从活动类打开Android导航抽屉

Question

I am working on android Navigation Drawer and through their documentation it looks like, the drawer can only extend Fragment Activity, so that to open drawer from all my activities, I need to make all my activities a fragment, which is not a feasible solution.

Is there a way I can open a drawer that extends FragmentActivity from an Activity?

When I try to extend my drawer activity from Activity class, and another activity that will open the drawer extending the draweractivity class (here SlideMenuActivity), the app crashes giving NullPointerException.

Below is the code for opening a drawer layout but once the first activity launches, I am unable to access the drawer.

App is crashing on syncState point in onPostCreate method

@Override
protected void onPostCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onPostCreate(savedInstanceState);
    getActionDrawerToggle().syncState();
}

public class SlideMenuActivity extends FragmentActivity implements OnItemClickListener


{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setDrawerLayout();
        setDrawerList();
        if (savedInstanceState == null) 
        {
            getDrawerListView().setSelectionAfterHeaderView();
            getDrawerListView().setSelection(1);
            selectItem(1);
        }
    }
//  
//  @Override
//  public void setContentView(int layoutResID) {
//      // TODO Auto-generated method stub
//      super.setContentView(layoutResID);
//  }

    private DrawerLayout getDrawerView()
    {
        return (DrawerLayout)findViewById(R.id.drawer_layout);
    }

    private ListView getDrawerListView()
    {
        return (ListView) findViewById(R.id.left_drawer);
    }

    private ActionBarDrawerToggle getActionDrawerToggle()
    {
        ActionBarDrawerToggle drawerToggle=new ActionBarDrawerToggle(
                this,                  /* host Activity */
                getDrawerView(),         /* DrawerLayout object */
                R.drawable.ic_drawer,  /* nav drawer image to replace 'Up' caret */
                R.string.drawer_open,  /* "open drawer" description for accessibility */
                R.string.drawer_close  /* "close drawer" description for accessibility */
                ) {
            @Override
            public void onDrawerClosed(View view) {
               super.onDrawerClosed(view);
            }

            @Override
            public void onDrawerOpened(View view) {
                super.onDrawerOpened(view);
            }
        };
        return drawerToggle;
    }

    private void setDrawerLayout(){
        // set a custom shadow that overlays the main content when the drawer opens
        getDrawerView().setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.RELATIVE_HORIZONTAL_GRAVITY_MASK);
        // enable ActionBar app icon to behave as action to toggle navigation drawer
        getDrawerView().setDrawerListener(getActionDrawerToggle());

    }

    /**
     *  Set up the drawer's list view with items and click listener
     */
    private void setDrawerList()
    {
        ImageView imageView=new ImageView(this);
        imageView.setImageDrawable(getResources().getDrawable(R.drawable.precision_logo));
        CustomBaseAdapter adapter=new CustomBaseAdapter();
        adapter.list=getListViewData();
        adapter.context=this;
        ListView drawerList=getDrawerListView();
        drawerList.setHeaderDividersEnabled(true);
        drawerList.addHeaderView(imageView, null, false);
        drawerList.setScrollingCacheEnabled(false);
        drawerList.setAdapter(adapter);
        drawerList.setOnItemClickListener(this);

    }

    private void selectItem(int position){

         // update the main content by replacing fragments

//        Fragment fragment=null;
//      FragmentManager manager=getSupportFragmentManager();
        switch (position) {
        case 1:
            this.startActivity(new Intent(this,SavedTankListActivity.class));
//          fragment = new SavedMixesFragment();
//          fragment = new SavedTankListActivity();
//          manager.beginTransaction().replace(R.id.content_frame, fragment).commit();
            break;

        case 2:
//          fragment=new MixGuideFragment();
//          manager.beginTransaction().replace(R.id.content_frame, fragment).commit();
            break;

        default:
//          fragment = new SavedMixesFragment();
//          manager.beginTransaction().replace(R.id.content_frame, fragment).commit();

            break;
        }

        getDrawerView().closeDrawer(getDrawerListView());

    }

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onPostCreate(savedInstanceState);
        getActionDrawerToggle().syncState();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        // TODO Auto-generated method stub
        super.onConfigurationChanged(newConfig);
        getActionDrawerToggle().onConfigurationChanged(newConfig);
    }

    private ArrayList<DrawerListModel> getListViewData()
    {
        ArrayList<DrawerListModel> listViewData=new ArrayList<DrawerListModel>();
        String[] listItemArray=getResources().getStringArray(R.array.slide_bar_list_item_array);
        for(int index=0;index<listItemArray.length;index++)
        {
            DrawerListModel model=new DrawerListModel();
            model.listItem=listItemArray[index];
            listViewData.add(model);
        }
        return listViewData;
    }

    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position,long id)
    {
        view.setSelected(true);
        selectItem(position); 
    }

    public void openDrawerList(View view){
        getDrawerView().openDrawer(getDrawerListView());
    }
}

Answer 1

I too was looking through the documentation and thought that I had to switch all my activities into fragments. Just to clear it up, this is simply not the case. You can have as many elements under the linear layout or whatever as needed.

For example if your base activity without the appdrawer is:

<RelativeLayout>
   <TextView>
   </TextView>
   <Button>
   <Button>
</RelativeLayout>

Simply do

<android.support.v4.widget.DrawerLayout>

    <RelativeLayout>
       <TextView>
       </TextView>
       <Button>
       <Button>
    </RelativeLayout>

    <ListView>
    </ListView>
</android.support.v4.widget.DrawerLayout>

Answer 2

假设您可以在主活动中放置导航抽屉，所有子活动类都可以使用该抽屉，但是我不明白的是如何避免为所有子活动重复包含抽屉的布局。

Answer 3

Navigation Drawers do NOT need to be in a fragment. You can create a class that will then be extended from all of your activities (as you were attempting to do).

public class SlideMenuActivity extends Activity{..}

your main activity would look like

public class MainActivity extends SlideMenuActivity{..}

The SlideMenuActivity can be implemented in the same way as described in creating a navigation activity .

All of your XML pages would include this:

<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#FFFFFF" >

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

</LinearLayout>

<ListView
    android:id="@+id/left_drawer"
    android:layout_width="240dp"
    android:layout_height="match_parent"
    android:layout_gravity="start"
    android:background="#111"
    android:choiceMode="singleChoice"
    android:divider="#CCCCCC"
    android:dividerHeight="1dp" />

</android.support.v4.widget.DrawerLayout>

Without seeing your logcat output, I am not sure why you are receiving an error, but hopefully this can help you get through a bit more of the navigation drawer code.