There are many questions like this asked but everything I have tried seems to not work.
Essentially I have a main activity that calls different fragments depending on what the user clicks with the home fragment being default.
I would like to have a back button on the title bar, to go back to the previous fragment.
My fragment is called from the main activity like so:
Fragment fragment = null;
fragment = new nextFragment();
if (fragment != null) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.frame_container, fragment).addToBackStack(null);
fragmentTransaction.commit();
fragmentTransaction.addToBackStack(null);
} else {
// error in creating fragment
Log.e("MainActivity", "Error in creating fragment");
}
But since ActionBarActivity activity is deprecated I need to extend AppCompatActivity instead of FragmentActivity so I can use actionbar (I'm assuming this is what I need).
However then I am unable to switch to my fragment. So does anyone know how I could implement a back button in my fragment or how to use AppCompatActivity in this situation.
Thanks for any help.
Please try this if you extend AppCompatActivity:
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Include these 2 lines ONLY if need to use Toolbar from layout xml as Action Bar
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
//Add back navigation in the title bar
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
//
//Other works to be done in onCreate.....
//
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
if (item.getItemId() == android.R.id.home) {
//Title bar back press triggers onBackPressed()
onBackPressed();
return true;
}
return super.onOptionsItemSelected(item);
}
//Both navigation bar back press and title bar back press will trigger this method
#Override
public void onBackPressed() {
if (getFragmentManager().getBackStackEntryCount() > 0 ) {
getFragmentManager().popBackStack();
}
else {
super.onBackPressed();
}
}
}
To add Back Button in title bar, you must add the following code to your Fragment.
Toolbar toolbar = (Toolbar)view.findViewById(R.id.app_bar);
AppCompatActivity AppCompatActivity = (AppCompatActivity)getActivity();
AppCompatActivity.setSupportActionBar(toolbar);
AppCompatActivity.getSupportActionBar().setDisplayHomeAsUpEnabled(true);
return view;
}
Don't forget to extend your MainActivity to AppCompatActivity.
You must then use this Java code in my Fragment class to react to the user tapping the back/up icon in the action bar.
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
getActivity().onBackPressed();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
You've saved the last fragment used by calling
addToBacktack(null).commit()
So the next step forward to call it is by overriding onBackPressed() in the activity hosting the fragment.
#Override
public void onBackPressed() {
if (getFragmentManager().getBackStackEntryCount() > 0 ){
getFragmentManager().popBackStack();
}
else {
super.onBackPressed();
}
}
So whenever you call the activity's onBackPressed() from the fragment, the fragment would go back to the last saved fragment.
Related
I have an activity, and a bunch of fragments in it. The fragments are not transitioned by sliding, but by button click. I'm trying to build a tab indicator like the one in the bottom that shows which fragment the user is. I don't even know how it's called.
This is my main Activity where all the fragments belong, and with the actionbar menu the user navigates throught the fragments. In the activity it's switched straight to the first fragment out of 4 fragments (DetailsFragment)
public class CreateWorkoutActivity extends AppCompatActivity implements View.OnClickListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_create_workout);
DetailsFragment fragment = new DetailsFragment();
getSupportFragmentManager().beginTransaction()
.replace(R.id.create_activity_frameLayout, fragment)
.addToBackStack(null)
.commit();
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
FragmentManager fm = getSupportFragmentManager();
if (fm.getBackStackEntryCount() > 0) {
fm.popBackStack();
}
return true;
}
return false;
}
image example
as i cannot see your code, I have this to offer https://guides.codepath.com/android/ViewPager-with-FragmentPagerAdapter ... refer this
I am using a single activity and multiple fragments(screenshot attached) within the same activity to provide a seamless navigation. But after implementing the latest toolbar and navigation view, it seems hard to handle the navigation and home buttons. I am having trouble with the following things.
Managing the Hamburger/Back button at left top. Toggling the icon and functionality to Menu and Back nav.
Page title - Changing the page titles whenever a fragment in pushed and popped.
I have tried several things like overriding onBackPressed(), setHomeAsUpIndicator, popping fragments manually. Earlier i was using ActionBarDrawer toggle to handle this but it is failing somehow now. I checked the google samples they seem to use separate activities at most of the places.
