FragmentTabHost 在 popBackStack 之后得到空片段
FragmentTabHost getting empty fragments after popBackStack
我已经尝试了 Whosebug 中的每一个 post 但都没有成功,我有一个 FragmentTabHost activity 带有标签 A B C D E
当我转到选项卡 A 然后转到选项卡 B 时一切正常,但是如果我 return 到选项卡 A 是空白,那么 return 到选项卡 B 也是空白!!
A -> B -> A = 空白 -> B = 空白
我按照此 post 使其正常工作 Dynamically changing the fragments inside a fragment tab host?,但选项卡之间的转换不起作用。
我尝试更改我的 BaseContainerFragment 以使用 getSupportFragmentManager 而不是 getChildFragmentManager 但没有成功,此时我还删除了 addToBackStack(null) 我没有想法,我们将不胜感激,谢谢。
这是包含使用片段创建选项卡的代码的 mainActivity。
public class ActivityMain extends FragmentActivity {
public static final String TAB_1_TAG = "tab_1";
public static final String TAB_2_TAG = "tab_2";
public static final String TAB_3_TAG = "tab_3";
public static final String TAB_4_TAG = "tab_4";
public static final String TAB_5_TAG = "tab_5";
private FragmentTabHost mTabHost;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
}
private void initView() {
mTabHost = (FragmentTabHost)findViewById(android.R.id.tabhost);
mTabHost.setup(this, getSupportFragmentManager(), R.id.realtabcontent);
mTabHost.getTabWidget().setDividerDrawable(null);
mTabHost.getTabWidget().setStripEnabled(false);
mTabHost.addTab(mTabHost.newTabSpec(TAB_1_TAG).setIndicator("", getResources().getDrawable(R.drawable.tab_account)), FragmentAccountContainer.class, null);
mTabHost.addTab(mTabHost.newTabSpec(TAB_2_TAG).setIndicator("", getResources().getDrawable(R.drawable.tab_discounts)), FragmentPromotionsContainer.class, null);
mTabHost.addTab(mTabHost.newTabSpec(TAB_3_TAG).setIndicator("", getResources().getDrawable(R.drawable.tab_payment)), FragmentAccountContainer.class, null);
mTabHost.addTab(mTabHost.newTabSpec(TAB_4_TAG).setIndicator("", getResources().getDrawable(R.drawable.tab_gas)), FragmentAccountContainer.class, null);
mTabHost.addTab(mTabHost.newTabSpec(TAB_5_TAG).setIndicator("", getResources().getDrawable(R.drawable.tab_rest)), FragmentAccountContainer.class, null);
}
@Override
public void onBackPressed() {
boolean isPopFragment = false;
String currentTabTag = mTabHost.getCurrentTabTag();
Log.e("ActivityMain", "currentTabTag: " + currentTabTag);
if (currentTabTag.equals(TAB_1_TAG)) {
isPopFragment = ((BaseContainerFragment) getSupportFragmentManager().findFragmentByTag(TAB_1_TAG)).popFragment();
} else if (currentTabTag.equals(TAB_2_TAG)) {
isPopFragment = ((BaseContainerFragment) getSupportFragmentManager().findFragmentByTag(TAB_2_TAG)).popFragment();
} else if (currentTabTag.equals(TAB_3_TAG)) {
isPopFragment = ((BaseContainerFragment) getSupportFragmentManager().findFragmentByTag(TAB_3_TAG)).popFragment();
} else if (currentTabTag.equals(TAB_4_TAG)) {
isPopFragment = ((BaseContainerFragment) getSupportFragmentManager().findFragmentByTag(TAB_4_TAG)).popFragment();
} else if (currentTabTag.equals(TAB_5_TAG)) {
isPopFragment = ((BaseContainerFragment) getSupportFragmentManager().findFragmentByTag(TAB_5_TAG)).popFragment();
}
Log.e("ActivityMain", "isPopFragment: " + isPopFragment);
if (!isPopFragment) {
finish();
}
}
}
这是我的允许回溯和替换片段的 BaseContainerFragment
public class BaseContainerFragment extends Fragment {
public void replaceFragment(Fragment fragment, boolean addToBackStack) {
FragmentTransaction transaction = getChildFragmentManager().beginTransaction();
if (addToBackStack) {
transaction.addToBackStack(null);
}
transaction.replace(R.id.container_framelayout, fragment);
transaction.commit();
getChildFragmentManager().executePendingTransactions();
}
public boolean popFragment() {
