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How to make a Tabs Fragment inside Navigation Drawer Fragment? [duplicate]

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What is a NullPointerException, and how do I fix it?
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Closed 4 years ago.
I have a navigation drawer with two items(each item is a fragment)
The first item "import" ,should display this Fragment:
Here is the Fragment class:
public class Import extends Fragment {
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.import_main,container,false);
}
}
it's layout
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/colorPrimaryDark">
</android.support.constraint.ConstraintLayout>
The second item "Gallery",should display a TabsLayout that contains 2 fragments (TabLeft and TabRight) :
Here is it's classe:
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.tabs,container,false);
}
and the layout:
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 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">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="#style/AppTheme.PopupOverlay" />
<android.support.design.widget.TabLayout
android:id="#+id/tab_id"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.TabItem
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="left"/>
<android.support.design.widget.TabItem
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="right"/>
</android.support.design.widget.TabLayout>
<android.support.v4.view.ViewPager
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:id="#+id/pager" />
</android.support.design.widget.AppBarLayout>
<android.support.design.widget.FloatingActionButton
android:id="#+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:layout_margin="#dimen/fab_margin"
app:srcCompat="#android:drawable/ic_dialog_email" />
</android.support.design.widget.CoordinatorLayout>
I have tried to implement that but i get a weird error which is:
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.abzo.fragmentstut/com.example.abzo.fragmentstut.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v4.view.ViewPager.setAdapter(android.support.v4.view.PagerAdapter)' on a null object reference
Here is my MainActivity code:
package com.example.abzo.fragmentstut;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.design.widget.TabLayout;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
////////
TabLayout tabLayout = (TabLayout)findViewById(R.id.tab_id);
ViewPager viewPager = (ViewPager)findViewById(R.id.pager);
TabPagerAdapter tabsAdapter = new TabPagerAdapter(getSupportFragmentManager());
viewPager.setAdapter(tabsAdapter);
//tabLayout.setupWithViewPager(viewPager);
/////
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.addDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
}
#Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} 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;
}
return super.onOptionsItemSelected(item);
}
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.nav_camera) {
// Handle the camera action
getSupportFragmentManager().beginTransaction().replace(R.id.content_main, new Import()).commit();
} else if (id == R.id.nav_gallery) {
getSupportFragmentManager().beginTransaction().replace(R.id.content_main, new Tabs()).commit();
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
My TabPagerAdapter:
package com.example.abzo.fragmentstut;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
public class TabPagerAdapter extends FragmentPagerAdapter {
String [] pagetitle = new String []{"one","two"};
public TabPagerAdapter(FragmentManager fm) {
super(fm);
}
#Nullable
#Override
public CharSequence getPageTitle(int position) {
return super.getPageTitle(position);
}
#Override
public Fragment getItem(int position) {
switch (position)
{
case 0:
TabOne one= new TabOne();
return one;
case 1:
TabTwo two= new TabTwo();
return two;
}
return null;
}
#Override
public int getCount() {
return 2;
}
}
and here is one of the 2 tab classes (fragments): (the 2nd tab class is similar)
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.tab_left,container,false);
}

Try this one
#Override
public Fragment getItem(int position) {
switch (position)
{
case 0:
TabOne one= new TabOne();
return one;
deafault:
TabTwo two= new TabTwo();
return two;
}
}
You have to return Fragment here not null. Always try to use default in switch