Can anyone guide me how to implement a proper back navigation to handle the NavigationView, Back button in inner fragments and page titles? I am using AppCompatActivity, android.app.Fragment, NavigationView and Toolbar.
It's much easier to illustrate with some sort of division of responsibility for your Activity and Fragment.
Problem 1: Managing the Hamburger/Back button at left top. Toggling the icon and functionality to Menu and Back nav.
From the illustration, the solution should be encapsulated by the Activity, which will look something like this:
public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {
private ActionBarDrawerToggle mDrawerToggle;
private DrawerLayout mDrawer;
private ActionBar mActionBar;
private boolean mToolBarNavigationListenerIsRegistered = false;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
mActionBar = getSupportActionBar();
mDrawer = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerToggle = new ActionBarDrawerToggle(this, mDrawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
mDrawer.addDrawerListener(mDrawerToggle);
mDrawerToggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
// On orientation change savedInstanceState will not be null.
// Use this to show hamburger or up icon based on fragment back stack.
if(savedInstanceState != null){
resolveUpButtonWithFragmentStack();
} else {
// You probably want to add your ListFragment here.
}
}
#Override
public void onBackPressed() {
if (mDrawer.isDrawerOpen(GravityCompat.START)) {
mDrawer.closeDrawer(GravityCompat.START);
} else {
int backStackCount = getSupportFragmentManager().getBackStackEntryCount();
if (backStackCount >= 1) {
getSupportFragmentManager().popBackStack();
// Change to hamburger icon if at bottom of stack
if(backStackCount == 1){
showUpButton(false);
}
} else {
super.onBackPressed();
}
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
} else if (id == android.R.id.home) {
// Home/Up logic handled by onBackPressed implementation
onBackPressed();
}
return super.onOptionsItemSelected(item);
}
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
// Navigation drawer item selection logic goes here
mDrawer.closeDrawer(GravityCompat.START);
return true;
}
private void replaceFragment() {
/**
* Your fragment replacement logic goes here
* e.g.
* FragmentTransaction ft = getFragmentManager().beginTransaction();
* String tag = "MyFragment";
* ft.replace(R.id.content, MyFragment.newInstance(tag), tag).addToBackStack(null).commit();
*/
// The part that changes the hamburger icon to the up icon
showUpButton(true);
}
private void resolveUpButtonWithFragmentStack() {
showUpButton(getSupportFragmentManager().getBackStackEntryCount() > 0);
}
private void showUpButton(boolean show) {
// To keep states of ActionBar and ActionBarDrawerToggle synchronized,
// when you enable on one, you disable on the other.
// And as you may notice, the order for this operation is disable first, then enable - VERY VERY IMPORTANT.
if(show) {
// Remove hamburger
mDrawerToggle.setDrawerIndicatorEnabled(false);
// Show back button
mActionBar.setDisplayHomeAsUpEnabled(true);
// when DrawerToggle is disabled i.e. setDrawerIndicatorEnabled(false), navigation icon
// clicks are disabled i.e. the UP button will not work.
// We need to add a listener, as in below, so DrawerToggle will forward
// click events to this listener.
if(!mToolBarNavigationListenerIsRegistered) {
mDrawerToggle.setToolbarNavigationClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
onBackPressed();
}
});
mToolBarNavigationListenerIsRegistered = true;
}
} else {
// Remove back button
mActionBar.setDisplayHomeAsUpEnabled(false);
// Show hamburger
mDrawerToggle.setDrawerIndicatorEnabled(true);
// Remove the/any drawer toggle listener
mDrawerToggle.setToolbarNavigationClickListener(null);
mToolBarNavigationListenerIsRegistered = false;
}
// So, one may think "Hmm why not simplify to:
// .....
// getSupportActionBar().setDisplayHomeAsUpEnabled(enable);
// mDrawer.setDrawerIndicatorEnabled(!enable);
// ......
// To re-iterate, the order in which you enable and disable views IS important #dontSimplify.
}
}
Problem 2: Page title - Changing the page titles whenever a fragment in pushed and popped.
Essentially, this can be handled in the onStart for each Fragment i.e. your ListFragment, DetailsFragment and CommentsFragment look something like this:
#Override
public void onStart() {
super.onStart();
// where mText is the title you want on your toolbar/actionBar
getActivity().setTitle(mText);
}
Probably worth having setRetainInstance(true) in the onCreate of your fragments as well.
tl;dr
Watch this:
https://youtu.be/ANpBWIT3vlU
Clone this:
https://github.com/shredderskelton/androidtemplate.
