I'm building a simple app and I want to go back from fragment to activity with physical button. How do I do that? I have tried to kill the fragment but it isn't working.
You can get a reference to the FragmentActivity by calling getActivity() on your current Fragment and then call from the Activity retrieved onBackPressed() method.
getActivity().onBackPressed();
I do it like this and it's working very fine.
Start fragment:
public void showMyFragment(View V){
Fragment fragment = null;
fragment = new MyFragment();
if (fragment != null) {
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction().replace(R.id.frame_container, fragment).addToBackStack(null).commit();
}
}
This is how to end fragment with back button:
#Override
public void onBackPressed() {
if (getFragmentManager().getBackStackEntryCount() == 0) {
this.finish();
} else {
getFragmentManager().popBackStack();
}
}
Your Fragment:
public class MyFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v=inflater.inflate(R.layout.activity_info, null);
return v;
}
}
Show fragment with this:
getSupportFragmentManager().beginTransaction()
.setReorderingAllowed(true)
.replace(R.id.frame_container,fragment.class,null).addToBackStack("desc_fragment")
.commit();
and then override onBackPressed in your activity:
#Override
public void onBackPressed() {
if(getSupportFragmentManager().getBackStackEntryCount() > 0)
getSupportFragmentManager().popBackStack();
else
super.onBackPressed();
}
Related
I am trying to retain the state of Fragment. I have MotherActivity in which I have FragmentOne,FragmentTwo,FragmentThree and inside from FragmentTwo I am calling another activity ChildActivity. Problem is that When I am pressing back button in ChildActivity it is refreshing MotherActivity and not keeping the state of my FragmentTwo instead it is showing me FragmentOne which come first time.
I only want when I am pressing BackButton from ChildActivity, on container FragmentTwo should be there:
MainAcitivity:
public class MotherActivity extends FragmentActivity {
AHBottomNavigation bottomNavigation;
Fragment selectedFragment = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
bottomNavigation = (AHBottomNavigation) findViewById(R.id.navigation);
bottomNavigation.addItem(item1);
bottomNavigation.addItem(item2);
bottomNavigation.addItem(item3);
bottomNavigation.setOnTabSelectedListener(new AHBottomNavigation.OnTabSelectedListener() {
#Override
public boolean onTabSelected(int position, boolean wasSelected) {
if (position == 0) {
selectedFragment = FragmentOne.newInstance(bottomNavigation);
} else if (position == 1) {
selectedFragment = FragmentTwo.newInstance(bottomNavigation);
} else if (position == 2) {
selectedFragment = FragmentThree.newInstance(bottomNavigation);
}
android.app.FragmentManager fragmentManager = getFragmentManager();
android.app.FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.frame_layout,selectedFragment);
fragmentTransaction.commit();
return true;
}
});
}
#Override
protected void onStart() {
super.onStart();
android.app.FragmentManager fragmentManager = getFragmentManager();
android.app.FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.frame_layout, FragmentOne.newInstance(bottomNavigation));
fragmentTransaction.commit();
}
public void setNotification(){
bottomNavigation.setNotification("1", 1);
}
#Override
protected void onSaveInstanceState(Bundle outState) {
//No call for super().
}
#Override
public void onBackPressed() {
Intent intent = new Intent();
setResult(113, intent);
finish();
return;
}
}
FragmentTwo from where I am calling childActivity:
public class FragmentTwo extends Fragment {
public static AHBottomNavigation bottomNavigation1;
Card_detail_Adapter_Footer searchabledapter;
public static boolean showAddress = false;
Fragment selectedFragment;
public static FragmentTwo newInstance(AHBottomNavigation bottomNavigation) {
FragmentTwo fragment = new FragmentTwo();
bottomNavigation1 = bottomNavigation;
showNotificationCounter(3);
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_cart, container, false);
if(showAddress == true){
showAddress = false;
// From here I am calling ChildActivity
Intent intent = new Intent(getActivity(), ChildActivity.class);
startActivity(intent);
}
return view;
}
}
In ChildActivity simply calling onBackPressed()
The problem is with the onStart() method of your MotherActivity.java because when you open another activity from FragmentTwo, your MotherActivity onStop() gets called. When you press back button from ChildActivity onStart() of MotherActivity called which is replacing FragmentTwo from FragmentOne by committing transaction.