Unable to do fragment transition from navigation bar

I have created a Tab Layout of seven tabs. There is also a Navigation Drawer in my app. The drawer opens well but when I select any of the item in the navigation Drawer, the app closes forcefully.Below is my Main Activity.Java
public class MainActivity extends AppCompatActivity {
private static final String TAG_HOME = "home";
private static final String TAG_HISTORY = "history";
private static final String TAG_LOCATION = "location";
private static final String TAG_DEVELOPMENTS = "developments";
private static final String TAG_DONATIONS = "donations";
private static final String TAG_FEEDBACK = "feedback";
private static final String TAG_RESOURCES = "resources";
private static final String TAG_CONTACTUS = "contactus";
public static String CURRENT_TAG = TAG_HOME;
private DrawerLayout mDrawerLayout;
// flag to load home fragment when user presses back key
public static int navItemIndex = 0;
private boolean shouldLoadHomeFragOnBackPress = true;
private Handler mHandler;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Adding Toolbar to Main screen
mHandler = new Handler();
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Setting ViewPager for each Tabs
ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
// Set Tabs inside Toolbar
TabLayout tabs = (TabLayout) findViewById(R.id.tabs);
tabs.setupWithViewPager(viewPager);
// Create Navigation drawer and inlfate layout
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer);
// Set behavior of Navigation drawer
navigationView.setNavigationItemSelectedListener(
new NavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
//Check to see which item was being clicked and perform appropriate action
switch (menuItem.getItemId()) {
//Replacing the main content with ContentFragment Which is our Inbox View;
case R.id.nav_home:
navItemIndex = 0;
CURRENT_TAG = TAG_HOME;
break;
case R.id.nav_history:
navItemIndex = 1;
CURRENT_TAG = TAG_HISTORY;
break;
case R.id.nav_location:
navItemIndex = 2;
CURRENT_TAG = TAG_LOCATION;
break;
case R.id.nav_developments:
navItemIndex = 3;
CURRENT_TAG = TAG_DEVELOPMENTS;
break;
case R.id.nav_donations:
navItemIndex = 4;
CURRENT_TAG = TAG_DONATIONS;
break;
case R.id.nav_resources:
navItemIndex = 5;
CURRENT_TAG = TAG_RESOURCES;
break;
case R.id.nav_feedback:
navItemIndex = 6;
CURRENT_TAG = TAG_FEEDBACK;
break;
case R.id.nav_contactus:
navItemIndex = 7;
CURRENT_TAG = TAG_CONTACTUS;
break;
default:
navItemIndex = 0;
}
//Checking if the item is in checked state or not, if not make it in checked state
if (menuItem.isChecked()) {
menuItem.setChecked(false);
} else {
menuItem.setChecked(true);
}
menuItem.setChecked(true);
loadHomeFragment();
return true;
}
});
// Adding Floating Action Button to bottom right of main view
}
private void loadHomeFragment() {
// if user select the current navigation menu again, don't do anything
// just close the navigation drawer
if (getSupportFragmentManager().findFragmentByTag(CURRENT_TAG) != null) {
mDrawerLayout.closeDrawers();
// show or hide the fab button
return;
}
Runnable mPendingRunnable = new Runnable() {
#Override
public void run() {
// update the main content by replacing fragments
Fragment fragment = getHomeFragment();
FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.tabs, fragment, CURRENT_TAG);
fragmentTransaction.commitAllowingStateLoss();
}
};
// If mPendingRunnable is not null, then add to the message queue
if (mPendingRunnable != null) {
mHandler.post(mPendingRunnable);
}
mDrawerLayout.closeDrawers();
invalidateOptionsMenu();
}
private Fragment getHomeFragment() {
switch (navItemIndex) {
case 0:
// home
one_main oneMain = new one_main();
return oneMain;
case 1:
one_fragment oneFragment = new one_fragment();
return oneFragment;
case 2:
two_location twoLocation = new two_location();
return twoLocation;
case 3:
four_future fourFuture = new four_future();
return fourFuture;
case 4:
three_donation threeDonation = new three_donation();
return threeDonation;
case 5:
six_download sixDownload = new six_download();
return sixDownload;
case 6:
five_feedback fiveFeedback = new five_feedback();
return fiveFeedback;
case 7:
seven_contact sevenContact = new seven_contact();
return sevenContact;
default:
return new one_main();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
} else if (id == android.R.id.home) {
mDrawerLayout.openDrawer(GravityCompat.START);
}
return super.onOptionsItemSelected(item);
}
//Checking if the item is in checked state or not, if not make it in checked state
#Override
public void onBackPressed() {
if (mDrawerLayout.isDrawerOpen(GravityCompat.START)) {
mDrawerLayout.closeDrawers();
return;
}
if (shouldLoadHomeFragOnBackPress) {
// checking if user is on other navigation menu
// rather than home
if (navItemIndex != 0) {
navItemIndex = 0;
CURRENT_TAG = TAG_HOME;
loadHomeFragment();
return;
}
}
super.onBackPressed();
}
}
My menu_navigation.xml is as below:
<menu xmlns:android="http://schemas.android.com/apk/res/android">
<group android:checkableBehavior="single">
<item
android:id="#+id/nav_home"
android:icon="#drawable/ic_home_black_24dp"
android:tint="#color/button_grey"
android:title="Home" />
<item
android:id="#+id/nav_history"
android:icon="#drawable/ic_bookmark_border_black_24dp"
android:tint="#color/button_grey"
android:title="History" />
<item
android:id="#+id/nav_location"
android:icon="#drawable/ic_bookmark_border_black_24dp"
android:tint="#color/button_grey"
android:title="Location" />
<item
android:id="#+id/nav_developments"
android:icon="#drawable/ic_bookmark_border_black_24dp"
android:tint="#color/button_grey"
android:title="Developments" />
<item
android:id="#+id/nav_donations"
android:icon="#drawable/ic_bookmark_border_black_24dp"
android:tint="#color/button_grey"
android:title="Donations" />
<item
android:id="#+id/nav_resources"
android:icon="#drawable/ic_bookmark_border_black_24dp"
android:tint="#color/button_grey"
android:title="Resources" />
<item
android:id="#+id/nav_feedback"
android:icon="#drawable/ic_bookmark_border_black_24dp"
android:tint="#color/button_grey"
android:title="Feedback" />
<item
android:id="#+id/nav_contactus"
android:icon="#drawable/ic_bookmark_border_black_24dp"
android:tint="#color/button_grey"
android:title="Contact Us" />
</group>
</menu>
My activity main.xml
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/drawer"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">
<android.support.design.widget.CoordinatorLayout
android:id="#+id/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light" />
<android.support.design.widget.TabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabGravity="fill"
app:tabMode="scrollable"
app:tabTextAppearance="#style/TabTextAppearance"/>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
</android.support.design.widget.CoordinatorLayout>
<android.support.design.widget.NavigationView
android:id="#+id/nav_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:fitsSystemWindows="true"
app:headerLayout="#layout/navheader"
app:menu="#menu/menu_navigation" />
</android.support.v4.widget.DrawerLayout>
Can someone tell me the reason why the app is closing on selecting aany of the item in navigation menu?

