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Why does my activity reset when I tap on the back button?

I have a back button in one activity and when I tap on it to return to the parent activity it will reset the parent activity. It's like onCreate() is being called again. I'm not sure why that is because when you tap on the back button it just calls finish() to exist the activity I'm currently in.
Here is how I'm declaring the toolbar:
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_item);
Toolbar toolbar = (Toolbar) findViewById(R.id.my_toolbar);
setSupportActionBar(toolbar);
if(getSupportActionBar() != null)
{
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setDisplayShowHomeEnabled(true);
}
This is what happens when you tap on the button:
public boolean onOptionsItemSelected(MenuItem item)
{
if (item.getItemId()==android.R.id.home)
{
finish();
}
return super.onOptionsItemSelected(item);
}
The strange this is that when I hit the save button I return to the parent activity without any reset. So I'm not sure why this is happening.

You need to return true or else it will always call the onCreat() method. Also, you can create an "empty" intent and just not process it on the activity you return true.
#Override
public boolean onOptionsItemSelected(MenuItem item)
{
if (item.getItemId()==android.R.id.home)
{
Intent intent = new Intent();
setResult(Intent_Constant.TAPPED_BACK_BUTTON, intent);
finish();
return true;
}
return super.onOptionsItemSelected(item);
}

pressed the back button on the toolbar [duplicate]

This question already has answers here:
When toolbar back button is pressed
(4 answers)
Closed 6 years ago.
how can I create a code for my android app where When I pressed the back button on the toolbar (Action Bar) some code will happening.
I tried but it does not work.
Added in main activity. onbackpress method
#Override
public void onBackPressed() {
super.onBackPressed();
stopActivityTask();
}

You can Try this way..
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
// this takes the user 'back', as if they pressed the left-facing
triangle icon on the main android toolbar.
// if this doesn't work as desired, another possibility is to call
stopActivityTask(); // finish() here.
getActivity().onBackPressed();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
If Not Work
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
// Title and subtitle
toolbar.setTitle(R.string.about_toolbar_title);
toolbar.setNavigationIcon(R.drawable.ic_action_back);
toolbar.setNavigationOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
stopActivityTask();
finish();
}
});

private Toolbar toolbar;
Then add this in your onCreate method
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
Then you add these lines :
#Override
public boolean onOptionsItemSelected(MenuItem item) {
/*
ADD WHAT YOU WANT TO DO WHEN ARROW IS PRESSED
*/
return super.onOptionsItemSelected(item);
}

#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
// click on icon to go back
//triangle icon on the main android toolbar.
if (id == android.R.id.home) {
//your code
return true;
}
return super.onOptionsItemSelected(item);
}

activity is called mutiple times when back navigation from toolbar is pressed

Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setTitle("Your Interests");
getSupportActionBar().setDisplayShowHomeEnabled(true);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
finish();
}
});
above is my code - where i am finishing/destroying my activity on calling finish() on back button is pressed.

How to implement android Toolbar Back button

I am using a custom toolbar. I need to add back button to it. Now I am using this code to add the back button.
Toolbar toolbar = (Toolbar) getActivity().findViewById(R.id.toolbar);
toolbar.setBackgroundColor(getResources().getColor(R.color.white));
toolbar.setNavigationIcon(getResources().getDrawable(R.drawable.back_arrow));
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
onBackPressed();
}
});
This works fine. I can see the back button added. But consider the case where I am in Fragment1 which has no back button. Now I move to Fragment2 and I add in Back Button. From Fragment 2 I open Fragment 3 and I add the back button again.
Now when I press back button from fragment3 to go back to fragment2 i have to check the Fragment Stack to see whether the back button is required in fragment 2 or not.
Is there any other way to handle back button automatically as we push fragments to stack?