This is a really common problem and one that I've overcome by creating a kind of template project which I use whenever I start a new Android project. The idea is to abstract as much of the logic that handles the back button, the 'hamburger' indicator and fragment management into reusable classes:
Start by creating a BaseActivity and BaseFragment class. This is where you are going to as much of the reusable code as possible.
Lets start with your BaseActivity
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
fragmentManager = getSupportFragmentManager();
fragmentHandler = new AddFragmentHandler(fragmentManager);
fragmentManager.addOnBackStackChangedListener(backStackListener);
}
The FragmentManager is the key to owning the back stack, so you need to listen for changes to the back stack from here. The AddFramentHandler is a little class I cooked up to make it easier to add Fragments, from Fragments. More on that later.
#Override
public void onBackPressed() {
if (sendBackPressToDrawer()) {
//the drawer consumed the backpress
return;
}
if (sendBackPressToFragmentOnTop()) {
// fragment on top consumed the back press
return;
}
//let the android system handle the back press, usually by popping the fragment
super.onBackPressed();
//close the activity if back is pressed on the root fragment
if (fragmentManager.getBackStackEntryCount() == 0) {
finish();
}
}
onBackPressed is where most of the magic happens. You notice the plain text formatting of the methods.. I'm a huge Clean Code fan - if you need to write comments, your code isn't clean. Basically you need to really have a central place where you can run to when you're not sure why a back button press is not happening the way you expect. This method is that place.
private void syncDrawerToggleState() {
ActionBarDrawerToggle drawerToggle = getDrawerToggle();
if (getDrawerToggle() == null) {
return;
}
if (fragmentManager.getBackStackEntryCount() > 1) {
drawerToggle.setDrawerIndicatorEnabled(false);
drawerToggle.setToolbarNavigationClickListener(navigationBackPressListener); //pop backstack
} else {
drawerToggle.setDrawerIndicatorEnabled(true);
drawerToggle.setToolbarNavigationClickListener(drawerToggle.getToolbarNavigationClickListener()); //open nav menu drawer
}
}
This is the other key part of the BaseActivity. Basically this method checks whether you are at the root fragment and sets up the indicator accordingly. Notice that it changes the listener depending on how many fragments are in the back stack.
Then there is the BaseFragment:
#Override
public void onResume() {
super.onResume();
getActivity().setTitle(getTitle());
}
protected abstract String getTitle();
The code above shows how the title is handled by the fragments.
Try something like this:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
if (getSupportActionBar()!=null) {
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
}
drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
final ActionBarDrawerToggle drawerToggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.addDrawerListener(drawerToggle);
drawerToggle.syncState();
final View.OnClickListener originalToolbarListener = drawerToggle.getToolbarNavigationClickListener();
final View.OnClickListener navigationBackPressListener = new View.OnClickListener() {
#Override
public void onClick(View v) {
getFragmentManager().popBackStack();
}
};
getFragmentManager().addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
if (getFragmentManager().getBackStackEntryCount() > 0) {
drawerToggle.setDrawerIndicatorEnabled(false);
drawerToggle.setToolbarNavigationClickListener(navigationBackPressListener);
} else {
drawerToggle.setDrawerIndicatorEnabled(true);
drawerToggle.setToolbarNavigationClickListener(originalToolbarListener);
}
}
});
// Though below steps are not related but I have included to show drawer close on Navigation Item click.
navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(MenuItem item) {
int id = item.getItemId();
/**
* handle item clicks using id
*/
drawer.closeDrawer(GravityCompat.START);
return true;
}
});
}
Handle the drawer state onBackPressed:
#Override
public void onBackPressed() {
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
To reload previous fragment on back press, always add the fragment transaction to back stack like this:
FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
SomeFragment fragmentToBeLoaded = new SomeFragment();
fragmentTransaction.replace(R.id.fragment_container, fragmentToBeLoaded,
fragmentToBeLoaded.getName());
fragmentTransaction.addToBackStack(fragmentToBeLoaded.getName());
fragmentTransaction.commit();
To dynamically change the page title, you can call this from every Fragments onStart or onResume method:
#Override
public void onStart() {
super.onStart();
getActivity().setTitle("Title for fragment");
}
Note: I have considered standard layout declaration and thus I have not included any layouts.