Your code should look like this:
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/drawer"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">
<android.support.design.widget.CoordinatorLayout
android:id="#+id/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light" />
<android.support.design.widget.TabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabGravity="fill"
app:tabTextColor="#android:color/white"
app:tabMode="scrollable"/>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
</android.support.design.widget.CoordinatorLayout>
<android.support.design.widget.NavigationView
android:id="#+id/nav_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:fitsSystemWindows="true"
app:menu="#menu/menu_navigation" />
</android.support.v4.widget.DrawerLayout>
fragment class(I created one but you can create as much as you want):
MyFragment.java:
package com.example.pager.view.myapplication;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class MyFragment extends Fragment {
public static MyFragment newInstance(String title) {
Bundle args = new Bundle();
args.putString("page_title", title);
MyFragment fragment = new MyFragment();
fragment.setArguments(args);
return fragment;
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, Bundle savedInstanceState) {
final View inflatedView = LayoutInflater.from(getActivity()).inflate(R.layout.fragment_my, container, false);
TextView title = (TextView) inflatedView.findViewById(R.id.title);
title.setText(getArguments().getString("page_title"));
return inflatedView;
}
}
fragment_my.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center">
<TextView
android:id="#+id/title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"/>
</LinearLayout>
PagerAdapter.java (this class create fragments for view pager):
package com.example.pager.view.myapplication;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import java.util.List;
class PagerAdapter extends FragmentPagerAdapter {
private final List<String> titleList;
PagerAdapter(FragmentManager fm, List<String> titleList) {
super(fm);
this.titleList = titleList;
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
// here you can put different fragments for each position
return MyFragment.newInstance(titleList.get(position));
default:
return MyFragment.newInstance(titleList.get(position));
}
}
#Override
public int getCount() {
return titleList.size();
}
#Override
public CharSequence getPageTitle(int position) {
// This method return title for each fragment that will be display in tab layout
return titleList.get(position);
}
}
and MainActivity.java should look like this:
package com.example.pager.view.myapplication;
import android.support.design.widget.NavigationView;
import android.support.design.widget.TabLayout;
import android.support.v4.view.GravityCompat;
import android.support.v4.view.ViewPager;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import java.util.Arrays;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private static final String TAG_HOME = "home";
private static final String TAG_HISTORY = "history";
private static final String TAG_LOCATION = "location";
private static final String TAG_DEVELOPMENTS = "developments";
private static final String TAG_DONATIONS = "donations";
private static final String TAG_FEEDBACK = "feedback";
private static final String TAG_RESOURCES = "resources";
private static final String TAG_CONTACTUS = "contactus";
public static String CURRENT_TAG = TAG_HOME;
private DrawerLayout mDrawerLayout;
private List<String> titles = Arrays.asList(TAG_HOME, TAG_HISTORY, TAG_LOCATION, TAG_DEVELOPMENTS, TAG_DONATIONS,
TAG_FEEDBACK, TAG_RESOURCES, TAG_CONTACTUS);
private ViewPager viewPager;
private PagerAdapter pagerAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
initViewPagerWithTabLayout();
setupNavigationDrawer();
}
private void initViewPagerWithTabLayout() {
viewPager = (ViewPager) findViewById(R.id.viewpager);
pagerAdapter = new PagerAdapter(getSupportFragmentManager(), titles);
viewPager.setAdapter(pagerAdapter);
TabLayout tabs = (TabLayout) findViewById(R.id.tabs);
tabs.setupWithViewPager(viewPager);
}
private void setupNavigationDrawer() {
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer);
navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
switch (menuItem.getItemId()) {
case R.id.nav_home:
CURRENT_TAG = TAG_HOME;
break;
case R.id.nav_history:
CURRENT_TAG = TAG_HISTORY;
break;
case R.id.nav_location:
CURRENT_TAG = TAG_LOCATION;
break;
case R.id.nav_developments:
CURRENT_TAG = TAG_DEVELOPMENTS;
break;
case R.id.nav_donations:
CURRENT_TAG = TAG_DONATIONS;
break;
case R.id.nav_resources:
CURRENT_TAG = TAG_RESOURCES;
break;
case R.id.nav_feedback:
CURRENT_TAG = TAG_FEEDBACK;
break;
case R.id.nav_contactus:
CURRENT_TAG = TAG_CONTACTUS;
break;
}
mDrawerLayout.closeDrawer(GravityCompat.START);
viewPager.setCurrentItem(titles.indexOf(CURRENT_TAG));
return true;
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == android.R.id.home) {
mDrawerLayout.openDrawer(GravityCompat.START);
}
return super.onOptionsItemSelected(item);
}
#Override
public void onBackPressed() {
if (mDrawerLayout.isDrawerOpen(GravityCompat.START)) {
mDrawerLayout.closeDrawers();
return;
}
if (viewPager.getCurrentItem() != 0) {
viewPager.setCurrentItem(0);
CURRENT_TAG = TAG_HOME;
return;
}
super.onBackPressed();
}
}
and everything should work great.
Good luck with your app!

