只加載一個片段並僅替換它的內容

Question

實際上，我創建了一個導航抽屜，其中有三個項目，並且在點擊每個項目時它會轉到其顯示特定類型產品的片段，因此我有一個包含三個片段的Activity他們的每種類型。

如果我想添加另一種產品類型，我將不得不創建它的片段。 所以，我的問題是，是否有任何方法只能製作一個片段，每次只有一個片段中的數據被更改/替換，而不是用另一個片段替換整個片段？

編輯我的主要活動：

public class MainActivity extends AppCompatActivity { 


Toolbar toolbar; 

DrawerLayout drawerLayout; 

RecyclerView recyclerView; 

String navTitles[]; 
private NavigationView navigationView; 
TypedArray navIcons; 

RecyclerViewAdapter recyclerViewAdapter; 

ActionBarDrawerToggle drawerToggle; 
Fragment[] fFragments = new Fragment[3]; 

@Override 

protected void onCreate(Bundle savedInstanceState) { 


    super.onCreate(savedInstanceState); 

    setContentView(R.layout.activity_main); 

    //Let's first set up toolbar 

    setupToolbar(); 

    //Initialize Views 

    recyclerView = (RecyclerView) findViewById(R.id.recyclerView); 

    drawerLayout = (DrawerLayout) findViewById(R.id.drawerMainActivity); 


    //Setup Titles and Icons of Navigation Drawer 

    navTitles = getResources().getStringArray(R.array.navDrawerItems); 

    navIcons = getResources().obtainTypedArray(R.array.navDrawerIcons); 

    recyclerViewAdapter = new RecyclerViewAdapter(navTitles, navIcons, this); 

    recyclerView.setAdapter(recyclerViewAdapter); 


    recyclerViewAdapter.setClickedListener(new RecyclerViewAdapter.ClickListerner() { 

     @Override 

     public void onItemlistener(int index) { 

      updateUIWithIndex(index); 

     } 

    }); 


    recyclerView.setLayoutManager(new LinearLayoutManager(this)); 
    //Finally setup ActionBarDrawerToggle 

    setupDrawerToggle(); 


    //Add the Very First Fragment to the Container 

    updateUIWithIndex(1); 


} 



// on click update fragment 
private void updateUIWithIndex(int index) { 


    drawerLayout.closeDrawers(); 


    FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction(); 

    Fragment fFragment = null; 


    if (fFragments[index - 1] == null) { 

     switch (index) { 

      case 1: 

       fFragment = new FirstFragment(); 

       break; 

      case 2: 

       fFragment = new SecondFragment(); 

       break; 

      case 3: 

       fFragment = new ThirdFragment(); 

       break; 

     } 

     fFragments[index - 1] = fFragment; 

    } else { 

     fFragment = fFragments[index - 1]; 

    } 

    fragmentTransaction.replace(R.id.containerView, fFragment); 

    fragmentTransaction.commit(); 


} 


void setupToolbar() { 

    toolbar = (Toolbar) findViewById(R.id.toolBar); 

    setSupportActionBar(toolbar); 

    getSupportActionBar().setDisplayShowHomeEnabled(true); 

} 


void setupDrawerToggle() { 

    drawerToggle = new ActionBarDrawerToggle(this, drawerLayout, toolbar, R.string.app_name, R.string.app_name); 

    //This is necessary to change the icon of the Drawer Toggle upon state change. 

    drawerToggle.syncState(); 

} 


} 

我的片段：

public class FirstFragment extends Fragment implements ClickListner { 

private final String LOG_TAG = FirstFragment.class.getSimpleName(); 
private DisplayAdapter recyclerViewAdapter; 
private RecyclerView recyclView; 
private ArrayList<Products> pProduct = null; 

private List<Products> prods = null; 
ProductDbHelper pDB; 
ProgressDialog mJsonDialog; 


public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 

    View myView = inflater.inflate(R.layout.all_products, container, false); 
    pDB = new ProductDbHelper(getActivity()); 
    mJsonDialog = new ProgressDialog(getActivity()); 
    mJsonDialog.setIndeterminate(true); 


    if (pDB.isDataAvailable() == 0) { 
     mJsonDialog.setMessage("Parsing JSON feed..."); 
     mJsonDialog.show(); 
     getFeed(); 

    } else { 

     new FetchDatabaseTask().execute(); 
    } 


    return myView; 
} 


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

    recyclView = (RecyclerView) view.findViewById(R.id.RecycleList); 


    StaggeredGridLayoutManager layoutManager = new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL); 

    recyclView.setLayoutManager(layoutManager); 

    recyclerViewAdapter = new DisplayAdapter(getActivity(), new ArrayList<Products>()); 
    recyclView.setAdapter(recyclerViewAdapter); 
    recyclerViewAdapter.setClickListener(this); 


} 

@Override 
public void itemClicked(View view, Parcelable product) { 

    Intent intent = new Intent(getActivity(), DetailActivity.class); 
    intent.putExtra("P", product); 
    startActivity(intent); 

} 

public void getFeed() { 

    RestInterface interfaces = Client.getClient().create(RestInterface.class); 

    Call<List<Products>> call = interfaces.getProductsReport(); 
    call.enqueue(new Callback<List<Products>>() { 

     @Override 
     public void onResponse(Call<List<Products>> call, Response<List<Products>> response) { 

      prods = response.body(); 


      for (int i = 0; i < prods.size(); i++) { 
       pDB.addShop(prods.get(i)); 
      } 

      new FetchDatabaseTask().execute(); 

      if (mJsonDialog.isShowing()) 
       mJsonDialog.dismiss(); 

