如何使用ActionBar的选项卡和片段进行导航？

Question

我正在使用动作栏和带有片段的选项卡导航。

每个选项卡都包含一个带有列表视图的片段X，当单击列表中的一个项目时，片段X被另一个带有项目详细信息的片段取代。

当我在FragmentY中时，如何设置ActionBar的Up按钮以加载FragmentX？

文档显示导航应该在活动之间完成，但ActionBar的导航选项卡允许在Fragments之间导航，而不是活动。

我错过了什么？

public class MainActivity extends FragmentActivity implements
ActionBar.TabListener {

    /**
     * The {@link android.support.v4.view.PagerAdapter} that will provide
     * fragments for each of the sections. We use a
     * {@link android.support.v4.app.FragmentPagerAdapter} derivative, which
     * will keep every loaded fragment in memory. If this becomes too memory
     * intensive, it may be best to switch to a
     * {@link android.support.v4.app.FragmentStatePagerAdapter}.
     */
    SectionsPagerAdapter mSectionsPagerAdapter;

    /**
     * The {@link ViewPager} that will host the section contents.
     */
    ViewPager mViewPager;

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

        // Set up the action bar.
        final ActionBar actionBar = getActionBar();
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

        // Create the adapter that will return a fragment for each of the three
        // primary sections of the app.
        mSectionsPagerAdapter = new SectionsPagerAdapter(
                getSupportFragmentManager());

        // Set up the ViewPager with the sections adapter.
        mViewPager = (ViewPager) findViewById(R.id.pager);
        mViewPager.setAdapter(mSectionsPagerAdapter);

        // When swiping between different sections, select the corresponding
        // tab. We can also use ActionBar.Tab#select() to do this if we have
        // a reference to the Tab.
        mViewPager
        .setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
            @Override
            public void onPageSelected(int position) {
                actionBar.setSelectedNavigationItem(position);
            }
        });

        // For each of the sections in the app, add a tab to the action bar.
        for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
            // Create a tab with text corresponding to the page title defined by
            // the adapter. Also specify this Activity object, which implements
            // the TabListener interface, as the callback (listener) for when
            // this tab is selected.

            LinearLayout view = (LinearLayout) getLayoutInflater().inflate(R.layout.tab, null);

            ImageView icon = (ImageView) view.findViewById(R.id.icon);
            icon.setImageResource(tabIconList[i]);

            TextView title = (TextView) view.findViewById(R.id.title);
            title.setText(tabTitleList[i]);


            actionBar.addTab(actionBar.newTab()
                    .setCustomView(view)
                    .setTabListener(this));
        }
    }

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

    @Override
    public void onTabSelected(ActionBar.Tab tab,
            FragmentTransaction fragmentTransaction) {
        // When the given tab is selected, switch to the corresponding page in
        // the ViewPager.
        mViewPager.setCurrentItem(tab.getPosition());
    }

    @Override
    public void onTabUnselected(ActionBar.Tab tab,
            FragmentTransaction fragmentTransaction) {
    }

    @Override
    public void onTabReselected(ActionBar.Tab tab,
            FragmentTransaction fragmentTransaction) {
    }

    /**
     * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
     * one of the sections/tabs/pages.
     */
    public class SectionsPagerAdapter extends FragmentPagerAdapter {

        public SectionsPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            // getItem is called to instantiate the fragment for the given page.
            // Return a DummySectionFragment (defined as a static inner class
            // below) with the page number as its lone argument.


            Fragment fragment = null;

            switch(position){
            case 0:
                fragment = new MyListFragment1();
                break;
            case 1:
                fragment = new MyListFragment2();
                break;
            case 2:
                fragment = new MyListFragment3();
                break;
            default: fragment = new MyListFragment1();

            }

            return fragment;

        }

        @Override
        public int getCount() {
            // Show 3 total pages.
            return 3;
        }

        @Override
        public CharSequence getPageTitle(int position) {
            Locale l = Locale.getDefault();
            switch (position) {
            case 0:
                return getString(R.string.title1).toUpperCase(l);
            case 1:
                return getString(R.string.title2).toUpperCase(l);
            case 2:
                return getString(R.string.title3).toUpperCase(l);
            }
            return null;
        }
    }

}

Answer 1

我最终没有使用ActionBar。约束太多（我有另一个问题，我想在ActionBar上方添加一个View，这似乎很复杂）。

从头开始做自己的布局要简单得多。

Answer 2

加载碎片时激活向上导航。然后在OnOptions ItemSelected上拦截向上导航，只需弹出Backback并启动FragmentX。

我对SO进行了快速搜索，发现了这个，这启发了我。