Just add two new line of code. Something like this
Toolbar toolbar = (Toolbar) getActivity().findViewById(R.id.toolbar);
toolbar.setBackgroundColor(getResources().getColor(R.color.white));
toolbar.setNavigationIcon(getResources().getDrawable(R.drawable.back_arrow));
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
onBackPressed();
}
});

This assumes you are using an AppCompatActivity
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.tool_bar); // Attaching the layout to the toolbar object
setSupportActionBar(toolbar);
// enabling action bar app icon and behaving it as toggle button
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setHomeButtonEnabled(true);
}
Then in the onOptionsItemSelected you can override the home button as follows:
#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){
Intent i= new Intent(this, MainActivity.class);
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(i);
finish();
return true;
}
return super.onOptionsItemSelected(item);
}

You can handle back icon very easily. If all of your fragment are in single Activity I really recommend to handle this with following way :
first crate a abstract BaseFragment class which implement FragmentManager .OnBackStackChangedListener then put following method inside that :
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mainActivity = (MainActivity) getActivity();
getFragmentManager().addOnBackStackChangedListener(this);
shouldDisplayHomeUp();
}
#Override
public void onBackStackChanged() {
shouldDisplayHomeUp();
}
public boolean shouldDisplayHomeUp() {
//Enable Up button only if there are entries in the back stack
boolean canBack = false;
try {
canBack = getFragmentManager().getBackStackEntryCount() > 0;
} catch (Exception ex) {
// Log.e(getClass().getCanonicalName(), ex.getMessage());getMessage
}
if (canBack) {
mainActivity.drawerDisable();
} else {
mainActivity.drawerEnable();
}
return canBack;
}
By this way disableDrawer & enableDrawer function handle your Icon and OnBackPressed method handle your BackStack Now in your activity when you press back-icon display if needed. your onBackPressed should be something like this :
int backStackCount = getSupportFragmentManager().getBackStackEntryCount();
if (backStackCount == 0) {
//nothing exist in backStack OS handle it
super.onBackPressed();
} else {
getSupportFragmentManager().popBackStack();
}
See full implementation here.

use Method in Class your Activity
private void setupToolbar(){
Toolbar toolbar=(Toolbar)findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
ActionBar actionBar=getSupportActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setDisplayShowHomeEnabled(true);
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
finish();
}
});
}

It's works on back pressed function to toolbar
private setUpToolBar() {
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setDisplayShowHomeEnabled(true);
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
onBackPressed();
}
});
}

i have Main activity and Four fragments.
In MainActivity i write this code
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
onBackPressed();
}
});
this is working fine and if you have fragments then create a onBackPressed() method
#Override
public void onBackPressed() {
int position = mViewPager.getCurrentItem();
if(position == 2) { // go back to search / result tab from info detail tab
mViewPager.setCurrentItem(2);
} else if(position == 0) { // switch from result to search tab or go back to home tab
SectionsPagerAdapter sectionsPagerAdapter = (SectionsPagerAdapter) mViewPager.getAdapter();
Fragment fragment = sectionsPagerAdapter.getItem(position);
if(fragment instanceof ResultFragment) {
Bundle bundle = ((ResultFragment) fragment).getArguments();
if(bundle != null) {
sectionsPagerAdapter.replaceFragment(SearchFragment.newInstance(bundle.getString(GlobalInfo.TAG_ID), bundle.getString(GlobalInfo.PART_NO), bundle.getString(GlobalInfo.SERIAL_NO), bundle.getString(GlobalInfo.PART_NAME)), getString(R.string.search), 0);
}
} else {
mViewPager.setCurrentItem(1);
}
}
else if(position == 3){
SectionsPagerAdapter sectionsPagerAdapter = (SectionsPagerAdapter) mViewPager.getAdapter();
Fragment fragment = new ToolMgtFragment();
sectionsPagerAdapter.replaceFragment(fragment,"Tool Mgt", 3);
}
else {
super.onBackPressed();
}
}

"Back button" using getSupportActionbar and appcompat v7 toolbar

I'm using the new toolbar from the Appcompat V7 library and I'm making an application with navigation drawer and with fragments.
In some fragments I don't want to show the hamburger icon but the arrow instead... That is fine I did this in this way:
mDrawerToggle.setDrawerIndicatorEnabled(false);
mDrawerToggle.syncState();
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setHomeButtonEnabled(true);
getSupportActionBar().setDisplayShowHomeEnabled(true);
getSupportActionBar().setHomeAsUpIndicator(R.drawable.abc_ic_ab_back_mtrl_am_alpha);
My question is that: How or where i need to set up the home button lisener or what i need to listen for the "back" button ?
I want to call the main backpressed method and to set back the navigation drawer icon with the hamburger icon..

