Problem mit der BackStack-Methode und ViewPager in Android

Question

Ich habe eine Aktivität, die ein Framelayout enthält.Darin habe ich ein Fragment, das den ViewPager mit zwei verschiedenen Fragmenten darin enthält.Wenn ich den Knopf im angegebenen Fragment drücke, ersetze ich den Framelayout-Container durch ein neues Fragment.Wenn ich jetzt auf „Zurück“ drücke, wird die ViewPager-Ansicht nicht wiederhergestellt, sondern ist verschwunden.

Dies ist das erste Fragment:

public class CurrencyFragment extends BaseFragment {


    @Override
    public void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setHasOptionsMenu(true);
    }


    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {

        super.onCreateOptionsMenu(menu, inflater);

    }

    // onclick method for the refresh button on the action bar
    // the method itself calls the anoteher method getCurrency()
    // it also sets visibility to progress bar and loading text and
    // sets invisible to the listview

    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
        case R.id.action_refresh:


            Log.i("TAG", "refresh pressed =>");
            return true;
        }
        // Handle your other action bar items...

        return super.onOptionsItemSelected(item);
    }



    // oncreateView() where the basic view is created

    @Override
    public View onCreateView(final LayoutInflater inflater,
            ViewGroup container, Bundle savedInstanceState) {
        final View view = inflater.inflate(R.layout.fragment_currency_layout,
                container, false);



        mBankName = (TextView) view.findViewById(R.id.Currency_name);
        mBuySell = (LinearLayout) view.findViewById(R.id.Buy_Sell);
        mButtonBuy = (TextView) view.findViewById(R.id.Button_buy);
        mButtonSell = (TextView) view.findViewById(R.id.Button_sell);
        mViewpager = (ViewPager) view.findViewById(R.id.Detailpager);



        Bundle bundle = getArguments();
        if(bundle != null){
        Bank object = (Bank) bundle.getSerializable("message");
        mBankName.setText(object.getName());
        code = object.getCode();
        }

        testadapter = new ViewPagerAdapter(getFragmentManager(),code);
        mViewpager.setAdapter(testadapter);

        if(code.equals("NBG")){
            mBuySell.setVisibility(View.GONE);
             mViewpager.setOnTouchListener(new View.OnTouchListener() {

                @Override
                public boolean onTouch(View v, MotionEvent event) {
                    // TODO Auto-generated method stub
                    return false;
                }
            });
        }else{
            mBuySell.setVisibility(View.VISIBLE);
        }

        mViewpager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {

            @Override
            public void onPageSelected(int position) {
                // TODO Auto-generated method stub
                if (position == 0){
                    mButtonBuy.setBackgroundColor(Color.parseColor("#2FCEB8"));
                    mButtonSell.setBackgroundColor(Color.parseColor("#333333"));
                }
                else{
                    mButtonSell.setBackgroundColor(Color.parseColor("#2FCEB8"));
                    mButtonBuy.setBackgroundColor(Color.parseColor("#333333"));
                }
            }

            @Override
            public void onPageScrollStateChanged(int arg0) {
                // TODO Auto-generated method stub

            }

            @Override
            public void onPageScrolled(int arg0, float arg1, int arg2) {
                // TODO Auto-generated method stub

            }


        });





        mButtonBuy.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                mButtonBuy.setBackgroundColor(Color.parseColor("#2FCEB8"));
                mButtonSell.setBackgroundColor(Color.parseColor("#333333"));
                mViewpager.setCurrentItem(0);



            }
        });

        mButtonSell.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                mButtonSell.setBackgroundColor(Color.parseColor("#2FCEB8"));
                mButtonBuy.setBackgroundColor(Color.parseColor("#333333"));
                mViewpager.setCurrentItem(1);


            }
        });

        return view;

    }  

}

after wird durch das andere ersetzt

public class DetailedCalculator extends BaseFragment {

    private View detailedView;
    private TextView mButtonBuy;
    private TextView mButtonSell;
    private TextView mDetailedBank;
    private ViewPager mDetailpager;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        // TODO Auto-generated method stub

        DetailPagerAdapter myAdapter = new DetailPagerAdapter(getFragmentManager());

        detailedView = inflater.inflate(R.layout.detail_buy_sell, container, false);
        mButtonBuy = (TextView) detailedView.findViewById(R.id.Detail_buying);
        mButtonSell = (TextView) detailedView.findViewById(R.id.Detail_selling);
        mDetailedBank = (TextView) detailedView.findViewById(R.id.Detail_BankNAme);

        mDetailpager = (ViewPager) detailedView.findViewById(R.id.Detailpager);
        mDetailpager.setAdapter(myAdapter);


        mDetailpager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {

            @Override
            public void onPageSelected(int position) {
                // TODO Auto-generated method stub
                if(position == 0){
                    mButtonBuy.setBackgroundColor(Color.parseColor("#2FCEB8"));
                    mButtonSell.setBackgroundColor(Color.parseColor("#333333"));
                }
                else{
                    mButtonSell.setBackgroundColor(Color.parseColor("#2FCEB8"));
                    mButtonBuy.setBackgroundColor(Color.parseColor("#333333"));
                }
            }

            @Override
            public void onPageScrolled(int arg0, float arg1, int arg2) {
                // TODO Auto-generated method stub

            }

            @Override
            public void onPageScrollStateChanged(int arg0) {
                // TODO Auto-generated method stub

            }
        });

        mButtonBuy.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub
                mButtonBuy.setBackgroundColor(Color.parseColor("#2FCEB8"));
                mButtonSell.setBackgroundColor(Color.parseColor("#333333"));
                mDetailpager.setCurrentItem(0);
            }
        });

        mButtonSell.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                mButtonSell.setBackgroundColor(Color.parseColor("#2FCEB8"));
                mButtonBuy.setBackgroundColor(Color.parseColor("#333333"));
                mDetailpager.setCurrentItem(1);

            }
        });


        return detailedView;


    }



}

Answer 1

Versuchen zu benutzen getChildFragmentManager() anstatt getFragmentManager() in dem Fragment, das die enthält ViewPager :

testadapter = new ViewPagerAdapter(getFragmentManager(),code);

Zu

testadapter = new ViewPagerAdapter(getChildFragmentManager(),code);