blocks|key|1061787|text|这是快速滚动中的一个错误。它不能很好地与ExpandableListView配合使用。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1061788|参见my+code。|1061789|(它还包括某些情况下的变通方法)|1061790|entityMap|0|LINK|mutability|MUTABLE|url|http://code.google.com/p/android/issues/detail?id=24635^0|K|I|0|2|7|0|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@$9|S|A|T|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|U|8|@]|D|@$9|V|A|W|1|X]]|E|$]]|$1|H|3|I|5|6|7|Y|8|@]|D|@]|E|$]]|$1|J|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|K|$L|$5|M|N|O|E|$P|Q]]]]

This is a bug in the fast scroller. It does not play well with <code>ExpandableListView</code>.

See <a href="http://code.google.com/p/android/issues/detail?id=24635" rel="nofollow">my code</a>.

(it also includes a work-around for some cases)

blocks|key|847519|text|我刚刚找到了一种解决方法，可以防止系统显示这种错误行为。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|847520|有两种情况使用不同的代码使SectionIndexer工作。|offset|length|style|CODE|847521|第一个场景是使用FastScrollbar-Thumb导航到下一节。假设组是您的部分，用于实现SectionIndexer的覆盖方法将如下所示：|847522|@Override
public+int+getPositionForSection(int+section)+{
++++return+section;
}

//+Gets+called+when+scrolling+the+list+manually
@Override
public+int+getSectionForPosition(int+position)+{
++++return+ExpandableListView.getPackedPositionGroup(
+++++++++++++++expandableListView
+++++++++++++++++++.getExpandableListPosition(position));
}|code-block|syntax|javascript|847523|第二种情况是手动滚动列表，快速滚动条根据部分移动，而不是移动到所有项。因此，代码看起来像这样：|847524|@Override
public+int+getPositionForSection(int+section)+{
++++return+expandableListView.getFlatListPosition(
+++++++++++++++ExpandableListView.getPackedPositionForGroup(section));
}

//+Gets+called+when+scrolling+the+list+manually
@Override
public+int+getSectionForPosition(int+position)+{
++++return+ExpandableListView.getPackedPositionGroup(
+++++++++++++++expandableListView
+++++++++++++++++++.getExpandableListPosition(position));
}|847525|可以看出，如果没有进一步的采用，这两种行为就不能一起发挥作用。|847526|让两者都工作的变通方法是，当有人用手滚动(即通过触摸滚动)时，捕捉到这种情况。这可以通过使用适配器类实现OnScrollListener接口并将其设置到ExpandableListView上来完成|847527|public+class+MyExpandableListAdapter+extends+BaseExpandableListAdapter+
+++++++++++++++++implements+SectionIndexer,+AbsListView.OnScrollListener+{

++++//+Your+fields+here
++++//+...
++++private+final+ExpandableListView+expandableListView;
++++private+boolean+manualScroll;

++++public+MyExpandableListAdapter(ExpandableListView+expandableListView
+++++++++++++++++++++++++++++++++++/*+Your+other+arguments+*/)+{
++++++++this.expandableListView+=+expandableListView;
++++++++this.expandableListView.setOnScrollListener(this);
++++++++//+Other+initializations
++++}

++++@Override
++++public+void+onScrollStateChanged(AbsListView+view,+int+scrollState)+{
++++++++this.manualScroll+=+scrollState+==+SCROLL_STATE_TOUCH_SCROLL;
++++}

++++@Override
++++public+void+onScroll(AbsListView+view,+
+++++++++++++++++++++++++int+firstVisibleItem,+
+++++++++++++++++++++++++int+visibleItemCount,+
+++++++++++++++++++++++++int+totalItemCount)+{}

++++@Override
++++public+int+getPositionForSection(int+section)+{
++++++++if+(manualScroll)+{
++++++++++++return+section;
++++++++}+else+{++++++++++++
++++++++++++return+expandableListView.getFlatListPosition(
+++++++++++++++++++++++ExpandableListView.getPackedPositionForGroup(section));
++++++++}
++++}

++++//+Gets+called+when+scrolling+the+list+manually
++++@Override
++++public+int+getSectionForPosition(int+position)+{
++++++++return+ExpandableListView.getPackedPositionGroup(
+++++++++++++++++++expandableListView
+++++++++++++++++++++++.getExpandableListPosition(position));
++++}