Log.e("test", "pop fragment: " + getChildFragmentManager().getBackStackEntryCount());
boolean isPop = false;
if (getChildFragmentManager().getBackStackEntryCount() > 0) {
isPop = true;
getChildFragmentManager().popBackStack();
}
return isPop;
}
}
这是第一个选项卡的容器(这个选项卡包含 2 个活动,一个是主要的,另一个是在列表视图上调用的)
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
myPrefs = this.getActivity().getSharedPreferences("getLogin", Context.MODE_PRIVATE);
idUser = myPrefs.getInt("idUser", 0);
d(TAG, "idUser: " + idUser);
/*
Map<String,?> keys = myPrefs.getAll();
for(Map.Entry<String,?> entry : keys.entrySet()){
Log.d("map values",entry.getKey() + ": " +
entry.getValue().toString());
}
*/
context = getActivity();
pDialog = new SweetAlertDialog(context, PROGRESS_TYPE);
// Check if Internet present
if (!isOnline(context)) {
// Internet Connection is not present
makeText(context, "Error en la conexion de Internet",
LENGTH_LONG).show();
// stop executing code by return
return;
}
new asyncGetFeedClass(context).execute();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.activity_cardholder, container, false);
toolbar = (Toolbar) v.findViewById(R.id.toolbar);
TextView mTitle = (TextView) toolbar.findViewById(toolbar_title);
mTitle.setText("TARJETAS");
list = (ListView) v.findViewById(R.id.list);
// Click event for single list row
list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
FragmentAccount fragment = new FragmentAccount();
// if U need to pass some data
Bundle bundle = new Bundle();
if (listBalance.get(position).get(TAG_ACCOUNT_BANKACCOUNTS_ID) != null) {
bundle.putString("idBankAccount", listBalance.get(position).get(TAG_ACCOUNT_BANKACCOUNTS_ID));
bundle.putString("idGiftCard", "0");
} else if (listBalance.get(position).get(TAG_ACCOUNT_GIFTCARDS_ID) != null) {
bundle.putString("idGiftCard", listBalance.get(position).get(TAG_ACCOUNT_GIFTCARDS_ID));
bundle.putString("idBankAccount", "0");
} else {
bundle.putString("idBankAccount", "0");
bundle.putString("idGiftCard", "0");
}
fragment.setArguments(bundle);
((BaseContainerFragment) getParentFragment()).replaceFragment(fragment, false);
}
});
return v;
}
选项卡 #1
的主要 class
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
myPrefs = this.getActivity().getSharedPreferences("getLogin", Context.MODE_PRIVATE);
idUser = myPrefs.getInt("idUser", 0);
d(TAG, "idUser: " + idUser);
/*
Map<String,?> keys = myPrefs.getAll();
for(Map.Entry<String,?> entry : keys.entrySet()){
Log.d("map values",entry.getKey() + ": " +
entry.getValue().toString());
}
*/
context = getActivity();
pDialog = new SweetAlertDialog(context, PROGRESS_TYPE);
// Check if Internet present
if (!isOnline(context)) {
// Internet Connection is not present
makeText(context, "Error en la conexion de Internet",
LENGTH_LONG).show();
// stop executing code by return
return;
}
Bundle bundle = this.getArguments();
idBankAccount = Integer.parseInt(bundle.getString(FragmentCardHolder.TAG_ACCOUNT_BANKACCOUNTS_ID, "0"));
idGiftCard = Integer.parseInt(bundle.getString(FragmentCardHolder.TAG_ACCOUNT_GIFTCARDS_ID, "0"));
if(idBankAccount > 0){
new asyncGetBankTransactions(context).execute();
} else if(idGiftCard > 0) {
new asyncGetGiftCardTransactions(context).execute();
} else {
new asyncGetX111Transactions(context).execute();
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.activity_account, container, false);
toolbar = (Toolbar) v.findViewById(id.toolbar);
TextView mTitle = (TextView) toolbar.findViewById(toolbar_title);
mTitle.setText("MI CUENTA");
