Android游标与ORMLite在CursorAdapter中使用 [英] Android Cursor with ORMLite to use in CursorAdapter

问题描述

有什么办法，如何获取Cursor查询，我正在用ORMLite Dao对象处理？

解决方案

ORMLite 现在支持 next（）， ）的上一个（）， moveRelative（offset） ormlite-core / com / j256 / ormlite / dao / CloseableIterator.htmlrel =noreferrer> CloseableIterator class 。这将允许你移动底层的 Cursor 对象。

它还支持以下DAO Cursor方法：

• dao.mapSelectStarRow（databaseResults） 返回最新行从数据库查询到 select * 。这样，您可以更改光标位置（例如），然后获取当前对象。


• dao.getSelectStarRowMapper（） 提供一个映射器，您




---





当你建立你的使用 ORMLite 查询自己的查询，则使用 QueryBuilder 对象。 queryBuilder.prepare（）返回一个 PreparedQuery ，它由DAO中的各种方法使用。您可以调用 dao.iterator（preparedQuery），它将返回一个 CloseableIterator ，用于遍历结果。有一个 iterator.getRawResults（）可以访问 DatabaseResults 类。在Android下，可以将其转换为 AndroidDatabaseResults ，它具有 getCursor（）方法， code> Cursor 。





类似下面的代码：

  //构建查询
 QueryBuilder< Foo，String> qb = fooDao.queryBuilder（）; 
 qb.where（）...; 
 //完成后，准​​备您的查询并构建一个迭代器
 CloseableIterator< Foo> iterator = dao.iterator（qb.prepare（））; 
 try {
 //获取在Android下可以转换的原始结果
 AndroidDatabaseResults results = 
（AndroidDatabaseResults）iterator.getRawResults（）; 
 Cursor cursor = results.getRawCursor（）; 
 ... 
} finally {
 iterator.closeQuietly（）; 
} 
  

这有点复杂，但你是不得不在数据库后面找到被数据库抽象类隐藏的这个对象。




Is there any way, how to get Cursor for a query, which I am processing with ORMLite Dao object?

解决方案

ORMLite now supports next(), previous(), moveRelative(offset), ... methods on the CloseableIterator class. This should allow you to move the underlying Cursor object around at will.

It also supports the following DAO Cursor methods:

• dao.mapSelectStarRow(databaseResults) Return the latest row from the database results from a query to select *. With this you can change the cursor location (for example) and then get the current object.
• dao.getSelectStarRowMapper() Provides a mapper that you can use to map the object outside of the Dao.

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When you are building your own query with ORMLite, you use the QueryBuilder object. queryBuilder.prepare() returns a PreparedQuery which is used by various methods in the DAO. You can call dao.iterator(preparedQuery) which will return a CloseableIterator which is used to iterate through the results. There is a iterator.getRawResults() to get access to the DatabaseResults class. Under Android, this can be cast to an AndroidDatabaseResults which has a getCursor() method on it to return the Android Cursor.

Something like the following code:

// build your query
QueryBuilder<Foo, String> qb = fooDao.queryBuilder();
qb.where()...;
// when you are done, prepare your query and build an iterator
CloseableIterator<Foo> iterator = dao.iterator(qb.prepare());
try {
   // get the raw results which can be cast under Android
   AndroidDatabaseResults results =
       (AndroidDatabaseResults)iterator.getRawResults();
   Cursor cursor = results.getRawCursor();
   ...
} finally {
   iterator.closeQuietly();
}

This is a bit complicated but you are definitely having to peer behind the vale to get to this object which is hidden by the database abstraction classes.

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