我的Android应用程序在SQLite数据库中有一个产品表，该数据库在用户安装时预先填充。该表可以从Azure Web服务更新。
我只想将2900条记录返回给应用程序，而不是仅从Web服务返回更新的记录并使用更新的记录填充SQLite表。这是因为大多数产品都会发生变化。打开App时，将使用SQL查询删除products表，并将ksoap2响应发送到插入数据库的Product对象。
虽然对产品表的更新正在进行，但我希望用户能够在不中断的情况下使用该应用程序。如果Products表已被删除，则他们无法正常操作App。
我有什么选择？我可以填充一个临时的Product表，当服务完成填充后，我可以将它复制到'live'Product表中。或者我可以完全删除Product表并将临时表重命名为“Product”吗？
或者我完全错了。任何建议都将非常感激。 代码摘录如下：
try {
productDatasource.open();
productDatasource.deleteProductTable();
productDatasource.close();
ArrayList<Product> arrProduct = new ArrayList<Product>();
SoapObject request = new SoapObject(NAMESPACE, PRODUCT_METHOD_NAME);
SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11);
envelope.dotNet = true;
envelope.setOutputSoapObject(request);
System.out.println("startit");
HttpTransportSE ht = new HttpTransportSE(URL);
ht.debug = true;
ht.call(SOAP_ACTION_PRODUCT, envelope);
SoapObject response = (SoapObject) envelope.getResponse();
productDatasource.open();
productDatasource.deleteProductTable();
Product[] products = new Product[response.getPropertyCount()];
for (int i = 0; i < products.length; i++) {
SoapObject prodObj = (SoapObject)response.getProperty(i);
Product product = new Product();
product.setProductID(Integer.parseInt(prodObj.getProperty(10).toString()));
product.setProductName(prodObj.getProperty(11).toString());
product.setFKCategoryID(Integer.parseInt(prodObj.getProperty(5).toString()));
product.setFKSubCategoryID(Integer.parseInt(prodObj.getProperty(13).toString()));
product.setFKBrandID(Integer.parseInt(prodObj.getProperty(2).toString()));
productDatasource.createProduct(product);
}
答案 0 :(得分：3)
DBHelper类遵循Respsitory模式。对底层数据的访问权限包含在“存储库”类中。这将释放您的主要逻辑，专注于业务逻辑，并将所有数据处理职责推送到存储库。根据应用程序的复杂性，存储库可以充当“Facade”，其中调用只是代理到负责域对象的存储库。
下面的代码为DBHelper
创建了一个非常简单的模板public class DBHelper
{
Context context;
private SQLiteDatabase db;
private final String DB_NAME = "MYDataBase";
private final int DB_VERSION = 1;
private final String TABLE_NAME = "Animal";
private final String TABLE_ROW_ID = "id";
private final String TABLE_ROW_ONE = "animal_name";
private final String TABLE_ROW_TWO = "animal_bio";
public DBHelper(Context context)
{
this.context = context;
CustomSQLiteOpenHelper helper = new CustomSQLiteOpenHelper(context);
this.db = helper.getWritableDatabase();
}
public static byte[] getBitmapAsByteArray(Bitmap bitmap)
{
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
bitmap.compress(CompressFormat.PNG, 0, outputStream);
return outputStream.toByteArray();
}
public void addRow(String name, String bio)
{
ContentValues values = new ContentValues();
values.put(TABLE_ROW_ONE, name);
values.put(TABLE_ROW_TWO, bio);
try
{
db.insert(TABLE_NAME, null, values);
Log.w("database message","Insert successfully");
}
catch(Exception e)
{
Log.e("DB ERROR", e.toString());
//e.printStackTrace();
}
}
public void deleteRow(long rowID)
{
try
{
db.delete(TABLE_NAME, TABLE_ROW_ID + "=" + rowID, null);
Log.w("database message","delete successfully");
}
catch (Exception e)
{
Log.e("DB ERROR", e.toString());