toolbar.setNavigationIcon(R.drawable.icon_user);
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
goToCards();
}
});
layoutAccount = (LinearLayout) v.findViewById(id.layoutAccount);
layoutGetCredit = (LinearLayout) v.findViewById(id.layoutGetCredit);
layoutTransactions = (LinearLayout) v.findViewById(id.layoutTransactions);
btnAccount = (Button) v.findViewById(id.btnMyBalance);
btnGetCredit = (Button) v.findViewById(id.btnGetCredit);
btnSendCredit = (Button) v.findViewById(id.btnSendCredit);
btnTransactions = (Button) v.findViewById(id.btnTransactions);
list = (ListView) v.findViewById(id.list);
btnTransactions.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
layoutAccount.setVisibility(View.GONE);
layoutGetCredit.setVisibility(View.GONE);
layoutTransactions.setVisibility(View.VISIBLE);
}
});
btnGetCredit.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
layoutAccount.setVisibility(View.GONE);
layoutGetCredit.setVisibility(View.VISIBLE);
layoutTransactions.setVisibility(View.GONE);
}
});
btnAccount.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
layoutAccount.setVisibility(View.VISIBLE);
layoutGetCredit.setVisibility(View.GONE);
layoutTransactions.setVisibility(View.GONE);
}
});
return v;
}
private void goToCards() {
FragmentCardHolder fragment = new FragmentCardHolder();
((BaseContainerFragment) getParentFragment()).replaceFragment(fragment, true);
}
你为什么要跟踪碎片并自己弹出它们?您不需要那样做,也不应该覆盖 onBackPressed()。让 FragmentManager 处理片段事务。
如果 activity 中有片段,请使用
FragmentManager fManager = getFragmentManager();
或者如果您想支持 Android 3.0 之前的设备,请使用
FragmentManager fManager = getSupportFragmentManager();
如果片段在另一个片段中,则使用
FragmentManager fManager = getChildFragmentManager();
拥有 fManager 后,要显示片段,请使用
fManager.beginTransaction().add(R.id.fragment_parent, new FirstTabFragment()).commit();
其中 fragment_parent 是您要放置片段的父视图。
当你想切换到下一个片段时,使用
fManager.beginTransaction().replace(R.id.fragment_parent, new SecondTabFragment())
.addToBackStack(null)
.commit();
由于您将其添加到后退堆栈,因此当您返回时,您将看到您的第一个片段。而已。
此外,您很容易意识到这会导致您的片段每次都从头开始创建,您可以通过初始化一次并重新使用它们来防止这种情况。
HTH
我认为问题出在代码的隐藏部分,您将第一个片段添加到容器(FragmentAccountContainer 和 FragmentPromotionsContainer classes)。我建议你在 BaseContainerFragment.class 中创建带有示例签名的抽象方法
protected abstract Fragment getFirstFragment();
因此,具体容器 class 将覆盖此方法并将第一个片段的 return 新实例添加到超级 class 中,然后在父 class 中使用添加事务将其添加到片段容器中。
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (savedInstanceState == null) {
addFragment(getFirstFragment(), false);
}
}
请注意,您应该在添加片段之前检查 savedInstanceState 是否为 null,以避免在 activity 系统重新创建时重复。
在嵌套片段中,您可以像以前那样使用替换 ((BaseContainerFragment) getParentFragment()).replaceFragment(___, true);
另外,我对您的代码有一些建议。你不能像@NecipAllef 建议的那样避免在 activity 中覆盖 onBackPressed,因为 known bug with default back logic and child fragment manager ,但你可以简化对 popFragment 的调用,比如
@Override
public void onBackPressed() {
String currentTabTag = mTabHost.getCurrentTabTag();
boolean isPopFragment = ((BaseContainerFragment) getSupportFragmentManager().findFragmentByTag(currentTabTag)).popFragment();
if (!isPopFragment) {
super.onBackPressed();
}
}
为了将包设置为片段,我建议使用结构方法模式,例如
public class TestFragment extends Fragment {
public static Fragment newInstance(String text){
Fragment fragment = new TestFragment();
Bundle args = new Bundle();
args.putString("text", text);
fragment.setArguments(args);
return fragment;
}
}
Ps:我为你创建了一个 simple project 具有描述的逻辑
我已经尝试了 Whosebug 中的每一个 post 但都没有成功,我有一个 FragmentTabHost activity 带有标签 A B C D E
当我转到选项卡 A 然后转到选项卡 B 时一切正常,但是如果我 return 到选项卡 A 是空白,那么 return 到选项卡 B 也是空白!!