ViewPager not showing fragments

I can't get this to work. The basic app functions as it's supposed to but the ViewPager on one of the layout files doesn't show any fragment at all. I checked the code multiple times but I can't find a bug. When I tried debugging it I noticed that it doesn't even initialize the fragments classes which it's supposed to when you select a tab.
My MainActivity:
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
new GetData(this).execute();
TabLayout tab_layout = (TabLayout) findViewById(R.id.tab_layout);
tab_layout.addTab(tab_layout.newTab().setText("CASUAL"));
tab_layout.addTab(tab_layout.newTab().setText("RANKED"));
tab_layout.setTabGravity(TabLayout.GRAVITY_FILL);
final ViewPager viewPager = (ViewPager) findViewById(R.id.view_pager);
PagerAdapter adapter = new PagerAdapter(getSupportFragmentManager(), tab_layout.getTabCount());
viewPager.setAdapter(adapter);
tab_layout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
}
#Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} 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;
}
return super.onOptionsItemSelected(item);
}
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.nav_stats) {
// Handle the camera action
} else if (id == R.id.nav_about) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
My PagerAdapter:
public class PagerAdapter extends FragmentStatePagerAdapter {
int mNumOfTabs;
public PagerAdapter(FragmentManager fm, int NumOfTabs) {
super(fm);
this.mNumOfTabs = NumOfTabs;
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
CasualStats tab1 = new CasualStats();
return tab1;
case 1:
RankedStats tab2 = new RankedStats();
return tab2;
default:
return null;
}
}
#Override
public int getCount() {
return mNumOfTabs;
}
}
Layout with the ViewPager:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"><![CDATA[
        android:id="#+id/pager"
        android:layout_width="match_parent"
        android:layout_height="fill_parent"
        android:layout_below="#id/tab_layout"/>
]]>
<android.support.design.widget.TabLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_alignParentStart="true"
android:id="#+id/tab_layout">
</android.support.design.widget.TabLayout>
<view
android:layout_width="wrap_content"
android:layout_height="wrap_content"
class="android.support.v4.view.ViewPager"
android:layout_alignParentStart="true"
android:id="#+id/view_pager"
android:layout_below="#+id/tab_layout" />
</RelativeLayout>
The classes for the tab fragments which are supposed to be displayed in the ViewPager are just normal auto generated Android Studio fragment classes.
One of the fragments:
public class CasualStats extends Fragment{
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private OnFragmentInteractionListener mListener;
public CasualStats() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* #param param1 Parameter 1.
* #param param2 Parameter 2.
* #return A new instance of fragment CasualStats.
*/
// TODO: Rename and change types and number of parameters
public static CasualStats newInstance(String param1, String param2) {
CasualStats fragment = new CasualStats();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_casual_stats, container, false);
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
#Override
public void onDetach() {
super.onDetach();
mListener = null;
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}
}
The xml:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.app.anzel.r6s.CasualStats">
<!-- TODO: Update blank fragment layout -->
<TextView
android:text="1st fragment"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_alignParentStart="true"
android:layout_marginStart="28dp"
android:layout_marginTop="22dp"
android:id="#+id/textView"
android:visibility="visible" />
</RelativeLayout>

The problem is that you have nested fragments and use getFragmentManager(); You should use getChildFragmentManager() instead.
java:
viewPagerAdapter = new PagerAdapter(getChildFragmentManager())
kotlin:
viewPagerAdapter = PagerAdapter(childFragmentManager)

I feel kind of stupid. The problem was with the ViewPager as I suspected. After 3h of code debugging I just moved the ViewPager from the layout with the tabs to another layout which basically connects all of the layouts.

