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BottomNavigationView doesn't appear after running it in the emulator

my BottomNavigationView appear in the preview of the android studio but when i run it in emulator it doesn't appear so it's only the fragment which appear in the emulator and the program isn't give me any error so i tried to switch the home page layout and it also doesn't appear!
and here is my code
in the Home_activity xml
public class HomeActivity extends AppCompatActivity {
#Override
public void onCreate(#Nullable Bundle savedInstanceState, #Nullable PersistableBundle persistentState) {
super.onCreate(savedInstanceState, persistentState);
setContentView(R.layout.activity_home);
BottomNavigationView bottomNavigationView =findViewById(R.id.nav_view);
bottomNavigationView.setOnNavigationItemSelectedListener(navlistener);
}
private BottomNavigationView.OnNavigationItemSelectedListener navlistener = new BottomNavigationView.OnNavigationItemSelectedListener(){
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem menuItem) {
Fragment selectedFragment =null;
switch (menuItem.getItemId()){
case R.id.navigation_home:
selectedFragment=new Home_fragment();
break;
case R.id.navigation_dashboard:
selectedFragment=new Dashboard_fragment();
break;
case R.id.navigation_notifications:
selectedFragment=new Notificatons_fragment();
break;
}
//to show them
getSupportFragmentManager().beginTransaction().replace(R.id.nav_host_fragment,selectedFragment).commit();
return true;
}
};
}
in xml of the home layout page
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingTop="?attr/actionBarSize">
<fragment
android:id="#+id/nav_host_fragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="#id/nav_view"/>
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="#+id/nav_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
app:menu="#menu/bottom_nav_menu"
/>
</RelativeLayout>

Add library in gradle file
dependencies {
implementation 'com.google.android.material:material:1.1.0'
}
Xml file without fragment tag. fragment is giving error on my side.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingTop="?attr/actionBarSize">
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="#+id/nav_view"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:layout_alignParentBottom="true"
app:menu="#menu/bottom_nav_menu"
/>
</RelativeLayout>
bottom_nav_menu.xml file in menu folder in res
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
<item
android:id="#+id/home"
android:icon="#android:drawable/arrow_down_float"
android:title="home" />
<item
android:id="#+id/id1"
android:icon="#android:drawable/btn_plus"
android:title="deeplink" />
</menu>
You can change your custom icons in menu.
Try it. Hopefully, may resolve you issue your issue. I have tested it
on Android Q emulator. Thanks in advance.

onNavigationItemSelected not being called for Bottom Navigation Bar

I'm trying to implement a bottom nav bar that changes fragments when the nav items are clicked. However, when I click on the nav bar items, the fragments don't change. Using log.d, I noticed onNavigationItemSelected is not being called. How do I fix this?
To note, the startFeedFragment, startScheduleFragment, & startSettingsFragmentare implemented the same way and they work for the buttons in the toolbar. I also referenced this tutorial and this question for help.
MainActivity.java
public class MainActivity extends AppCompatActivity implements BottomNavigationView.OnNavigationItemSelectedListener {
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
setUpRecycler();
startFeedFragment();
BottomNavigationView bottomNavBar = (BottomNavigationView) findViewById(R.id.navigation);
bottomNavBar.bringToFront();
bottomNavBar.setOnNavigationItemSelectedListener(this);
}
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
Log.d("NAV BAR", "onNavigationItemSelected hit");
switch (item.getItemId()) {
case R.id.feedMenu:
startFeedFragment();
Log.d("NAV BAR", "feed");
break;
case R.id.myScheduleMenu:
startScheduleFragment();
Log.d("NAV BAR", "schedule");
break;
case R.id.settingsMenu:
startSettingsFragment();
Log.d("NAV BAR", "settings lol");
break;
default:
Log.d("NAV BAR", "false");
return false;
}
return true;
}
/**
* Switches out the fragment for {#link FeedFragment} and sets an appropriate title. startScheduleFragmens & startSettingsFragment are implemented the same way
*/
private void startFeedFragment()
{
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.fragmentContainer, new FeedFragment());
transaction.commit();
getSupportActionBar().setTitle(R.string.title_fragment_feed);
}
}
Snippet from xml file
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
<FrameLayout
android:id="#+id/fragmentContainer"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toTopOf="#+id/navigation"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<android.support.design.widget.BottomNavigationView
android:id="#+id/navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:itemBackground="#android:color/white"
app:itemIconTint="#color/colorPrimaryDark"
app:itemTextColor="#color/colorPrimaryDark"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:menu="#menu/bottom_nav"
android:elevation="8dp"/>
</android.support.constraint.ConstraintLayout>
</android.support.design.widget.CoordinatorLayout>

Solved! It was because I had set the buttons in the menu to android:enabled="false". That meant they couldn't be pressed, which is why onNavigationItemSelected wasn't being called. I set all buttons to android:enabled="true" to fix this.
Correct code for bottom_nav.xml
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
<item android:id="#+id/bottom_nav_my_schedule"
android:title="#string/menu_my_schedule"
android:icon="#drawable/ic_event_available_white_24dp"
android:enabled="true"/> <!--make sure enabled is set to true!-->
<item android:id="#+id/bottom_nav_feed"
android:title="#string/menu_feed"
android:icon="#drawable/ic_view_list_white_24dp"
android:enabled="true" /> <!--make sure enabled is set to true!-->
<item android:id="#+id/bottom_nav_settings"
android:title="#string/menu_settings"
android:icon="#drawable/ic_settings_white_24dp"
android:enabled="true"/> <!--make sure enabled is set to true!-->
</menu>

