Android使用DatabaseHandler退出Activity

Question

大家都知道我是Android的新手，这个应用程序是我第一个使用数据库的应用程序。在我的应用程序中，我有DatabaseHandler类这个简单的结构

public class DatabaseHandler extends SQLiteOpenHelper{
        private static String DB_PATH                   = "";
        private static final String DATABASE_NAME       = "tsms";
        private static String RECEIVE_FIELDS_TABLE      = "ReceiveFields";
        private static final String COLUMN_ID           = "id";

    public DatabaseHandler(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

现在在名为TSMS的其他课程中，我可以将字段ReceivedFields填充为：

public class ReceiveFields {
    public long lastId;
    public String smsNumber;
    public String mobileNumber;
    public String senderName;
    public String smsBody;
    public DateTimeD1 receiveDate;

    public ReceiveFields(){

    }
    public ReceiveFields(long lastId, String smsNumber, String mobileNumber, String senderName, String smsBody, DateTimeD1 receiveDate) {
        this.lastId = lastId;
        this.smsNumber = smsNumber;
        this.mobileNumber = mobileNumber;
        this.senderName = senderName;
        this.smsBody = smsBody;
        this.receiveDate = receiveDate;
    }

TSMS类函数填充没有任何错误，我想将其保存到数据库：

for (int i = 0; i <= strings.length - 1; i++) {
                String[] str1 = WSDLHelper.convert3(strings[i]);
                try {
                    receiveArray.add(new ReceiveFields(
                            Long.valueOf(str1[0]),
                            str1[1],
                            str1[2],
                            URLDecoder.decode(str1[3], "UTF-8"),
                            URLDecoder.decode(str1[4], "UTF-8"),
                            WSDLHelper.convertDate(str1[5])));
                }
                catch (UnsupportedEncodingException ex) {
                    throw new TException(PublicErrorList.NOT_EXIST_ERROR_DETAIL);
                }
            }

现在我想将记录保存到数据库for我之前定义DatabaseHandler db = new DatabaseHandler(this);所以我得到了这个错误，我无法解决这个问题：

Answer 1

您必须将上下文传递给DatabaseHandler类。所以你可以使用Activity，Service或Broadcast Receiver来完成它。所以改变这个构造函数

public ReceiveFields(){

    }

到

 public ReceiveFields(Context ctx){
    this.ctx=ctx; //create a field Context ctx;
    }

从活动，服务或接收方传递上下文，您可以使用ctx代替this。