03import android.c

3、ontent.Context; 04import android.database.Cursor; 05import android.database.sqlite.SQLiteDatabase; 06import android.database.sqlite.SQLiteOpenHelper; 07public class BooksDB extends SQLiteOpenHelper 08private final static String DATABASE_NAME = BOOKS.db; 09private final static int DATABASE_VERSION =

4、1; 10private final static String TABLE_NAME = books_table; 11public final static String BOOK_ID = book_id; 12public final static String BOOK_NAME = book_name; 13public final static String BOOK_AUTHOR = book_author; 1415public BooksDB(Context context) 16/ TODO Auto-generated constructor stub 17super(

5、context, DATABASE_NAME, null, DATABASE_VERSION); 18 19/创建table 20Override21public void onCreate(SQLiteDatabase db) 22String sql = CREATE TABLE + TABLE_NAME + ( + BOOK_ID 23+ INTEGER primary key autoincrement, + BOOK_NAME + text, + BOOK_AUTHOR + text); 24db.execSQL(sql); 25 26Override27public void on

6、Upgrade(SQLiteDatabase db, int oldVersion, int newVersion) 28String sql = DROP TABLE IF EXISTS + TABLE_NAME; 29db.execSQL(sql); 30onCreate(db); 31 3233public Cursor select() 34SQLiteDatabase db = this.getReadableDatabase(); 35Cursor cursor = db 36.query(TABLE_NAME, null, null, null, null, null, null

7、); 37return cursor; 38 39/增加操作 40public long insert(String bookname,String author) 41 42SQLiteDatabase db = this.getWritableDatabase(); 43/* ContentValues */44ContentValues cv = new ContentValues(); 45cv.put(BOOK_NAME, bookname); 46cv.put(BOOK_AUTHOR, author); 47long row = db.insert(TABLE_NAME, null

8、, cv); 48return row; 49 50/删除操作 51public void delete(int id) 52 53SQLiteDatabase db = this.getWritableDatabase(); 54String where = BOOK_ID + = ?; 55String whereValue = Integer.toString(id) ; 56db.delete(TABLE_NAME, where, whereValue); 57 58/修改操作 59public void update(int id, String bookname,String au

9、thor) 60 61SQLiteDatabase db = this.getWritableDatabase(); 62String where = BOOK_ID + = ?; 63String whereValue = Integer.toString(id) ; 6465ContentValues cv = new ContentValues(); 66cv.put(BOOK_NAME, bookname); 67cv.put(BOOK_AUTHOR, author); 68db.update(TABLE_NAME, cv, where, whereValue); 69 70第三步:修

10、改main.xml布局如下，由两个EditText和一个ListView组成，代码如下: 01 02 08 14 15 20 21 27 28第四步:修改SQLiteDatabaseDemo.java代码如下: 001package com.android.tutor; 002import android.app.Activity; 003import android.content.Context; 004import android.database.Cursor; 005import android.os.Bundle; 006import android.view.Menu; 007i

11、mport android.view.MenuItem; 008import android.view.View; 009import android.view.ViewGroup; 010import android.widget.AdapterView; 011import android.widget.BaseAdapter; 012import android.widget.EditText; 013import android.widget.ListView; 014import android.widget.TextView; 015import android.widget.To

12、ast; 016public class SQLiteDatabaseDemo extends Activity implements AdapterView.OnItemClickListener 017private BooksDB mBooksDB; 018private Cursor mCursor; 019private EditText BookName; 020private EditText BookAuthor; 021private ListView BooksList; 022023private int BOOK_ID = 0; 024protected final s

13、tatic int MENU_ADD = Menu.FIRST; 025protected final static int MENU_DELETE = Menu.FIRST + 1; 026protected final static int MENU_UPDATE = Menu.FIRST + 2; 027028public void onCreate(Bundle savedInstanceState) 029super.onCreate(savedInstanceState); 030setContentView(R.layout.main); 031setUpViews(); 032

14、 033034public void setUpViews() 035mBooksDB = new BooksDB(this); 036mCursor = mBooksDB.select(); 037038BookName = (EditText)findViewById(R.id.bookname); 039BookAuthor = (EditText)findViewById(R.id.author); 040BooksList = (ListView)findViewById(R.id.bookslist); 041042BooksList.setAdapter(new BooksLis

15、tAdapter(this, mCursor); 043BooksList.setOnItemClickListener(this); 044 045046Override047public boolean onCreateOptionsMenu(Menu menu) 048super.onCreateOptionsMenu(menu); 049050menu.add(Menu.NONE, MENU_ADD, 0, ADD); 051menu.add(Menu.NONE, MENU_DELETE, 0, DELETE); 052menu.add(Menu.NONE, MENU_DELETE,

16、0, UPDATE); 053return true; 054 055056public boolean onOptionsItemSelected(MenuItem item) 057 058super.onOptionsItemSelected(item); 059switch (item.getItemId() 060 061case MENU_ADD: 062add(); 063break; 064case MENU_DELETE: 065delete(); 066break; 067case MENU_UPDATE: 068update(); 069break; 070 071ret

17、urn true; 072 073074public void add() 075String bookname = BookName.getText().toString(); 076String author = BookAuthor.getText().toString(); 077/书名和作者都不能为空，或者退出 078if (bookname.equals() | author.equals() 079return; 080 081mBooksDB.insert(bookname, author); 082mCursor.requery(); 083BooksList.invalid

18、ateViews(); 084BookName.setText(); 085BookAuthor.setText(); 086Toast.makeText(this, Add Successed!, Toast.LENGTH_SHORT).show(); 087 088089public void delete() 090if (BOOK_ID = 0) 091return; 092 093mBooksDB.delete(BOOK_ID); 094mCursor.requery(); 095BooksList.invalidateViews(); 096BookName.setText();

19、097BookAuthor.setText(); 098Toast.makeText(this, Delete Successed!, Toast.LENGTH_SHORT).show(); 099 100101public void update() 102String bookname = BookName.getText().toString(); 103String author = BookAuthor.getText().toString(); 104/书名和作者都不能为空，或者退出 105if (bookname.equals() | author.equals() 106ret

20、urn; 107 108mBooksDB.update(BOOK_ID, bookname, author); 109mCursor.requery(); 110BooksList.invalidateViews(); 111BookName.setText(); 112BookAuthor.setText(); 113Toast.makeText(this, Update Successed!, Toast.LENGTH_SHORT).show(); 114 115116Override117public void onItemClick(AdapterView parent, View v

21、iew, int position, long id) 118119mCursor.moveToPosition(position); 120BOOK_ID = mCursor.getInt(0); 121BookName.setText(mCursor.getString(1); 122BookAuthor.setText(mCursor.getString(2); 123124 125126public class BooksListAdapter extends BaseAdapter 127private Context mContext; 128private Cursor mCur

22、sor; 129public BooksListAdapter(Context context,Cursor cursor) 130131mContext = context; 132mCursor = cursor; 133 134Override135public int getCount() 136return mCursor.getCount(); 137 138Override139public Object getItem(int position) 140return null; 141 142Override143public long getItemId(int positi

23、on) 144return 0; 145 146Override147public View getView(int position, View convertView, ViewGroup parent) 148TextView mTextView = new TextView(mContext); 149mCursor.moveToPosition(position); 150mTextView.setText(mCursor.getString(1) + _ + mCursor.getString(2); 151return mTextView; 152 153154 155第五步:运行程序效果如下: 第六步：查看我们所建的数据库。有两种方法：第一种用命令查看：