Question

我想在抽屉布局中创建多级菜单。我的Activity.xml： -

<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">


<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <LinearLayout
        android:id="@+id/container_toolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <include
            android:id="@+id/toolbar"
            layout="@layout/toolbar" />
    </LinearLayout>

    <FrameLayout
        android:id="@+id/container_body"
        android:layout_width="fill_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />


</LinearLayout>


<fragment
    android:id="@+id/fragment_navigation_drawer"
    android:name="com.android.ShoppingMazza.activity.FragmentDrawer"
    android:layout_width="@dimen/nav_drawer_width"
    android:layout_height="match_parent"
    android:layout_gravity="start"
    app:layout="@layout/fragment_navigation_drawer"
    tools:layout="@layout/fragment_navigation_drawer" />

这里我的fragment_navigation_drawer.xml： -

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:color/white">

<android.support.v7.widget.RecyclerView
    android:id="@+id/drawerList"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="15dp" />

这里是我的FragmentDrawer.java

public class FragmentDrawer extends Fragment {

private static String TAG = FragmentDrawer.class.getSimpleName();

private RecyclerView recyclerView;
private ActionBarDrawerToggle mDrawerToggle;
private DrawerLayout mDrawerLayout;
private NavigationDrawerAdapter adapter;
private View containerView;
private static String[] titles = null;
private FragmentDrawerListener drawerListener;

public FragmentDrawer() {

}

public void setDrawerListener(FragmentDrawerListener listener) {
    this.drawerListener = listener;
}

public static List<NavDrawerItem> getData() {
    List<NavDrawerItem> data = new ArrayList<>();


    // preparing navigation drawer items
    for (int i = 0; i < titles.length; i++) {
        NavDrawerItem navItem = new NavDrawerItem();
        navItem.setTitle(titles[i]);
        data.add(navItem);
    }
    return data;
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    // drawer labels
    titles = getActivity().getResources().getStringArray(R.array.nav_drawer_labels);
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflating view layout
    View layout = inflater.inflate(R.layout.fragment_navigation_drawer, container, false);
    recyclerView = (RecyclerView) layout.findViewById(R.id.drawerList);

    adapter = new NavigationDrawerAdapter(getActivity(), getData());
    recyclerView.setAdapter(adapter);
    recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
    recyclerView.addOnItemTouchListener(new RecyclerTouchListener(getActivity(), recyclerView, new ClickListener() {
        @Override
        public void onClick(View view, int position) {
            drawerListener.onDrawerItemSelected(view, position);
            mDrawerLayout.closeDrawer(containerView);
        }

        @Override
        public void onLongClick(View view, int position) {

        }
    }));

    return layout;
}


public void setUp(int fragmentId, DrawerLayout drawerLayout, final Toolbar toolbar) {
    containerView = getActivity().findViewById(fragmentId);
    mDrawerLayout = drawerLayout;
    mDrawerToggle = new ActionBarDrawerToggle(getActivity(), drawerLayout, toolbar, R.string.drawer_open, R.string.drawer_close) {
        @Override
        public void onDrawerOpened(View drawerView) {
            super.onDrawerOpened(drawerView);
            getActivity().invalidateOptionsMenu();
        }

        @Override
        public void onDrawerClosed(View drawerView) {
            super.onDrawerClosed(drawerView);
            getActivity().invalidateOptionsMenu();
        }

        @Override
        public void onDrawerSlide(View drawerView, float slideOffset) {
            super.onDrawerSlide(drawerView, slideOffset);
            toolbar.setAlpha(1 - slideOffset / 2);
        }
    };

    mDrawerLayout.setDrawerListener(mDrawerToggle);
    mDrawerLayout.post(new Runnable() {
        @Override
        public void run() {
            mDrawerToggle.syncState();
        }
    });

}

public static interface ClickListener {
    public void onClick(View view, int position);

    public void onLongClick(View view, int position);
}

static class RecyclerTouchListener implements RecyclerView.OnItemTouchListener {

    private GestureDetector gestureDetector;
    private ClickListener clickListener;

    public RecyclerTouchListener(Context context, final RecyclerView recyclerView, final ClickListener clickListener) {
        this.clickListener = clickListener;
        gestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {
            @Override
            public boolean onSingleTapUp(MotionEvent e) {
                return true;
            }

            @Override
            public void onLongPress(MotionEvent e) {
                View child = recyclerView.findChildViewUnder(e.getX(), e.getY());
                if (child != null && clickListener != null) {
                    clickListener.onLongClick(child, recyclerView.getChildPosition(child));
                }
            }
        });
    }

    @Override
    public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {

        View child = rv.findChildViewUnder(e.getX(), e.getY());
        if (child != null && clickListener != null && gestureDetector.onTouchEvent(e)) {
            clickListener.onClick(child, rv.getChildPosition(child));
        }
        return false;
    }

    @Override
    public void onTouchEvent(RecyclerView rv, MotionEvent e) {
    }

    @Override
    public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {

    }


}

public interface FragmentDrawerListener {
    public void onDrawerItemSelected(View view, int position);
}

}

这里是我的MainActivity.java： -

 public class MainActivity extends AppCompatActivity implements           FragmentDrawer.FragmentDrawerListener {

private static String TAG = MainActivity.class.getSimpleName();

private Toolbar mToolbar;
private FragmentDrawer drawerFragment;

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

    mToolbar = (Toolbar) findViewById(R.id.toolbar);

    setSupportActionBar(mToolbar);
    getSupportActionBar().setDisplayShowHomeEnabled(true);

    drawerFragment = (FragmentDrawer)
            getSupportFragmentManager().findFragmentById(R.id.fragment_navigation_drawer);
    drawerFragment.setUp(R.id.fragment_navigation_drawer, (DrawerLayout) findViewById(R.id.drawer_layout), mToolbar);
    drawerFragment.setDrawerListener(this);

    // display the first navigation drawer view on app launch
    displayView(0);
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    if(id == R.id.action_search){
        Toast.makeText(getApplicationContext(), "Search action is selected!", Toast.LENGTH_SHORT).show();
        return true;
    }

    return super.onOptionsItemSelected(item);
}

@Override
public void onDrawerItemSelected(View view, int position) {
    displayView(position);
}

private void displayView(int position) {
    Fragment fragment = null;
    String title = getString(R.string.app_name);
    switch (position) {
        case 0:
            fragment = new HomeFragment();
            title = getString(R.string.title_home);
            break;
        case 1:
            fragment = new FriendsFragment();
            title = getString(R.string.title_friends);
            break;
        case 2:
            fragment = new MessagesFragment();
            title = getString(R.string.title_messages);
            break;
        default:
            break;
    }

    if (fragment != null) {
        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.replace(R.id.container_body, fragment);
        fragmentTransaction.commit();

        // set the toolbar title
        getSupportActionBar().setTitle(title);
    }
}

}

我目前的应用程序视图如下： -