在屏幕旋转后恢复 Fragment 中的微调器位置

Question

正如我在标题中所写的那样，我想在屏幕旋转后恢复微调器中的选定位置。尝试通过在 bundle 中保存位置来做到这一点，并在旋转后从 savedInstanceState 获取位置

onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { }

或

onViewCreated(View view, Bundle savedInstanceState)

或

onActivityCreated(Bundle savedInstanceState)

但没有人工作:-/

添加食谱片段

public class AddRecipeFragment extends Fragment implements ObservableScrollViewCallbacks {


    private static final String SELECTED_CATEGORY = "SELECTED_CATEGORY";
    private Spinner categoriesSpinner;


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_add_recipe, container, false);
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        categoriesSpinner = (Spinner) view.findViewById(R.id.categories_spinner);
        ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(getActivity(), R.array.categories, android.R.layout.simple_spinner_item);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        categoriesSpinner.setAdapter(adapter);

        if (savedInstanceState != null) {
            categoriesSpinner.setSelection(savedInstanceState.getInt(SELECTED_CATEGORY, 0), true);
        }
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putInt(SELECTED_CATEGORY, categoriesSpinner.getSelectedItemPosition());
    }
}

我也尝试过 setSelection(position, false) false。

Answer 1

如果都失败了，为什么不使用静态变量？！

private static int selectedPosition = 0;

并且当微调器项目被选中时

categoriesSpinner.setOnItemSelectedListener(new OnItemSelectedListener() {
    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
        selectedPosition = position;
    }

    @Override
    public void onNothingSelected(AdapterView<?> parent) {
    }
});

和内部 onViewCreated() 方法

categoriesSpinner.setSelection(selectedPosition);

在屏幕旋转后恢复 Fragment 中的微调器位置

Restore spinner position in Fragment, after screen rotation

java

android

android-fragments

spinner

screen-rotation

添加食谱片段