Develop Reference

How to make bottom navigation selected automatically when moving from one fragment to another?

I'm trying to make action button to move from the home fragment to the promo fragment.
In the fragment home there is an action button that will move to the promo fragment. However, when the promo action button on the home fragment is clicked, the display will move to the promo fragment but the bottom navigation is still selected in the home fragment.
Screenshot Home Fragment
Screenshot Promo Fragment
This is my action button code in Home Fragment:
imagePromo.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
((MainActivity)getActivity()).selectFragment(2);
}
});
This is my selectfragment code in MainActivity:
public void selectFragment(int position){
viewPager.setCurrentItem(position, true);
viewPager.dispatchSetSelected(true);
}
This is my bottom navigation code in MainActivity:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
view = findViewById(android.R.id.content);
viewPager = findViewById(R.id.viewpager);
viewPager.setAdapter(new MyAdapter(getSupportFragmentManager()));
viewPager.setOffscreenPageLimit(pager_number);
navigation = findViewById(R.id.navigation);
navigation.setOnNavigationItemSelectedListener(item -> {
switch (item.getItemId()) {
case R.id.navigation_home:
viewPager.setCurrentItem(0);
return true;
case R.id.navigation_category:
viewPager.setCurrentItem(1);
return true;
case R.id.navigation_promo:
viewPager.setCurrentItem(2);
return true;
case R.id.navigation_wishlist:
viewPager.setCurrentItem(3);
return true;
}
return false;
});
}

I'm trying to use the code I found on github. Below is the code snippet:
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
if (prevMenuItem != null) {
prevMenuItem.setChecked(false);
} else {
navigation.getMenu().getItem(0).setChecked(false);
}
navigation.getMenu().getItem(position).setChecked(true);
prevMenuItem = navigation.getMenu().getItem(position);
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
I tried to apply it in MainActivity and it solved my problem above.

You can set it in your setOnClickListener to change the Fragment of the ViewPager and it's CurrentItem to get the icon changed aswell.
Button to_promo = view.findViewById(R.id.to_promo);
to_promo.setOnClickListener(view1 -> {
viewPager.setCurrentItem(2);
});

Getting the number of the Current Tab in Tabbed Activity

First of all I am new to Android development, and I would appreciate your help.
I have a tabbed activity in android studio and I have a FloatingActionButton to add an Item in each fragment of the tabbed activity. This button then calls a new Activty and I would like to pass to the new activity the tab Number, so that I can store it in a database.
How can I get the tab Number that the new activity was generated from?
Below is the code:
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_portal);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
mViewPager.addOnPageChangeListener(new
TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.addOnTabSelectedListener(new
TabLayout.ViewPagerOnTabSelectedListener(mViewPager));
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent startNewPostActivity = new Intent(getApplicationContext(), NewPostActivity.class);
startNewPostActivity.putExtra("Fragment_Position", position_fragment);
startActivity(startNewPostActivity);
}
});
}
To get the position I was doing the following :
Setting position_fragment = position;
however this returns wrong tab Number.
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a PlaceholderFragment (defined as a static inner class below).
position_fragment = position; // not good
return PlaceholderFragment.newInstance(position);
}
#Override
public int getCount() {
// Show 5 total pages.
return 5;
}
}
}

Try this:
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent startNewPostActivity = new Intent(getApplicationContext(), NewPostActivity.class);
startNewPostActivity.putExtra("Fragment_Position", mViewPager.getCurrentItem());
startActivity(startNewPostActivity);
}
});

You can identify your tab id from these switch case and call necessary function inside
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());//setting current selected item over viewpager
switch (tab.getPosition()) {
case 0:
//Log.e("TAG","TAB1");
break;
case 1:
//Log.e("TAG","TAB2");
break;
case 2:
//Log.e("TAG","TAB3");
break;
case 3:
//Log.e("TAG","TAB4");
break;
case 4:
//Log.e("TAG","TAB5");
break;
case 5:
//Log.e("TAG","TAB6");
break;
case 6:
//Log.e("TAG","TAB7");
break;
}
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});

There are two ways to get number of the Current Tab in Tabbed Activity
1. use ViewPager.getCurrentItem()
Returns the number of pages that will be retained to either side of the current page in the view hierarchy in an idle state. Defaults to 1.
SAMPLE CODE
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent startNewPostActivity = new Intent(getApplicationContext(), NewPostActivity.class);
startNewPostActivity.putExtra("Fragment_Position", mViewPager.getCurrentItem());
startActivity(startNewPostActivity);
}
2. Use TabLayout.addOnTabSelectedListener()
Add a TabLayout.OnTabSelectedListener that will be invoked when tab selection changes.
SAMPLE CODE
tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
int position = tab.getPosition();
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});