The below sample code is working fine with viewpager and tabs. Try it out.
Main activity layout
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="#style/AppTheme.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
<android.support.design.widget.TabLayout
android:id="#+id/tab_container"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="?attr/actionBarSize" />
<include layout="#layout/content_main" />
<android.support.design.widget.FloatingActionButton
android:id="#+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:layout_margin="#dimen/fab_margin"
app:srcCompat="#android:drawable/ic_dialog_email" />
Then viewpager container layout
<?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"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/content_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="?attr/actionBarSize"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context="com.test.myapplication.MainActivity"
tools:showIn="#layout/app_bar_main">
<android.support.v4.view.ViewPager
android:id="#+id/page_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#FF0000" />
</RelativeLayout>
And here is the main activity part:
package com.test.myapplication;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.design.widget.TabLayout;
import android.support.v4.app.*;
import android.support.v4.app.Fragment;
import android.support.v4.view.ViewPager;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
ViewPager pager = (ViewPager)findViewById(R.id.page_container);
pager.setAdapter(new Adapter(getSupportFragmentManager()));
TabLayout tabs = (TabLayout)findViewById(R.id.tab_container);
tabs.setupWithViewPager(pager, true);
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
}
#Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} 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;
}
return super.onOptionsItemSelected(item);
}
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.nav_camera) {
// Handle the camera action
} else if (id == R.id.nav_gallery) {
} else if (id == R.id.nav_slideshow) {
} else if (id == R.id.nav_manage) {
} else if (id == R.id.nav_share) {
} else if (id == R.id.nav_send) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
public static class Adapter extends FragmentStatePagerAdapter {
private String[] titles = new String[] {"ONE", "TWO"};
public Adapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
switch (position){
case 0:
return new com.test.myapplication.Fragment();
case 1:
return new Fragment1();
}
return null;
}
#Override
public int getCount() {
return 2;
}
#Override
public CharSequence getPageTitle(int position) {
return titles[position];
}
}
}

If you are using any tablayout with viewpager inside NestedScrollView, make sure to put android:fillViewport="true"
Reference in the nested scrollview. Note that, if you are working with navigation drawer, your fragment may not have a nested scrollview, but your activity fragment container maybe inside a nested scroll view. Because even an empty layout with a background color (for debugging the issue) does not show up, so it was not the problem of view pager in my case, it was the problem with nested scroll view.
Debugging tip: Instead of viewpager, put some layout and set a
background color to see if the layout is visible. If the layout itself
is not visible, then you have issue with the parent layout, most
probably NestedScrollView.

You are missing setupWithViewPager, and you don't need setOnTabSelectedListener:
tab_layout.setupWithViewPager(viewPager)
Let's look here:
http://www.androidhive.info/2015/09/android-material-design-working-with-tabs/
You have to override also getPageTitle in adapter and there return tab title.
Last, don't use <view ..class> in xml, create normal xml view:
<android.support.v4.view.ViewPager
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:id="#+id/view_pager"
android:layout_below="#+id/tab_layout"/>

try this:
in your layout:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.TabLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_alignParentStart="true"
android:id="#+id/tab_layout">
</android.support.design.widget.TabLayout>
<android.support.v4.view.ViewPager
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentStart="true"
android:id="#+id/view_pager"
android:layout_below="#+id/tab_layout" />
</RelativeLayout>
in activity:
TabLayout tab_layout = (TabLayout) findViewById(R.id.tab_layout);
tab_layout.addTab(tab_layout.newTab().setText("CASUAL"));
tab_layout.addTab(tab_layout.newTab().setText("RANKED"));
tab_layout.setTabGravity(TabLayout.GRAVITY_FILL);
final ViewPager viewPager = (ViewPager) findViewById(R.id.view_pager);
PagerAdapter adapter = new PagerAdapter(getSupportFragmentManager(), tab_layout.getTabCount());
viewPager.setAdapter(adapter);
viewPager.setOffscreenPageLimit(2);
tab_layout.post(new Runnable() {
#Override
public void run() {
tab_layout.setupWithViewPager(viewPager);
}
});
tab_layout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
PagerAdapter :
public class PagerAdapter extends FragmentStatePagerAdapter {
int mNumOfTabs;
// an array of tab titles
private String tabTitles[] = new String[]{"CASUAL", "RANKED"};
public PagerAdapter(FragmentManager fm, int NumOfTabs) {
super(fm);
this.mNumOfTabs = NumOfTabs;
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
CasualStats tab1 = new CasualStats();
return tab1;
case 1:
RankedStats tab2 = new RankedStats();
return tab2;
default:
return null;
}
}
#Override
public int getCount() {
return mNumOfTabs;
}
#Override
public CharSequence getPageTitle(int position) {
return tabTitles[position];
}
}

How to add a header with an image and a textview to my navigation drawer?