Please have a look at https://developer.android.com/guide/components/activities/activity-lifecycle.html
Put code from onStart() method into onCreate() method and check if configuration been changed:
if (savedInstanceState == null) {
android.app.FragmentManager fragmentManager = getFragmentManager();
android.app.FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.add(R.id.frame_layout, FragmentOne.newInstance(bottomNavigation));
fragmentTransaction.commit();
}
On Fragment1 i have onClick method, when i click the button, i got the recycleview list of items. When i click the item in recycleview(use getPlaceFromItem method), i go to the Fragment2. if device is phone then put the
Fragment2 in container1, but if device is tablet(landscape) then i put Fragment2 into container2 next to Fragment1 in container1.
Now, when i press back button when device is phone, i get empty recycleview.
In addition i check orientation of the screen and when the device is phone and i am in Fragment2(i.e Fragment2 in container1), then when the screen will be landscape i will put into container1 Fragment1, and into container2 at Fragment2. My problem is how can i cut Fragment2 from container1 and put it into container2.
Main Activity :
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
View v = findViewById(R.id.container2);
v.setVisibility(View.GONE);
getSupportFragmentManager().beginTransaction()
.add(R.id.container1, new FragmentA())
.commit();
}
#Override
public void getPlaceFromItem(Place place) {
Bundle bundle = new Bundle();
bundle.putDouble("lat", place.getLat());
bundle.putDouble("lng", place.getLng());
Fragment2 fragment2 = new Fragment2();
fragment2.setArguments(bundle);
if(getResources().getBoolean(R.bool.isTab)) {
View v = findViewById(R.id.container2);
v.setVisibility(View.VISIBLE);
getSupportFragmentManager().beginTransaction()
.replace(R.id.container2,fragment2)
.addToBackStack(null)
.commit();
}
else {
getSupportFragmentManager().beginTransaction()
.replace(R.id.container1, fragment2)
.addToBackStack(null)
.commit();
}
}
#Override
public void onBackPressed() {
if (getFragmentManager().getBackStackEntryCount() > 0) {
getFragmentManager().popBackStack();
} else {
super.onBackPressed();
}
}
#Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
// Checks the orientation of the screen
if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE) {
View v = findViewById(R.id.container2);
v.setVisibility(View.VISIBLE);
getSupportFragmentManager().beginTransaction()
.replace(R.id.container1, new Fragment1())
// The next row is a problematic!!!
.replace(R.id.container2, new Fragment2())
.commit();
} else if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT){
}
}
Remember when a fragment is popped out from back stack it comes back with no view. So you have to attach the view again.
I recommend for you to keep track of the main View in Fragment in order to avoid views from recreating. This way once you come back to the fragment with the RecyclerView it will be there. The code would look like this.
public class BlankFragment2 extends Fragment {
public View myRoot;
public BlankFragment2() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
if (myRoot == null) {
myRoot = inflater.inflate(R.layout.fragment_blank_fragment2, container, false);
}
return myRoot;
}
}
.addToBackStack(null) remove it from code
i hope it will work for you
Add .addToBackStack(fragment.getClass().getCanonicalName()) or .addToBackStack("anyString") to save fragment instance. Also use add method, not replace when you add new fragments.
when you are adding your first fragment you should not use addToBackStack(null).
for first fragment write like this
getSupportFragmentManager().beginTransaction()
.add(R.id.container1, FragmentA)
.commit();
for other fragments you should use
getSupportFragmentManager().beginTransaction()
.replace(R.id.container1, FragmentB)
.addToBackStack(null)
.commit();
hope it helps!
