在OpenCL中创建线程网格(Create grid of threads in OpenCL)

 如果DatabaseHandler不是Activity类，则无需将Activity扩展到它。 您需要创建DatabaseHandler的参数化构造函数，以将Activity上下文传递给它以创建数据库。 将您的DatabaseHandler类更改为： 
 
public class DatabaseHandler implements DatabaseConnector
{
    private SQLiteDatabase database;
     ....
    Context context;

   public DatabaseHandler(Context context){

       this.context=context;
   }

    @Override
    public void createConnection() 
    {

        try
        {
            database = context.openOrCreateDatabase("esoftDatabase", 
                           MODE_PRIVATE, null);
            // your code here....
        }
        catch(SQLException sql)
        {
            Toast.makeText(context, sql.getMessage(), 
                    Toast.LENGTH_LONG).show();
        }

    }
 
 并从表单活动传递活动上下文： 
 
DatabaseConnector databaseConnector = 
                    new DatabaseHandler(Form.this);
databaseConnector.createConnection();

if DatabaseHandler is non Activity class then no need to extends Activity to it. you will need to create a parameterized constructor of DatabaseHandler to pass Activity context to it for creating database . change your DatabaseHandler class as:
 
public class DatabaseHandler implements DatabaseConnector
{
    private SQLiteDatabase database;
     ....
    Context context;

   public DatabaseHandler(Context context){

       this.context=context;
   }

    @Override
    public void createConnection() 
    {

        try
        {
            database = context.openOrCreateDatabase("esoftDatabase", 
                           MODE_PRIVATE, null);
            // your code here....
        }
        catch(SQLException sql)
        {
            Toast.makeText(context, sql.getMessage(), 
                    Toast.LENGTH_LONG).show();
        }

    }
 
and pass Activity Context as from Form Activity :
 
DatabaseConnector databaseConnector = 
                    new DatabaseHandler(Form.this);
databaseConnector.createConnection();