【发布时间】：2018-06-05 02:19:50
【问题描述】：
我到处寻找解决方案，但没有找到，我需要一些帮助。
我有一个应用程序，它有两个活动，活动 A 和活动 B，但 B 有片段，来自 B 的第一个片段有一个重要数据，当用户返回活动时我不想丢失这些数据A.
我的问题是每次我回到活动 A 并转到 B 时，我的数据都会变空，因为 android 清除了它，所以我对代码进行了一些搜索和更改，但仍然没有找到解决方案。现在我的代码：
活动 A
fbReceive.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
startActivity(new Intent(MainActivity.this, OmniActivity.class));
}
});
我从这一行调用 B，当他们转到 B 时，这是代码：
活动 B
public class OmniActivity extends BaseActivity {
private View parent_view;
private TabLayout tab_layout;
FragmentOmni fragmentOmni = new FragmentOmni();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_omni_om);
parent_view = findViewById(R.id.container);
Tools.setSystemBarColor(this, R.color.new_purple_O200);
openFragment(fragmentOmni);
initToolbar();
initComponent();
}
public void openFragment(final Fragment fragment) {
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.containerView, fragment, fragment.getTag());
transaction.addToBackStack(null);
transaction.commit();
}
@Override
public void onBackPressed() {
Intent intent = new Intent(this, MainActivity.class);
startActivityForResult(intent, 1);
}
private void initToolbar() {
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
toolbar.setNavigationIcon(R.drawable.ic_arrow_back_black_24dp);
setSupportActionBar(toolbar);
getSupportActionBar().setTitle("Voltar");
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
toolbar.getNavigationIcon().setColorFilter(getResources().getColor(android.R.color.white), PorterDuff.Mode.SRC_ATOP);
toolbar.setNavigationOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View view) {
Intent intent = new Intent(OmniActivity.this, MainActivity.class);
startActivityForResult(intent, 1);
}
});
}
当应用程序执行 OpenFragment() 时，它们会从 Fragment 转到这段代码：
片段 A
public class FragmentOmni extends Fragment {
RecyclerView recyclerView;
MDOmniturn controller;
List<HashMap<String, String>> listproduct;
private ArrayList<Product> producttypelist;
Product tpobjproduct;
private ActionMode actionMode;
private ActionModeCallback actionModeCallback;
private ListProductAdapter lpAdapter;
private NestedScrollView nested_scroll_view;
private ImageButton bt_toggle_input;
private Button bt_hide_input;
private View lyt_expand_input;
EditText edOmni, edMani,edEan ;
LinearLayout layoutNoResult;
Handler time;
TextWatcher textexample;
private ProgressBar progressBarProduct;
LinearLayout linearLayout;
public FragmentOmni() {
}
public static FragmentOmni newInstance() {
FragmentOmni fragment = new FragmentOmni();
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
if(savedInstanceState != null){
producttypelist = savedInstanceState.getParcelableArrayList("list");
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View root = inflater.inflate(R.layout.fragment_omni, container, false);
return root;
}
@Override
public void onSaveInstanceState(Bundle outState) {
outState.putParcelableArrayList("list", producttypelist);
super.onSaveInstanceState(outState);
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
if (savedInstanceState != null) {
producttypelist = savedInstanceState.getParcelableArrayList("list");
}
initexpand(view);
linearLayout = (LinearLayout) view.findViewById(R.id.container);
edOmni = (EditText) view.findViewById(R.id.edOmni);
edMani = (EditText) view.findViewById(R.id.edBManifesto);
edEan = (EditText) view.findViewById(R.id.edEan);
progressBarProduct = (ProgressBar) view.findViewById(R.id.progressBarProduct);
layoutNoResult = (LinearLayout) view.findViewById(R.id.layoutNoResult);
recyclerView = (RecyclerView) view.findViewById(R.id.recyclerView);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
recyclerView.addItemDecoration(new LineItemDecoration(getActivity(), LinearLayout.VERTICAL));
recyclerView.setHasFixedSize(true);
controller = new MDOmniturn(getActivity());
producttypelist = new ArrayList<>();
listproduct = new ArrayList<>();
addListenerTextChange(edOmni);
//set data and list adapter
lpAdapter = new ListProductAdapter(getActivity(), producttypelist);
recyclerView.setAdapter(lpAdapter);
lpAdapter.setOnClickListener(new ListProductAdapter.OnClickListener() {
@Override
public void onItemClick(View view, Product obj, int pos) {
if (lpAdapter.getSelectedItemCount() > 0) {
enableActionMode(pos);
} else {
// read the inbox which removes bold from the row
Product product = lpAdapter.getItem(pos);
Toast.makeText(getActivity(), "Read: " + product.prd_description, Toast.LENGTH_SHORT).show();
}
}
@Override
public void onItemLongClick(View view, Product obj, int pos) {
enableActionMode(pos);
}
});
actionModeCallback = new ActionModeCallback();
}
FRAGMENT A 中的 savedInstanceState 总是为 NULL，我做错了什么？
【问题讨论】：
标签： android android-fragments android-activity