I have a navigation draw with sections and items, but I need to put an image and a text as header but don't know how exactly from what I have, the navigation drawer that I have is the default one that android studio create when you right click and select new > activity > navigation drawer activity.
this is the xml that I want to have as header:
nav_header.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<!-- Character's Avatar -->
<ImageView android:id="#+id/navigation_drawer_header_iv_image"
android:layout_width="200dp"
android:layout_height="200dp"
android:src="#drawable/image_sorcerer"/>
<!-- Character's name -->
<TextView android:id="#+id/navigation_drawer_header_tv_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Example text"
android:paddingLeft="16dp"/>
</LinearLayout>
The navigation drawer content is set through a custom adapter
GameNavigationFragment class (This is the fragment that manage the navigation drawer)
public class GameNavigationFragment extends Fragment {
private static final String STATE_SELECTED_POSITION = "selected_navigation_drawer_position";
private static final String PREF_USER_LEARNED_DRAWER = "navigation_drawer_learned";
private NavigationDrawerCallbacks mCallbacks;
private ActionBarDrawerToggle mDrawerToggle;
private DrawerLayout mDrawerLayout;
private ListView mDrawerListView;
private View mFragmentContainerView;
private int mCurrentSelectedPosition = 0;
private boolean mFromSavedInstanceState;
private boolean mUserLearnedDrawer;
public GameNavigationFragment() {
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Read in the flag indicating whether or not the user has demonstrated awareness of the
// drawer. See PREF_USER_LEARNED_DRAWER for details.
SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(getActivity());
mUserLearnedDrawer = sp.getBoolean(PREF_USER_LEARNED_DRAWER, false);
if (savedInstanceState != null) {
mCurrentSelectedPosition = savedInstanceState.getInt(STATE_SELECTED_POSITION);
mFromSavedInstanceState = true;
}
// Select either the default item (0) or the last selected item.
selectItem(mCurrentSelectedPosition);
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
// Indicate that this fragment would like to influence the set of actions in the action bar.
setHasOptionsMenu(true);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
mDrawerListView = (ListView) inflater.inflate(
R.layout.fragment_navigation_drawer, container, false);
mDrawerListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
selectItem(position);
}
});
CustomListViewAdapter adapter = new CustomListViewAdapter(getActivity());
adapter.addSeparatorItem("Menu");
adapter.addItem("Section 1");
adapter.addItem("Section 2");
adapter.addItem("Section 3");
adapter.addSeparatorItem("Opciones");
adapter.addItem("Section 1");
adapter.addItem("Section 2");
adapter.addItem("Section 3");
mDrawerListView.setAdapter(adapter);
return mDrawerListView;
}
CustomAdapterListView
package com.jomasa.pocketfantasy.adapters;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.TreeSet;
import com.jomasa.pocketfantasy.R;
public class CustomListViewAdapter extends BaseAdapter {
private static final int TYPE_ITEM = 0;
private static final int TYPE_SEPARATOR = 1;
private ArrayList<String> mData = new ArrayList<String>();
private TreeSet<Integer> sectionHeader = new TreeSet<Integer>();
private LayoutInflater mInflater;
public CustomListViewAdapter(Context context){
mInflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public void addItem(final String item) {
mData.add(item);
notifyDataSetChanged();
}
public void addSeparatorItem(final String item) {
mData.add(item);
sectionHeader.add(mData.size() - 1);
notifyDataSetChanged();
}
#Override
public int getItemViewType(int position) {
return sectionHeader.contains(position) ? TYPE_SEPARATOR : TYPE_ITEM;
}
#Override
public int getViewTypeCount() {
return 2;
}
#Override
public int getCount() {
return mData.size();
}
#Override
public String getItem(int position) {
return mData.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
int rowType = getItemViewType(position);
if (convertView == null) {
holder = new ViewHolder();
switch (rowType) {
case TYPE_ITEM:
convertView = mInflater.inflate(R.layout.snippet_item1, null);
holder.textView = (TextView) convertView.findViewById(R.id.text);
break;
case TYPE_SEPARATOR:
convertView = mInflater.inflate(R.layout.snippet_item2, null);
holder.textView = (TextView) convertView.findViewById(R.id.textSeparator);
break;
}
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.textView.setText(mData.get(position));
return convertView;
}
public static class ViewHolder {
public TextView textView;
}
}
GameActivity
package com.jomasa.pocketfantasy.activities;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.FragmentManager;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.support.v4.widget.DrawerLayout;
import com.jomasa.pocketfantasy.R;
import com.jomasa.pocketfantasy.fragments.GameInventoryFragment;
import com.jomasa.pocketfantasy.fragments.GameMainFragment;
import com.jomasa.pocketfantasy.fragments.GameNavigationFragment;
import com.jomasa.pocketfantasy.fragments.GameSheetFragment;
public class GameActivity extends AppCompatActivity
implements GameNavigationFragment.NavigationDrawerCallbacks {
/**
* Fragment managing the behaviors, interactions and presentation of the navigation drawer.
*/
private GameNavigationFragment mGameNavigationFragment;
/**
* Used to store the last screen title. For use in {#link #restoreActionBar()}.
*/
private CharSequence mTitle;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_game);
mGameNavigationFragment = (GameNavigationFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
mTitle = getTitle();
// Set up the drawer.
mGameNavigationFragment.setUp(
R.id.navigation_drawer,
(DrawerLayout) findViewById(R.id.drawer_layout));
}
#Override
public void onNavigationDrawerItemSelected(int position) {
FragmentManager fragmentManager = getSupportFragmentManager();
switch (position)
{
case 0:
fragmentManager.beginTransaction()
.replace(R.id.container, GameMainFragment.newInstance(position))
.commit();
break;
case 1:
fragmentManager.beginTransaction()
.replace(R.id.container, GameInventoryFragment.newInstance(position))
.commit();
break;
case 2:
fragmentManager.beginTransaction()
.replace(R.id.container, GameSheetFragment.newInstance(position))
.commit();
break;
default: break;
}
}
public void onSectionAttached(int number) {
switch (number) {
case 1:
mTitle = getString(R.string.navigation_title_main);
break;
case 2:
mTitle = getString(R.string.navigation_title_inventory);
break;
case 3:
mTitle = getString(R.string.navigation_title_sheet);
break;
}
}
public void restoreActionBar() {
ActionBar actionBar = getSupportActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setTitle(mTitle);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
if (!mGameNavigationFragment.isDrawerOpen()) {
// Only show items in the action bar relevant to this screen
// if the drawer is not showing. Otherwise, let the drawer
// decide what to show in the action bar.
getMenuInflater().inflate(R.menu.menu_game, menu);
restoreActionBar();
return true;
}
return super.onCreateOptionsMenu(menu);
}
#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);
}
}
this is how navigation looks like right now:

