getArguments()返回null因为“它没有得到任何东西”

试试这段代码来处理这种情况

if(getArguments()!=null)
{
int myInt = getArguments().getInt(key, defaultValue);
}

输入片段

public class SecondFragment extends Fragment  {


    EditText etext;
    Button btn;
    String etex;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.secondfragment, container, false);
        etext = (EditText) v.findViewById(R.id.editText4);
        btn = (Button) v.findViewById(R.id.button);
        btn.setOnClickListener(mClickListener);
        return v;
    }

    View.OnClickListener mClickListener = new View.OnClickListener() {
        @Override
        public void onClick(View v) {


            etex = etext.getText().toString();
            FragmentTransaction transection = getFragmentManager().beginTransaction();
            Viewfragment mfragment = new Viewfragment();
            //using Bundle to send data
            Bundle bundle = new Bundle();
            bundle.putString("textbox", etex);
            mfragment.setArguments(bundle); //data being send to SecondFragment
            transection.replace(R.id.frame, mfragment);
            transection.isAddToBackStackAllowed();
            transection.addToBackStack(null);
            transection.commit();

        }
    };



}

你的视图片段

public class Viewfragment extends Fragment {

    TextView txtv;
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.viewfrag,container,false);
        txtv = (TextView)  v.findViewById(R.id.textView4);
        Bundle bundle=getArguments();
        txtv.setText(String.valueOf(bundle.getString("textbox")));
        return v;
    }


}

只是扩展一下前面的答案——它可以帮助到一些人。如果你的getArguments()返回null，把它放在onCreate()方法，而不是你的片段的构造函数:

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    int index = getArguments().getInt("index");
}

getArguments()返回null因为“它没有得到任何东西”

试试这段代码来处理这种情况

if(getArguments()!=null)
{
int myInt = getArguments().getInt(key, defaultValue);
}

如果你使用图表在片段之间导航，你可以这样做:

    Bundle bundle = new Bundle();
    bundle.putSerializable(KEY, yourObject);
    Navigation.findNavController(view).navigate(R.id.fragment, bundle);

片段B:

    Bundle bundle = getArguments();
    object = (Object) bundle.getSerializable(KEY);

当然你的对象必须实现Serializable

这是你使用bundle的方式:

Bundle b = new Bundle();
b.putInt("id", id);
Fragment frag= new Fragment();
frag.setArguments(b);

从bundle中检索值:

 bundle = getArguments();
 if (bundle != null) {
    id = bundle.getInt("id");
 }