We Keep Coding

TabLayout swiping does not change Tab focus

I have a tabLayout and a viewPager underneath it. When I click on the tab, it switches tabs perfectly fine. However, when I swipe, the viewPage swipes over, but the tab does not change focus. I have to manually click on the corresponding tab in order to change the focus (viewPager does not change).
For example, if I'm on the 4th slide, and I swipe left, the viewPage goes to the 3rd slide, but the tab isn't focused over. I have to manually tap on the 3rd tab in order to change the focus.
I'm wondering how I can let the tabs follow the swiping when I swipe from view to view in the viewPager.
fragment XML:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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=".MainActivity">
<com.google.android.material.tabs.TabLayout
android:layout_height="wrap_content"
android:id="#+id/tab_layout"
android:layout_width="match_parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintBottom_toTopOf="#id/pager"/>
<androidx.viewpager.widget.ViewPager
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/pager"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/tab_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</androidx.constraintlayout.widget.ConstraintLayout>
PagerFragment:
public class PagerFragment extends Fragment {
ViewPagerAdapter pagerAdapter;
ViewPager pager;
TabLayout tl;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
pagerAdapter = new ViewPagerAdapter(this.getContext(), getChildFragmentManager(), 4, getActivity());
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final View view = super.onCreateView(inflater, container, savedInstanceState);
ViewGroup root = (ViewGroup) inflater.inflate(R.layout.fragment_pager, null);
pager = root.findViewById(R.id.pager);
pager.setAdapter(pagerAdapter);
tl = root.findViewById(R.id.tab_layout);
tl.addTab(tl.newTab().setText("1"));
tl.addTab(tl.newTab().setText("2"));
tl.addTab(tl.newTab().setText("3"));
tl.addTab(tl.newTab().setText("4"));
tl.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
pager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
tl.addOnTabSelectedListener(new TabLayout.ViewPagerOnTabSelectedListener(pager));
return root;
}
}
Adapter:
public class ViewPagerAdapter extends FragmentPagerAdapter {
private Context myContext;
int totalTabs;
public ViewPagerAdapter(Context context, FragmentManager fm, int totalTabs, FragmentActivity fa) {
super(fm);
myContext = context;
this.totalTabs = totalTabs;
}
public Fragment getItem(int position) {
graph_test gt = new graph_test(String.valueOf(position), position);
return gt;
}
#Override
public int getCount() {
return totalTabs;
}
}
Note: I know that FragmentPagerAdapter is deprecated. I was asked to do it this way.
Thanks.

Using the androidx.viewpager.widget.ViewPager you have to set also the ViewPager.OnPageChangeListener with TabLayout.TabLayoutOnPageChangeListener like the below:
pager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tl));
By doing the above you should be able to change the Tab focus when swiping the ViewPager left or right.

onViewCreated() use
TabLayoutMediator(tabLayout, viewPager){ tab, position ->
// set tab text by given *position*
tab.text = "Tab_{position}" // for example
}.atach()
to link TabLayout and ViewPager and atach it

How to Load fragment when the app launches

I have created an app which basically has navigation drawer and I wish to load an fragment "home" whenever the activity launches instead of main activity.
Any idea how to do it.

You can call this method to view Fragments. In your case call this method on your onCreate()
//Fragment Changer
public void changeFragment(Fragment targetfragment) {
getSupportFragmentManager()
.beginTransaction()
.replace(R.id.content_fragment, targetfragment, "fragment")
.setTransitionStyle(FragmentTransaction.TRANSIT_FRAGMENT_FADE)
.addToBackStack(null)
.commitAllowingStateLoss();
}
Example Usage
changeFragment(new YourFragment());

Basic solution can be implementing something like the below code in your onCreate method.
// get fragment manager
FragmentManager fm = getFragmentManager();
// replace
FragmentTransaction ft = fm.beginTransaction();
ft.replace(R.id.main_layout, new HomeFragment());
ft.commit();

