Android toolbar navigation back button callback never called - android

I know there are a lot of question like this answered, but nothing I found works.
I have an activity (MainActivity) that takes care of showing different fragments. Also, in the activity, I have navigation drawer which I show only on one fragment (it is hidden on others).
The problem is that toolbar navigation callback is never called. Back button is showed, but click on it does nothing. Also (I don't know if it makes any difference) but user get to that fragment from another one in which I do same things as in this one except navigation back button is hidden.
XML for activity is this:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
android:id="#+id/drawer_layout"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:openDrawer="start">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<include
android:id="#+id/main_toolbar"
layout="#layout/toolbar"/>
<FrameLayout
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>
<android.support.design.widget.NavigationView
android:id="#+id/nav_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:fitsSystemWindows="true"
app:headerLayout="#layout/drawer_header"
app:menu="#menu/activity_main_drawer"/>
</android.support.v4.widget.DrawerLayout>
Included toolbar:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.Toolbar
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#color/colorPrimary"
app:theme="#style/Base.ThemeOverlay.AppCompat.Dark.ActionBar"/>
Now, in activity I setup a toolbar and put a listener on its back button:
setSupportActionBar(mainToolbar);
setTitle(getResources().getString("Some title"));
mainToolbar.setNavigationOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
onBackPressed();
}
});
In that specific fragment where I need back button I do this to show it:
if (this.context.getSupportActionBar() != null) {
this.context.getSupportActionBar().setTitle("Fragment title"));
this.context.getSupportActionBar().setDisplayHomeAsUpEnabled(true);
this.context.getSupportActionBar().setDisplayShowHomeEnabled(true);
}
And, since I don't want navigation drawer to be used/showed, in the fragment I call a method defined in the activity that executes this code:
drawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED);
drawerToggle.setDrawerIndicatorEnabled(false);


On a specific fragment where you want to show back button simply add that fragment to backstack
add this BackStack change listener to Activity
#Override
public void onBackStackChanged() {
if (getSupportFragmentManager().getBackStackEntryCount() != 0)
mToolbar.setNavigationIcon(R.drawable.ic_action_back);
mToolbar.setNavigationOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
onBackPressed();
}
});
}
}
to add to backStack you can use that line
if you pass true to addtoback stack then it will add in and backstack.
public void changeFragment(Fragment fragment, boolean addtobackstack) {
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.setCustomAnimations(R.anim.fragment_enter, R.anim.fragment_exit);
fragmentTransaction.replace(R.id.fragment_container, fragment, MainActivity.TAG);
if (addtobackstack)
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
}

Related

How to fix overlapping of previous fragment's collapsing toolbar and current fragment's content?

I'm new to android, and want to find solution for the following situation:
I have implemented fragment called profile, In which I have collapsing toolbar and TabLayout. Whenever I clicked on any of the button of current fragment, It will display next page as a new fragment accordingly.Next fragment have it's own toolbar.
Problem: Whenever I scroll the content, previous fragment Collapsing Toolbar appears on top. It overlaps the current fragment.
I have tried the solution using Framelayout and "fitSystemWindows = true".Another solution I have tried is giving "clickable=true" to next fragment. None of them helped me. Where I made a mistake?
Here's the overview of my code:
ProfileFragment is loaded from MainActivity which has bottom navigation view.
private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.navigation_profile:
ProfileFragment f5=new ProfileFragment();
FragmentTransaction ft5= getSupportFragmentManager().beginTransaction();
ft5.replace(R.id.fragment_container,f5,"");
ft5.commit();
return true;
}
return false;
}
};
activity_main.xml
<LinearLayout
android:id="#+id/container"
tools:context="com.work.workapp.MainActivity">
<FrameLayout
android:id="#+id/fragment_container">
</FrameLayout>
<android.support.design.widget.BottomNavigationView/>
</LinearLayout>
profile_fragment.xml
<android.support.design.widget.CoordinatorLayout
android:id="#+id/profile_main">
<android.support.design.widget.AppBarLayout
android:fitsSystemWindows="true">
<android.support.design.widget.CollapsingToolbarLayout
android:fitsSystemWindows="true"
app:layout_scrollFlags="scroll|exitUntilCollapsed">
<LinearLayout
android:fitsSystemWindows="true"
app:layout_collapseMode="parallax">
<ImageView/>
<TextView/>
</LinearLayout>
<android.support.v7.widget.Toolbar>
<RelativeLayout>
<!-- Settings Button -->
<!-- Edit Button -->
</RelativeLayout>
</android.support.v7.widget.Toolbar>
</android.support.design.widget.CollapsingToolbarLayout>
<android.support.design.widget.TabLayout/>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
app:layout_behavior="#string/appbar_scrolling_view_behavior"/>
<FrameLayout
android:id="#+id/container_profile"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</android.support.design.widget.CoordinatorLayout>
profile-toolbar
collapse toolbar - Tab post
tab_post and tab_work Adapter files:
/* Button click event from post Tab of tablayout*/
myViewHolder.button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
RequestsFragment req_list = new RequestsFragment();
FragmentTransaction ft = ((FragmentActivity)mContext).getSupportFragmentManager().beginTransaction();
ft.replace(R.id.container_profile, req_list, "");
ft.addToBackStack(null).commit();
}
});
When Click on "5" - button on Post tab, following fragment displayed:
Button click on Post tab
When scroll on above fragment, previous fragment's collapsed toolbar appears on new fragment:
content and toolbar overlaps
No error message appears. App is successfully running. I want to remove this Overlapping.