Start a tab fragments from an activity with the tabs layout

I have a tab fragments app. The problem is when I go into an activity inside my app and want going back to my tabs layout it returns without the tabs row layout. I can see only the specific fragment page without the row above (the tab's row) that makes me able to navigate between the tabs.
Do you know what can I do to solve it? How can I see the tab's row too?
Thanks for any help,
This is the first tab that I want to see back from the activity:
public class Tab1MyProfile extends Fragment {
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.tab1_my_profile, container, false);
return rootView;
}
}
This is the activity that contains code to go back to the fragment tab:
public class GameLive extends AppCompatActivity implements RecognitionListener {
private Intent intent;
private Button mStopButton;
public void stopGame (View view) {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Are you sure you want to finish the game?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
Tab1MyProfile fragment = new Tab1MyProfile();
fragmentTransaction.replace(android.R.id.content, fragment);
fragmentTransaction.commit();
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dialog.cancel();
}
});
AlertDialog alert = builder.create();
alert.show();
}
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.game_live);
mStopButton = (Button) findViewById(R.id.btnEndGame);
mStopButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
stopGame(view);
}
});
}
}
And this is the activity that contains all the tab's fragment:
public class StartActivity extends AppCompatActivity {
private SectionsPagerAdapter mSectionsPagerAdapter;
private ViewPager mViewPager;
#TargetApi(Build.VERSION_CODES.M)
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_start);
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mViewPager);
}
#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_start, 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;
}
return super.onOptionsItemSelected(item);
}
/**
* A {#link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
Tab1MyProfile tab1=new Tab1MyProfile();
return tab1;
case 1:
Tab2StartGame tab2=new Tab2StartGame();
return tab2;
case 2:
Tab3StatsArea tab3=new Tab3StatsArea();
return tab3;
case 3:
Tab4Settings tab4=new Tab4Settings();
return tab4;
}
return null;
}
#Override
public int getCount() {
// Show 4 total pages.
return 4;
}
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return "My profile";
case 1:
return "Start Game";
case 2:
return "Stats Area";
case 3:
return "Settings";
}
return null;
}
}
}
Thank again!

What if you replace everything inside the onClick method of the DialogInterface.OnClickListener with GameLive.this.finish();. This will close the GameLive activity on click and return you to the previous activity, which should be the one that contains the missing navigation bar.

How to swipe between Fragments with FragmentPagerAdapter

I can't figure out why swiping between my Fragments isn't working,
Here is my custom FragmentPagerAdapter:
public class TabsPagerAdapter extends FragmentPagerAdapter {
public TabsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int index) {
switch (index) {
case 0:
return new PrearrivalPlan();
case 1:
return new PrimarySurvey();
case 2:
return new Vitals();
case 3:
return new SecondarySurvey();
case 4:
return new PrepareForTravel();
}
return null;
}
#Override
public int getCount() {
// get item count - equal to number of tabs
return 5;
}
}
And here is my activity that uses it:
public class MainActivity extends FragmentActivity implements ActionBar.TabListener {
private CustomViewPager viewPager;
private TabsPagerAdapter tabsPagerAdapter;
private ActionBar actionBar;
private String[] tabTitles = {"Pre-arrival Plan", "Primary Survey", "Vitals", "Secondary Survey", "Prepare for Travel"};
private int totalTabs = 5;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
viewPager = (CustomViewPager) findViewById(R.id.pager);
actionBar = getActionBar();
tabsPagerAdapter = new TabsPagerAdapter(getSupportFragmentManager());
viewPager.setAdapter(tabsPagerAdapter);
viewPager.setPagingEnabled(false);
actionBar.setHomeButtonEnabled(true);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
viewPager.setOnPageChangeListener(new CustomViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
viewPager.setOffscreenPageLimit(totalTabs);
// Remove Android icon from Action Bar
getActionBar().setIcon(new ColorDrawable(getResources().getColor(android.R.color.transparent)));
getActionBar().setDisplayShowHomeEnabled(false);
// Add tabs to Action Bar
for (String tab_name : tabTitles) {
SpannableString s = new SpannableString(tab_name);
s.setSpan(new TypefaceSpan("helveticaneuelight.ttf"), 0, s.length(),
Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
actionBar.addTab(actionBar.newTab().setText(s).setTabListener(this));
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
public void updateTabTitles(int tabNumber, int checkBoxesRemaining) {
String text = tabTitles[tabNumber] + "\n (" + checkBoxesRemaining + " unchecked)";
actionBar.getTabAt(tabNumber).setText(text);
}
#Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) {
}
#Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
Intent intent = new Intent(this, MainMenu.class);
startActivity(intent);
return true;
case R.id.complete:
DialogInterface.OnClickListener dialogClickListener = new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
switch (which){
case DialogInterface.BUTTON_POSITIVE:
goToReport();
break;
case DialogInterface.BUTTON_NEGATIVE:
// "No" button clicked, do nothing
break;
}
}
};
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Are you sure you want to complete the checklist?").setPositiveButton("Yes", dialogClickListener).setNegativeButton("No", dialogClickListener).show();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
public void goToReport() {
Intent intent = new Intent(this, Report.class);
startActivity(intent);
}
};

could it be this viewPager.setPagingEnabled(false); method? Try taking that method out, or at least setting it to true.