Update your android studio to 1.4 then you can create a navigation drawer activity with header image

This is something I'm working into.
activity_main.xml
<android.support.v4.widget.DrawerLayout
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:id="#+id/drawerLayout"
android:fitsSystemWindows="true">
<!-- Contenido Principal -->
<include layout="#layout/main_content"
android:id="#+id/mainContent"/>
<!-- Navigation Drawer -->
<android.support.design.widget.NavigationView
android:id="#+id/navigationView"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
app:headerLayout="#layout/drawer_header"
app:menu="#menu/nav_menu"/>
</android.support.v4.widget.DrawerLayout>
I am currently using Navigation View pattern. See this property in the NavigationView:
app:headerLayout="#layout/drawer_header"
Where you need yo replace drawer_header with your layout file.
If you want to use NavigationView, you have to add this dependency in your Gradle:
compile 'com.android.support:design:22.2.0'
Hope this helps.

How to add sliding tabs on an existing navigation bar?

I have a navigation drawer on my current application. However, it seems like I'm having more modules coming in, I have to make sure that my application is still organized. So I was thinking to add a sliding tab on one of my navigation drawer fragment.
During my attempt, something went wrong and the log shows the following error
NullPointerException: Attempt to invoke virtual method 'boolean android.content.Intent.migrateExtraStreamToClipData()' on a null object reference
I tried googling for the issue with no success in getting the solution. Can anyone tell me what is actually wrong with my code?
My following files are.
MainActivity.java
package com.epsilon.rfcalculator;
import android.content.Intent;
import android.content.res.Configuration;
import android.os.Bundle;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBarDrawerToggle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
public class MainActivity extends ActionBarActivity {
private ListView mDrawerList;
private DrawerLayout mDrawerLayout;
private ArrayAdapter<String> mAdapter;
private ActionBarDrawerToggle mDrawerToggle;
private String mActivityTitle;
private MyFragment fragment;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mDrawerList = (ListView) findViewById(R.id.navList);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mActivityTitle = getTitle().toString();
addDrawerItems();
setupDrawer();
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setHomeButtonEnabled(true);
}
private void addDrawerItems() {
String[] osArray = {"Free Space Propagation Model", "Two Ray Ground Propagation Model", "Power Conversion", "Wavelength Conversion", "Link Budget"};
mAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, osArray);
mDrawerList.setAdapter(mAdapter);
mDrawerList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
//Toast.makeText(MainActivity.this, "Time for an upgrade!", Toast.LENGTH_SHORT).show();
displayView(position);
}
});
}
private void displayView(int position) {
// update the main content by replacing fragments
Intent intent = null;
switch (position) {
case 0:
fragment = new MyFragment();
break;
//intent = new Intent(this, FreeSpaceActivity.class);
//break;
case 1:
intent = new Intent(this, TransmissionActivity.class);
break;
case 2:
intent = new Intent(this, PowerActivity.class);
break;
case 3:
intent = new Intent(this, WavelengthActivity.class);
break;
case 4:
intent = new Intent(this, LinkBudgetActivity.class);
break;
//case 5: intent = new Intent(this,MapActivity.class);break;
}
startActivity(intent);
}
private void setupDrawer() {
mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout, R.string.drawer_open, R.string.drawer_close) {
/** Called when a drawer has settled in a completely open state. */
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
getSupportActionBar().setTitle("Menu");
invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
}
/** Called when a drawer has settled in a completely closed state. */
public void onDrawerClosed(View view) {
super.onDrawerClosed(view);
getSupportActionBar().setTitle(mActivityTitle);
invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
}
};
mDrawerToggle.setDrawerIndicatorEnabled(true);
mDrawerLayout.setDrawerListener(mDrawerToggle);
}
#Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
// Sync the toggle state after onRestoreInstanceState has occurred.
mDrawerToggle.syncState();
}
#Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
mDrawerToggle.onConfigurationChanged(newConfig);
}
#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;
}
// Activate the navigation drawer toggle
