Android API之android.content.AsyncQueryHandler

android.content.AsyncQueryHandler

A helper class to help make handling asynchronous ContentResolver queries easier.

 

void android.content.AsyncQueryHandler.startQuery(int token, Object cookie, Uri uri, String[] projection, String selection, String[] selectionArgs, String orderBy)

This method begins an asynchronous query. When the query is done onQueryComplete is called.

Parameters:

token A token passed into onQueryComplete to identify the query.

cookie An object that gets passed into onQueryComplete

uri The URI, using the content:// scheme, for the content to retrieve.

projection A list of which columns to return. Passing null will return all columns, which is discouraged to prevent reading data from storage that isn't going to be used.

selection A filter declaring which rows to return, formatted as an SQL WHERE clause (excluding the WHERE itself). Passing null will return all rows for the given URI.

selectionArgs You may include ?s in selection, which will be replaced by the values from selectionArgs, in the order that they appear in the selection. The values will be bound as Strings.

orderBy How to order the rows, formatted as an SQL ORDER BY clause (excluding the ORDER BY itself). Passing null will use the default sort order, which may be unordered.

 

protected void onQueryComplete(int token, Object cookie, Cursor cursor)

Overrides: onQueryComplete(...) in AsyncQueryHandler

Parameters:

token the token to identify the query, passed in from startQuery.

cookie the cookie object passed in from startQuery.

cursor The cursor holding the results from the query.