A -> B -> A = 空白 -> B = 空白
我按照此 post 使其正常工作 Dynamically changing the fragments inside a fragment tab host?,但选项卡之间的转换不起作用。
我尝试更改我的 BaseContainerFragment 以使用 getSupportFragmentManager 而不是 getChildFragmentManager 但没有成功,此时我还删除了 addToBackStack(null) 我没有想法,我们将不胜感激,谢谢。
这是包含使用片段创建选项卡的代码的 mainActivity。
public class ActivityMain extends FragmentActivity {
public static final String TAB_1_TAG = "tab_1";
public static final String TAB_2_TAG = "tab_2";
public static final String TAB_3_TAG = "tab_3";
public static final String TAB_4_TAG = "tab_4";
public static final String TAB_5_TAG = "tab_5";
private FragmentTabHost mTabHost;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
}
private void initView() {
mTabHost = (FragmentTabHost)findViewById(android.R.id.tabhost);
mTabHost.setup(this, getSupportFragmentManager(), R.id.realtabcontent);
mTabHost.getTabWidget().setDividerDrawable(null);
mTabHost.getTabWidget().setStripEnabled(false);
mTabHost.addTab(mTabHost.newTabSpec(TAB_1_TAG).setIndicator("", getResources().getDrawable(R.drawable.tab_account)), FragmentAccountContainer.class, null);
mTabHost.addTab(mTabHost.newTabSpec(TAB_2_TAG).setIndicator("", getResources().getDrawable(R.drawable.tab_discounts)), FragmentPromotionsContainer.class, null);
mTabHost.addTab(mTabHost.newTabSpec(TAB_3_TAG).setIndicator("", getResources().getDrawable(R.drawable.tab_payment)), FragmentAccountContainer.class, null);
mTabHost.addTab(mTabHost.newTabSpec(TAB_4_TAG).setIndicator("", getResources().getDrawable(R.drawable.tab_gas)), FragmentAccountContainer.class, null);
mTabHost.addTab(mTabHost.newTabSpec(TAB_5_TAG).setIndicator("", getResources().getDrawable(R.drawable.tab_rest)), FragmentAccountContainer.class, null);
}
@Override
public void onBackPressed() {
boolean isPopFragment = false;
String currentTabTag = mTabHost.getCurrentTabTag();
Log.e("ActivityMain", "currentTabTag: " + currentTabTag);
if (currentTabTag.equals(TAB_1_TAG)) {
isPopFragment = ((BaseContainerFragment) getSupportFragmentManager().findFragmentByTag(TAB_1_TAG)).popFragment();
} else if (currentTabTag.equals(TAB_2_TAG)) {
isPopFragment = ((BaseContainerFragment) getSupportFragmentManager().findFragmentByTag(TAB_2_TAG)).popFragment();
} else if (currentTabTag.equals(TAB_3_TAG)) {
isPopFragment = ((BaseContainerFragment) getSupportFragmentManager().findFragmentByTag(TAB_3_TAG)).popFragment();
} else if (currentTabTag.equals(TAB_4_TAG)) {
isPopFragment = ((BaseContainerFragment) getSupportFragmentManager().findFragmentByTag(TAB_4_TAG)).popFragment();
} else if (currentTabTag.equals(TAB_5_TAG)) {
isPopFragment = ((BaseContainerFragment) getSupportFragmentManager().findFragmentByTag(TAB_5_TAG)).popFragment();
}
Log.e("ActivityMain", "isPopFragment: " + isPopFragment);
if (!isPopFragment) {
finish();
}
}
}
这是我的允许回溯和替换片段的 BaseContainerFragment
public class BaseContainerFragment extends Fragment {
public void replaceFragment(Fragment fragment, boolean addToBackStack) {
FragmentTransaction transaction = getChildFragmentManager().beginTransaction();
if (addToBackStack) {
transaction.addToBackStack(null);
}
transaction.replace(R.id.container_framelayout, fragment);
transaction.commit();
getChildFragmentManager().executePendingTransactions();
}
public boolean popFragment() {
Log.e("test", "pop fragment: " + getChildFragmentManager().getBackStackEntryCount());
boolean isPop = false;