Your Activity:
public class MainActivity extends AppCompatActivity {
public static final String TAG = MainActivity.class.getSimpleName();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity);
}
public String getHelloMessage() {
return "Hello!";
}
}
Your View:
public class MainView extends Fragment {
// Declarations
private Button testButton;
#Override
public View onCreateView(#NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.main_view, container, false);
// Getting the reference of controller from Application
MainController mainController = Application.getInstance().getMainController();
// Initializing view objects
testButton = view.findViewById(R.id.test_button);
// Setting actions
testButton.setOnClickListener(mainController.getTestAction());
return view;
}
// Reference to the view Object
public Button getTestButton() {
return testButton;
}
Your main_activity.xm lto connect the fragment
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/containerMainView"
android:layout_width="match_parent"
android:layout_height="match_parent">
<fragment
android:id="#+id/mainView"
android:name="com.template.views.MainView"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</FrameLayout>
Your main_view.xml file your final view definition
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<Button
android:id="#+id/test_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:text="#string/say_hello" />
</RelativeLayout>

How can I nest fragments with a navigation drawer?

I've been trying for the last few hours to search around SO, but I couldn't find a solution outside of trying to create a workaround. I'm trying to create a navigation drawer for my app, but to do so I had to end up trying to change my base activity into a fragment. This is the result:
public class ToolReaderActivity extends Fragment implements ToolListFragment.OnToolSelectedListener, CompatActionBarNavListener, OnClickListener {
boolean mIsDualPane = false;
Context c;
ToolListFragment mToolListFragment;
InfoFragment mInfoFragment;
Fragment mContent;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
c = getActivity();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.onepane_with_bar, container, false);
// find our fragments
mToolListFragment = (ToolListFragment) getActivity().getSupportFragmentManager().findFragmentById(R.id.toolList);
mInfoFragment = (InfoFragment) getActivity().getSupportFragmentManager().findFragmentById(R.id.toolInfo);
FragmentTransaction transaction = getActivity().getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.toolList, mToolListFragment).commit();
FragmentTransaction transaction2 = getActivity().getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.toolInfo, mInfoFragment).commit();
mToolListFragment.setContext(c);
mToolListFragment.setOnToolSelectedListener(this);
View infoView = getView().findViewById(R.id.toolInfo);
mIsDualPane = infoView != null && infoView.getVisibility() == View.VISIBLE;
int catIndex = savedInstanceState == null ? 0 : savedInstanceState.getInt("catIndex", 0);
setUpActionBar(mIsDualPane, catIndex);
mToolListFragment.setSelectable(mIsDualPane);
restoreSelection(savedInstanceState);
if (savedInstanceState != null) {
//Restore the fragment's instance
mContent = getActivity().getSupportFragmentManager().getFragment(savedInstanceState, "mContent");
}
return rootView;
}
...
...
...
}
The intended output is a activity with a navigation drawer and thus a fragment. The fragment contains this main activity ToolReaderActivity (named so because it was formerly an activity) which has 1-2 fragments inside of it. It's a ListFragment with a fragment showing the selected items information (as either another fragment if mDualPane is true or launched as a seperate activity otherwise).
I can't figure out a way to get this to work, I've tired changing the order that things are done using onCreate, onCreateView, onActivityCreated, but the error I keep getting is that mToolsListFragment is null at mToolsListFragment.setContext(c);

