viewpager+fragment结合

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    private ViewPager viewPager1;
    private Button btnweather,btnlvshi;
    ArrayList<Button> viewlist = new ArrayList<Button>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.item);

        initView();
        viewPager1.setAdapter(new FragmentPagerAdapter(getSupportFragmentManager()) {

            @Override
            public int getCount() {
                return ;
            }
            @Override
            public Fragment getItem(int position) {
              Fragment fragment = null;

               switch (position){
                   case :
                       fragment = new WeatherFragment();
                       break;
                   case :
                       fragment = new LvshiFragment();
                       break;
               }
                return fragment;
            }
        });

        viewPager1.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

            }
            @Override
            public void onPageSelected(int position) {
                for(int i = ;i<viewlist.size();i ++){
                    Button button = viewlist.get(i);
                    if (i==position) {
                        button.setTextColor(Color.RED);
                    }else {
                        button.setTextColor(Color.BLACK);
                    }
                }
            }
            @Override
            public void onPageScrollStateChanged(int state) {

            }
        });

    }
    private void initView(){

        viewPager1 = (ViewPager) findViewById(R.id.mypagerall);
        btnweather = (Button) findViewById(R.id.weather);
        btnlvshi = (Button) findViewById(R.id.lvshi);

        viewlist.add(btnweather);
        viewlist.add(btnlvshi);

        for (int i = ;i<viewlist.size();i++){
            viewlist.get(i).setOnClickListener(this);
        }
    }

    @Override
    public void onClick(View view) {
        switch (view.getId()){
            case R.id.weather:
                viewPager1.setCurrentItem();
                break;
            case R.id.lvshi:
                viewPager1.setCurrentItem();
                break;
        }
    }

}