在每個片段上處理壓縮

Question

我在瀏覽器上瀏覽了很多東西，並且爲我的項目製作了一組最好的事務，但在處理壓抑時遇到了問題。

這是我baseactivity類：

public class BaseAppCompatActivity extends LifecycleActivity { 
    protected IBackPressedListener onBackPressedListener; 

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


    protected FragmentTransaction getFragmentTransaction() { 
     return getSupportFragmentManager().beginTransaction(); 
    } 

    protected void addFragment(int fragmentContainer, Fragment fragment, String fragName, boolean addToBackStack) { 
     FragmentTransaction ft = getFragmentTransaction(); 
     ft.add(fragmentContainer, fragment); 
     if (addToBackStack) 
      ft.addToBackStack(fragName); 
     // Complete the changes added above 
     ft.commitAllowingStateLoss(); 
    } 

    public void setOnBackPressedListener(IBackPressedListener onBackPressedListener) { 
     this.onBackPressedListener = onBackPressedListener; 
    } 

    @Override 
    public void onBackPressed() { 

    } 

    @Override 
    protected void onDestroy() { 
     super.onDestroy(); 
     onBackPressedListener = null; 
    } 
} 

這是我的活動CLAS那裏我加入片段和處理backpressed事件：

public class RechargeFragmentActivity extends BaseAppCompatActivity { 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_recharge_fragment); 

     /*Replace fragment*/ 
     addFragment(R.id.fragmentFrame, new SelectRechargeOperatorFragment(), AppFragments.FRAG_SELECT_RECHARGE_OPERATORS, true); 
    } 

    @Override 
    public void onBackPressed() { 
     if (getSupportFragmentManager().getBackStackEntryCount() > 1 && onBackPressedListener != null) { 
      onBackPressedListener.onBackPressed(); 
     } else 
      finish(); 
    } 

} 

現在我在片段實施Onbackpressed偵聽器，對於一個壓抑的人來說工作得很好，之後它會拾取僅彈出的最後一個片段的實例。

public class SelectRechargeOperatorFragment extends BaseFragment { 
    @Inject 
    public SelectRechargeOperatorLiveDataModel operatorLiveDataModel; 
    @BindView(R.id.rv_select_operator) 
    RecyclerView rvSelectOperators; 
    @BindView(R.id.proceedLayout) 
    RelativeLayout btnProceed; 
    private RechargeOperatorsAdapter adapter; 


    public SelectRechargeOperatorFragment() { 
     //empty constructor required 
    } 

    @Override 
    public void onCreate(@Nullable Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     ((BaseAppCompatActivity) fragmentContext).setOnBackPressedListener(this); 
    } 

    @Override 
    protected void onInject(GraphComponent applicationComponent) { 
     super.onInject(applicationComponent); 
     applicationComponent.inject(this); 
    } 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
          Bundle savedInstanceState) { 
     View convertView = inflater.inflate(R.layout.fragment_select_recharge_operator, container, false); 
     ButterKnife.bind(this, convertView); 

     /*fetch-views*/ 
     setUpOperatorRecyclerView(); 
     proceedToRecharge(); 

     return convertView; 
    } 

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

    @Override 
    public void onResume() { 
     super.onResume(); 
    } 

    private void proceedToRecharge() { 
     btnProceed.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       addFragment(R.id.fragmentFrame, new RechargeAirtimeFargment(), AppFragments.FRAG_RECHARGE_AIRTIME_PLANS, true); 
      } 
     }); 
    } 
@Override 
    public void onBackPressed() { 
     super.onBackPressed(); 
     getActivity().getSupportFragmentManager().popBackStack(); 
    } 


} 

這個效果很好，當我只添加一個片段。當我添加多個片段時，它僅適用於第一次彈出片段之後，它會返回舊片段onBackpressed偵聽器。爲什麼？

Answer 1

問題是，每當您添加一個片段時，您的活動中的onBackPressedListener正在被新對象覆蓋。所以彈出最後一個片段後，邏輯失敗。嘗試以下操作。

1. 從活動
2. 取出setOnBackPressedListener和onBackPressedListener實現您的片段IBackPressedListener。也許你可以使用basefragment來避免代碼重複。根據您的需要選擇。

3. 變化的活動onBackPressed爲，

   @Override 
   public void onBackPressed() { 
        if (getSupportFragmentManager().getBackStackEntryCount() > 1) { 
         Fragment currentFragment = getSupportFragmentManager().findFragmentById(R.id.fragmentFrame); 
         if(null != currentFragment && currentFragment instance of IBackPressedListener) { 
          ((IBackPressedListener)currentFragment).onBackPressed(); 
         } 
        } else 
         finish(); 
       }