"Page title - Changing the page titles whenever a fragment in pushed and popped"
When you remove a fragment, there is the method isRemoving(). It helps to change title back.
#Override
public void onStop() {
super.onStop();
if (isRemoving()) {
// Change your title here
}
}
"functionality to Menu and Back nav"
Suggestion: we have to rely on the default android navigation system. If we use addToBackStack() for our fragments, in theory we don't have to override onBackPressed() at all.
"App does not redefine the expected function of a system icon (such as the Back button)."
"App supports standard system Back button navigation and does not make use of any custom, on-screen "Back button" prompts."
Core App Quality: https://developer.android.com/distribute/essentials/quality/core.html
"Managing the Hamburger/Back button at left top"
I suggest to use activity instead of 'MainActivityDetailFragment' to avoid complication.
Add this in your MainActivity where you are calling Fragments. getBackStackEntryCount() Return number of fragments in the back stack. where the fragment on the bottom of the stack has index 0. popBackStack() Pop the top Fragment off the back stack
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == android.R.id.home) {
if (getSupportFragmentManager().getBackStackEntryCount() == 1) {
getSupportFragmentManager().popBackStack();
} else {
super.onBackPressed();
}
}
return true;
}
And in your Fragment where you want to go back use this function
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == android.R.id.home) {
getActivity().onBackPressed();
}
return true;
}
Ok, after a lot of tests I finally succeeded to setup a good navigation. I needed exactly the same as you, the only difference is that I am using v4 Fragments, but I don't think this will change anything here.
I am not using ActionBarDrawerToggle since the latest examples from Google do not use this component anymore.
The solution below also works for deep navigation: parent activity --> fragment --> fragment etc.
The only change needed in the Fragments is to change the title:
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
getActivity().setTitle(R.string.targets);
}
In the parent Activity onCreate method, I initialize the following:
mNavigationView = (NavigationView) findViewById(R.id.navigation_view);
setupDrawerContent(mNavigationView);
final Toolbar toolbar = (Toolbar) findViewById(R.id.drawer_toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setHomeAsUpIndicator(R.drawable.ic_menu_24);// Set the hamburger icon
getSupportActionBar().setDisplayHomeAsUpEnabled(true);// Set home button pressable
// Handle the changes on the actionbar
getSupportFragmentManager().addOnBackStackChangedListener(
new FragmentManager.OnBackStackChangedListener() {
public void onBackStackChanged() {
// When no more fragments to remove, we display back the hamburger icon and the original activity title
if (getSupportFragmentManager().getBackStackEntryCount() <= 0) {
getSupportActionBar().setHomeAsUpIndicator(R.drawable.ic_menu_24);
setTitle(R.string.app_name);
}
// Else displays the back arrow
else {
getSupportActionBar().setHomeAsUpIndicator(R.drawable.ic_arrow_back_24);
}
}
});
Here is now the code to handle the action on the Home button:
#Override
public boolean onOptionsItemSelected(MenuItem item){
// Close the soft keyboard right away
Tools.setSoftKeyboardVisible(mViewPager, false);
switch (item.getItemId()) {
case android.R.id.home:
// When no more fragments to remove, open the navigation drawer
if (getSupportFragmentManager().getBackStackEntryCount() <= 0) {
mDrawerLayout.openDrawer(GravityCompat.START);
}
// Removes the latest fragment
else {
getSupportFragmentManager().popBackStack();
}
return true;
}
return super.onOptionsItemSelected(item);
}
And finally the code to handle the back press action:
#Override
public void onBackPressed() {
// When no more fragments to remove, closes the activity
if (getSupportFragmentManager().getBackStackEntryCount() <= 0) {
super.onBackPressed();
}
// Else removes the latest fragment
else {
getSupportFragmentManager().popBackStack();
}
}
NOTE: I am using an AppCompatActivity, a NavigationView and the theme Theme.AppCompat.Light.NoActionBar.
I'm building a pretty simple app. At it's core are 2 screens:
1) list-screen: a list of items
2) detail-screen: a detailed view of an item
I used one Activity (which extends AppCompatActivity) with an Action-Bar, a Navigation-Drawer and a main-content part (a FrameLayout).
