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);
}

使用片段传递数据的完整代码

Fragment fragment = new Fragment(); // replace your custom fragment class 
Bundle bundle = new Bundle();
FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
                bundle.putString("key","value"); // use as per your need
                fragment.setArguments(bundle);
                fragmentTransaction.addToBackStack(null);
                fragmentTransaction.replace(viewID,fragment);
                fragmentTransaction.commit();

在自定义片段类中

Bundle mBundle = new Bundle();
mBundle = getArguments();
mBundle.getString(key);  // key must be same which was given in first fragment

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");
}

为了进一步扩展前面的答案，就像Ankit说的，对于复杂的对象，你需要实现Serializable。例如，对于简单对象:

public class MyClass implements Serializable {
    private static final long serialVersionUID = -2163051469151804394L;
    private int id;
    private String created;
}

在你的FromFragment中:

Bundle args = new Bundle();
args.putSerializable(TAG_MY_CLASS, myClass);
Fragment toFragment = new ToFragment();
toFragment.setArguments(args);
getFragmentManager()
    .beginTransaction()
    .replace(R.id.body, toFragment, TAG_TO_FRAGMENT)
    .addToBackStack(TAG_TO_FRAGMENT).commit();

在你的ToFragment:

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

    Bundle args = getArguments();
    MyClass myClass = (MyClass) args
        .getSerializable(TAG_MY_CLASS);

使用Bundle。这里有一个例子:

Fragment fragment = new Fragment();
Bundle bundle = new Bundle();
bundle.putInt(key, value);
fragment.setArguments(bundle);

Bundle为许多数据类型提供了方法。看到这个

然后在你的片段，检索数据(例如在onCreate()方法):

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