android - textswitcher片段

Question

在android studio中使用horizo​​ntalpaging示例， 我放了两个活动，Tab1.Java和Tab2.Java。 我想把textwitcher放在这两个活动中。 但是，Tab1.Java中的TextView（Tab1.this）出错。 我认为它还有另一个问题。 如何使这些代码有效？

MainActivity.Java

public class MainActivity extends FragmentActivity implements
    ActionBar.TabListener {

SectionsPagerAdapter mSectionsPagerAdapter;

ViewPager mViewPager;

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

    final ActionBar actionBar = getActionBar();
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

    mSectionsPagerAdapter = new SectionsPagerAdapter(
            getSupportFragmentManager());

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


    mViewPager
            .setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
                @Override
                public void onPageSelected(int position) {
                    actionBar.setSelectedNavigationItem(position);
                }
            });


    for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {

        actionBar.addTab(actionBar.newTab()
                .setText(mSectionsPagerAdapter.getPageTitle(i))
                .setTabListener(this));
    }
}

@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) {
}


public class SectionsPagerAdapter extends FragmentPagerAdapter {
    Context mContext;

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

    @Override
    public Fragment getItem(int position) {

        switch(position) {
            case 0:
                return new Tab1(mContext);
            case 1:
                return new Tab2(mContext);

        }
        return null;
    }

    @Override
    public int getCount() {
        // Show 3 total pages.
        return 2;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        Locale l = Locale.getDefault();
        switch (position) {
            case 0:
                return getString(R.string.title_section1).toUpperCase(l);
            case 1:
                return getString(R.string.title_section2).toUpperCase(l);

        }
        return null;
    }
}


public static class DummySectionFragment extends Fragment {

    public static final String ARG_SECTION_NUMBER = "section_number";

    public DummySectionFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_main_dummy,
                container, false);
        TextView dummyTextView = (TextView) rootView
                .findViewById(R.id.section_label);
        dummyTextView.setText(Integer.toString(getArguments().getInt(
                ARG_SECTION_NUMBER)));
        return rootView;
    }
}}

Tab1.Java

public class Tab1 extends Fragment {
Context mContext;

public Tab1(Context context) {
    mContext = context;
}
private TextSwitcher mSwitcher;
Button button1;

String textToShow[]={"st1","st2","st3","st4","st5","st6"};
int messageCount=textToShow.length;

int currentIndex=-1;

public View onCreateView(LayoutInflater inflater,
                        ViewGroup container,Bundle savedInstanceState)
{
    View view = inflater.inflate(R.layout.activity_tab1, null);
    super.onCreate(savedInstanceState);

    button1=(Button)view.findViewById(R.id.button1);
    mSwitcher = (TextSwitcher) view.findViewById(R.id.textSwitcher);
    mSwitcher.setFactory(new ViewSwitcher.ViewFactory() {
@Override
    public View makeView() {
    TextView myText = new TextView(Tab1.this);
    myText.setGravity(Gravity.TOP | Gravity.CENTER_HORIZONTAL);
    myText.setTextSize(36);
    return myText; }});

    button1.setOnClickListener(new View.OnClickListener() {

        public void onClick(View v) {
    // TODO Auto-generated method stub
    currentIndex++;
    // If index reaches maximum reset it
    if (currentIndex == messageCount)
        currentIndex = 0;
    mSwitcher.setText(textToShow[currentIndex]);
}});
    return view; }
}

activity_tab1.xml

 <TextSwitcher
    android:layout_marginTop="50dp"
    android:id="@+id/textSwitcher"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal" />

<Button
    android:id="@+id/button1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Next"
    android:layout_alignParentBottom="true"
    android:layout_alignParentRight="true"
    android:layout_alignParentEnd="true"
    android:singleLine="false"
    android:typeface="normal" />