Add this method in onCreate():
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
Then override the onOptionItemSelected() as below:
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
onBackPressed();
return true;
default:
return super.onOptionsItemSelected(item);
}
}

You can do it like this:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
toolbar = (Toolbar)findViewById(R.id.toolbar);
if (toolbar != null) {
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
}
setUpNavigationDrawer();
getFragmentManager().addOnBackStackChangedListener(backStackListener); // listen to the backstack of the fragment manager
}
Define the onBackSTackChangedListener:
private FragmentManager.OnBackStackChangedListener backStackListener = new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
setNavIcon();
};
}
Set the icon according to your fragment's backstack:
protected void setNavIcon() {
int backStackEntryCount = getFragmentManager().getBackStackEntryCount();
drawerToggle.setDrawerIndicatorEnabled(backStackEntryCount == 0);
}
Detect when the drawer icon is pressed:
public boolean onOptionsItemSelected(MenuItem item) {
if (drawerToggle.isDrawerIndicatorEnabled() && drawerToggle.onOptionsItemSelected(item)) {
return true;
}
switch (item.getItemId()) {
case x:
return true;
default:
return false;
}
}
And handle the up button:
public boolean onSupportNavigateUp() {
onBackPressed();
return true;
}
This works for me. Good luck.

Not sure if this works in OP's case, but in many cases this is probably the simplest option to implement Back button with the AppCompat Toolbar.
Skip all the setHomeButtonEnabled, setDisplayHomeAsUpEnabled and onOptionsItemSelected stuff, and related issues.
Instead, when initialising the Toolbar, simply set 1) navigation icon and 2) navigation OnClickListener for it:
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
if (enableBackNavigation) {
toolbar.setNavigationIcon(R.drawable.ic_back);
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
onBackPressed();
}
});
}

1- Create Toolbar layout;
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:local="http://schemas.android.com/apk/res-auto"
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#color/dark_blue"
android:minHeight="?attr/actionBarSize"
local:popupTheme="#style/ThemeOverlay.AppCompat.Light"
local:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar" />
2- Include this in your layout at the place where you want the toolbar to be.
3- Paste the following code in your activity.(extends ActionBarActivity)
private Toolbar mToolbar;
//For Toolbar (Action bar) start
mToolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(mToolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setDisplayShowHomeEnabled(true);
mToolbar.setNavigationIcon(R.drawable.ic_back_arrow);
mToolbar.setNavigationOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
onBackPressed();
}
});
getSupportActionBar().setTitle("Event Details");
//For Toolbar (Action bar) end
4- change the back click icon to whatever you want.

activate the back button:
getActionBar().setDisplayHomeAsUpEnabled(enable);
and listen for clicks in onBackPressed()
Obviously your activity must extend ActionBarActivity

Simply you can set Navigation icon and make sure you are setting setNavigationOnClickListener() after setting setSupportActionBar(toolbar)
toolbar.setNavigationIcon(getResources().getDrawable(R.drawable.ic_arrow_back));
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
onBackPressed();
}
});

in manifest add these lines under the activity you want the back arrow working
android:parentActivityName="Your parent activity name"

Add setDisplayHomeAsUpEnabled(true)
Toolbar toolbar = findViewById(R.id.toolbar);
ActionBar actionBar = getSupportActionBar();
if (actionBar != null) {
actionBar.setDisplayHomeAsUpEnabled(true);
}
Handle the back button
public boolean onSupportNavigateUp() {
onBackPressed();
return true;
}