     } 

     @Override 
     public void onFailure(Call<List<Products>> call, Throwable t) { 

      Log.e(LOG_TAG, "FFFF" + t.toString()); 
     } 
    }); 

} 


public class FetchDatabaseTask extends AsyncTask<Void, Void, List<Products>> { 


    protected void onPreExecute() { 
     mJsonDialog.setMessage("Reading from internal storage..."); 
     mJsonDialog.show(); 

    } 

    @Override 
    protected List<Products> doInBackground(Void... voids) { 

     // get all the shop's products 
     List<Products> lProduct = pDB.getAllShops(); 

     // in the second fragment , sort the products' price in ascending order 
     List<Products> lProduct = pDB.sortShopsAscend(); 


     // in the third fragment sort the products descendingly 
      List<Products> lProduct = pDB.sortShopsDescend(); 

     return lProduct; 
    } 


    protected void onPostExecute(List<Products> shops) { 
     super.onPostExecute(shops); 
     if (shops != null) { 
      if (recyclerViewAdapter != null) { 
       recyclerViewAdapter.setData(shops); 
      } else { 
       pProduct = new ArrayList<>(); 
       pProduct.addAll(shops); 
      } 
     } 


     if (mJsonDialog.isShowing()) 
      mJsonDialog.dismiss(); 
    } 
} 


} 

Answer 1

請在MainActivity類的變化：

public class MainActivity extends AppCompatActivity { 

Toolbar toolbar;  
DrawerLayout drawerLayout;  
RecyclerView recyclerView;  
String navTitles[]; 
private NavigationView navigationView; 
TypedArray navIcons;  
RecyclerViewAdapter recyclerViewAdapter;  
ActionBarDrawerToggle drawerToggle;< 

//If you want to use the first fragment only 
FirstFragment fragment = null; 
. 
. 
. 
recyclerViewAdapter.setClickedListener(new RecyclerViewAdapter.ClickListerner() { 

    @Override 

    public void onItemlistener(int index) { 
     //Call this method to close the drawer layout or you can simply call the close method here 
     updateUIWithIndex(index); 

     //Do something depending on the index 
     if(index == 0){ 
      //Call getFeed() for example 
      fragment.getFeed(); 
     } 
     else if(index == 1){ 
      //call another method 
     } 
    } 
}); 
. 
. 
. 

// on click update fragment 
//I don't know if you still need the index in this method 
private void updateUIWithIndex(int index) {  
    //Close the drawer Layout anyway 
    drawerLayout.closeDrawers();  

    if (fragment == null) { 
     FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction(); 
     //Create an instance of the FirstFragment 
     fragment = new FirstFragment(); 
     fragmentTransaction.replace(R.id.containerView, fragment);  
     fragmentTransaction.commit();  
    } 


} 

Answer 2

你可以簡單地傳遞變量Fragment方法。

完全更新後

你的情況：

組片段場在MainActivity

private FirstFragment firstFragment; 

運行此片段在OnCreate方法MainActivity

FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction(); 
firstFragment = null; 
firstFragment = new FirstFragment(); 
fragmentTransaction.replace(R.id.containerView, firstFragment); 
fragmentTransaction.commit(); 

然後更換updateUIWithIndex方法片段的方法，讓你擁有：

recyclerViewAdapter.setClickedListener(new RecyclerViewAdapter.ClickListerner() { 
    @Override 
    public void onItemlistener(int index) { 
     firstFragment.getFeed(index) 
    } 
}); 

證指數getFeed：

public void getFeed(int index) { 

final int currentIndex = index; 

    RestInterface interfaces = Client.getClient().create(RestInterface.class); 

Call<List<Products>> call = interfaces.getProductsReport(); 
call.enqueue(new Callback<List<Products>>() { 

    @Override 
    public void onResponse(Call<List<Products>> call, Response<List<Products>> response) { 
     prods = response.body(); 
     for (int i = 0; i < prods.size(); i++) { 
      pDB.addShop(prods.get(i)); 
     } 
     new FetchDatabaseTask(currentIndex).execute(); 
     if (mJsonDialog.isShowing()) 
      mJsonDialog.dismiss(); 
    } 

    @Override 
    public void onFailure(Call<List<Products>> call, Throwable t) { 
     Log.e(LOG_TAG, "FFFF" + t.toString()); 
    } 
}); 

添加構造函數FetchDatabaseTask類

public class FetchDatabaseTask extends AsyncTask<Void, Void, List<Products>> { 

    private int currentIndex = 0; 

    FetchDatabaseTask(int index) { 
     currentIndex = index; 
    } 

    //ur others methods here 
} 

然後你就可以做你需要在onPreExecute,doInBackground和onPostExecute這樣的方法：

protected void onPostExecute(List<Products> shops) { 
    super.onPostExecute(shops); 

    switch (currentIndex) { 
     case 0: 
      if (shops != null) { 
       if (recyclerViewAdapter != null) { 
        recyclerViewAdapter.setData(shops); 
       } else { 
        pProduct = new ArrayList<>(); 
        pProduct.addAll(shops); 
       } 
      } 
      if (mJsonDialog.isShowing()) 
       mJsonDialog.dismiss(); 
      break; 
     case 1: 
      //ur SecondFragment code 
      break; 
     case 2: 
      //ur ThirdFragment code 
      break; 
    } 
} 

因此，您只能爲每種產品或任何您想要的產品使用一個片段。