Question

我想构建下一个UI：
带有2个选项卡和2个不同片段的TabLayout（已解决和未解决）我永远不会调用片段中的onCreateView。

这里我给viewPager充气：

 @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);

    mToolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(mToolbar);

    ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
    setupViewPager(viewPager);

    mAdapter = new ViewPagerAdapter(getSupportFragmentManager());
    mAdapter.addFragment(new UnsolvedTasksFragment());
    mAdapter.addFragment(new SolvedTasksFragment());
    viewPager.setAdapter(mAdapter);

    mTabLayout = (TabLayout) findViewById(R.id.tabs);
    mTabLayout.setupWithViewPager(viewPager);

    mTabLayout.getTabAt(0).setText(getString(R.string.tablayout_unsolved));
    mTabLayout.getTabAt(1).setText(getString(R.string.tablayout_solved));

}

我的自定义ViewPagerAdapter：

 public class ViewPagerAdapter extends FragmentPagerAdapter {
 private final List<Fragment> mFragmentList = new ArrayList<>();

public ViewPagerAdapter(FragmentManager manager) {
    super(manager);
}

@Override
public Fragment getItem(int position) {
    if (!mFragmentList.isEmpty() && mFragmentList.size() > id)
        return mFragmentList.get(position);
    return new Fragment();
}

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

public void addFragment(Fragment fragment) {
    mFragmentList.add(fragment);
}

@Override
public CharSequence getPageTitle(int position) {
    return null;
}
}

这是我片段的一个例子：

 public class SolvedTasksFragment extends Fragment implements RecyclerViewClickListenerSolved {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
       //Some code here;
        return rootView;
    }

    @Override
    public void itemClick(View v, int position) {
       }
}

也许有人能分辨出什么是错的我不需要整个解决方案。

Answer 1

From docs

id的值为16842960所以

if (true && 2 > 16842960) // will not be executed 
   // true && false => false

解决方案：您可以针对position检查尺寸，或者如果不是特定于实施，则删除此检查

@Override
public Fragment getItem(int position) {
    if (mFragmentList.size() > position)
        return mFragmentList.get(position);
    return new Fragment();
}

Answer 2

首先设置适配器，然后添加片段。像这样做。更改这些陈述

    mAdapter = new ViewPagerAdapter(getSupportFragmentManager());
    mAdapter.addFragment(new UnsolvedTasksFragment());
    mAdapter.addFragment(new SolvedTasksFragment());
    viewPager.setAdapter(mAdapter);

到这些

mAdapter = new ViewPagerAdapter(getSupportFragmentManager());
viewPager.setAdapter(mAdapter);
mAdapter.addFragment(new UnsolvedTasksFragment());
mAdapter.addFragment(new SolvedTasksFragment());

永远不会在Fragment中调用onCreateView（）

2 个答案: