Question

在我的应用中，我使用寻呼机适配器加载2个片段，片段未加载，视图寻呼机保持为空。我哪里错了？任何帮助将不胜感激这是我的代码我正在将此适配器设置为来自活动

的视图寻呼机

public class ViewPagerActivityAdapter extends PagerAdapter {
    ArrayList<Fragment> tablist;

    public ViewPagerActivityAdapter(ArrayList<Fragment> tablist) {
        this.tablist = tablist;
    }

    @Override
    public int getCount() {
        return tablist.size();
    }


    @Override
    public boolean isViewFromObject(View view, Object object) {
        return false;
    }

    @Override
    public Object instantiateItem(ViewGroup collection, int position) {

        return null;
    }

    @Override
    public void destroyItem(ViewGroup collection, int position, Object view) {

    }

}

活动部分

private ViewPagerActivityAdapter viewPagerAdapter;
private ArrayList<Fragment> fragments_faq;

fragments_faq = new ArrayList<>();
FragmentOne frag1 = new FragmentOne();
tablayout.addTab(tablayout.newTab().setText("fragone"));
fragments_faq.add(frag1);
FragmentTwo frag2 = new FragmentTwo();
tablayout.addTab(tablayout.newTab().setText("fragtwo"));
fragments_faq.add(frag2);

private void setPagerAdapter() {
    viewPagerAdapter = new ViewPagerActivityAdapter(fragments_faq);
    viewpager.setAdapter(viewPagerAdapter);
    viewpager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tablayout));
    viewpager.setOffscreenPageLimit(2);
    tablayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
        @Override
        public void onTabSelected(TabLayout.Tab tab) {
            viewpager.setCurrentItem(tab.getPosition());
        }

        @Override
        public void onTabUnselected(TabLayout.Tab tab) {
        }

        @Override
        public void onTabReselected(TabLayout.Tab tab) {
        }
    });
}

Answer 1

@Override

  public Fragment getItem(int position) {

    return this.fragments.get(position);

  }

详细信息请查看此要点 https://gist.github.com/vinay6kr/33359c3f3b0e9f28e33bd383b01e9d9f

Answer 2

如果要在viewpager中显示片段，则应使用FragmentStatePagerAdapter

public class MyViewPagerAdapter extends FragmentStatePagerAdapter {

    CharSequence Titles[];

    public MyViewPagerAdapter(FragmentManager fm, CharSequence mTitles[]) {
        super(fm);
        this.Titles = mTitles;
    }

    @Override
    public Fragment getItem(int position) {
        if (position == 0)
            return new Fragment1().getInstance();
        else if (position == 1)
            return new Fragment2().getInstance();

    }

    @Override
    public CharSequence getPageTitle(int position) {
        return Titles[position];
    }

    @Override
    public int getCount() {
        return Titles.length;
    }
}

并设置它们

 void setUpTabs() {
        String Titles[] = {"Frag1","Frag2"};
        MyViewPagerAdapter adapter = new MyViewPagerAdapter(this.getSupportFragmentManager(), Titles);
        viewPager.setAdapter(adapter);

    }

Answer 3

您可以尝试像适配器一样

      class ViewPagerActivityAdapter extends FragmentPagerAdapter {

      // fragments to instantiate in the viewpager
      private List<Fragment> fragments;

      // constructor
        public ViewPagerActivityAdapter(FragmentManager fm,List<Fragment> fragments) {
       super(fm);
      this.fragments = fragments;
       }

   // return access to fragment from position, required override
    @Override
    public Fragment getItem(int position) {
     return this.fragments.get(position);
   }

   // number of fragments in list, required override
   @Override
   public int getCount() {
    return this.fragments.size();
   }

   }

添加片段

List<Fragment> fragments = new Vector<Fragment>();

    fragments.add(Fragment.instantiate(this,
            FragmentOne.class.getName()));
    fragments.add(Fragment.instantiate(this,
            FragmentTwo.class.getName()));

添加到查看寻呼机

ViewPagerActivityAdapter mPagerAdapter;
    this.mPagerAdapter = new ViewPagerActivityAdapter(
            super.getSupportFragmentManager(), fragments);
    mPager = (ViewPager) super.findViewById(R.id.pager);
    mPager.setAdapter(this.mPagerAdapter);

Answer 4

您应该使用FragmentPagerAdapter或FragmentStatePagerAdapter。
以下是示例代码。

public class ViewPagerActivityAdapter extends FragmentPagerAdapter {
    ArrayList<Fragment> tablist;

    public ViewPagerActivityAdapter(ArrayList<Fragment> tablist) {
        this.tablist = tablist;
    }

    @Override
    public int getCount() {
        return tablist.size();
    }
  @Override
        public Fragment getItem(int position) {
            return tablist.get(position);
        }
}

未使用PagerAdapter [ANDROID]加载碎片

4 个答案: