我目前正在开发 android 项目并使用 fragment 和 ListViews/ListFragments。我有处理标准 Activity (例如 ListActivity)的上下文操作栏。

现在我正在尝试做同样的事情，但在 fragment 布局上。我有一个扩展 Activity 的 MainActivity，它为包含 2 个 fragment ( fragment A 和 fragment B)的布局扩充 XML。

Fragment A 扩展了 ListFragment 并包含一个 ListView，该 ListView 从 SQLite 数据库中的数据填充。当我有一个在标准 ListActivity 上工作的上下文操作栏时，我有一个扩展 ListView.MultiChoiceModeListener 的类，但这不适用于 ListFragment 类或标准 Activity ，所以我将如何实现它。

我想要实现的基本目标是，当有人长按扩展 ListFragment 的 FragmentA 中的 ListView 中的项目时，操作栏会根据上下文发生变化，然后用户可以从 ListView 中选择多个项目。

感谢您提供的任何帮助。

最佳答案

When I have got a contextual action bar working on a standard ListActivity I have a class that Extends ListView.MultiChoiceModeListener but this isn't available for a ListFragment class or a standard activity so how would I go about implementing this.

我不明白为什么 MultiChoiceModeListener 不可用(也许我不明白你想做什么)。根据您的评论，我假设您使用了兼容包中的 fragment 。 下面是一个包含两个静态 fragment 的 FragmentActivity 示例，其中每个 fragment 都会触发带有自己菜单选项的上下文操作栏。

FragmentActivity 非常简单，它只包含下面的两个 fragment :

// the list fragment
public class ListCABFragment extends ListFragment {

    private String[] mCountries = { "Romania", "Germany", "England", "USA",
            "Japan", "France" };
    private static final boolean POST_HONEYCOMB = Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB;

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        if (POST_HONEYCOMB) {
            // make sure we are on a version above Honeycomb otherwise will
            // access things that aren't available
            postHoneycombCAB();
        } else {
            // probably do nothing and implement the normal context menu?!?
        }
        setListAdapter(new ArrayAdapter<String>(getActivity(),
                android.R.layout.simple_list_item_1, mCountries));
    }

    @SuppressLint({ "NewApi", "NewApi" })
    private void postHoneycombCAB() {
        getListView().setChoiceMode(ListView.CHOICE_MODE_MULTIPLE_MODAL);
        getListView().setOnItemLongClickListener(new OnItemLongClickListener() {

            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view,
                    int position, long id) {
                ((ListView) parent).setItemChecked(position,
                        ((ListView) parent).isItemChecked(position));
                return false;
            }
        });
        getListView().setMultiChoiceModeListener(new MultiChoiceModeListener() {

            private int nr = 0;

            @Override
            public boolean onCreateActionMode(ActionMode mode, Menu menu) {
                getActivity().getMenuInflater().inflate(R.menu.listcab_menu,
                        menu);
                return true;
            }

            @Override
            public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
                return false;
            }

            @Override
            public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
                switch (item.getItemId()) {
                case R.id.item1:
                    Toast.makeText(getActivity(), "Option1 clicked",
                            Toast.LENGTH_SHORT).show();
                    break;
                case R.id.item2:
                    Toast.makeText(getActivity(), "Option2 clicked",
                            Toast.LENGTH_SHORT).show();
                    break;

                }
                return false;
            }

            @Override
            public void onDestroyActionMode(ActionMode mode) {
                nr = 0;
            }

            @Override
            public void onItemCheckedStateChanged(ActionMode mode,
                    int position, long id, boolean checked) {
                if (checked) {
                    nr++;
                } else {
                    nr--;
                }
                mode.setTitle(nr + " rows selected!");
            }
        });
    }
}

and the other fragment for a Fragment which has a layout composed from a RadioGroup which triggers the CAB when a RadioButton is selected:

public class SimpleCABFragment extends Fragment implements Callback {

    private static final boolean POST_HONEYCOMB = Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        return inflater.inflate(R.layout.frag_simplecabfragment, container,
                false);
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        RadioGroup rg = (RadioGroup) getView().findViewById(R.id.radioGroup1);
        rg.setOnCheckedChangeListener(new OnCheckedChangeListener() {

            @Override
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                if (POST_HONEYCOMB) {
                    // this could be improved so we don't need to create the
                    // option
                    // menu if it is already available
                    getActivity().startActionMode(SimpleCABFragment.this);
                } else {
                    // something else
                }
            }
        });
    }

    @Override
    public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
        if (item.getItemId() == R.id.itemradio) {
            Toast.makeText(getActivity(), "CAB for Radiogroup!",
                    Toast.LENGTH_SHORT).show();
        }
        return false;
    }

    @Override
    public boolean onCreateActionMode(ActionMode mode, Menu menu) {
        getActivity().getMenuInflater().inflate(R.menu.simplecab_menu, menu);
        return true;
    }

    @Override
    public void onDestroyActionMode(ActionMode mode) {
    }

    @Override
    public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
        return false;
    }
}

看看这是否是您要查找的内容(您可以找到包括布局和菜单文件在内的完整示例 in my github project)。

关于android - 将上下文操作栏与 fragment 一起使用，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/12485698/