You can simply create NavigationDrawer with the code below.
public class MainActivity extends AppCompatActivity
{
private NavigationView mNavigationView;
private DrawerLayout mDrawerLayout;
private Toolbar toolbar;
private ActionBarDrawerToggle mDrawerToggle;
private FragmentActivity fragment;
private FragmentManager fragmentManager;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initDrawerNavigation();
fragmentManager = getFragmentManager();
}
public void initDrawerNavigation()
{
toolbar = (Toolbar) findViewById(R.id.toolbar);
toolbar.setTitle(R.string.app_name);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayShowHomeEnabled(true);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mNavigationView = (NavigationView) findViewById(R.id.navigation_view);
mNavigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener()
{
#Override
public boolean onNavigationItemSelected(MenuItem item)
{
item.setChecked(true);
switch (item.getItemId())
{
case R.id.st_menu:
fragment = new FirstFragment();
break;
case R.id.nd_menu:
fragment = new Second Fragment();
break;
}
fragmentManager.beginTransaction().replace(R.id.container, fragment).commit();
mDrawerLayout.closeDrawers();
return true;
}
});
mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout, toolbar, R.string.drawer_open,
R.string.drawer_close)
{
// Called when a drawer has settled in a completely closed state.
public void onDrawerClosed(View view)
{
super.onDrawerClosed(view);
}
// Called when a drawer has settled in a completely open state.
public void onDrawerOpened(View drawerView)
{
super.onDrawerOpened(drawerView);
}
};
mDrawerLayout.addDrawerListener(mDrawerToggle);
}
#Override
protected void onPostCreate(Bundle savedInstanceState)
{
super.onPostCreate(savedInstanceState);
mDrawerToggle.syncState();
}
#Override
public boolean onCreateOptionsMenu(Menu menu){
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item){
switch(item.getItemId())
{
case android.R.id.home:
mDrawerLayout.openDrawer(GravityCompat.START); // OPEN DRAWER
return true;
}
return super.onOptionsItemSelected(item);
}
}
Here you have activity_main.xml
<?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="match_parent"
android:orientation="vertical">
<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="?attr/colorPrimary"
android:minHeight="?attr/actionBarSize"
app:theme="#style/ThemeOverlay.AppCompat.ActionBar" />
<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:paddingBottom="#dimen/activity_vertical_margin"
tools:context=".MainActivity">
<include
layout="#layout/your_layout" />
<android.support.design.widget.NavigationView
android:id="#+id/navigation_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:choiceMode="singleChoice"
app:menu="#menu/navigation_items" />
</android.support.v4.widget.DrawerLayout>
</LinearLayout>
your_layout can be anything you want. Now you define your FirstFragment class like here:
public class FirstFragment extends Fragment
{
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
ViewGroup view = (ViewGroup) inflater.inflate(R.layout.target_layout, container, false);
return view;
}
}
You can also refer to this question Navigation Drawer to switch between activities if you want to switch between activities and not fragments. Hope this helps.