I used 2 different fragments for the 2 screens:
When opening the app I inflate the list-fragment into the main-content part.
When an item in the list is clicked I inflate the detail-fragment into the main-content part and it all works well.
On the detail-screen I want the Action-Bar to display an up-button that goes back to the list-screen.
Considering the fact that I am using fragments, rather than separate activites, how can I achieve that?
You can enable the up button each time the Detail Fragment loads, and disable it whenever any of the other Fragments load.
First define these methods in your Activity, which you can call from the Fragments in order to show/hide the up button:
public void showUpButton() {
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
}
public void hideUpButton() {
getSupportActionBar().setDisplayHomeAsUpEnabled(false);
}
You will probably want to just enable the up button in on Resume() of the detail Fragment (MainActivity is just an example, change to the name of your Activity) .....
#Override
public void onResume() {
super.onResume();
MainActivity activity = (MainActivity)getActivity();
if (activity != null) {
activity.showUpButton();
}
}
Then in the other Fragments:
#Override
public void onResume() {
super.onResume();
MainActivity activity = (MainActivity)getActivity();
if (activity != null) {
activity.hideUpButton();
}
}
The next thing is to make the up button actually go back. First ensure that you're adding the Fragment with the up button to the back stack, and then add this to that Fragment.
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
((MainActivity)getActivity()).onBackPressed();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
Then in the Activity, override onBackPressed() and pop from the back stack if the FragmentManager has any entries:
#Override
public void onBackPressed() {
FragmentManager fragmentManager = getSupportFragmentManager();
if (fragmentManager.getBackStackEntryCount() > 1) {
fragmentManager.popBackStackImmediate();
} else {
super.onBackPressed();
}
}
In a Bluetooth-related app (with minSdkVersion="18") I have a single MainActivity.java, displaying one of the following 3 UI Fragments:
MainFragment.java (the top screen)
SettingsFragment.java (settings screen, entered through menu)
ScanningFragment.java (lists nearby Bluetooth devices)
To display an "Up button" and handle the "Back button" I have the following code in place:
public class MainActivity extends Activity
implements BleWrapperUiCallbacks {
// set in onResume() of each fragment
private Fragment mActiveFragment = null;
´ #Override
public void onBackPressed() {
if (!getFragmentManager().popBackStackImmediate())
super.onBackPressed();
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_ACTION_BAR);
setContentView(R.layout.activity_root);
getActionBar().setDisplayHomeAsUpEnabled(true);
if (savedInstanceState == null) {
Fragment fragment = new MainFragment();
getFragmentManager().beginTransaction()
.replace(R.id.root, fragment, "main")
.commit();
}
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
getFragmentManager().popBackStackImmediate();
break;
case R.id.action_settings:
Fragment fragment = new SettingsFragment();
getFragmentManager().beginTransaction()
.addToBackStack(null)
.replace(R.id.root, fragment, "settings")
.commit();
break;
}
return super.onOptionsItemSelected(item);
}
This works well, but has a cosmetic problem, that the "Up button" is still displayed when the MainFragment.java is being displayed - as you can see on the left side of the above screenshot.
I have tried calling
getActionBar().setHomeButtonEnabled(false);
when that fragment is being active, but that only disables the "Up button" - without really hiding it.
With help of Little Child (thanks!) here my solution using the FragmentManager.OnBackStackChangedListener:
public class MainActivity extends Activity
implements OnBackStackChangedListener,
BleWrapperUiCallbacks {
#Override
public void onCreate(Bundle savedInstanceState) {
...
getFragmentManager().addOnBackStackChangedListener(this);
}
#Override
public void onBackStackChanged() {
getActionBar().setDisplayHomeAsUpEnabled(
getFragmentManager().getBackStackEntryCount() > 0);
}
You are in luck because in API level 18 there is this:
getActionBar().setHomeAsUpIndicator(R.drawable.ic_yourindicator);
for support library, it is:
getSupportActionBar().setHomeAsUpIndicator(R.drawable.ic_yourindicator);
So now depending upon what fragment you are in, you can change the icon of "up" button.
Also, try this:
getActionBar().setDisplayHomeAsUpEnabled(false);
Set whether home should be displayed as an "up" affordance.