DrawerLayout stops working when fragment back stack is popped

I have a DrawerLayout connected to the ActionBar with an ActionBarDrawerToggle that stops working. I know the question about why it doesn't open has been asked 100 times but my question is a little different. My drawer works! Yep, you click on the hamburger and the drawer opens and closes like a champ...
The problem is that it stops working when I dismiss any fragment that was added to the activity. Here is the activity layout
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/renderer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<RelativeLayout
android:id="#+id/activity_root_view"
android:layout_width="match_parent"
android:layout_height="match_parent">
...header stuff...
<ViewStub
android:id="#+id/view_stub"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentTop="true"/>
...footer stuff...
</RelativeLayout>
<FrameLayout
android:id="#+id/left_drawer"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"/>
</android.support.v4.widget.DrawerLayout>
Then the activity contains this...
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_layout);
mRendererLayout = (DrawerLayout) findViewById(R.id.renderer_layout);
mDrawerToggle = new ActionBarDrawerToggle(
this,
mRendererLayout,
R.string.alert_ok,
R.string.cancel_all
) {
#Override
public void onDrawerOpened(View drawerView) {
Log.e("===", "RA.Drawer Opened ");
}
#Override
public void onDrawerClosed(View drawerView) {
Log.e("===", "RA.Drawer Closed ");
}
};
mRendererLayout.addDrawerListener( mDrawerToggle );
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
Log.e("===", "RA.onOptionsItemSelected(): ");
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
} else {
return super.onOptionsItemSelected(item);
}
}
At a few points I add various fragments to the activity with
addFragment( new MyFragment() );
Each fragment has a view with an onClick() that calls
getActivity().getSupportFragmentManager().popBackStack();
It is at this point that the drawer stops working. The fragment disappears as expected and it does log "RA.onOptionsItemSelected()" when the hamburger is clicked but "RA.Drawer Opened" is no longer logged and the drawer does not open. This continues until the activity is relaunched.
To make things more complicated the activity uses a ViewStub to swap out two layouts: either a FrameLayout or a FrameLayout containing a ViewPager. Only the latter has the problem. I swap out the viewStub like this...
ViewStub viewStub = findViewById(R.id.view_stub);
viewStub.setLayoutResource(R.layout.either_layout_here);
viewStub.inflate();
Swapping in this layout has no problems with the drawer. It gets a fragment added to it via addFragment():
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/content_frame"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
Swapping in this layout, on the other hand, has the problem...
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/content_frame"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ViewPager
android:id="#+id/view_pager"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</FrameLayout>
This one does not get a fragment added to its content_frame (yet), since the ViewPager handles its fragments. That's really the only difference. For some reason popping the fragment back stack breaks the drawer button on the ActionBar.
I'm stumped. Help!

How to handle drawer toggle and toolbar up when having toolbar for each fragment

I am using single activity and many fragments approach in my app
Now since in my some fragments I have custom view in toolbar I decided to have separate toolbar for each fragment.
How to implement separate toolbar for each fragment also the drawer layout is in my activity

I have the same problem, I will add custom toolbar view for each fragment.
My Utility method is:
public static View addRemoveViewFromToolbar(FragmentActivity fragmentActivity, int resourceId) {
Toolbar toolbar = removeViewFromToolbar(fragmentActivity);
if (resourceId == 0) {
return null;
} else {
View view = LayoutInflater.from(fragmentActivity).inflate(resourceId, toolbar, false);
toolbar.addView(view);
return view;
}
}
public static Toolbar removeViewFromToolbar(FragmentActivity fragmentActivity) {
Toolbar toolbar = (Toolbar) fragmentActivity.findViewById(R.id.toolbar);
if (toolbar.getChildCount() > 1) {
for (int i = 1; i <= toolbar.getChildCount(); i++) {
toolbar.removeViewAt(1);
}
}
return toolbar;
}
In my each fragment
//Create your custom view based on requirement
View view = Utility.addRemoveViewFromToolbar(getActivity(), R.layout.toolbar_search_view);
if (view != null) {
edtCategory1 = (EditText) view.findViewById(R.id.edtCategory1);
edtCategory1.setOnClickListener(this);
}
Hope this explanation help you :)

I'm not sure if I understood your description of the your app correctly, but I recently did what I think you described.
My activity layout was a DrawerLayout with an included CoordinatorLayout/AppBar layout with a single toolbar and a FrameLayout below. The menu.xml contained all the items I needed in my toolbar for all the fragments. Items clicked in the nav menu would swap out fragments in the FrameLayout. My onNavigationItemSelected() called on this method to swap out the fragments and handle the backstack:
public void switchView(int id, int optArg) {
if (currentView != id) {
currentView = id; //currentView keeps track of which fragment is loaded
FragmentTransaction transaction = getFragmentManager().beginTransaction();
//Fragment contentFragment is the current fragment in the FrameLayout
switch (id) {
case 0: //menu item 1
contentFragment = new Nav_Item1_Fragment();
transaction.replace(R.id.fragment_container, contentFragment, "");
break;
case 1: //menu item 2
contentFragment = new Nav_Item2_Fragment();
transaction.replace(R.id.fragment_container, contentFragment, "");
break;
case 2: //menu item 3
contentFragment = new Nav_Item3_Fragment();
transaction.replace(R.id.fragment_container, contentFragment, "");
break;
}
// Replace whatever is in the fragment_container view with this fragment,
// and add the transaction to the back stack
// transaction.replace(R.id.fragment_container, contentFragment);
transaction.addToBackStack(null);
// Commit the transaction
transaction.commit();
}
}
and in each fragment's onPrepareOptionsMenu() I setVisible() hid/showed the menu items in the toolbar related to that fragment. Each item had an method in the activity pointed to by the menu item's onClick attribute that knew what fragment it was from and what views were passed to it.
The drawer was setup in the onCreate() of the activity with a ActionBarDrawerToggle like so:
drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.addDrawerListener(toggle);
toggle.syncState();
activity xml:
<android.support.v4.widget.DrawerLayout
android:id="#+id/drawer_layout"
...>
<include
layout="#layout/app_bar_main"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
<android.support.design.widget.NavigationView
android:id="#+id/nav_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:fitsSystemWindows="true"
.../>
</android.support.v4.widget.DrawerLayout>
app_bar_main.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
...>
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
...>
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:gravity="top"
.../>
</android.support.design.widget.AppBarLayout>
<FrameLayout
android:id="#+id/fragment_container"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
</FrameLayout>
</android.support.design.widget.CoordinatorLayout>
So...One Nav menu, one App/Tool Bar, multiple fragments

Why do you specifically want a separate toolbar for each fragment?
You can easily change the toolbar view for each fragment.
In your function to switch fragments -
public void selectDrawerItem(MenuItem item) {
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction;
switch (item.getItemId()) {
case R.id.nav_home :
getSupportActionBar().setCustomView(R.layout.home_nav_bar);
fragmentClass = HomeFragment.class;
break;
case R.id.nav_settings :
getSupportActionBar().setCustomView(R.layout.settings_nav_bar);
fragmentClass = SettingsFragment.class;
break;
}
fragment = (Fragment) fragmentClass.newInstance();
fragmentManager.popBackStack(null,
FragmentManager.POP_BACK_STACK_INCLUSIVE);
fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.fragment_container, fragment);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
}
So you can easily use the same toolbar and customize it according to your requirements for each fragment.

It can be done in a quite straightforward way.
First create an activity with a drawerlayout.
Second create a container viewpager inside the activity to hold
the fragments
Third implement a listener on your viewpager that will set the
relevant toolbar based on the fragment on display.
Let me illustrate by relevant XMLs and code
First the Drawerlayout XML for the main activity
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:openDrawer="start">
<include
layout="#layout/app_bar_landing_page"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<android.support.design.widget.NavigationView
android:id="#+id/nav_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:fitsSystemWindows="true"
app:headerLayout="#layout/nav_header_landing_page"
app:menu="#menu/activity_landing_page_drawer" />
</android.support.v4.widget.DrawerLayout>
Please note the container layout app_bar_landing_page. Now the XML for this
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="me.veganbuddy.veganbuddy.ui.LandingPage">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
android:elevation="4dp"
app:logo="#drawable/vegan_buddy_menu_icon"
app:popupTheme="#style/AppTheme.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/container_for_fragments"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
</android.support.design.widget.CoordinatorLayout>
Note the viewpager which will act as container for fragments. Now the OnPageChangeListener on the viewpager.
mViewPager = (ViewPager) findViewById(R.id.container_for_fragments);
mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
switch (position+1){
case 0:setSupportActionBar(aToolbar);
break;
case 1:setSupportActionBar(bToolbar);
break;
case 2:setSupportActionBar(cToolbar);;
break;
case 3:setSupportActionBar(dToolbar);
break;
default:
break;
}
}
Let me know if any further clarification is needed

The simplest approach I would suggest is to use callbacks to activity. Whenever each fragment loads in the activity, arrange a callback to the activity and load the appropriate toolbar in the activity.
Have separate toolbar xmls in your layout folder. Use the include tag to put the toolbars in your activity. Keep only 1 toolbar visible at a time. When the fragment callbacks come to your activity make the necessary one visible.

It's very simple. Besides the onclick action for the Category fragment is taking you into a new activity, not a Fragment. Now, since drawer layout is in parent activity with navigation view and without toolbar then in the first drawer fragment is a tablayout having four tabs with viewpager and a toolbar on the top and inside one tab i.e HOME is the TOP CHARTS, CATEGORIES, EDITORS. Each toolbar must be implemented in each fragment layout and not in the activity layout since you want different toolbars for each fragment. Note that Toolbar is not a property of Fragment but it's a property of ActionBarActivity or AppCompatActivity, then in the onCreateView, of the fragment that's holding the HOME, GAMES, MOVIES, MUSIC, put down these codes.
public class Drawer1Fragment extends Fragment{
public Drawer1Fragment () {}
TabLayout tabLayout;
Toolbar toolbar;
DrawerLayout drawerLayout;
ViewPager viewPager;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
View myChildRoot = inflater.inflate(R.layout.child_fragment_attachment, container, false);
tabLayout = myChildRoot.findViewById(R.id.tab_layout);
viewPager= myChildRoot.findViewById(R.id.container_viewPager);
toolbar = myChildRoot.findViewById(R.id.toolbar);
drawerLayout = getActivity().findViewById(R.id.drawer_layout);
((AppCompatActivity)requireActivity()).setSupportActionBar(toolbar);
((AppCompatActivity)requireActivity()).getSupportActionBar().setTitle(getActivity().getResources().getString(R.string.app_name));
((AppCompatActivity)requireActivity()).getSupportActionBar().setHomeButtonEnabled(true);
((AppCompatActivity)getParentFragment().requireActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(true);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(getActivity(),drawerLayout,toolbar,R.drawable.icons,R.string.app_name);
drawerLayout.addDrawerListener(toggle);
toggle.syncState();
// The back arrow of a toolbar in fragment is implemented below
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view)
{
if(!drawerLayout.isDrawerOpen(GravityCompat.START)) {
drawerLayout.openDrawer(GravityCompat.START);
} else {
getActivity().finish();
}
}
});
return myChildRoot;
}
}

