在使用ListFragment和DetailFragment的平板电脑活动中，仅使用上下文操作栏CAB进行onLongClick，仅执行onListItemClick

Question

我有一个从ListActivity调用的ListFragment，在平板电脑上使用双片段布局。 我使用了Android Studio 0.3.6 API 19中的标准MasterDetail Fragment设置。

MyListFragment如下所示：

import android.app.Activity;
import android.content.ContentUris;
import android.net.Uri;
import android.support.v4.content.CursorLoader;
import android.support.v4.content.Loader;
import android.database.Cursor;
import android.os.Bundle;
import android.support.v4.app.ListFragment;
import android.view.ActionMode;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ListView;
import android.support.v4.widget.SimpleCursorAdapter;

import com.supascale.supascale.contentprovider.SupaScaleContentProvider;
import com.supascale.supascale.database.SupascaleDb;

/**
     * A list fragment representing a list of Animals. This fragment
     * also supports tablet devices by allowing list items to be given an
     * 'activated' state upon selection. This helps indicate which item is
     * currently being viewed in a {@link AnimalDetailFragment}.
     * <p>
     * Activities containing this fragment MUST implement the {@link Callbacks}
     * interface.
     *
     * You can create new ones via the ActionBar entry "Insert".
     * You can delete existing ones via a long press on the item.
     */


public class AnimalListFragment extends ListFragment implements
        android.support.v4.app.LoaderManager.LoaderCallbacks<Cursor>{

    private static final int ACTIVITY_CREATE = 0;
    private static final int ACTIVITY_EDIT = 1;
    private static final int DELETE_ID = Menu.FIRST + 1;

    private SimpleCursorAdapter adapter;
    protected Object mActionMode;
    private ActionMode.Callback mActionModeCallback;

    /**
     * The serialization (saved instance state) Bundle key representing the
     * activated item position. Only used on tablets.
     */
    private static final String STATE_ACTIVATED_POSITION = "activated_position";

    /**
     * The fragment's current callback object, which is notified of list item
     * clicks.
     */
    private Callbacks mCallbacks = sDummyCallbacks;


    /**
     * The current activated item position. Only used on tablets.
     */
    private int mActivatedPosition = ListView.INVALID_POSITION;

    /**
     * A callback interface that all activities containing this fragment must
     * implement. This mechanism allows activities to be notified of item
     * selections. NB AJW
     */
    public interface Callbacks {
        /**
         * Callback for when an item has been selected.
         */
        public void onItemSelected(Uri id);  
    }

    /**
     * A dummy implementation of the {@link Callbacks} interface that does
     * nothing. Used only when this fragment is not attached to an activity.
     */
    private static Callbacks sDummyCallbacks = new Callbacks() {
        @Override
        public void onItemSelected(Uri animalUri) {
        }
    };

    /**
     * Mandatory empty constructor for the fragment manager to instantiate the
     * fragment (e.g. upon screen orientation changes).
     */
    public AnimalListFragment() {
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
       // super.onCreate(savedInstanceState);

        return inflater.inflate(R.layout.animal_list, container, false);
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        String[] from = new String[] { SupascaleDb.KEY_Animal_ANIMALIDENTIFICATION };
        // Fields on the UI to which we map
        int[] to = new int[] { R.id.label };

        getLoaderManager().initLoader(0, null, this);
        adapter = new SimpleCursorAdapter(getActivity(), R.layout.animal_row, null, from,
                to, 0);

        setListAdapter(adapter);

        // Restore the previously serialized activated item position.
        if (savedInstanceState != null
                && savedInstanceState.containsKey(STATE_ACTIVATED_POSITION)) {
            setActivatedPosition(savedInstanceState.getInt(STATE_ACTIVATED_POSITION));
        }



        mActionModeCallback = new ActionMode.Callback() {

            // Called when the action mode is created; startActionMode() was called
            @Override
            public boolean onCreateActionMode(ActionMode mode, Menu menu) {
                // Inflate a menu resource providing context menu items
                MenuInflater inflater = mode.getMenuInflater();
                inflater.inflate(R.menu.listmenu, menu);
                return true;
            }

            // Called each time the action mode is shown. Always called after onCreateActionMode, but
            // may be called multiple times if the mode is invalidated.
            @Override
            public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
                return false; // Return false if nothing is done
            }

            // Called when the user selects a contextual menu item
            @Override
            public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
                switch (item.getItemId()) {

                    case DELETE_ID:
                        AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) item
                                .getMenuInfo();
                        Uri uri = Uri.parse(SupaScaleContentProvider.CONTENT_URI_ANIMAL + "/"
                                + info.id);
                        getActivity().getContentResolver().delete(uri, null, null);
                        mode.finish(); // Action picked, so close the CAB
                        return true;
                    default:
                        return false;
                }
            }

