Question

我遇到了由合并游标填充的列表视图的问题。我的应用程序中有一个按钮，用于选择列表视图中的所有条目。按下按钮时调用的函数如下：

private void selectAllEntries() {
    int numberOfItemsInList = listView.getCount();
    for (int i = 0; i < numberOfItemsInList; i++) {
        this.listView.setItemChecked(i, true);
    }
}

问题是并非所有条目最终都会被检查。确实非常奇怪。经过一些测试后，我注意到如果我在mergecursor中有10个条目（光标a中有5个条目，光标b中有5个条目），那么如果我只在前5个元素上使用setItemChecked，那么一切正常（这5个条目都会被检查）。如果我再次对最后5个元素使用setItemchecked，一切正常（光标b中的条目被检查），但是如果我对两个游标中的元素使用setItemChecked，则获取的最大元素数是光标a中的元素数（在我们的示例中为5），偏移量为（我想要设置的项目数 - 光标a中的项目数）。我会写下几个例子，因为这是一种非常奇怪的行为。

Example 1:
element 0 (from cursor a, unchecked)
element 1 (from cursor a, unchecked)
element 2 (from cursor a, unchecked)
element 3 (from cursor a, unchecked)
element 4 (from cursor a, unchecked)
element 5 (from cursor b, unchecked)
element 6 (from cursor b, unchecked) 
element 7 (from cursor b, unchecked)
element 8 (from cursor b, unchecked)
element 9 (from cursor b, unchecked)

setItemChecked(0,true);
setItemChecked(1,true);
setItemChecked(2,true);
setItemChecked(3,true);
setItemChecked(4,true);

Results:

element 0 (from cursor a, checked)
element 1 (from cursor a, checked)
element 2 (from cursor a, checked)
element 3 (from cursor a, checked)
element 4 (from cursor a, checked)
element 5 (from cursor b, unchecked)
element 6 (from cursor b, unchecked) 
element 7 (from cursor b, unchecked)
element 8 (from cursor b, unchecked)
element 9 (from cursor b, unchecked)

Example 2:
element 0 (from cursor a, unchecked)
element 1 (from cursor a, unchecked)
element 2 (from cursor a, unchecked)
element 3 (from cursor a, unchecked)
element 4 (from cursor a, unchecked)
element 5 (from cursor b, unchecked)
element 6 (from cursor b, unchecked) 
element 7 (from cursor b, unchecked)
element 8 (from cursor b, unchecked)
element 9 (from cursor b, unchecked)

setItemChecked(5,true);
setItemChecked(6,true);
setItemChecked(7,true);
setItemChecked(8,true);
setItemChecked(9,true);

results:

element 0 (from cursor a, unchecked)
element 1 (from cursor a, unchecked)
element 2 (from cursor a, unchecked)
element 3 (from cursor a, unchecked)
element 4 (from cursor a, unchecked)
element 5 (from cursor b, checked)
element 6 (from cursor b, checked) 
element 7 (from cursor b, checked)
element 8 (from cursor b, checked)
element 9 (from cursor b, checked)

Example 3:
element 0 (from cursor a, unchecked)
element 1 (from cursor a, unchecked)
element 2 (from cursor a, unchecked)
element 3 (from cursor a, unchecked)
element 4 (from cursor a, unchecked)
element 5 (from cursor b, unchecked)
element 6 (from cursor b, unchecked) 
element 7 (from cursor b, unchecked)
element 8 (from cursor b, unchecked)
element 9 (from cursor b, unchecked)

setItemChecked(0,true);
setItemChecked(1,true);
setItemChecked(2,true);
setItemChecked(3,true);
setItemChecked(4,true);
setItemChecked(5,true);

results in

element 0 (from cursor a, unchecked)
element 1 (from cursor a, checked)
element 2 (from cursor a, checked)
element 3 (from cursor a, checked)
element 4 (from cursor a, checked)
element 5 (from cursor b, checked)
element 6 (from cursor b, unchecked) 
element 7 (from cursor b, unchecked)
element 8 (from cursor b, unchecked)
element 9 (from cursor b, unchecked)


Example 4:
element 0 (from cursor a, unchecked)
element 1 (from cursor a, unchecked)
element 2 (from cursor a, unchecked)
element 3 (from cursor a, unchecked)
element 4 (from cursor a, unchecked)
element 5 (from cursor b, unchecked)
element 6 (from cursor b, unchecked) 
element 7 (from cursor b, unchecked)
element 8 (from cursor b, unchecked)
element 9 (from cursor b, unchecked)

setItemChecked(0,true);
setItemChecked(1,true);
setItemChecked(2,true);
setItemChecked(3,true);
setItemChecked(4,true);
setItemChecked(5,true);
setItemChecked(6,true);

results:

element 0 (from cursor a, unchecked)
element 1 (from cursor a, unchecked)
element 2 (from cursor a, checked)
element 3 (from cursor a, checked)
element 4 (from cursor a, checked)
element 5 (from cursor b, checked)
element 6 (from cursor b, checked) 
element 7 (from cursor b, unchecked)
element 8 (from cursor b, unchecked)
element 9 (from cursor b, unchecked)


Example 5:
element 0 (from cursor a, unchecked)
element 1 (from cursor a, unchecked)
element 2 (from cursor a, unchecked)
element 3 (from cursor a, unchecked)
element 4 (from cursor a, unchecked)
element 5 (from cursor b, unchecked)
element 6 (from cursor b, unchecked) 
element 7 (from cursor b, unchecked)
element 8 (from cursor b, unchecked)
element 9 (from cursor b, unchecked)

setItemChecked(0,true);
setItemChecked(1,true);
setItemChecked(2,true);
setItemChecked(3,true);
setItemChecked(4,true);
setItemChecked(5,true);
setItemChecked(6,true);
setItemChecked(7,true);

results:

element 0 (from cursor a, unchecked)
element 1 (from cursor a, unchecked)
element 2 (from cursor a, unchecked)
element 3 (from cursor a, checked)
element 4 (from cursor a, checked)
element 5 (from cursor b, checked)
element 6 (from cursor b, checked) 
element 7 (from cursor b, checked)
element 8 (from cursor b, unchecked)
element 9 (from cursor b, unchecked)

我正在使用

        listView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);

和

notifyDataSetChanged()

也没有帮助。有什么帮助吗？

作为旁注，

listView.getCount();

始终在视图中返回正确数量的条目

Answer 1

正如阿兰夫所说， “CursorAdapter使用数据库中的_id列来标识行，而AbsListView使用此值来跟踪检查哪些行。听起来你的MergeCursor可能正在返回重复的ID，例如光标A中第一行的_id值是与光标B中第一行的_id相同。是这种情况吗？“

情况确实如此。更改光标以提供不同的ID后，一切正常但是：

合并游标是其他游标的串联，合并游标不应该使用来自不同子游标的相同ID来处理（例如，通过在内部创建新的id）。
查看合并光标的所有结果，并与它们进行交互（单击它们）可以正常工作，所以我希望检查它们是否正常工作？

listview setItemChecked无法正常工作

1 个答案: