如何從活動旋轉器替換片段沒有backstack

我有一個活動，其中包含在appbar中的微調控制。在homeActivity我使用的片段有默認片段作爲parentoptionfragment，從該片段有3個選項來更改片段，如果我選擇了一個片段從parentoption片段，我想更改微調器值，然後片段應更新而不添加到backstack意味着如果我按回按鈕，那麼它應該調用父選項片段，但是當我試圖這樣做時，我得到錯誤。如何從活動旋轉器替換片段沒有backstack

public void GetChildData(String token) { 
    ParentOptionsFragment fragment =new ParentOptionsFragment(); 
      FragmentManager fm = getSupportFragmentManager(); 
      FragmentTransaction fragmentTransaction = fm.beginTransaction(); 
      fragmentTransaction.replace(R.id.fragment_container, fragment); 
      fragmentTransaction.commit(); 
    } 

@Override 
     public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { 
      tv_childClassname.setText(classNameArr[position]); 
      tv_childSchoolName.setText(schoolNameArr[position]); 

      Fragment f = getSupportFragmentManager().findFragmentById(R.id.fragment_container); 
      if (f instanceof ChildMapFragment){ 
       Toast.makeText(HomeActivity.this, "refreshing childmapfragment", Toast.LENGTH_SHORT).show(); 

       ChildMapFragment fragment = new ChildMapFragment(); 
       FragmentManager fragmentManager = getSupportFragmentManager(); 
       fragmentManager.popBackStackImmediate (fragment.getClass().getName(), 0); 
       FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction(); 
       fragmentTransaction.replace(R.id.fragment_container, fragment); 
       fragmentTransaction.commit(); 
      }else if(f instanceof ParentOptionsFragment){ 
       Toast.makeText(HomeActivity.this, "spinner changed from ParentOptionsFragment", Toast.LENGTH_SHORT).show(); 

      } 
     }

使用旋塗器更新childfragment而不返回堆棧

parentoptionfragment.java

public class ParentOptionsFragment extends Fragment { 
    @Override 
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { 
     return inflater.inflate(R.layout.fragment_parent_options, container, false); 
    } 

    @Override 
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) { 
     super.onViewCreated(view, savedInstanceState); 

     final ImageView img1=(ImageView)view.findViewById(R.id.imageView); 
     ImageView img2=(ImageView)view.findViewById(R.id.imageView2); 
     ImageView img3=(ImageView)view.findViewById(R.id.img_transport); 

     img3.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       ChildMapFragment fragment = new ChildMapFragment(); 
       FragmentManager fragmentManager = getActivity().getSupportFragmentManager(); 
       FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction(); 
       fragmentTransaction.replace(R.id.fragment_container, fragment); 
       fragmentTransaction.addToBackStack(null); 
       fragmentTransaction.commit(); 
      } 
     }); 
     /*final ViewTreeObserver vto = img1.getViewTreeObserver(); 
     vto.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() { 
      public boolean onPreDraw() { 
       int x; 
       img1.getViewTreeObserver().removeOnPreDrawListener(this); 
       x = img1.getMeasuredWidth(); 
       img1.setLayoutParams(new LinearLayout.LayoutParams(x,x)); 
       return true; 
      } 
     });*/ 
    } 
}

childfragment.java

public class ChildFragment extends Fragment { 
    @Override 
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { 
     return inflater.inflate(R.layout.fragment_child_map, container, false); 
    } 
}

homeActivity ---> defaultfragment-- parentoptionfragment parentoptiofragment ---> childfragment onbackpress of childfragment - > parentoptionfragment

來源

2017-04-27 Tushar Kotecha

取代

Toast.makeText（HomeActivity.this，「提神childmapfragment」，Toast.LENGTH_SHORT）.show（）;

  ChildMapFragment fragment = new ChildMapFragment(); 
      FragmentManager fragmentManager = getSupportFragmentManager(); 
      fragmentManager.popBackStackImmediate (fragment.getClass().getName(), 0); 
      FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction(); 
      fragmentTransaction.replace(R.id.fragment_container, fragment); 
      fragmentTransaction.commit();

有：

FragmentManager fragmentManager = getSupportFragmentManager(); 
      fragmentManager.popBackStack()

更新：你的孩子片段添加一個方法：update()，並調用它：

FragmentManager fragmentManager = getSupportFragmentManager(); 
      Fragment fragment = fragmentManager.findFragmentById(R.id.fragment_container) 
    if(fragment isInstanceOf ChildMapFragment){ 
    ((ChildMapFragment)fragment).update() //call your update method here 
    }

來源

2017-04-27 09:07:14

是它會刷新childmapfragment？ –

通過使用它將返回到父項optionfragment，但我想更新childfragment。 –

如果你想刷新你的孩子片段，你最好使用一個回調，只要你的微調值改變 –

FragmentManager fragmentManager = getSupportFragmentManager(); 
     // String f_name=fragment.getClass().getName(); 
     if (!fragmentManager.popBackStackImmediate(tag, 0)) { 

      FragmentTransaction ft = fragmentManager.beginTransaction(); 
      ft.replace(R.id.content_frame, fragment, tag); 
      ft.addToBackStack(tag); 
      ft.commit(); 

     }

刷新片段活動執行回棧像這樣

@Override 
    public void onBackStackChanged() { 
     FragmentManager fragmentManager = getSupportFragmentManager(); 
     Fragment fr = fragmentManager.findFragmentById(R.id.content_frame); 
     if (fr != null) { 
      fr.onResume(); 
     } 
    }

路過這裏的不同片段的不同標籤基地

來源

2017-04-27 09:34:38

如何從活動旋轉器替換片段沒有backstack

回答

相關問題