            // Called when the user exits the action mode
            @Override
            public void onDestroyActionMode(ActionMode mode) {
                mActionMode = null;
            }
        };

        getView().setOnLongClickListener( new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View view) {
                if (mActionMode != null) {
                    return false;
                }

                // Start the CAB using the ActionMode.Callback defined above
                mActionMode = view.startActionMode(mActionModeCallback);
                view.setSelected(true);
                return true;
            }
        });

    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);

        // Activities containing this fragment must implement its callbacks.
        if (!(activity instanceof Callbacks)) {
            throw new IllegalStateException("Activity must implement fragment's callbacks.");
        }

        mCallbacks = (Callbacks) activity;
    }

    @Override
    public void onDetach() {
        super.onDetach();

        // Reset the active callbacks interface to the dummy implementation.
        mCallbacks = sDummyCallbacks;
    }


    @Override
    public void onListItemClick(ListView listView, View view, int position, long id) {
        super.onListItemClick(listView, view, position, id);

        // Notify the active callbacks interface (the activity, if the
        // fragment is attached to one) that an item has been selected.

        //2013-11-26 AJW  Append the clicked item's row ID with the content provider Uri
        Uri animalUri = ContentUris.withAppendedId(SupaScaleContentProvider.CONTENT_URI_ANIMAL, id);
        // Send the event and Uri to the host activity
        mCallbacks.onItemSelected(animalUri);
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        if (mActivatedPosition != ListView.INVALID_POSITION) {
            // Serialize and persist the activated item position.
            outState.putInt(STATE_ACTIVATED_POSITION, mActivatedPosition);
        }
    }


    /**
     * Turns on activate-on-click mode. When this mode is on, list items will be
     * given the 'activated' state when touched.
     */
    public void setActivateOnItemClick(boolean activateOnItemClick) {
        // When setting CHOICE_MODE_SINGLE, ListView will automatically
        // give items the 'activated' state when touched.

        getListView().setChoiceMode(activateOnItemClick
                ? ListView.CHOICE_MODE_SINGLE
                : ListView.CHOICE_MODE_NONE);
    }

    private void setActivatedPosition(int position) {
        if (position == ListView.INVALID_POSITION) {
            getListView().setItemChecked(mActivatedPosition, false);
        } else {
            getListView().setItemChecked(position, true);
        }

        mActivatedPosition = position;
    }

    /**
     *  Creates a new loader after the initLoader () call
     */
    //@Override
    public Loader<Cursor> onCreateLoader(int id, Bundle args) {
        String[] projection = { SupascaleDb.KEY_ROWID, SupascaleDb.KEY_Animal_ANIMALIDENTIFICATION };
        CursorLoader cursorLoader = new CursorLoader(getActivity(),
                SupaScaleContentProvider.CONTENT_URI_ANIMAL, projection, null, null, null);
        return cursorLoader;
    }

    //@Override
    public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
        adapter.swapCursor(data);
    }

    //@Override
    public void onLoaderReset(Loader<Cursor> loader) {
        // data is not available anymore, delete reference
        adapter.swapCursor(null);
    }

}

我的AnimalListActivity如下所示：

/**
 * An activity representing a list of Animals. This activity
 * has different presentations for handset and tablet-size devices. On
 * handsets, the activity presents a list of items, which when touched,
 * lead to a {@link AnimalDetailActivity} representing
 * item details. On tablets, the activity presents the list of items and
 * item details side-by-side using two vertical panes.
 * <p>
 * The activity makes heavy use of fragments. The list of items is a
 * {@link AnimalListFragment} and the item details
 * (if present) is a {@link AnimalDetailFragment}.
 * <p>
 * This activity also implements the required
 * {@link AnimalListFragment.Callbacks} interface
 * to listen for item selections.
 */
public class AnimalListActivity extends FragmentActivity
        implements AnimalListFragment.Callbacks {

    /**
     * Whether or not the activity is in two-pane mode, i.e. running on a tablet
     * device.
     */
    private boolean mTwoPane;
    private SimpleCursorAdapter adapter;

    private static final int ACTIVITY_CREATE = 0;
    private static final int ACTIVITY_EDIT = 1;
    private static final int DELETE_ID = Menu.FIRST + 1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_animal_list);

        if (findViewById(R.id.animal_detail_container) != null) {
            // The detail container view will be present only in the
            // large-screen layouts (res/values-large and
            // res/values-sw600dp). If this view is present, then the
            // activity should be in two-pane mode.
            mTwoPane = true;

            // In two-pane mode, list items should be given the
            // 'activated' state when touched.
            ((AnimalListFragment) getSupportFragmentManager()
                    .findFragmentById(R.id.animal_list))
                    .setActivateOnItemClick(true);
        }



        // TODO: If exposing deep links into your app, handle intents here.
    }

    /**
     * Callback method from {@link AnimalListFragment.Callbacks}
     * indicating that the item with the given ID was selected.
     */
    @Override
    public void onItemSelected(Uri animalUri) {
       //String id = Long.toString(ContentUris.parseId(animalUri));
        if (mTwoPane) {
            // In two-pane mode, show the detail view in this activity by
            // adding or replacing the detail fragment using a
            // fragment transaction.
            Bundle arguments = new Bundle();
            arguments.putString(AnimalDetailFragment.ARG_URI, animalUri.toString()); //Key value pair Adrian "animal_uri = .."

