安卓android期末项目之纸牌游戏之三

</pre><pre code_snippet_id="1727164" snippet_file_name="blog_20160623_3_3108055" name="code" class="java">package com.example.azhipai;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.widget.Toast;
public class MyDatabaseHelper extends SQLiteOpenHelper{
  public static final String CREATE_EXAM="create table exam(id integer primary key autoincrement,name text,examcm integer)";
  private Context mcontext;
  public MyDatabaseHelper(Context context, String name,
      CursorFactory factory, int version) {
    super(context, name, factory, version);
    mcontext=context;
  }
  @Override
  public void onCreate(SQLiteDatabase db) {
    db.execSQL(CREATE_EXAM);
    Toast.makeText(mcontext, "创建数据库成功", Toast.LENGTH_LONG).show();
  }
  @Override
  public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("drop table if exists exam");//删除表若果表存在
    onCreate(db);
  }
}