I am using tabs to switch between different lists in my app. When a user touches an item in a list, the following is the code to show and hide the detail. I am wondering how to add a back-button that goes back to the correct list it came from. I am replacing fragments so I don't know if the standard back button works in my case?
public class MainActivity extends AppCompatActivity implements
NavigationView.OnNavigationItemSelectedListener,
TabLayout.OnTabSelectedListener,
CustomerFragment.CustomerListListener,
CustomerDetailListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
ActionBar actionBar = getSupportActionBar();
actionBar.setHomeButtonEnabled(true);
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setDisplayShowHomeEnabled(true);
}
public void onShowCustomerDetail(Customer customer){
HostFragment hostFragment = (HostFragment) customPagerAdapter.getItem(viewPager.getCurrentItem());
CustomerDetailFragment fragment = CustomerDetailFragment.newInstance(customer);
hostFragment.replaceFragment(fragment, true);
}
public void onCloseCustomerDetail() {
HostFragment hostFragment = (HostFragment) customPagerAdapter.getItem(viewPager.getCurrentItem());
CustomerFragment fragment = new CustomerFragment();
hostFragment.replaceFragment(fragment, true);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// just for testing. will do switch case here
onBackPressed();
}
#Override
public void onBackPressed() {
if (getFragmentManager().getBackStackEntryCount() > 0) {
getFragmentManager().popBackStack();
} else {
super.onBackPressed();
}
}
}
CustomPagerAdapter:
public class CustomPagerAdapter extends FragmentStatePagerAdapter {
private final List<String> tabTitles = new ArrayList<String>() {{
add("Messages");
add("Customers");
add("Jobs");
add("Maps");
}};
private List<Fragment> tabs = new ArrayList<>();
public CustomPagerAdapter(FragmentManager fragmentManager) {
super(fragmentManager);
initializeTabs();
}
private void initializeTabs() {
tabs.add(HostFragment.newInstance(new MessageFragment()));
tabs.add(HostFragment.newInstance(new CustomerFragment()));
tabs.add(HostFragment.newInstance(new JobFragment()));
tabs.add(HostFragment.newInstance(new MapFragment()));
}
#Override
public Fragment getItem(int position) {
return tabs.get(position);
}
#Override
public int getCount() {
return tabs.size();
}
#Override
public CharSequence getPageTitle(int position) {
return tabTitles.get(position);
}
}
HostFragment:
public class HostFragment extends BackStackFragment {
private Fragment fragment;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
View view = inflater.inflate(R.layout.fragment_host, container, false);
if (fragment != null) {
replaceFragment(fragment, false);
}
return view;
}
public void replaceFragment(Fragment fragment, boolean addToBackstack) {
if (addToBackstack) {
getChildFragmentManager().beginTransaction().replace(R.id.hosted_fragment, fragment).addToBackStack(null).commit();
} else {
getChildFragmentManager().beginTransaction().replace(R.id.hosted_fragment, fragment).commit();
}
}
public static HostFragment newInstance(Fragment fragment) {
HostFragment hostFragment = new HostFragment();
hostFragment.fragment = fragment;
return hostFragment;
}
}
Because of the way I set up my fragments inside tabs using Child Fragment Manager, I had to do this in my onBackPressed to make it work:
#Override
public void onBackPressed() {
HostFragment hostFragment = (HostFragment) customPagerAdapter.getItem(viewPager.getCurrentItem());
FragmentManager fm = hostFragment.getChildFragmentManager();
if (fm.getBackStackEntryCount() > 0) {
fm.popBackStack();
} else {
super.onBackPressed();
}
}
First of all you need to add fragments in backstack while using it
see below code for creating a fragment and adding inside it to backstack
public final static String TAG_FRAGMENT = "HostFragment"; // used inside every fragment
final HostFragment fragment = new HostFragment();
final FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.fragment, fragment, TAG_FRAGMENT);
transaction.addToBackStack(TAG_FRAGMENT);
transaction.commit();
After that inside activity onBackPressed() you need to pop fragment every backpressed that you want.
#Override
public void onBackPressed() {
if (getFragmentManager().getBackStackEntryCount() > 0) {
getFragmentManager().popBackStack(); // pop fragment here
} else {
super.onBackPressed(); // after nothing is there default behavior of android works.