            AnimalDetailFragment fragment = new AnimalDetailFragment();
            fragment.setArguments(arguments);
            getSupportFragmentManager().beginTransaction()
                    .replace(R.id.animal_detail_container, fragment)
                    .commit();

        } else {
            // In single-pane mode, simply start the detail activity
            // for the selected item ID.
            Intent detailIntent = new Intent(this, AnimalDetailActivity.class);
            //Uri todoUri = Uri.parse(SupaScaleContentProvider.CONTENT_URI_ANIMAL + "/" + id);
            //detailIntent.putExtra(AnimalDetailFragment.ARG_ITEM_ID, id);
            //startActivity(detailIntent);
            detailIntent.putExtra(SupaScaleContentProvider.CONTENT_ITEM_TYPE, animalUri);

            // Activity returns an result if called with startActivityForResult
            startActivityForResult(detailIntent, ACTIVITY_EDIT);
        }
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.listmenu, menu);
        return true;
    }

    // Reaction to the menu selection
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.insert:
                createAnimal();
                return true;
        }
        return super.onOptionsItemSelected(item);
    }

    private void createAnimal() {
        if (mTwoPane) {
            // In two-pane mode, show the detail view in this activity by
            // adding or replacing the detail fragment using a
            // fragment transaction.
            Bundle arguments = new Bundle();
            //arguments.putString(AnimalDetailFragment.ARG_URI, animalUri.toString()); //Key value pair Adrian "animal_uri = .."

            AnimalDetailFragment fragment = new AnimalDetailFragment();
            fragment.setArguments(arguments);
            getSupportFragmentManager().beginTransaction()
                    .replace(R.id.animal_detail_container, fragment)
                    .commit();

        } else {
            // In single-pane mode, simply start the detail activity
            Intent i = new Intent(this, AnimalDetailActivity.class);
            startActivityForResult(i, ACTIVITY_EDIT);
        }
    }

}

AnimalListActivity.xml

<fragment xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/animal_list"
    android:name="com.supascale.supascale.AnimalListFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_marginLeft="16dp"
    android:layout_marginRight="16dp"
    tools:context=".AnimalListActivity"
    tools:layout="@android:layout/list_content" />

List.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ListView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@android:id/list" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="No Animal Data"
        android:id="@android:id/empty" />

</LinearLayout>

row.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="wrap_content" >

    <ImageView
            android:id="@+id/icon"
            android:layout_width="30dp"
            android:layout_height="24dp"
            android:layout_marginLeft="4dp"
            android:layout_marginRight="8dp"
            android:layout_marginTop="8dp"
            android:src="@drawable/reminder" >
    </ImageView>

    <TextView
            android:id="@+id/label"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="6dp"
            android:lines="1"
            android:text="@+id/textViewNormalTotal"
            android:textSize="24sp"
            >
    </TextView>

</LinearLayout>

片段列表正确滚动，单击时会正确填充详细信息片段。当我长按时，没有任何反应，当我释放longclick时，会触发click事件。

我需要长按才能显示CAB（上下文操作栏），以便我可以删除记录或共享记录等。

mActionMode = view.startActionMode(mActionModeCallback);似乎永远不会被召唤。

希望我已经足够清楚了。 此致

阿德里安

我编辑并添加了ListFragment的导入，因为它可能与support.v4有关吗？

Answer 1

好的，所以我不太了解CAB的帮助。

http://developer.android.com/guide/topics/ui/menus.html#CAB

对于ListView或ListFragment，而不是其他类型的视图，您必须使用setOnItemLongClickListener， 而不是setOnLongClickListener，如developer.android.com的帮助。

setOnLongClickListener永远不会被列表视图激活，因此永远无法继续创建CAB。

我删除了以下代码：

getView().setOnLongClickListener( new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View view) {
                if (mActionMode != null) {
                    return false;
                }

                // Start the CAB using the ActionMode.Callback defined above
                mActionMode = view.startActionMode(mActionModeCallback);
                view.setSelected(true);
                return true;
            }
        });

并替换为以下内容：

getListView().setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {

            @Override
            public boolean onItemLongClick(AdapterView<?> arg0, View view,
                                           int position, long id) {
                if (mActionMode != null) {
                    return false;
                }

                Animal_id = id;
                // Start the CAB using the ActionMode.Callback defined above
                mActionMode = getActivity().startActionMode(mActionModeCallback);
                view.setSelected(true);
                return true;
            }
        });

现在点击长按事件，我可以让CAB正常显示。