得到錯誤，同時使用片段

Question

public class MistakeGridFragment extends Fragment { 

private Set<String> mistakeSelected = new HashSet<>(); 
private ListView listView; 
private ITransfer iTransfer; 

public MistakeGridFragment() { 
} 

@Override 
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { 
    View view = inflater.inflate(R.layout.mistake_dialog, container, false); 
    MistakeListHelper mistakeListHelper = new MistakeListHelper(getActivity()); 
    mistakeLists.addAll(mistakeListHelper.getAllMistakegrid()); 
    init(view); 
    return view; 
} 

@TargetApi(23) 
@Override 
public void onAttach(Context context) { 
    super.onAttach(context); 
    try { 
     // This makes sure that the container activity has implemented 
     // the callback interface. If not, it throws an exception 
     iTransfer = (ITransfer) context; 
    } catch (ClassCastException e) { 
     e.printStackTrace(); 
    } 
} 

@Override 
public void onAttach(Activity context) { 
    super.onAttach(context); 
    try { 
     // This makes sure that the container activity has implemented 
     // the callback interface. If not, it throws an exception 
     iTransfer = (ITransfer) context; 
    } catch (ClassCastException e) { 
     e.printStackTrace(); 
    } 
} 

private void init(View view) { 
    relativeLayout = (LinearLayout) view.findViewById(R.id.mistakegrid_mainly); 
    GsonBuilder gsonBuilder = new GsonBuilder(); 
    Gson gson = gsonBuilder.create(); 

    // adding number of column 
    for (int i = 0; i < mistakeLists.size(); i++) { 
     String listvalue = mistakeLists.get(i).getListTypeValue(); 
     String name = mistakeLists.get(i).getListTypeName(); 
     Type type = new TypeToken<ArrayList<HashMap<Double, String>>>() { 
     }.getType(); 
     ArrayList<HashMap<Double, String>> myMap = gson.fromJson(listvalue, type); 
     for (int j = 0; j < myMap.size(); j++) { 
      HashMap<Double, String> hash = myMap.get(j); 
      view = setTypeOfMistake(name, hash, j); 
     } 
     relativeLayout.addView(view); 
    } 
} 

private View setTypeOfMistake(final String mistakeName, HashMap<Double, String> hashValue, int i) { 
    optionsArraylist = new ArrayList<>(); 
    //main mistake grid layout here added column 
    LayoutInflater layoutInflatermain = LayoutInflater.from(getActivity()); 
    View main = layoutInflatermain.inflate(R.layout.mistake_column_layout, null); 
    LinearLayout linearLayout = (LinearLayout) main.findViewById(R.id.linaerlayout); 

    //here added row layout for each column 
    LayoutInflater layoutInflater = LayoutInflater.from(getActivity()); 
    View view = layoutInflater.inflate(R.layout.mistake_row_layout, null); 
    TextView mistakeType = (TextView) view.findViewById(R.id.header_tv); 
    listView = (ListView) view.findViewById(R.id.listview); 
    Set set = (Set) hashValue.entrySet(); 
    Iterator it = set.iterator(); 
    optionsArraylist.clear(); 

    while (it.hasNext()) { 
     HashMap<Double, String> hashMap = new HashMap<>(); 
     Map.Entry entry = (Map.Entry) it.next(); 
     optionsArraylist.add((String) entry.getValue()); 
     hashMap.put((Double) entry.getKey(), (String) entry.getValue()); 
     mistakeHashArryList.add(hashMap); 

    } 

    mistakeType.setText(mistakeName + ""); 
    ArrayAdapter<String> adaptor = new ArrayAdapter<>(getActivity(), android.R.layout.simple_list_item_1, optionsArraylist); 
    listView.setAdapter(adaptor); 
    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() { 

     @Override 
     public void onItemClick(AdapterView<?> parent, View view, int position, long id) { 

      toggleSelection(optionsArraylist.get(position).toString(), view); 
      //Toast.makeText(QuestionActivity.this,parent.getItemAtPosition(position).toString(),Toast.LENGTH_SHORT).show(); 
      if (mistakeSelected.contains(parent.getItemAtPosition(position).toString())) { 
       mistakeSelected.remove(parent.getItemAtPosition(position).toString()); 
       view.setBackgroundColor(ContextCompat.getColor(getActivity(), R.color.md_blue_grey_400)); 
      } else { 
       mistakeSelected.add(parent.getItemAtPosition(position).toString()); 
       view.setBackgroundColor(ContextCompat.getColor(getActivity(), R.color.md_blue_grey_500)); 
      } 
     } 
    }); 

    linearLayout.addView(view); 
    return linearLayout; 
} 

public boolean getMistake() { 

    if (mistakeSelected.size() > 0) { 

     iTransfer.getData(mistakeSelected); 
     return true; 
    } else { 
     new MyUtils(getActivity()).setMessageShort("Please selected any one mistake"); 
    } 
    return false; 
} 

public interface ITransfer { 
    public void getData(Set<String> strings); 
} 

public class MistakeReasonFragment extends Fragment implements MistakeGridFragment.ITransfer { 
    private ArrayList<String> arrayList = new ArrayList<>(); 
    private TableLayout tableLayout; 
    private LayoutInflater layoutInflater; 
    private LinearLayout addMistake_row; 
    public MistakeReasonFragment() { 
    } 





    @Override 
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { 
     View view = inflater.inflate(R.layout.mistake_reason_layout, container, false); 
     init(view); 
     return view; 
    } 

    private void init(View view) { 
     tableLayout = (TableLayout) view.findViewById(R.id.tablelayout); 
     addMistake_row = (LinearLayout) view.findViewById(R.id.linaerl_row); 
    } 

    @Override 
    public void onPause() { 
     EventBus.getDefault().unregister(this); 
     super.onPause(); 
    } 


    @Override 
    public void getData(Set<String> strings) { 
     Log.v("value size ", strings.size() + " "); 
    } 

} 

logcat中在機器人從一個片段將數據傳輸到另一個片段：

java.lang.ClassCastException：com.android.root.ui.activity.QueActivity不能cast to com.tapasya.root.tapasya.ui.fragment.MistakeGridFragment $ ITransfer
10-27 11：44：54.811 30409-30409/com.tapasya.root.tapasya W/System.err：
at com.android .root.ui.fragment.MistakeGridFragment.onAttach（MistakeGridFragment.java:70）
10-27 11：44：54.811 30409-30409/com.android.root W/System.err的：
在android.support.v4.app.FragmentManagerImpl.moveToState（FragmentManager.java:1043）
10-27 11：44：54.811 30409-30409/com.android.root W/System.err：
at android.support.v4.app.BackStackRecord.setLastIn（BackStackRecord.java:838）
10-27 11:44： 54.811 30409-30409/com.android.root W/System.err的：
在android.support.v4.app.BackStackRecord.calculateFragments（BackStackRecord.java:861）

Answer 1

由於在onAttach上下文實例（）是我請確保容器活動已實施ITransfer回調，否則不能將onAttach（）中的上下文對象實例轉換爲ITransfer引用變量。