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
MyFragment.java //This is a new java file added corresponding to my attempt to add the sliding tab.
package com.epsilon.rfcalculator;
import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TabHost;
import android.widget.TabWidget;
import java.util.ArrayList;
public class MyFragment extends Fragment
{
private TabHost mTabHost;
private ViewPager mViewPager;
private TabsAdapter mTabsAdapter;
public MyFragment() {
}
#Override
public void onCreate(Bundle instance)
{
super.onCreate(instance);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_main, container, false);
mTabHost = (TabHost) v.findViewById(android.R.id.tabhost);
mTabHost.setup();
mViewPager = (ViewPager) v.findViewById(R.id.pager);
mTabsAdapter = new TabsAdapter(getActivity(), mTabHost, mViewPager);
// Here we load the content for each tab.
mTabsAdapter.addTab(mTabHost.newTabSpec("one").setIndicator("One"), FreeSpaceActivity.class, null);
mTabsAdapter.addTab(mTabHost.newTabSpec("two").setIndicator("Two"), TransmissionActivity.class, null);
return v;
}
public static class TabsAdapter extends FragmentPagerAdapter implements TabHost.OnTabChangeListener, ViewPager.OnPageChangeListener
{
private final Context mContext;
private final TabHost mTabHost;
private final ViewPager mViewPager;
private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>();
static final class TabInfo
{
private final String tag;
private final Class<?> clss;
private final Bundle args;
TabInfo(String _tag, Class<?> _class, Bundle _args)
{
tag = _tag;
clss = _class;
args = _args;
}
}
static class DummyTabFactory implements TabHost.TabContentFactory
{
private final Context mContext;
public DummyTabFactory(Context context)
{
mContext = context;
}
public View createTabContent(String tag)
{
View v = new View(mContext);
v.setMinimumWidth(0);
v.setMinimumHeight(0);
return v;
}
}
public TabsAdapter(FragmentActivity activity, TabHost tabHost, ViewPager pager)
{
super(activity.getSupportFragmentManager());
mContext = activity;
mTabHost = tabHost;
mViewPager = pager;
mTabHost.setOnTabChangedListener(this);
mViewPager.setAdapter(this);
mViewPager.setOnPageChangeListener(this);
}
public void addTab(TabHost.TabSpec tabSpec, Class<?> clss, Bundle args)
{
tabSpec.setContent(new DummyTabFactory(mContext));
String tag = tabSpec.getTag();
TabInfo info = new TabInfo(tag, clss, args);
mTabs.add(info);
mTabHost.addTab(tabSpec);
notifyDataSetChanged();
}
#Override
public int getCount()
{
return mTabs.size();
}
#Override
public Fragment getItem(int position)
{
TabInfo info = mTabs.get(position);
return Fragment.instantiate(mContext, info.clss.getName(), info.args);
}
public void onTabChanged(String tabId)
{
int position = mTabHost.getCurrentTab();
mViewPager.setCurrentItem(position);
}
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels)
{
}
public void onPageSelected(int position)
{
// Unfortunately when TabHost changes the current tab, it kindly
// also takes care of putting focus on it when not in touch mode.
// The jerk.
// This hack tries to prevent this from pulling focus out of our
// ViewPager.
TabWidget widget = mTabHost.getTabWidget();
int oldFocusability = widget.getDescendantFocusability();
widget.setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS);
mTabHost.setCurrentTab(position);
widget.setDescendantFocusability(oldFocusability);
}
public void onPageScrollStateChanged(int state)
{
}
}
}
activity_main.xml
<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">
<!-- The first child in the layout is for the main Activity UI-->
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
tools:context=".MainActivity"
android:background="#ffffffff">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:text="Holy Operating Systems, Batdroid!"
android:textSize="24sp"
android:gravity="center"
android:layout_marginTop="100dp"/>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"/>
</RelativeLayout>
<!-- Side navigation drawer UI -->
<ListView
android:id="#+id/navList"
android:layout_width="200dp"
android:layout_height="match_parent"
android:layout_gravity="left|start"
android:background="#ffeeeeee"/>
</android.support.v4.widget.DrawerLayout>
fragment_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TabHost
android:id="#android:id/tabhost"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TabWidget
android:id="#android:id/tabs"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="0"/>
<FrameLayout
android:id="#android:id/tabcontent"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_weight="0"/>
<android.support.v4.view.ViewPager
android:id="#+id/pager"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"/>
</LinearLayout>
</TabHost>
</LinearLayout>