Fragment to fragment to fragment get crash

I have a main activity , it contains lots of fragments.
Main activity layout looks like this:
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/drawerLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.user.taiwandigestionsociety_v11.MainActivity">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#FFFFFF">
<include layout="#layout/toolbar"/>
//switch fragment over here
<FrameLayout
android:id="#+id/mainFrame"
android:layout_gravity="end"
android:layout_width="match_parent"
android:layout_height="match_parent">
</FrameLayout>
</android.support.design.widget.AppBarLayout>
<android.support.design.widget.NavigationView
android:id="#+id/nav_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:background="#android:color/transparent"
android:fitsSystemWindows="true"
app:headerLayout="#layout/nav_header">
</android.support.design.widget.NavigationView>
</android.support.v4.widget.DrawerLayout>
and I click the drawer item it will change to first fragment:
#Override
public void onClick(View view) {
int id = view.getId();
if (id == R.id.activitiesContents) {
//change to first fragment successful
switchFragment(ActivityList.newInstance());
toolbar.setTitle(R.string.activitiesContents);
drawerLayout.closeDrawer(GravityCompat.START);
}
}
my switch fragment function:
public void switchFragment(Fragment fragment) {
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(R.id.mainFrame, fragment, null);
//transaction.addToBackStack(null);
transaction.commit();
}
then i click the button in first fragment, it changes to second fragment too:
//take me to second fragment succeed
switchFragment(ActivityHomePage.newInstance());
finally i click the button in second fragment, it crashed
//i want to switch to third fragment , just the same with previous
switchFragment(NewsInformation.newInstance());
the error log:
Why i got crash when i switch to third fragment? I completely have no clue.
I found the crash function function , because I set the class:
public class CommonSwitch extends Fragment {
//switch Fragment
public void switchFragment(Fragment fragment) {
FragmentManager manager = getActivity().getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(R.id.mainFrame, fragment, null);
//transaction.addToBackStack(null);
transaction.commit();
}
}
and I try to call it new CommonSwitch.switchFragment(goToFragment);
now I have set public void switchFragment every Fragment class.
Why when I set new CommonSwitch will cause crash ?

Your Activity state is Not Maintain.
On second layer use Activity instead of Fragment . Follow Android Standards.
According to standards Third Fragment should be Activity. otherwise you have to maintain MainActivity state.
Thanks

fragment of fragments toolbar title setting

I have one Activity and lots of fragments switch between this Activity, i set the toolbar title just in this Activity , like this :
this Activity:
#Override
public void onClick(View view) {
int id = view.getId();
if (id == R.id.logIn){
switchFragment(LogInFragment.newInstance());
//when i switch fragment , i change the tile by this code
toolbar.setTitle(R.string.pageLogIn);
drawerLayout.closeDrawer(GravityCompat.START);
}
if (id == R.id.singUp){
switchFragment(SignUp.newInstance());
toolbar.setTitle(R.string.singUp);
drawerLayout.closeDrawer(GravityCompat.START);
}
}
private void switchFragment(Fragment fragment) {
FragmentManager manager = getActivity().getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(R.id.mainFrame, fragment, null);
//transaction.addToBackStack(null);
transaction.commit();
}
and this my Activity layout:
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/drawerLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.user.taiwandigestionsociety_v11.MainActivity">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#FFFFFF">
<android.support.v7.widget.Toolbar
android:id="#+id/toolBar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:theme="#style/ToolBarStyle"
android:background="#drawable/actionbar">
</android.support.v7.widget.Toolbar>
<FrameLayout
android:id="#+id/mainFrame"
android:layout_gravity="end"
android:layout_width="match_parent"
android:layout_height="match_parent">
</FrameLayout>
</android.support.design.widget.AppBarLayout>
<android.support.design.widget.NavigationView
android:id="#+id/nav_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:background="#android:color/transparent"
android:fitsSystemWindows="true"
app:headerLayout="#layout/nav_header">
</android.support.design.widget.NavigationView>
</android.support.v4.widget.DrawerLayout>
My question is one of fragments has a button that it will switch to new fragment, i can't switch the toolbar title by the Activity java .
I try another way to set the function to call the Activity switch function, the app will crash .
I try like this:
public class Welcome extends Fragment implements View.OnClickListener {
#Override
public void onClick(View view) {
int id = view.getId();
if (id == R.id.welcomeLogin){
MainActivity mainActivity=new MainActivity();
mainActivity.switchFragment(ActivityHomePage.newInstance());
}
}
}
How can i set the fragment toolbar title like those fragments ?

Create One Method in Activity :
public void setToolBar(String title) {
getSupportActionBar().setTitle(title);
}
And call this method in onCreateView of Fragment :
((MainActivity) getActivity()).setToolBar(title);

Do not create instance of Activity like this! Rather pass your context of MainActivity to the Fragment then use that to change.
- MainActivity mainActivity=new MainActivity();
- mainActivity.switchFragment(ActivityHomePage.newInstance());

First of defined main activity
private HomeActivity activity;
after set values "onCreate" method
activity = (HomeActivity) getActivity();
set toolbar values:
HeaderBar headerBar;
headerBar = (HeaderBar) view.findViewById(R.id.headerBar);
Example i hv set right side image in tital bar:
headerBar.ivRight.setImageResource(R.mipmap.save);

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