android - ListView setItemChecked 无法正常工作

Question

我在使用合并游标填充的 ListView 时遇到问题。我的应用程序中有一个按钮可以选择 ListView 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);
    }
}

问题是最后并没有检查所有条目。确实很奇怪。经过一些测试后，我注意到如果我在 mergecursor 中有 10 个条目(5 个来自光标 a，5 个来自光标 b)，那么如果我只对前 5 个元素使用 setItemChecked 一切正常(这 5 个条目被检查)。如果我再次对最后 5 个元素使用 setItemchecked 一切正常(检查游标 b 的条目)，但是如果我对两个游标的元素使用 setItemChecked 那么检查的最大元素数是游标 a 中的元素数( 5 在我们的例子中)，偏移量为(我想设置的项目数 - 光标 a 中的项目数)。我将写下几个示例，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()

也没有用。有什么帮助吗？

作为旁注，

listView.getCount();

总是在 View 中返回正确数量的条目

Answer 1

正如alanv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了哪些行。听起来您的 MergeCursor 可能会返回重复的 ID，例如游标 A 中第一行的 _id 值是与游标 B 中第一行的 _id 相同。是这样吗？”

原来如此。更改光标以提供不同的 ID 后一切正常然而:

1. 合并游标是其他游标的串联，合并游标不应该能够处理来自不同子游标的相同 ID(例如，通过在内部创建新 ID)。
2. 查看合并游标的所有结果并与它们交互(单击它们)工作正常，所以我希望检查它们是否正常工作？