在方位变化时将数据以片段形式保存

Question

我试图做的事情：：我试图保存输入到编辑文本中的数据和旋转定向更改

正在发生的事情：我无法保存数据，如何解决这个问题

MainActivity.java

public class MainActivity extends FragmentActivity {

    Fragment_A frgObj;

    @Override
    protected void onCreate(Bundle arg0) {
        super.onCreate(arg0);
        Log.d("MAIN-ACTIVITY", "onCreate");
        setContentView(R.layout.activity_main);
    }

    @Override
    protected void onStart() {
        super.onStart();
        Log.d("MAIN-ACTIVITY", "onStart");
        frgObj=Fragment_A.newInstance();

        getSupportFragmentManager().beginTransaction().replace(R.id.container, frgObj).addToBackStack(null).commit();
    }

    public void onSaveInstanceState(Bundle outState){
           getSupportFragmentManager().putFragment(outState,"myfragment",frgObj);
        }
        public void onRetoreInstanceState(Bundle inState){
            frgObj = (Fragment_A) getSupportFragmentManager().getFragment(inState,"myfragment");
        }
}

Fragment_A.java

public class Fragment_A extends Fragment{

    Button btn;
    Spinner spinner;
    EditText editText;
    SeekBar seekBar;

    public static Fragment_A newInstance() {
        Log.d("FRAGMENT-A", "newInstance");

        Fragment_A fragment = new Fragment_A();
        return fragment;
    }

    @Override
    public void onAttach(Activity activity) {
        Log.d("FRAGMENT-A", "onAttach");
        super.onAttach(activity);
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        Log.d("FRAGMENT-A", "onCreate");
        super.onCreate(savedInstanceState);


    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        Log.d("FRAGMENT-A", "onSaveInstanceState");

        super.onSaveInstanceState(outState);
        //City Spinner state
        outState.putString("editText", editText.getText().toString());
        outState.putInt("yourSpinner", spinner.getSelectedItemPosition());

    }



    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        Log.d("FRAGMENT-A", "onCreateView");
        View view=inflater.inflate(R.layout.fragment_a, container, false);

        btn=(Button) view.findViewById(R.id.buttonId1);
        spinner=(Spinner) view.findViewById(R.id.spinnerId1);
        editText=(EditText) view.findViewById(R.id.editTextId1);
        seekBar=(SeekBar) view.findViewById(R.id.seekBarId1);

        return view;
    }


    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        Log.d("FRAGMENT-A", "onActivityCreated");
        super.onActivityCreated(savedInstanceState);

         if (savedInstanceState != null) {
                //City Spinner state
             editText.setText(savedInstanceState.getString("editText"));
             spinner.setSelection(savedInstanceState.getInt("yourSpinner", 0));

            }       
    }

    @Override
    public void onStart() {
        Log.d("FRAGMENT-A", "onStart");
        super.onStart();

        btn.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                Log.d("FRAGMENT-A", "button Clicked");

                Fragment_B frgObj=Fragment_B.newInstance();

                getActivity().getSupportFragmentManager().beginTransaction().replace(R.id.container, frgObj,"Fragment_B").addToBackStack(null).commit();

            }
        });
    }

}

Answer 1

我认为除了调用super.onSaveInstanceState(Bundle)之外，您不需要在您的活动中改变任何东西。在片段中保存数据onSaveInstanceState就足够了。我会将恢复逻辑放在onCreateView中而不是onActivityCreated中。无论何时重新创建片段，都可以保证调用onCreateView，但是onActivityCreated的情况并非如此。

您可以尝试的另一件事是，不要使用任何一种方法，而是使用setRetainInstance(true)，它应该通过改变方向来保留实例变量。