}
}
All you need to do is add the fragment to the back stack when you create your fragment. It would look something like this:
CustomerDetailFragment fragment=CustomerDetailFragment.newInstance(customer);
getFragmentManager().beginTransaction()
.addToBackStack("Fragment Tag")
.replace(R.id.yourContainer, fragment, "Fragment Tag")
.commit();
Once you have this, you can just use the home back button to pop the fragments off the stack. If you want to use a custom button to go back, you would have to implement your own popping of the stack, which would call getFragmentManager().popBackStack();
Write a fuction onBackpress()
#Override
public void onBackPressed() {
new AlertDialog.Builder(this)
.setTitle("Exit?")
.setMessage("Do you really want to exit?")
.setNegativeButton("No")
.setPositiveButton("Yes", new OnClickListener() {
public void onClick(DialogInterface arg0, int arg1) {
YourActivityname.super.onBackPressed();
}
}).create().show();
}
I have only 1 activity with 2 Fragments within it. When start the activity, Fragment A will launch. After user key in sth and click the button will direct to Fragment B. So what I want to do is that by adding a "Back Arrow" sth like this <- at the top left hand corner.
Does it has to do with FragmentManager.popBackStack()? Please advice ! Thx
MainActivity.java
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
FragmentManager manager=getSupportFragmentManager();
FragmentTransaction transaction=manager.beginTransaction();
first first=new first();
transaction.add(R.id.top,first);
transaction.commit();
}
}
first.java
public class first extends Fragment implements View.OnClickListener{
Button get_button;
EditText get_input_name;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_first,container,false);
get_input_name=(EditText)rootView.findViewById(R.id.input_name);
get_button=(Button)rootView.findViewById(R.id.submit);
get_button.setOnClickListener(this);
return rootView;
}
public void onClick(View v){
FragmentManager manager=getFragmentManager();
FragmentTransaction transaction=manager.beginTransaction();
two Two=new two();
Bundle bundle = new Bundle();
bundle.putString("input_name_value",get_input_name.getText().toString());
Two.setArguments(bundle);
transaction.replace(R.id.top,Two);
transaction.commit();
}
}
two.java
public class two extends Fragment implements View.OnClickListener {
TextView get_display_input;
ImageView get_back_button;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_two, container, false);
}
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
get_display_input=(TextView)getActivity().findViewById(R.id.display_input);
get_back_button=(ImageView) getActivity().findViewById(R.id.back_button);
Bundle bundle = getArguments();
String get_name = bundle.getString("input_name_value");
//int store_get_input=Integer.parseInt(get_name);
get_display_input.setText("You have entered "+get_name);
}
public void onClick(View v){
// WHAT TO DO HERE IN ORDER TO RETURN TO PREVIOUS Fragment when clicking the button?
}
}
To be more precise, please refer to the screenshot.
You can do it by using the popBackStack() method of FragmentManager, put this inside the onClickListener of your back button :
if (getFragmentManager().getBackStackEntryCount() != 0) {
getFragmentManager().popBackStack();
}
If you're using the default back button of the toolbar i.e, the home button, then you can do it by placing this code in the onOptionsItemSelected() method of your Activity:
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == android.R.id.home) {
if (getFragmentManager().getBackStackEntryCount() != 0) {
getFragmentManager().popBackStack();
}
return true;
}
return super.onOptionsItemSelected(item);
}
or, if you want the same behaviour on hardware back button press then override the onBackPressed() method in your Activity class like this:
#Override
public void onBackPressed() {
if (getFragmentManager().getBackStackEntryCount() != 0) {
getFragmentManager().popBackStack();
} else {
super.onBackPressed();
}
}
Check out the training docs here -- they should give you a good start.
// Works with either the framework FragmentManager or the
// support package FragmentManager (getSupportFragmentManager).
getSupportFragmentManager().beginTransaction()
.add(detailFragment, "detail")
// Add this transaction to the back stack
.addToBackStack()
.commit();
You just need this one single line of code!
getFragmentManager().popBackStackImmediate();
Yes, it has to do with FragmentManager.popBackStack();
Take a look here, there are plenty of methods:
https://developer.android.com/reference/android/app/FragmentManager.html#popBackStack
For me, getFragmentManager().popBackStackImmediate(); made exactly that.