As for me the problem was when my activity main layout was LinearLayout, so I've solved it by changing it to RelativeLayout, I have absolutely no thoughts why it's working, because RelativeLayout layouts reply only for elements location, not its view or something else, but it's working.
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<android.support.v4.view.ViewPager
android:id="#+id/view_pager"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
<android.support.design.widget.BottomNavigationView
android:id="#+id/bottom_navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
app:itemBackground="#drawable/selector"
android:background="#color/white"
app:menu="#menu/menu_bottom"
app:itemIconTint="#drawable/menu_trainings"
app:labelVisibilityMode="unlabeled"
/>
</RelativeLayout>

Button in dialog not behaving as a button when clicked

After create and testing my custom dialog I've noticed that my button does not show any visual sign of change (such as the ripple effect or highlighting) when clicked. Does anyone know what I'm doing wrong and how to resolve this issue?
XML
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin">
<Button
android:id="#+id/world"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:layout_marginBottom="10dp"
android:padding="10dp"
android:background="#color/green"
android:textColor="#color/white"
android:text="#string/world"
android:textAllCaps="false"
style="#android:style/TextAppearance.Medium"/>
</LinearLayout>
Java
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_other_lines) {
final Dialog dialog = new Dialog(this);
dialog.setContentView(R.layout.dialog_hello_world);
dialog.setTitle("Dialog");
Button world = (Button) dialog.findViewById(R.id.world);
world.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
dialog.dismiss();
}
});
dialog.show();
}
return super.onOptionsItemSelected(item);
}

You override the default onClick effect by putting a background color.
android:background="#color/green"
You can do it by creating a custom background xml file on drawable, like this.
custom_background.xml
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_pressed="true" android:drawable="#color/Pressed_Color" />
<item android:state_activated="false" android:drawable="#color/green"/>
</selector>
then you call it on the button styling as like this:
android:background="#drawable/custom_background"

when you change your default appearance, you should handle different state if you want like this
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="#drawable/button_sel" android:state_selected="true" />
<item android:drawable="#drawable/button_sel" android:state_pressed="true" />
<item android:drawable="#drawable/button_unsel" />
</selector>
save this as xml drawable and add as android:background

Android setting custom actionbar

In my project i would to set a custom actionBar (with a custom layout) after a specific action.
I have this simple Activity:
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity2 extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_activity2);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main_activity2, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.action_settings:
//apriImpostazioni ();
return true;
case R.id.information_item:
//apriInformazioni ();
return true;
case R.id.search_item:
apriBarraRicerca ();
System.out.println ("IL BOTTONE RICERCA E' PREMUTO");
return true;
default:
return super.onOptionsItemSelected(item);
}
}
private void apriBarraRicerca () {
getActionBar ().setCustomView(getLayoutInflater().inflate(R.layout.search_layout, null));
}
}
Where "menu_main_activity2" is this xml:
<menu 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"
tools:context="zipangulu.myapplication.MainActivity2">
<item android:id="#+id/action_settings" android:title="#string/action_settings"
android:orderInCategory="100" app:showAsAction="never" />
<item android:id="#+id/information_item"
android:title="Info"
android:icon="#drawable/info"
android:orderInCategory="100"
app:showAsAction="always"/>
<item android:id="#+id/search_item"
android:title="Search"
android:icon="#drawable/search_icon"
android:orderInCategory="100"
app:showAsAction="always"/>
</menu>
I would, pressing the search_item on the main actionbar, set a custom actionBar whith this layout:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="wrap_content"
android:background="#4584d3">
<ImageButton
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:id="#+id/back_button"
android:background="#null"
android:src="#drawable/back_icon"/>
<AutoCompleteTextView
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="6"
android:id="#+id/campo_ricerca"/>
<Spinner
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="2"
android:spinnerMode="dropdown"
android:id="#+id/spinner_anno"/>
<ImageButton
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:src="#drawable/search_icon"
android:id="#+id/avvia_ricerca"/>
</LinearLayout>
But at runtime I have a NullPointerException in the body of "apriBarraRicerca" method..why?How can I fix this problem?
EDIT: as suggested I replaced "getActionBar ()" with "getSupportActionBar ()", now I don't have any exception but nothing happens.
EDIT2: I added getSupportActionBar().setDisplayShowCustomEnabled(true); and now my custom actionbar is visible but not as i want, look at the following image:
http://bit.ly/1Dc2kGg
The bar is visible but cutted, and are visible also the items of the previous actionBar..

You can try do the same thing with the android.support.v7.widget.ToolBar
Your Layout which you can populate as you desire:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:background="#688A08"
android:layout_height="?attr/actionBarSize">
</android.support.v7.widget.Toolbar>
You have to modify the values->styles.xml:
<resources>
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
</style>
</resources>
And the in the onCreate() method you do the following:
Toolbar tb = (Toolbar)findViewById(R.id.top_bar);
if(tb != null){
setSupportActionBar(tb);
}
Hope it helps!!!

change image in button while is pressed

i have this code
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_pressed="true"
android:drawable="#drawable/fundo" /> <!-- pressed -->
<item android:drawable="#drawable/fundo2" /> <!-- default -->
</selector>
in other file
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<Button android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#drawable/btn"
/>
</FrameLayout>
and in the class
#Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
mp.setLooping(true);
mp.start();
return true;
case MotionEvent.ACTION_UP:
mp.pause();
return true;
}
return true;
}
i don't know why, when the button is pressed the image don't change, what is the reason?
thanks!!

Instead of android:background="#drawable/btn" please use android:src="#drawable/btn".
It Works for me .

Inside ur xml, for the button background give ur selector xml file name.
<Button android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#drawable/ur state change xml file name"
/>

You can use setBackgroundResource(ResId) for the change on button u can write this in the OnClick() method of the Button.