e.printStackTrace();
}
}
public void updateRow(long rowID,String name,String bio)
{
ContentValues values = new ContentValues();
values.put(TABLE_ROW_ONE, name);
values.put(TABLE_ROW_TWO, bio);
try
{
db.update(TABLE_NAME, values, TABLE_ROW_ID + "=" + rowID, null);
Log.w("database message","Update successfully");
}
catch (Exception e)
{
Log.e("DB Error", e.toString());
e.printStackTrace();
}
}
public int count_row()
{
int row=0;
Cursor cursor;
try
{
cursor = db.query(
TABLE_NAME,
new String[]{TABLE_ROW_ID, TABLE_ROW_ONE, TABLE_ROW_TWO},
null, null, null, null, null
);
cursor.moveToFirst();
if (!cursor.isAfterLast())
{
do
{
row++;
}
while (cursor.moveToNext());
}
}
catch (SQLException e)
{
Log.e("DB Error", e.toString());
e.printStackTrace();
}
Log.w("row count..",""+row);
return row;
}
public void getRow(long rowID)
{
Cursor cursor;
try
{
cursor = db.query
(
TABLE_NAME,
new String[] { TABLE_ROW_ID, TABLE_ROW_ONE, TABLE_ROW_TWO},
TABLE_ROW_ID + "=" + rowID,
null, null, null, null, null
);
cursor.moveToFirst();
if (!cursor.isAfterLast())
{
do
{
Log.w("row ",""+cursor.getLong(0));
Log.w("row ",""+cursor.getString(1));
Log.w("row ",""+cursor.getFloat(2));
}
while (cursor.moveToNext());
}
cursor.close();
}
catch (SQLException e)
{
Log.e("DB ERROR", e.toString());
e.printStackTrace();
}
}
public void getAllRows()
{
int i=0;
Cursor cursor;
try
{
cursor = db.query(
TABLE_NAME,
new String[]{TABLE_ROW_ID, TABLE_ROW_ONE, TABLE_ROW_TWO},
null, null, null, null, null
);
cursor.moveToFirst();
if (!cursor.isAfterLast())
{
do
{
Log.w("row "+i,""+cursor.getLong(0));
Log.w("row "+i,""+cursor.getString(1));
Log.w("row "+i,""+cursor.getFloat(2));
i++;
}
while (cursor.moveToNext());
}
}
catch (SQLException e)
{
Log.e("DB Error", e.toString());
e.printStackTrace();
}
}
private class CustomSQLiteOpenHelper extends SQLiteOpenHelper
{
public CustomSQLiteOpenHelper(Context context)
{
super(context, DB_NAME, null, DB_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db)
{
String newTableQueryString = "create table " +
TABLE_NAME +
" (" +
TABLE_ROW_ID + " integer primary key autoincrement not null," +
TABLE_ROW_ONE + " text," +
TABLE_ROW_TWO + " text" +
");";
db.execSQL(newTableQueryString);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
{
}
}
}
public void onCreate（Bundle savedInstanceState） {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DBHelper database = new DBHelper(this);
database.addRow("name1","bio1");
database.addRow("name2","bio2");
database.addRow("name3","bio3");
database.addRow("name4","bio4");
database.addRow("name5","bio5");
database.getAllRows();
database.updateRow(2,"name20","bio20");
database.getAllRows();
database.deleteRow(2);
database.getAllRows();
}
在您的应用程序中复制DBHelper类 我希望它很有用.....
答案 1 :(得分：1)
将ContentProvider与CursorLoader一起使用，以便在内容更新时UI保持流畅。使用BulkInsert可以更快地添加行。如果您只是更新记录而不是替换它们，那么添加一个列，使您可以将记录标记为需要更新。有关在Android上开始使用SQL数据库的信息，请参阅http://developer.android.com/guide/topics/data/data-storage.html#db和http://developer.android.com/training/basics/data-storage/databases.html。