if (getChildFragmentManager().getBackStackEntryCount() > 0) {
isPop = true;
getChildFragmentManager().popBackStack();
}
return isPop;
}
}
这是第一个选项卡的容器(这个选项卡包含 2 个活动,一个是主要的,另一个是在列表视图上调用的)
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
myPrefs = this.getActivity().getSharedPreferences("getLogin", Context.MODE_PRIVATE);
idUser = myPrefs.getInt("idUser", 0);
d(TAG, "idUser: " + idUser);
/*
Map<String,?> keys = myPrefs.getAll();
for(Map.Entry<String,?> entry : keys.entrySet()){
Log.d("map values",entry.getKey() + ": " +
entry.getValue().toString());
}
*/
context = getActivity();
pDialog = new SweetAlertDialog(context, PROGRESS_TYPE);
// Check if Internet present
if (!isOnline(context)) {
// Internet Connection is not present
makeText(context, "Error en la conexion de Internet",
LENGTH_LONG).show();
// stop executing code by return
return;
}
new asyncGetFeedClass(context).execute();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.activity_cardholder, container, false);
toolbar = (Toolbar) v.findViewById(R.id.toolbar);
TextView mTitle = (TextView) toolbar.findViewById(toolbar_title);
mTitle.setText("TARJETAS");
list = (ListView) v.findViewById(R.id.list);
// Click event for single list row
list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
FragmentAccount fragment = new FragmentAccount();
// if U need to pass some data
Bundle bundle = new Bundle();
if (listBalance.get(position).get(TAG_ACCOUNT_BANKACCOUNTS_ID) != null) {
bundle.putString("idBankAccount", listBalance.get(position).get(TAG_ACCOUNT_BANKACCOUNTS_ID));
bundle.putString("idGiftCard", "0");
} else if (listBalance.get(position).get(TAG_ACCOUNT_GIFTCARDS_ID) != null) {
bundle.putString("idGiftCard", listBalance.get(position).get(TAG_ACCOUNT_GIFTCARDS_ID));
bundle.putString("idBankAccount", "0");
} else {
bundle.putString("idBankAccount", "0");
bundle.putString("idGiftCard", "0");
}
fragment.setArguments(bundle);
((BaseContainerFragment) getParentFragment()).replaceFragment(fragment, false);
}
});
return v;
}
选项卡 #1
的主要 classpublic void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
myPrefs = this.getActivity().getSharedPreferences("getLogin", Context.MODE_PRIVATE);
idUser = myPrefs.getInt("idUser", 0);
d(TAG, "idUser: " + idUser);
/*
Map<String,?> keys = myPrefs.getAll();
for(Map.Entry<String,?> entry : keys.entrySet()){
Log.d("map values",entry.getKey() + ": " +
entry.getValue().toString());
}
*/
context = getActivity();
pDialog = new SweetAlertDialog(context, PROGRESS_TYPE);
// Check if Internet present
if (!isOnline(context)) {
// Internet Connection is not present
makeText(context, "Error en la conexion de Internet",
LENGTH_LONG).show();
// stop executing code by return
return;
}
Bundle bundle = this.getArguments();
idBankAccount = Integer.parseInt(bundle.getString(FragmentCardHolder.TAG_ACCOUNT_BANKACCOUNTS_ID, "0"));
idGiftCard = Integer.parseInt(bundle.getString(FragmentCardHolder.TAG_ACCOUNT_GIFTCARDS_ID, "0"));
if(idBankAccount > 0){
new asyncGetBankTransactions(context).execute();
} else if(idGiftCard > 0) {
new asyncGetGiftCardTransactions(context).execute();
} else {
new asyncGetX111Transactions(context).execute();
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.activity_account, container, false);
toolbar = (Toolbar) v.findViewById(id.toolbar);
TextView mTitle = (TextView) toolbar.findViewById(toolbar_title);