++++//+Your+other+methods
++++//+...
}|847528|这就为我修复了bug。|847529|entityMap^0|0|D|E|0|1B|E|0|0|0|0|0|1G|G|24|I|0|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|13|8|@$D|14|E|15|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|16|8|@$D|17|E|18|F|G]]|9|@]|A|$]]|$1|J|3|K|5|L|7|19|8|@]|9|@]|A|$M|N]]|$1|O|3|P|5|6|7|1A|8|@]|9|@]|A|$]]|$1|Q|3|R|5|L|7|1B|8|@]|9|@]|A|$M|N]]|$1|S|3|T|5|6|7|1C|8|@]|9|@]|A|$]]|$1|U|3|V|5|6|7|1D|8|@$D|1E|E|1F|F|G]|$D|1G|E|1H|F|G]]|9|@]|A|$]]|$1|W|3|X|5|L|7|1I|8|@]|9|@]|A|$M|N]]|$1|Y|3|Z|5|6|7|1J|8|@]|9|@]|A|$]]|$1|10|3|-4|5|6|7|1K|8|@]|9|@]|A|$]]]|11|$]]

I've just found a workaround to prevent the system to display this wrong behaviour.

There are two scenarios which use different code for the <code>SectionIndexer</code> to work.

The first scenario is the case that you use the FastScrollbar-Thumb to navigate to the next section. Assuming that the groups are your sections the overriden methods for implementing the <code>SectionIndexer</code> would look like that:

<pre><code>@Override
public int getPositionForSection(int section) {
 return section;
}

// Gets called when scrolling the list manually
@Override
public int getSectionForPosition(int position) {
 return ExpandableListView.getPackedPositionGroup(
 expandableListView
 .getExpandableListPosition(position));
}
</code></pre>

The second scenario is the case that you scroll the list manually and the fast scrollbars move according to the sections, not to all items. The code therefore looks like that:

<pre><code>@Override
public int getPositionForSection(int section) {
 return expandableListView.getFlatListPosition(
 ExpandableListView.getPackedPositionForGroup(section));
}

// Gets called when scrolling the list manually
@Override
public int getSectionForPosition(int position) {
 return ExpandableListView.getPackedPositionGroup(
 expandableListView
 .getExpandableListPosition(position));
}
</code></pre>

As one can see these two behaviours can not play together without further adoption.

The workaround to make it both work is to catch the case when someone is scrolling per hand (i.e. scrolling via touch). This can be done with implementing the <code>OnScrollListener</code> interface with the adapter class and set it onto the <code>ExpandableListView</code>:

<pre><code>public class MyExpandableListAdapter extends BaseExpandableListAdapter 
 implements SectionIndexer, AbsListView.OnScrollListener {

 // Your fields here
 // ...
 private final ExpandableListView expandableListView;
 private boolean manualScroll;

 public MyExpandableListAdapter(ExpandableListView expandableListView
 /* Your other arguments */) {
 this.expandableListView = expandableListView;
 this.expandableListView.setOnScrollListener(this);
 // Other initializations
 }

 @Override
 public void onScrollStateChanged(AbsListView view, int scrollState) {
 this.manualScroll = scrollState == SCROLL_STATE_TOUCH_SCROLL;
 }

 @Override
 public void onScroll(AbsListView view, 
 int firstVisibleItem, 
 int visibleItemCount, 
 int totalItemCount) {}

 @Override
 public int getPositionForSection(int section) {
 if (manualScroll) {
 return section;
 } else { 
 return expandableListView.getFlatListPosition(
 ExpandableListView.getPackedPositionForGroup(section));
 }
 }

 // Gets called when scrolling the list manually
 @Override
 public int getSectionForPosition(int position) {
 return ExpandableListView.getPackedPositionGroup(
 expandableListView
 .getExpandableListPosition(position));
 }

 // Your other methods
 // ...
}
</code></pre>

That fixed the bug for me.

I have a class which implements <code>expandable list activity</code>. 
In the XML code (or I can do it in java), I set <code>fastScrollEnabled</code> to <code>true</code>. This does in deed enable fast scroll. BUT fast scroll only works in the top portion of the list. Like I can use the fastscroll thumb bar to scroll the whole list but only works in the top section of the scroll bar. It's not proportionate to the entire list. I can drag the thumb bar to the bottom of the list but it does no scrolling since the <code>listview</code> is already scrolled to the bottom due to the odd behaviour of it only working in the top portion of the list. 
Confusing I know, I can try to clarify more if needed....

I do implement a custom <code>BaseExpandableListAdapter.</code>

android fastScroll only covers part of the list

我有一个实现expandable list activity的类。在XML代码中(或者我可以在java中这样做)，我将fastScrollEnabled设置为true。这确实可以实现快速滚动。但是快速滚动只适用于列表的顶部。例如，我可以使用快速滚动拇指条来滚动整个列表，但只在滚动条的顶部有效。它与整个列表不成比例。我可...

问android fastScroll只涵盖了列表的一部分。
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问android fastScroll只涵盖了列表的一部分。EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问android fastScroll只涵盖了列表的一部分。
EN