java - 如何将图标添加到抽屉导航中

Question

我对复杂的代码感到模糊，这些代码都是自定义抽屉导航。我只想创建一个仅包含图标的简单导航，并使用片段来交换用户单击导航列表时要显示的内容。

public class MainActivity extends ActionBarActivity
        implements NavigationDrawerFragment.NavigationDrawerCallbacks {

    /**
     * Fragment managing the behaviors, interactions and presentation of the navigation drawer.
     */
    private NavigationDrawerFragment mNavigationDrawerFragment;

    /**
     * Used to store the last screen title. For use in {@link #restoreActionBar()}.
     */
    private CharSequence mTitle;

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

        mNavigationDrawerFragment = (NavigationDrawerFragment)
                getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
        mTitle = getTitle();

        // Set up the drawer.
        mNavigationDrawerFragment.setUp(
                R.id.navigation_drawer,
                (DrawerLayout) findViewById(R.id.drawer_layout));
    }

    @Override
    public void onNavigationDrawerItemSelected(int position) {
        android.app.Fragment objFragment = null;

        switch (position){
            case 0:
                objFragment = new Overview();
                mTitle = getString(R.string.title_section0);

                break;
            case 1:
                objFragment = new Income();
                mTitle = getString(R.string.title_section1);
                break;
            case 2:
                objFragment = new Expenses();
                mTitle = getString(R.string.title_section2);
                break;
            case 3:
                objFragment = new Category();
                mTitle = getString(R.string.title_section3);
                break;
            case 4:
                objFragment = new CashConverter();
                mTitle = getString(R.string.title_section4);
                break;
            case 5:
                objFragment = new History();
                mTitle = getString(R.string.title_section5);
                break;
        }


        // update the main content by replacing fragments
        android.app.FragmentManager fragmentManager = getFragmentManager();
        fragmentManager.beginTransaction()
                .replace(R.id.container, objFragment)
                .commit();
    }

    public void onSectionAttached(int position) {
        switch (position) {
            case 0:
                mTitle = getString(R.string.title_section0);
                break;
            case 1:
                mTitle = getString(R.string.title_section1);
                break;
            case 2:
                mTitle = getString(R.string.title_section2);
                break;
            case 3:
                mTitle = getString(R.string.title_section3);
                break;
            case 4:
                mTitle = getString(R.string.title_section4);
                break;
            case 5:
                mTitle = getString(R.string.title_section5);
                break;
        }
    }

    public void restoreActionBar() {
        ActionBar actionBar = getSupportActionBar();
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
        actionBar.setDisplayShowTitleEnabled(true);
        actionBar.setTitle(mTitle);
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        if (!mNavigationDrawerFragment.isDrawerOpen()) {
            // Only show items in the action bar relevant to this screen
            // if the drawer is not showing. Otherwise, let the drawer
            // decide what to show in the action bar.
            getMenuInflater().inflate(R.menu.main, menu);
            restoreActionBar();
            return true;
        }
        return super.onCreateOptionsMenu(menu);
    }

    @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;
        }

        return super.onOptionsItemSelected(item);
    }
}

占位符片段

/**
 * A placeholder fragment containing a simple view.
 */
public static class PlaceholderFragment extends Fragment {
    /**
     * The fragment argument representing the section number for this
     * fragment.
     */
    private static final String ARG_SECTION_NUMBER = "section_number";

    /**
     * Returns a new instance of this fragment for the given section
     * number.
     */
    public static PlaceholderFragment newInstance(int sectionNumber) {
        PlaceholderFragment fragment = new PlaceholderFragment();
        Bundle args = new Bundle();
        args.putInt(ARG_SECTION_NUMBER, sectionNumber);
        fragment.setArguments(args);
        return fragment;
    }

    public PlaceholderFragment() {
    }

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

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        ((MainActivity) activity).onSectionAttached(
                getArguments().getInt(ARG_SECTION_NUMBER));
    }
}

Answer 1

有两种方法可以做到这一点。
1. 手动为抽屉导航添加项目。
2. 仍然使用列表适配器，但重写 getView 方法并利用 TextView 复合绘图。您可以搜索 setCompoundDrawablesRelative 了解更多信息。

我不会发布第一个选项，因为它需要更改代码的许多部分，但这里是第二个选项的示例。

在 NavigationDrawerFragment 类中找到 onCreateView 方法，并将下面的伪代码改编为您的代码。

public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    mDrawerListView = <get your navigation drawer list view here or leave it like the original>
    mDrawerListView.setOnItemClickListener(<for the click listener, again leave it like the original>);

    final LayoutInflater inflater1 = inflater; //this is for the child AdapterView to access the inflater

    mDrawerListView.setAdapter(new ArrayAdapter<String>(
            <get your context here>,
            R.layout.simple_activated_list,
            R.id.item,
            <your array of items to be listed in the drawer>
        ){
        @Override
        public View getView(int pos, View convertView, ViewGroup parent){
            super.getView(pos, convertView, parent);
            if(convertView == null) {
                // if the view is null, you need to inflate the view explicitly
                convertView = inflater1.inflate(R.layout.simple_activated_list, parent, false);
            }

            TextView tv = (TextView)convertView.findViewById(R.id.item);
            String str = getItem(pos); // for displaying your menu text, since you have overridden it
            Drawable d; // for setting up your icon and its size
            float density = getResources().getDisplayMetrics().density;
            tv.setText(str); // set the text
            // you can branch out by menu name or menu order (pos)
            switch(str){
                case "Your menu text":
                    // your specific menu item
                    d = getResources().getDrawable(R.drawable.ic_history);
                    break;
                default:
                    // else
                    d = getResources().getDrawable(R.drawable.ic_arrow);
                    break;
            }
            // set it to 24dp x 24dp
            d.setBounds(0,0,Math.round(24*density),Math.round(24*density));
            tv.setCompoundDrawablesRelative(d, null, null, null); // set the icon

            return convertView;
        }
    });

    mDrawerListView.setItemChecked(mCurrentSelectedPosition, true);
    return mDrawerListView;
} 

希望有帮助