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DBAdapter.java

 

package com.android.db;

import android.content.ContentValues; import android.content.Context; import android.database.Cursor; import android.database.SQLException; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; import android.util.Log; public class DBAdapter { public static final String KEY_ROWID = "_id"; public static final String KEY_ISBN = "isbn"; public static final String KEY_TITLE = "title"; public static final String KEY_PUBLISHER = "publisher"; private static final String TAG = "DBAdapter"; private static final String DATABASE_NAME = "books"; private static final String DATABASE_TABLE = "titles"; private static final int DATABASE_VERSION = 1; private static final String DATABASE_CREATE = "create table titles (_id integer primary key autoincrement, " + "isbn text not null, title text not null, " + "publisher text not null);"; private final Context context; private DatabaseHelper DBHelper; private SQLiteDatabase db; public DBAdapter(Context ctx) { this.context = ctx; DBHelper = new DatabaseHelper(context); } private static class DatabaseHelper extends SQLiteOpenHelper { DatabaseHelper(Context context) { super(context, DATABASE_NAME, null, DATABASE_VERSION); } @Override public void onCreate(SQLiteDatabase db) { db.execSQL(DATABASE_CREATE); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { Log.w(TAG, "Upgrading database from version " + oldVersion + " to " + newVersion + ", which will destroy all old data"); db.execSQL("DROP TABLE IF EXISTS titles"); onCreate(db); } } //---打开数据库--- public DBAdapter open() throws SQLException { db = DBHelper.getWritableDatabase(); return this; } //---关闭数据库--- public void close() { DBHelper.close(); } //---向数据库中插入一个标题--- public long insertTitle(String isbn, String title, String publisher) { ContentValues initialValues = new ContentValues(); initialValues.put(KEY_ISBN, isbn); initialValues.put(KEY_TITLE, title); initialValues.put(KEY_PUBLISHER, publisher); return db.insert(DATABASE_TABLE, null, initialValues); } //---删除一个指定标题--- public boolean deleteTitle(long rowId) { return db.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0; } //---检索所有标题--- public Cursor getAllTitles() { return db.query(DATABASE_TABLE, new String[] { KEY_ROWID, KEY_ISBN, KEY_TITLE, KEY_PUBLISHER}, null, null, null, null, null); } //---检索一个指定标题--- public Cursor getTitle(long rowId) throws SQLException { Cursor mCursor = db.query(true, DATABASE_TABLE, new String[] { KEY_ROWID, KEY_ISBN, KEY_TITLE, KEY_PUBLISHER }, KEY_ROWID + "=" + rowId, null, null, null, null, null); if (mCursor != null) { mCursor.moveToFirst(); } return mCursor; } //---更新一个标题--- public boolean updateTitle(long rowId, String isbn, String title, String publisher) { ContentValues args = new ContentValues(); args.put(KEY_ISBN, isbn); args.put(KEY_TITLE, title); args.put(KEY_PUBLISHER, publisher); return db.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0; } }

 

firstDB.java

 

package com.android.db;

import android.app.Activity; import android.database.Cursor; import android.os.Bundle; import android.widget.TextView; import android.widget.Toast; public class firstDB extends Activity {     /** Called when the activity is first created. */     @Override     public void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.main);     DBAdapter db = new DBAdapter(this);     db.open();     long id;     id = db.insertTitle(     "0470285818",     "C# 2008 Programmer's Reference",     "Wrox");     id = db.insertTitle(     "047017661X",     "Professional Windows Vista Gadgets Programming",     "Wrox");     db.close();     String ss="";     db.open();     Cursor c = db.getAllTitles();     if (c.moveToFirst())     {     do { //        ss=ss+    DisplayTitle(c);     } while (c.moveToNext());     }     db.close();     TextView tv=(TextView)findViewById(R.id.tv);     tv.setText(ss);     }     public String DisplayTitle(Cursor c)     {     /*         Toast.makeText(this,     "id: " + c.getString(0) + "/n" +     "ISBN: " + c.getString(1) + "/n" +     "TITLE: " + c.getString(2) + "/n" +     "PUBLISHER: " + c.getString(3),     Toast.LENGTH_LONG).show();     */     return "id: " + c.getString(0) + "/n" +     "ISBN: " + c.getString(1) + "/n" +     "TITLE: " + c.getString(2) + "/n" +     "PUBLISHER: " + c.getString(3);     }     }