FilterQueryProvider，过滤器和ListView [英] FilterQueryProvider, filter and ListView

问题描述

我有一个数据库，如下所示：

I have a database as follows:

------------------------------
BOOK NAME | BOOK FORMAT | COUNT |
------------------------------
Android   | HTML       | 1
WPF       | PDF        | 10
Symbian   | PS         | 2
Windows   | HTML       | 2

我显示这个数据库用户 通过利用CustomSimpleCursorAdapter的。

I am showing this database to the user by making use of a CustomSimpleCursorAdapter.

CustomSimpleCursorAdapter extends SimpleCursorAdapter

实现的可筛选

implements Filterable

与 getView（）＆放大器; runQueryonBackgroundThread（）被覆盖。
书籍的网格视图中正常显示。

with getView() & runQueryonBackgroundThread() being overriden.
The Grid view of books is properly shown.

用户有以下选项：

HTML | PDF | PS |删除

HTML | PDF | PS | DELETE

Constraint: BOOK FORMAT
[HTML - 1, PDF - 2, PS - 3] 

当用户presses HTML菜单选项，使用HTML书籍 型已被示出。

When the user presses HTML menu option, the books with HTML type has to be shown.

MenuOption处理器（）里面，我写如下：

inside MenuOption handler(), I wrote as follows:

adapter.getFilter().filter("1");

runQueryonBackgroundThread() {
    if(mCursor != null)
        mCursor.close();
    mCursor = query(using the constraint)
    return mCursor;
}

这约束达到我重写 runQueryonBackgroundThread（） 方法。但它没有更新网格视图并抛出异常。

This constraint reaching my overriden runQueryonBackgroundThread() method. But its not updating the grid view and throws an exception.

FILTER：android.view.ViewRoot $ CalledFromWrongThreadException：只有   创建一个视图层次可以触摸的意见原帖

"FILTER: android.view.ViewRoot$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views"

请帮我。

推荐答案

我想你已经搞砸了事情有点。其实 SimpleCursorAdapter 已经实现了可筛选，所以没有必要重新实现它。相反，在你的 ListActivity 使用水木清华这样的：

I think you've messed up things a bit. Actually SimpleCursorAdapter already implements Filterable, so there's no need to reimplement it. Instead in your ListActivity use smth like this:

private void filterList(CharSequence constraint) {
    final YourListCursorAdapter adapter = 
        (YourListCursorAdapter) getListAdapter();
    final Cursor oldCursor = adapter.getCursor();
    adapter.setFilterQueryProvider(filterQueryProvider);
    adapter.getFilter().filter(constraint, new FilterListener() {
        public void onFilterComplete(int count) {
            // assuming your activity manages the Cursor 
            // (which is a recommended way)
            stopManagingCursor(oldCursor);
            final Cursor newCursor = adapter.getCursor();
            startManagingCursor(newCursor);
            // safely close the oldCursor
            if (oldCursor != null && !oldCursor.isClosed()) {
                oldCursor.close();
            }
        }
    });
}

private FilterQueryProvider filterQueryProvider = new FilterQueryProvider() {
    public Cursor runQuery(CharSequence constraint) {
        // assuming you have your custom DBHelper instance 
        // ready to execute the DB request
        return dbHelper.getListCursor(constraint);
    }
};

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