android - 在选项卡布局 Activity 中，我的 fragment 在滑动时不会刷新

Question

我正在使用 fragmentpageradapter 来扩充 fragment ，这是我的编码。我在一个 fragment 中添加购物车项目并将其显示给其他 fragment ，所有 fragment 都采用选项卡布局。我的问题是滑动 fragment 时购物车项目未在其他 fragment 上刷新。

public class ProfileDetailePagerAdapter extends FragmentPagerAdapter 
   {
    int TabCount;
    HashMap<Integer, String> mFragmentTags;
    FragmentManager mFragmentManager;
    private boolean isPagingEnabled = true;

    public ProfileDetailePagerAdapter(FragmentManager fm, int TabCount) {
        super(fm);
        this.TabCount = TabCount;
        mFragmentTags = new HashMap<Integer, String>();
        mFragmentManager = fm;
    }

    @Override
    public Fragment getItem(int position) {
        switch (position) {
            case 0:
                MenuFragment tab1 = new MenuFragment();
                return tab1;
            case 1:
                SelectMember_fragment tab2 = new SelectMember_fragment();
                return tab2;
            case 2:
                ViewCart_fragment tab3 = new ViewCart_fragment();
                return tab3;
          /*  case 3:
                PaymentMode_fragment tab4=new PaymentMode_fragment();
                return tab4;*/
        }
        return null;
    }

    @Override
    public int getCount() {
        return TabCount;
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        Object obj = super.instantiateItem(container, position);
        if (obj instanceof Fragment) {
            // record the fragment tag here.
            Fragment f = (Fragment) obj;
            String tag = f.getTag();
            mFragmentTags.put(position, tag);
        }
        return obj;
    }


    public Fragment getFragment(int position) {
        String tag = mFragmentTags.get(position);
        if (tag == null)
            return null;
        return mFragmentManager.findFragmentByTag(tag);
    }
}

Answer 1

• 调用FragmentStatePagerAdapter
• 你应该使用 addOnTabSelectedListener

This method is used to add a listener that will be invoked when tab selection changes.

tabLayoutOBJ.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener(){
        public void onTabReselected(TabLayout.Tab tab) {

        }
        public void onTabSelected(TabLayout.Tab tab){
            String getTAB = (String)tab.getText();
            // Do your WORK 

        }
        public void  onTabUnselected(TabLayout.Tab tab){

        }
    });