2021 Working Solution:
(requireActivity() as AppCompatActivity).supportActionBar?.setHomeAsUpIndicator(null)
When using the Navigation Drawer the Android devs are recommending that in the ActionBar "only those screens that are represented in the Navigation Drawer should actually have the Navigation Drawer image" and that "all other screens have the traditional up carat."
See here for details: http://youtu.be/F5COhlbpIbY
I'm using one activity to control multiple levels of fragments and can get the Navigation Drawer image to display and function at all levels.
When creating lower level fragments I can call the ActionBarDrawerToggle setDrawerIndicatorEnabled(false) to hide the Navigation Drawer image and have the Up caret displayed
LowerLevelFragment lowFrag = new LowerLevelFragment();
//disable the toggle menu and show up carat
theDrawerToggle.setDrawerIndicatorEnabled(false);
getSupportFragmentManager().beginTransaction().replace(R.id.frag_layout,
lowFrag, "lowerFrag").addToBackStack(null).commit();
The problem I'm having is when I navigate back to the top level fragments the Up carat still shows instead of the original Navigation Drawer image. Any suggestions on how to "refresh" the ActionBar on the top level fragments to re-display the Navigation Drawer image?
Solution
Tom's suggestion worked for me. Here’s what I did:
MainActivity
This activity controls all fragments in the app.
When preparing new fragments to replace others, I set the DrawerToggle setDrawerIndicatorEnabled(false) like this:
LowerLevelFragment lowFrag = new LowerLevelFragment();
//disable the toggle menu and show up carat
theDrawerToggle.setDrawerIndicatorEnabled(false);
getSupportFragmentManager().beginTransaction().replace(R.id.frag_layout,
lowFrag).addToBackStack(null).commit();
Next, in an override of onBackPressed, I reverted the above by setting the DrawerToggle to setDrawerIndicatorEnabled(true) like this:
#Override
public void onBackPressed() {
super.onBackPressed();
// turn on the Navigation Drawer image;
// this is called in the LowerLevelFragments
setDrawerIndicatorEnabled(true)
}
In the LowerLevelFragments
In the fragments I modified onCreate and onOptionsItemSelected like this:
In onCreate added setHasOptionsMenu(true) to enable configuring the options menu. Also set setDisplayHomeAsUpEnabled(true) to enable the < in the actionbar:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// needed to indicate that the fragment would
// like to add items to the Options Menu
setHasOptionsMenu(true);
// update the actionbar to show the up carat/affordance
getActivity().getActionBar().setDisplayHomeAsUpEnabled(true);
}
Then in onOptionsItemSelected whenever the < is pressed it calls the onBackPressed() from the activity to move up one level in the hierarchy and display the Navigation Drawer Image:
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Get item selected and deal with it
switch (item.getItemId()) {
case android.R.id.home:
//called when the up affordance/carat in actionbar is pressed
getActivity().onBackPressed();
return true;
…
}
It's easy as 1-2-3.
If you want to achieve:
1) Drawer Indicator - when no fragments are in the Back Stack or the Drawer is opened
2) Arrow - when some Fragments are in the Back Stack
private FragmentManager.OnBackStackChangedListener
mOnBackStackChangedListener = new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
syncActionBarArrowState();
}
};
#Override
protected void onCreate(Bundle savedInstanceState) {
getSupportActionBar().setDisplayShowHomeEnabled(true);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
mDrawerToggle = new ActionBarDrawerToggle(
this,
mDrawerLayout,
R.drawable.ic_navigation_drawer,
0,
0
) {
public void onDrawerClosed(View view) {
syncActionBarArrowState();
}
public void onDrawerOpened(View drawerView) {
mDrawerToggle.setDrawerIndicatorEnabled(true);
}
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
getSupportFragmentManager().addOnBackStackChangedListener(mOnBackStackChangedListener);
}
#Override
protected void onDestroy() {
getSupportFragmentManager().removeOnBackStackChangedListener(mOnBackStackChangedListener);
super.onDestroy();
}
private void syncActionBarArrowState() {
int backStackEntryCount =
getSupportFragmentManager().getBackStackEntryCount();
mDrawerToggle.setDrawerIndicatorEnabled(backStackEntryCount == 0);
}
3) Both indicators to act according to their shape
#Override
public boolean onOptionsItemSelected(MenuItem item) {
if (mDrawerToggle.isDrawerIndicatorEnabled() &&
mDrawerToggle.onOptionsItemSelected(item)) {
return true;
} else if (item.getItemId() == android.R.id.home &&
getSupportFragmentManager().popBackStackImmediate()) {
return true;
} else {
return super.onOptionsItemSelected(item);
}
}
P.S. See Creating a Navigation Drawer on Android Developers on other tips about the 3-lines indicator behavior.
