SectionsPagerAdapter Android Studio模板

Question

我正在尝试使用android studio附带的SectionsPagerAdapter。我无法从MainActivity的onCreate（）设置片段。

mSectionsPagerAdapter.getItem（1）

上面的语句返回一个片段，我需要帮助才能在视图中显示它。

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

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        // Create the adapter that will return a fragment for each of the three
        // primary sections of the activity.
        mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());

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


        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                mSectionsPagerAdapter.getItem(1);
            }
        });

    }