从Android中的片段管理工具栏的导航和后退按钮

我所有的片段都是通过ActionBarActivity(mainActivity)控制的，在mainActivity内实现了DrawerLayout，所有子片段都通过drawerLayout的列表项单击来推送.我面临的问题是通过抽屉布局推送一个片段后，我想将抽屉图标更改为ToolBar的后图标，以便用户可以导航到上一个片段并处理同一片段内的android.R.id.home回调或在mainActivity内部.

All of my fragments are controlled through ActionBarActivity (mainActivity), inside mainActivity a DrawerLayout is implemented and all the child fragments are pushed through drawerLayout's list item click. The problem that I'm facing is after pushing a fragment through drawerLayout I want to change the drawer icon into back icon of ToolBar so that user can navigate to previous fragment and to handle the callback of android.R.id.home either inside the same fragment or inside the mainActivity.

我正在使用的代码是:

MainActivity.java

public class MainActivity extends ActionBarActivity {
    private DrawerLayout layoutDrawer;
    private ActionBarDrawerToggle drawerToggler;
    private Stack<Fragment> stack;

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

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        stack = new Stack<Fragment>();
        layoutDrawer = (DrawerLayout) findViewById(R.id.layout_drawer);
        drawerToggler = new ActionBarDrawerToggle(this, layoutDrawer, toolbar,
                R.string.app_name, R.string.app_name);
        layoutDrawer.setDrawerListener(drawerToggler);

        setUpDrawerList();
        pushFragment(new FirstFragment(), true);

        Session.setContext(getApplicationContext());
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (drawerToggler.isDrawerIndicatorEnabled()
                && drawerToggler.onOptionsItemSelected(item))
            return true;
        switch (item.getItemId()) {
        case android.R.id.home:
            Toast.makeText(this, "Back from activity", Toast.LENGTH_SHORT)
                    .show();
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        drawerToggler.syncState();
    }

    @Override
    public void onBackPressed() {
        popFragment();
    }

    private void setUpDrawerList() {
        ListView listView = (ListView) findViewById(R.id.list_drawer);
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
                android.R.layout.simple_list_item_1,
                Arrays.asList(new String[] { "First Fragment",
                        "Second Fragment" }));
        listView.setAdapter(adapter);
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                layoutDrawer.closeDrawers();
                drawerToggler.setDrawerIndicatorEnabled(false);
                getSupportActionBar().setDisplayHomeAsUpEnabled(true);
                pushFragment(getFragment(position), true);
            }
        });
    }

    private Fragment getFragment(int pos) {
        switch (pos) {
        case 0:
            return new FirstFragment();
        case 1:
            return new SecondFragment();
        }
        return null;
    }

    public void pushFragment(Fragment fragment, boolean add) {
        FragmentTransaction transation = getSupportFragmentManager()
                .beginTransaction();
        if (add)
            stack.push(fragment);
        transation.replace(R.id.layout_content, fragment);
        transation.commit();
    }

    public void popFragment() {
        if (!stack.isEmpty()) {
            Fragment fragment = stack.elementAt(stack.size() - 2);
            stack.pop();
            pushFragment(fragment, false);
        } else
            super.onBackPressed();
        drawerToggler.setDrawerIndicatorEnabled(stack.size() == 1);
    }

    public void clearBackStack() {
        stack.clear();
    }
}

FirstFragment.java

public class FirstFragment extends Fragment {

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        setHasOptionsMenu(true);
    }

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

    @Override
    public void onResume() {
        super.onResume();
        ActionBar actionBar = ((ActionBarActivity)getActivity()).getSupportActionBar();
        actionBar.setTitle("First Fragment");
        actionBar.setDisplayHomeAsUpEnabled(true);
        actionBar.setHomeButtonEnabled(true);
    }

    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        super.onCreateOptionsMenu(menu, inflater);
        menu.clear();
        inflater.inflate(R.menu.fragment_menu, menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch(item.getItemId()) {
        case android.R.id.home:
            Toast.makeText(getActivity(), "Back from fragment", Toast.LENGTH_SHORT).show();
            getActivity().onBackPressed();
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

从上面的代码中，我无法获取android.R.id.home的回调，并且每次actionBar.setDisplayHomeAsUpEnabled(true); actionBar.setHomeButtonEnabled(true);

From the above code I am not able to get the callback of android.R.id.home and setting home button is not working everytime actionBar.setDisplayHomeAsUpEnabled(true); actionBar.setHomeButtonEnabled(true);

任何帮助将不胜感激.

谢谢