You have written that, to implement lower-level fragments, you are replacing the existing fragment, as opposed to implementing the lower-level fragment in a new activity.
I would think that you would then have to implement the back functionality manually: when the user pressed back you have code that pops the stack (e.g. in Activity::onBackPressed override). So, wherever you do that, you can reverse the setDrawerIndicatorEnabled.
I've used next thing:
getSupportFragmentManager().addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
if(getSupportFragmentManager().getBackStackEntryCount() > 0){
mDrawerToggle.setDrawerIndicatorEnabled(false);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
}
else {
getSupportActionBar().setDisplayHomeAsUpEnabled(false);
mDrawerToggle.setDrawerIndicatorEnabled(true);
}
}
});
If your up action bar button doesn't work, don't forget to add the listener :
// Navigation back icon listener
mDrawerToggle.setToolbarNavigationClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
onBackPressed();
}
});
I've got some trouble implementing a drawer navigation with a home button, everything worked except the action buton.
Try handling the Home item selection in the MainActivity depending on the state of the DrawerToggle. This way you don't have to add same code to every fragment.
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Only handle with DrawerToggle if the drawer indicator is enabled.
if (mDrawerToggle.isDrawerIndicatorEnabled() &&
mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
// Handle action buttons
switch (item.getItemId()) {
// Handle home button in non-drawer mode
case android.R.id.home:
onBackPressed();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
FOLLOW UP
The solution given by #dzeikei is neat, but it can be extended, when using fragments, to automatically handle setting back the drawer indicator when the backstack is empty.
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Only handle with DrawerToggle if the drawer indicator is enabled.
if (mDrawerToggle.isDrawerIndicatorEnabled() &&
mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
// Handle action buttons
switch (item.getItemId()) {
// Handle home button in non-drawer mode
case android.R.id.home:
// Use getSupportFragmentManager() to support older devices
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.popBackStack();
// Make sure transactions are finished before reading backstack count
fragmentManager.executePendingTransactions();
if (fragmentManager.getBackStackEntryCount() < 1){
mDrawerToggle.setDrawerIndicatorEnabled(true);
}
return true;
default:
return super.onOptionsItemSelected(item);
}
}
EDIT
For the question of #JJD.
The fragments are held/managed in an activity. The above code is written once in that activity, but only handle the up caret for the onOptionsItemSelected.
In one of my apps I also needed to handle the behavior of the up caret when the back button was pressed. This can be handle by overriding onBackPressed.
#Override
public void onBackPressed() {
// Use getSupportFragmentManager() to support older devices
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.executePendingTransactions();
if (fragmentManager.getBackStackEntryCount() < 1){
super.onBackPressed();
} else {
fragmentManager.executePendingTransactions();
fragmentManager.popBackStack();
fragmentManager.executePendingTransactions();
if (fragmentManager.getBackStackEntryCount() < 1){
mDrawerToggle.setDrawerIndicatorEnabled(true);
}
}
};
Note the code duplication between onOptionsItemSelected and onBackPressed which can be avoided by creating a method and calling that method in both places.
Also note I add two more times executePendingTransactions which in my case was required or else I had sometimes strange behaviors of the up caret.
I created an interface for the hosting activity to update the view state of the hamburger menu. For top level fragments I set the toggle to true and for fragments for which I want to display the up < arrow I set the toggle to false.
public class SomeFragment extends Fragment {
public interface OnFragmentInteractionListener {
public void showDrawerToggle(boolean showDrawerToggle);
}
private OnFragmentInteractionListener mListener;
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
this.mListener = (OnFragmentInteractionListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString() + " must implement OnFragmentInteractionListener");
}
}
#Override
public void onResume() {
super.onResume();
mListener.showDrawerToggle(false);
}
}
Then in my Activity ...
public class MainActivity extends Activity implements SomeFragment.OnFragmentInteractionListener {
private ActionBarDrawerToggle mDrawerToggle;
public void showDrawerToggle(boolean showDrawerIndicator) {
mDrawerToggle.setDrawerIndicatorEnabled(showDrawerIndicator);
}
}
This answer was working but there was a little problem with it.