mTitle.setText("MI CUENTA");
toolbar.setNavigationIcon(R.drawable.icon_user);
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
goToCards();
}
});
layoutAccount = (LinearLayout) v.findViewById(id.layoutAccount);
layoutGetCredit = (LinearLayout) v.findViewById(id.layoutGetCredit);
layoutTransactions = (LinearLayout) v.findViewById(id.layoutTransactions);
btnAccount = (Button) v.findViewById(id.btnMyBalance);
btnGetCredit = (Button) v.findViewById(id.btnGetCredit);
btnSendCredit = (Button) v.findViewById(id.btnSendCredit);
btnTransactions = (Button) v.findViewById(id.btnTransactions);
list = (ListView) v.findViewById(id.list);
btnTransactions.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
layoutAccount.setVisibility(View.GONE);
layoutGetCredit.setVisibility(View.GONE);
layoutTransactions.setVisibility(View.VISIBLE);
}
});
btnGetCredit.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
layoutAccount.setVisibility(View.GONE);
layoutGetCredit.setVisibility(View.VISIBLE);
layoutTransactions.setVisibility(View.GONE);
}
});
btnAccount.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
layoutAccount.setVisibility(View.VISIBLE);
layoutGetCredit.setVisibility(View.GONE);
layoutTransactions.setVisibility(View.GONE);
}
});
return v;
}
private void goToCards() {
FragmentCardHolder fragment = new FragmentCardHolder();
((BaseContainerFragment) getParentFragment()).replaceFragment(fragment, true);
}
你为什么要跟踪碎片并自己弹出它们?您不需要那样做,也不应该覆盖 onBackPressed()。让 FragmentManager 处理片段事务。
如果 activity 中有片段,请使用
FragmentManager fManager = getFragmentManager();
或者如果您想支持 Android 3.0 之前的设备,请使用
FragmentManager fManager = getSupportFragmentManager();
如果片段在另一个片段中,则使用
FragmentManager fManager = getChildFragmentManager();
拥有 fManager 后,要显示片段,请使用
fManager.beginTransaction().add(R.id.fragment_parent, new FirstTabFragment()).commit();
其中 fragment_parent 是您要放置片段的父视图。
当你想切换到下一个片段时,使用
fManager.beginTransaction().replace(R.id.fragment_parent, new SecondTabFragment())
.addToBackStack(null)
.commit();
由于您将其添加到后退堆栈,因此当您返回时,您将看到您的第一个片段。而已。
此外,您很容易意识到这会导致您的片段每次都从头开始创建,您可以通过初始化一次并重新使用它们来防止这种情况。
HTH
我认为问题出在代码的隐藏部分,您将第一个片段添加到容器(FragmentAccountContainer 和 FragmentPromotionsContainer classes)。我建议你在 BaseContainerFragment.class 中创建带有示例签名的抽象方法
protected abstract Fragment getFirstFragment();
因此,具体容器 class 将覆盖此方法并将第一个片段的 return 新实例添加到超级 class 中,然后在父 class 中使用添加事务将其添加到片段容器中。
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (savedInstanceState == null) {
addFragment(getFirstFragment(), false);
}
}
请注意,您应该在添加片段之前检查 savedInstanceState 是否为 null,以避免在 activity 系统重新创建时重复。
在嵌套片段中,您可以像以前那样使用替换 ((BaseContainerFragment) getParentFragment()).replaceFragment(___, true);
另外,我对您的代码有一些建议。你不能像@NecipAllef 建议的那样避免在 activity 中覆盖 onBackPressed,因为 known bug with default back logic and child fragment manager ,但你可以简化对 popFragment 的调用,比如
@Override
public void onBackPressed() {
String currentTabTag = mTabHost.getCurrentTabTag();
boolean isPopFragment = ((BaseContainerFragment) getSupportFragmentManager().findFragmentByTag(currentTabTag)).popFragment();
if (!isPopFragment) {
super.onBackPressed();
}
}
为了将包设置为片段,我建议使用结构方法模式,例如
public class TestFragment extends Fragment {
public static Fragment newInstance(String text){
Fragment fragment = new TestFragment();
Bundle args = new Bundle();
args.putString("text", text);
fragment.setArguments(args);
return fragment;
}
}
Ps:我为你创建了一个 simple project 具有描述的逻辑