Question

当我长按列表视图中的某个项目（触发上下文操作栏显示）时，列表视图会自动滚动到最后。如果用户在向上滚动后选择了一个项目，则此行为非常烦人。

使用断点我确认在onItemCheckedStateChanged()实施中的MultiChoiceModeListener完成后会发生这种情况。但我不确定在此之后执行什么代码会导致行为。

从列表视图布局中删除transcriptMode属性可解决此问题。但我不想删除它，因为当光标中的数据发生变化时需要自动滚动。是什么原因引起了这个问题？

    @Override
        public void onActivityCreated(Bundle savedInstanceState) {

            super.onActivityCreated(savedInstanceState);

            // Get the chat messages list view from the layout
            lv_chatMessages = (ListView) getActivity().findViewById(
                    R.id.listview_chat);

            // Instantiate the adapter for the chat messages
            adpt_chat = new ChatMessagesAdapter(getActivity());

            // connect the adapter to the list view
            lv_chatMessages.setAdapter(adpt_chat);

            //Implement multi choice mode listener for the list view
            //only if Android API 11 or higher 

            if (Utils.hasHoneycomb()) {

                //Enable selection of multiple chat messages
                lv_chatMessages.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE_MODAL);

                //Handle Action mode events
                lv_chatMessages
                        .setMultiChoiceModeListener(new MultiChoiceModeListener() {

                            @Override
                            public boolean onActionItemClicked(ActionMode mode,
                                    MenuItem item) {
                                switch(item.getItemId()){
                                case R.id.delete_menu :
                                    long[] selected_IDs = lv_chatMessages.getCheckedItemIds();
                                    int deletedRows = deleteMessages(selected_IDs);
                                    Toast.makeText(getActivity(), deletedRows + " message(s) deleted",
                                            Toast.LENGTH_SHORT).show();
                                    return true; // true indicates the menu selection is handled. no further
                                                    // system handling required
                                default :
                                    return false;
                                }

                            }

                            @Override
                            public boolean onCreateActionMode(ActionMode mode,
                                    Menu menu) {

                                MenuInflater inflater = mode.getMenuInflater();
                                inflater.inflate(R.menu.chatsession_contextmenu, menu);
                                return true;
                            }

                            @Override
                            public void onDestroyActionMode(ActionMode arg0) {
                                // TODO Auto-generated method stub

                            }

                            @Override
                            public boolean onPrepareActionMode(ActionMode arg0,
                                    Menu arg1) {
                                // TODO Auto-generated method stub
                                return false;
                            }

                            @Override
                            public void onItemCheckedStateChanged(ActionMode mode,
                                    int position, long id, boolean checked) {

                                mode.setTitle(lv_chatMessages.getCheckedItemCount() + " selected");


                            }

                        });
            }
...
..

}

列表视图布局：

<ListView
        android:id="@+id/listview_chat"
        android:layout_height="match_parent"
        android:layout_width="match_parent"
        android:layout_alignParentTop="true"
        android:transcriptMode="alwaysScroll"
        android:stackFromBottom="true"
        android:layout_above="@id/layout_input"
        android:divider="#00000000"
        />

Answer 1

删除transcriptMode属性似乎是唯一的解决方案。每当我需要自动滚动到结尾时，我都会使用下面的代码：

new Handler().postDelayed(new Runnable(){
            public void run(){
                lv_chatMessages.setSelection(lv_chatMessages.getCount());
            }
        },100);

列表视图滚动到显示上下文操作栏后结束

1 个答案: