【发布时间】：2016-12-01 08:20:29
【问题描述】：
我有三个片段和一个活动。它是这样工作的：
[activity]-> [MainFragment]->[MenuFragment]->[SignUpFragment]
当[SignUpFragment] 被回按时，[MainFragment] 会被创建两次。
我尝试了setRetaInInstance(true) 并检查了savedInstanceState，但我无法阻止[MainFragment] 重新创建。
这是我的 MainActivity：
public class MainActivity extends AppCompatActivity {
public Bundle mSavedInstanceState;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mSavedInstanceState = savedInstanceState;
setContentView(R.layout.activity_main);
}
@Override
protected void onResume() {
super.onResume();
callMainFragment();
}
private void callMainFragment() {
if (mSavedInstanceState == null) {
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(R.id.container_category, new MainFragment(), MainFragment.class.getSimpleName());
transaction.addToBackStack(null);
transaction.commit();
}
}
public ActionBar getMainActionBar(){
ActionBar actionBar = getSupportActionBar();
if (actionBar != null) {
// Action Bar Display settings
actionBar.setDisplayShowCustomEnabled(true);
actionBar.setDisplayShowTitleEnabled(false);
// Custom view inflater
LayoutInflater inflater = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
// Custom layout view
View viewActionBar = inflater.inflate(R.layout.action_bar, null);
// Set custom view
actionBar.setCustomView(viewActionBar);
actionBar.setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM);
}
return actionBar;
}
这是我的 MainFragment：
public class MainFragment extends BaseFragment implements AdapterView.OnItemClickListener, BuyersGuideCategoriesDelegate, View.OnClickListener {
private Bundle mSavedInstanceState;
private BuyersGuideCategoriesFragment mCategoriesFragment;
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setRetainInstance(true);
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
mSavedInstanceState = savedInstanceState;
if (mSavedInstanceState == null) {
mView = inflater.inflate(R.layout.fragment_main, container, false);
// Call Grid View Buyers Guide Fragment
mCategoriesFragment = new BuyersGuideCategoriesFragment();
mCategoriesFragment.mGridViewDelegate = this;
setIcons();
setTitles();
setTexts();
initListView();
}
return mView;
}
@Override
public void onResume() {
super.onResume();
ImageView menu = (ImageView) ((MainActivity) getActivity()).getMainActionBar().getCustomView().findViewById(R.id.action_bar_menu_icon);
menu.setOnClickListener(this);
}
@Override
public void onClick(View v) {
if (mSavedInstanceState == null) {
MainActivity activity = (MainActivity) getActivity();
FragmentManager manager = activity.getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(R.id.container_category, new MenuFragment(),MenuFragment.class.getSimpleName());
transaction.addToBackStack(null);
transaction.commit();
}
}
}
这是我的 MenuFragment：
public class MenuFragment extends BaseFragment implements AdapterView.OnItemClickListener, View.OnClickListener {
private Bundle mSavedInstanceState;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
mSavedInstanceState = savedInstanceState;
if (savedInstanceState == null) {
mView = inflater.inflate(R.layout.fragment_menu, container, false);
setMenuItemsListViewAdapter();
}
return mView;
}
private void setMenuItemsListViewAdapter() {
ListView menuItems = (ListView) mView.findViewById(R.id.list_menu_items);
ListMenuItemsListViewAdapter adapter = new ListMenuItemsListViewAdapter(getContext(),getMenuItemNames());
menuItems.setAdapter(adapter);
menuItems.setOnItemClickListener(this);
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
switch ((String) parent.getAdapter().getItem(position)){
case SIGN_UP:
replaceFragment(R.id.container_category,new SignUpFragment(),SignUpFragment.class.getSimpleName());
break;
}
}
private void replaceFragment(int containerId,Fragment fragment, String fragmentTag){
if (mSavedInstanceState == null){
MainActivity activity = (MainActivity) getActivity();
FragmentManager manager = activity.getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(containerId,fragment,fragmentTag);
transaction.addToBackStack(null);
transaction.commit();
}
}
@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.menu_back_icon:
replaceFragment(R.id.container_category, new MainFragment(),MainFragment.class.getSimpleName());
break;
}
}
}
这是我的 SignUpFragment：
public class SignUpFragment extends BaseFragment implements View.OnClickListener{
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
if (savedInstanceState == null) {
mView = inflater.inflate(R.layout.fragment_sign_up, container, false);
}
return mView;
}
}
编辑 1：仅当我从 SignUpFragment 返回到 MenuFragment 时，才重新创建 MainFragment。使用这么多片段我做错了吗？我应该使用活动吗？
【问题讨论】：
-
请给我们一些代码。没有任何实际信息就无法为您提供帮助！
-
您是否有一个活动托管三个不同的片段？
-
是的，我正在使用单个活动。
标签： android fragment onbackpressed