invalidateOptionsMenu() not working when "restarting" activity

I have an activity, let's call it FirstActivity.java, which has an actionBar with a navigation drawer instantiated via fragment. In this fragment, NavigationDrawerFragment.java, I've put the methods onCreateOptionsMenu(Menu menu, MenuInflater inflater), onOptionsItemSelected(MenuItem item) and onPrepareOptionsMenu(Menu menu) as anyone normally would in order to instantiate the actionBar. On the right side of the actionBar, I have a button with a "messages" icon that leads to the user's inbox fragment. When a new message incomes, I call invalidateOptionsMenu() inside my FirstActivity and change the icon to a brighter one in onPrepareOptionsMenu(Menu menu). Everything works fine so far.
The problem is: I can leave the FirstAcitivty via one of the options in the navigation drawer. I do it via Intent. Let's call it SecondActivity.java.
Intent myIntent = new Intent(FirstActivity.this, SecondActivity.class);
startActivity(myIntent);
finish();
When I call the FirstAcitivity again, also via Intent, the invalidateOptionsMenu() method stops working. It does not trigger the methods onCreateOptionsMenu nor onPrepareOptionsMenu. I have also tried supportInvalidateOptionsMenu() with no luck.
Only when I hit the MENU BUTTON (on the left side of the actionBar) is that these methods are called and the messages icon is changed. Does anyone know the reason for this strange behavior?
Better yet, does anyone know a solution for my problem? : )
FirstActivity.java
public class FirstActivity extends ActionBarActivity impements NavigationDrawerFragment.NavigationDrawerCallbacks {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.first_activity);
// When a new message arrives
if (thereIsAnIncomingMessage) {
invalidateOptionsMenu();
}
}
}
first_activity.xml
<?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="match_parent"
android:orientation="vertical" android:id="#+id/first_activity_layout">
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".FirstActivity">
<!-- As the main content view, the view below consumes the entire
space available using match_parent in both dimensions. -->
<FrameLayout android:id="#+id/container" android:layout_width="match_parent"
android:layout_height="match_parent" />
<!-- android:layout_gravity="start" tells DrawerLayout to treat
this as a sliding drawer on the left side for left-to-right
languages and on the right side for right-to-left languages.
If you're not building against API 17 or higher, use
android:layout_gravity="left" instead. -->
<!-- The drawer is given a fixed width in dp and extends the full height of
the container. -->
<fragment android:id="#+id/navigation_drawer"
android:layout_width="#dimen/navigation_drawer_width" android:layout_height="match_parent"
android:layout_gravity="start"
android:name="com.example.Controller.Main.NavigationBar.NavigationDrawerFragment"
tools:layout="#layout/fragment_navigation_drawer" />
</android.support.v4.widget.DrawerLayout>
</LinearLayout>
NavigationDrawerFragment.java
public class NavigationDrawerFragment extends Fragment {
private RelativeLayout relativeLayout;
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
setHasOptionsMenu(true);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
relativeLayout = inflater.inflate(R.layout.fragment_navigation_drawer, container, false);
return relativeLayout;
}
#Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
super.onCreateOptionsMenu(menu, inflater);
menu.clear();
inflater.inflate(R.menu.menu_main, menu);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
if (item.getItemId() == R.id.action_menu) {
// Open navigation drawer menu
return mDrawerToggle.onOptionsItemSelected(item) || super.onOptionsItemSelected(item);
} else if (item.getItemId == R.id.action_chat) {
// Open messages fragment
MessagesFragment messagesFragment = new MessagesFragment();
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.container, messagesFragment, "MESSAGES_FRAGMENT");
fragmentTransaction.addToBackStack("chatFrag");
fragmentTransaction.commit();
}
}
#Override
public void onPrepareOptionsMenu(Menu menu) {
super.onPrepareOptionsMenu(menu);
if (FirstActivity.thereIsAnIncomingMessage) {
menu.getItem(0).setIcon(R.drawable.new_message_icon);
} else {
menu.getItem(0).setIcon(R.drawable.message_icon);
}
}
public interface NavigationDrawerCallbacks {
void onNavigationDrawerItemSelected(int position);
}
}

The problem is that the OnCreate method of FirstActivity is not called when you hit the back button. Instead, you can put your code in OnResume, as follows:
#Override
public void onResume(){
super.onResume();
if(thereIsAnIncomingMessage)
invalidateOptionsMenu();
}
See the official Activity Lifecycle documentation.

Navigation drawer for multiple activities not working

I'm trying to get the same navigation drawer for multiple activities. At the moment I have a BaseActivity that holds the navigation drawer and a MainActivity that extends the BaseActivity class. It works fine when i run the BaseActivity first but instead if i run MainActivity first (Which is what I want to do) the navigation drawer doesn't work when i swipe the screen from left to right. I've been stuck on this for while now and can't seem to figure out what I am missing. Any help would be appreciated.
HomeActivity Class
public class HomeActivity extends BaseActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
}
}
BaseActivity Class
public class BaseActivity extends ActionBarActivity {
private String[] menuList;
private DrawerLayout drawerLayout;
private ListView listView;
private ActionBarDrawerToggle drawerToggle;
private CharSequence drawerTitle;
private CharSequence title;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_base);
// Initialize drawer's list of items. Get the array for the list
menuList = getResources().getStringArray(R.array.menuItems);
// Get the drawers layout
drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
// Get the list view
listView = (ListView) findViewById(R.id.list_view);
// Creating an ArrayAdapter to add items to the listview listView
listView.setAdapter(new ArrayAdapter(this, android.R.layout.simple_list_item_1,
menuList));
// Set listener for the list item clicks
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView adapterView, View view, int i, long l) {
}
});
}
activity_base.xml
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<!-- The main content view -->
<FrameLayout
android:id="#+id/frame_layout"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<!-- The navigation drawer -->
<ListView
android:id="#+id/list_view"
android:layout_width="240dp"
android:layout_height="match_parent"
android:layout_gravity="start"
android:choiceMode="singleChoice"
android:divider="#android:color/transparent"
android:dividerHeight="10dp" />
</android.support.v4.widget.DrawerLayout>