Question

我是Android的新手，当我使用片段跟随谷歌上的一些教程时，我遇到了一些问题。第一个问题：我尝试简单的发送数据有类型是字符串形式片段到其他片段，但它不起作用。这是我的SearchFargment：

public class SearchFragment extends Fragment {
private EditText et_departure;
private EditText et_arrival;
private EditText et_date;
// private Button btn_searching;
private DatePickerDialog fromDatePickerDialog;
private SimpleDateFormat dateFormatter;
private SearchTicketPresenter searchTicketPresenter;

public  SearchFragment(){

}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);

    et_departure = (EditText)getView().findViewById(R.id.et_departure);
    et_arrival = (EditText)getView().findViewById(R.id.et_arrival);
    et_date = (EditText)getView().findViewById(R.id.et_date);
    dateFormatter = new SimpleDateFormat("yyyy-MM-dd", Locale.US);

    searchTicketPresenter = new SearchTicketPresenter(this);
    //setDateTimeField();
    Button btn_searching = (Button)getView().findViewById(R.id.btn_searching);
    btn_searching.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            DataBundle("TEST Bundel");
           //JSonAsyncTask jSonAsyncTask = new JSonAsyncTask();
           // jSonAsyncTask.execute();
        }
    });
}

public  void DataBundle(String test){
    Bundle packageDataStation = new Bundle();
   // packageDataStation.putSerializable("arrTicket", result);
    packageDataStation.putString("s",test);
    Fragment rFrag = new ResultFragment();
    rFrag.setArguments(packageDataStation);
    //noinspection ResourceType
    FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
    fragmentTransaction.replace(R.id.container_body, rFrag);
    fragmentTransaction.commit();

    // set the toolbar title
    Toolbar toolbar = (Toolbar) getActivity().findViewById(R.id.toolbar);//get Toolbar from SearchingTicketActivity
    ((SearchingTicketActivity)getActivity()).setSupportActionBar(toolbar);
    ((SearchingTicketActivity)getActivity()).getSupportActionBar().setTitle(R.string.title_result);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.fragment_search, container, false);


    // Inflate the layout for this fragment
    return rootView;
}

@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);
}

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

这是ResultFargment：

public class ResultFragment extends Fragment {
    private ArrayList<TicketInforModel> arrayListResultTickets;
    private ArrayAdapter<TicketInforModel>arrayAdapterTicket;
    private ListView lv_resultTicket;
    public ResultFragment() {
        // Required empty public constructor
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        try{
            lv_resultTicket = (ListView)getView().findViewById(R.id.lv_ticket);
            TextView tv = (TextView)getView().findViewById(R.id.tv_test);
            tv.setText(getArguments().getString("s").toString());

            //arrayListResultTickets = (ArrayList<TicketInforModel>) b.getSerializable("arrTicket");
            //arrayAdapterTicket = new viewListTicket();
            //lv_resultTicket.setAdapter(arrayAdapterTicket);
        }catch (Exception ex){
            ex.getMessage();
        }

    }


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


        // Inflate the layout for this fragment
        return rootView;
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
    }

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

单击SearchFragment上的“搜索”按钮后，将显示ResultFragment，但Textview的值不会更改。我的代码出了什么问题？。

第二个问题：在ResultFragment中，如果我没有将此代码放在try catch块中，则Logcat将显示Nullpointer Exception。

lv_resultTicket = (ListView)getView().findViewById(R.id.lv_ticket);
        TextView tv = (TextView)getView().findViewById(R.id.tv_test);
        tv.setText(getArguments().getString("s").toString());

这是Logcat：

11-16 00:15:32.982 7314-7314/com.example.vuong.final_project_pott E/AndroidRuntime: FATAL EXCEPTION: main
                                                                                    java.lang.NullPointerException: println needs a message
                                                                                        at android.util.Log.println_native(Native Method)
                                                                                        at android.util.Log.d(Log.java:138)
                                                                                        at com.example.vuong.final_project_pott.view.ResultFragment.onCreate(ResultFragment.java:45)
                                                                                        at android.support.v4.app.Fragment.performCreate(Fragment.java:1766)
                                                                                        at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:917)
                                                                                        at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1138)
                                                                                        at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:740)
                                                                                        at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1501)
                                                                                        at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:458)
                                                                                        at android.os.Handler.handleCallback(Handler.java:730)
                                                                                        at android.os.Handler.dispatchMessage(Handler.java:92)
                                                                                        at android.os.Looper.loop(Looper.java:150)
                                                                                        at android.app.ActivityThread.main(ActivityThread.java:5390)
                                                                                        at java.lang.reflect.Method.invokeNative(Native Method)
                                                                                        at java.lang.reflect.Method.invoke(Method.java:525)
                                                                                        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
                                                                                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
                                                                                        at dalvik.system.NativeStart.main(Native Method)

如果我阻止try catch块上的代码，它可以工作，但可以从SearchFragment获取数据。我尝试在Google和Starkoverflow上搜索并遵循一些解决方案，但可以解决。请帮我。 p / s：感谢您阅读我的问题，很抱歉，如果我的问题很愚蠢。

Answer 1

我的问题已经解决了。我覆盖错误的方法。我应该覆盖方法onActivityCreated而不是onCreate方法。

[Android]将数据从片段捆绑到另一个片段时错误

1 个答案: