在两个片段之间传递字符串时获取NullPointerException[重复]

Question

我有两个动态片段与一个活动相关联，我试图使用Bundle将一个文本从第一个片段传递到第二个片段，但我得到了空指针异常。在两个片段之间传递字符串是正确的方法吗？下面是我的代码：

public class FirstFragment extends Fragment {

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



        View view = inflater.inflate(R.layout.content_main, container, false);

        String text = "GetThisStringInSecondFragment";

        TextView txtView = null;
        txtView = (TextView) view.findViewById(R.id.firstfragmenttext);
        txtView.setText(text);

        Bundle bundle = new Bundle();
        bundle.putString("HI", text);

        return view;
    }


}

public class SecondFragment extends Fragment {

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

        TextView txtView = null;
        txtView = (TextView) view.findViewById(R.id.secondfragmenttext);


        Bundle bundle = this.getArguments();
        String myInt = bundle.getString("HI");

        txtView.setText(myInt);

        return view;
    }


}

public class MainActivity extends AppCompatActivity {


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button btnLoad = (Button) findViewById(R.id.btn_load);

        View.OnClickListener listener = new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                FragmentManager fragmentManager = getFragmentManager();
                FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
                FirstFragment hello = new FirstFragment();
                fragmentTransaction.add(R.id.fragment_container, hello, "HELLO");
                fragmentTransaction.commit();

                FragmentManager fragmentManager2 = getFragmentManager();
                FragmentTransaction fragmentTransaction2 = fragmentManager2.beginTransaction();
                SecondFragment hello2 = new SecondFragment();
                fragmentTransaction2.add(R.id.fragment_container, hello2, "HELLO");
                fragmentTransaction2.commit();
            }
        };

        btnLoad.setOnClickListener(listener);

    }


}

Answer 1

您在第二个片段中执行getArguments，但是您将第一个片段中的这些参数发送到哪里。您可以在这里使用Interface并在Activity中定义它。在activity中，可以对第二个片段使用setArgument（）方法。

请查看以下链接以获得更详细的信息和步骤。https://developer.android.com/training/basics/fragments/communicating.html