In your Activity to handle hardware back button:
#Override
public void onBackPressed() {
if (getFragmentManager().getBackStackEntryCount() > 0) {
getFragmentManager().popBackStack();
} else {
super.onBackPressed();
}
}
So for button click method:
getFragmentManager().popBackStack();
Well I know I am too late to answer this but you can just call getActivity.onBackpress(); method on back click of that back icon.
I have a problem related to fragment life cycle.
Before doing this, I will set DONT KEEP ACTIVITY mode(Setting -> Developer options).
In my project have 2 activity:
Activity 1: keep and control Fragment A and Fragment B
Activity 2: do not have fragment.
Activity 1 will be called first, then Fragment A and Fragment B will be called to visible.
Start Activity 2 from Activity 1, this cause Activity 1 will be destroyed and Fragment A & Fragment B will be destroyed too (Because of dont keep activity mode).
Press back key from Activity 2 to back Activity 1
Problem occurs here: Fragment A and Fragment B will be automatically called onCreateView() after back from activity 2 -> I want to avoid this. Can you give me some tips to resolve it?
Update Code
Activity 1
public class MainActivity extends Activity implements OnClickListener {
private Button mBtnShowFragmentA;
private Button mBtnShowFragmentB;
private Button mBtnGoAcitivity2;
protected String mCurrentFragmentTag;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_activity_1);
mBtnShowFragmentA = (Button) findViewById(R.id.btn_show_fragmentA);
mBtnShowFragmentB = (Button) findViewById(R.id.btn_show_fragmentB);
mBtnGoAcitivity2 = (Button) findViewById(R.id.btn_go_activity2);
mBtnShowFragmentA.setOnClickListener(this);
mBtnShowFragmentB.setOnClickListener(this);
mBtnGoAcitivity2.setOnClickListener(this);
}
#Override
protected void onDestroy() {
super.onDestroy();
}
protected void addFragment(int contentId, Fragment fragment, boolean isAddStack,
String stackName) {
FragmentManager fm = getFragmentManager();
String newFragment = fragment.getClass().getName();
FragmentTransaction ft = fm.beginTransaction();
Fragment currentFragment = fm.findFragmentByTag(mCurrentFragmentTag);
if (currentFragment != null && !TextUtils.equals(currentFragment.getTag(), newFragment)) {
ft.hide(currentFragment);
}
if (fm.findFragmentByTag(newFragment) != null) {
fragment = (Fragment) fm.findFragmentByTag(newFragment);
}
if (!fragment.isAdded()) {
ft.add(contentId, fragment, newFragment);
} else {
ft.show(fragment);
}
if (isAddStack) {
ft.addToBackStack(stackName);
}
try {
ft.commitAllowingStateLoss();
} catch (Exception e) {
}
mCurrentFragmentTag = newFragment;
}
#Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btn_show_fragmentA:
FragmentA fragmentA = new FragmentA();
addFragment(R.id.activity_main_content, fragmentA, false, null);
break;
case R.id.btn_show_fragmentB:
FragmentB fragmentB = new FragmentB();
addFragment(R.id.activity_main_content, fragmentB, false, null);
break;
case R.id.btn_go_activity2:
Intent intent = new Intent(getApplicationContext(), SettingActivity.class);
startActivity(intent);
break;
default:
break;
}
}
}
Fragment A
public class FragmentA extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.layout_fragment_a, container, false);
return view;
}
}
Fragment B
public class FragmentB extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.layout_fragment_b, container, false);
return view;
}
}
Activity 2
public class SettingActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_activity_2);
}
#Override
protected void onDestroy() {
super.onDestroy();
}
#Override
public void onBackPressed() {
super.onBackPressed();
}
}
...................
Use below code to remove activity from stack.
FragmentManager fragmentManager = getSupportFragmentManager();
if (fragmentManager .getBackStackEntryCount() > 0) {
fragmentManager .popBackStack();
}