FragmentPagerAdapter getItem() is returning more than it should

I have a MainActivity that controls four fragments, each of which is a tab. When my main activity starts, I have a line being printed to the log to show me what fragment is being instantiated. Here is my FragmentPagerAdapter:
public class TabsPagerAdapter extends FragmentPagerAdapter {
public TabsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int index) {
switch (index) {
case 0:
System.out.println("Returning new PrearrivalPlan()");
return new PrearrivalPlan();
case 1:
System.out.println("Returning new PrimarySurvey()");
return new PrimarySurvey();
case 2:
System.out.println("Returning new SecondarySurvey()");
return new SecondarySurvey();
case 3:
System.out.println("Returning new PrepareForTravel()");
return new PrepareForTravel();
}
return null;
}
#Override
public int getCount() {
// get item count - equal to number of tabs
return 4;
}
}
The tab bar has the following options in order:
Prearrival Plan | Primary Survey | Secondary Survey | Prepare for Travel
When my main activity starts, the following is printed to the screen:
Returning new PrearrivalPlan()
Returning new PrimarySurvey()
What it seems to be doing is loading one tab ahead of the one I have selected. Since PrearrivalPlan is the first tab, I would think it should just return a new PrearrivalPlan() except it returns both. Another example, when I click on Primary Survey tab (second tab), the following is printed to the screen:
Returning new SecondarySurvey() // <- This is the third tab!?
Because PrimarySurvey was already instantiated when the activity first started (see output above), it jumped ahead just like it did before and loaded the third tab even though I only clicked on the second.
Here is my MainActivity:
public class MainActivity extends FragmentActivity implements ActionBar.TabListener {
private CustomViewPager viewPager;
private TabsPagerAdapter mAdapter;
private ActionBar actionBar;
private String[] tabTitles = {"Pre-arrival Plan", "Primary Survey", "Secondary Survey", "Prepare for Travel"};
#TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH)
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
viewPager = (CustomViewPager) findViewById(R.id.pager);
actionBar = getActionBar();
mAdapter = new TabsPagerAdapter(getSupportFragmentManager());
viewPager.setAdapter(mAdapter);
viewPager.setPagingEnabled(false);
actionBar.setHomeButtonEnabled(true);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
viewPager.setOnPageChangeListener(new CustomViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
// Remove Android icon from Action Bar
getActionBar().setIcon(new ColorDrawable(getResources().getColor(android.R.color.transparent)));
getActionBar().setDisplayShowHomeEnabled(false);
// Add tabs to Action Bar
for (String tab_name : tabTitles) {
actionBar.addTab(actionBar.newTab().setText(tab_name).setTabListener(this));
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
public void updateTabTitles(int tabNumber, int checkBoxesRemaining) {
String text = tabTitles[tabNumber] + " \n (" + checkBoxesRemaining + ")";
actionBar.getTabAt(tabNumber).setText(text);
}
#Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) {
}
#Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
Intent intent = new Intent(this, MainMenu.class);
startActivity(intent);
return true;
case R.id.complete:
DialogInterface.OnClickListener dialogClickListener = new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
switch (which){
case DialogInterface.BUTTON_POSITIVE:
goToReport();
break;
case DialogInterface.BUTTON_NEGATIVE:
//No button clicked
break;
}
}
};
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Are you sure you want to complete the checklist?").setPositiveButton("Yes", dialogClickListener).setNegativeButton("No", dialogClickListener).show();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
public void goToReport() {
Intent intent = new Intent(this, Report.class);
startActivity(intent);
}

It is the expected behaviour of ViewPager. ViewPager always keeps one tab ahead and behind in memory in order to show slider animation. If you don't you have the next or previous tab (or fragment) in memory, trying to initiate the fragment during the slider transition will cause a performance lag or at the worse you will have the sliding fragment to be empty and get loaded later.
ViewPager also allows you to set page offset limit through setOffscreenPageLimit() which will control amount fragment to keep them in memory. By default, this is 1 which means one fragment ahead and behind will always be there in memory