The getSupportActionBar().setDisplayHomeAsUpEnabled(false) was not called explicitly and it was causing drawer icon to be hidden even when there were no items in the backstack so changing the setActionBarArrowDependingOnFragmentsBackStack() method worked for me.
private void setActionBarArrowDependingOnFragmentsBackStack() {
int backStackEntryCount = getSupportFragmentManager()
.getBackStackEntryCount();
// If there are no items in the back stack
if (backStackEntryCount == 0) {
// Please make sure that UP CARAT is Hidden otherwise Drawer icon
// wont display
getSupportActionBar().setDisplayHomeAsUpEnabled(false);
// Display the Drawer Icon
mDrawerToggle.setDrawerIndicatorEnabled(true);
} else {
// Show the Up carat
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
// Hide the Drawer Icon
mDrawerToggle.setDrawerIndicatorEnabled(false);
}
}
Logic is clear.
Show back button if fragment back stack is clear.
Show material hamburger-back animation if fragment stack is not clear.
getSupportFragmentManager().addOnBackStackChangedListener(
new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
syncActionBarArrowState();
}
}
);
private void syncActionBarArrowState() {
int backStackEntryCount = getSupportFragmentManager().getBackStackEntryCount();
mNavigationDrawerFragment.setDrawerIndicatorEnabled(backStackEntryCount == 0);
}
//add these in Your NavigationDrawer fragment class
public void setDrawerIndicatorEnabled(boolean flag){
ActionBar actionBar = getActionBar();
if (!flag) {
mDrawerToggle.setDrawerIndicatorEnabled(false);
actionBar.setDisplayHomeAsUpEnabled(true);
mDrawerToggle.setHomeAsUpIndicator(getColoredArrow());
} else {
mDrawerToggle.setDrawerIndicatorEnabled(true);
}
mDrawerToggle.syncState();
getActivity().supportInvalidateOptionsMenu();
}
//download back button from this(https://www.google.com/design/icons/) website and add to your project
private Drawable getColoredArrow() {
Drawable arrowDrawable = ContextCompat.getDrawable(getActivity(), R.drawable.ic_arrow_back_black_24dp);
Drawable wrapped = DrawableCompat.wrap(arrowDrawable);
if (arrowDrawable != null && wrapped != null) {
// This should avoid tinting all the arrows
arrowDrawable.mutate();
DrawableCompat.setTint(wrapped, Color.GRAY);
}
return wrapped;
}
If you take a look at the GMAIL app and come here to search for the carret/affordance icon..
I would ask you to do this, none of the above answer was clear. i was able to modify the accepted answer.
NavigationDrawer --> Listview contains subfragments.
subfragments will be listed like this
firstFragment == position 0 ---> this will have subfragments --> fragment
secondFragment
thirdFragment and so forth....
In firstFragment you have other fragment.
Call this on DrawerActivity
getFragmentManager().addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
if (getFragmentManager().getBackStackEntryCount() > 0) {
mDrawerToggle.setDrawerIndicatorEnabled(false);
} else {
mDrawerToggle.setDrawerIndicatorEnabled(true);
}
}
});
and in fragment
setHasOptionsMenu(true);
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Get item selected and deal with it
switch (item.getItemId()) {
case android.R.id.home:
//called when the up affordance/carat in actionbar is pressed
activity.onBackPressed();
return true;
}
return false;
}
On the OnBackPressed Drawer activity method set the drawer toggle to true to enable navigation list icon again.
Thanks,
Pusp
You can look at this little example!
https://github.com/oskarko/NavDrawerExample
IMO, using onNavigateUp() (as shown here) in riwnodennyk's or Tom's solution is cleaner and seems to work better. Just replace the onOptionsItemSelected code with this:
#Override
public boolean onSupportNavigateUp() {
if (getSupportFragmentManager().getBackStackEntryCount() > 0) {
// handle up navigation
return true;
} else {
return super.onSupportNavigateUp();
}
}