Develop Reference

NullPointerException ViewPager SetAdapter

I am adding a tab view or (ViewPager) to my Fragment in an App I am working on.
I want to put the tab view inside the Contact Fragment
I have a Navigation Drawer that opens, and you see list of options...
Home
Services
Contact
Everything you click goes to a fragment
Then in that fragment loads the .XML file, with a corresponding class to program everything inside the .XML file.
I was following an online tutorial [CLICK HERE][3]
Obviously it was over 2 years ago. Android Code has changed since then. I started with a few more errors then what I have now.
I am experiencing an issue with getSupportFragmentManager(), and getActionBar() really confused at this point, all imports are there. It won't recognize those two. Obviously that makes me think well something is missing, but I am not sure what needs to put to allow the compiler to see those needed methods.
I still get Null when the ViewPager setAdapter is set.
All I am trying to accomplish is a tab view, with two tabs for Contact, and Social Media. If I could get a simplistic understanding of what is required for tabs to work properly.
I have already searched questions and they don't exactly touch on my specific issue, and so I am asking for help. Any help is definitely appreciated.
FragmentContact
package com.megliosolutions.bitsnbytes.Fragments;
import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.view.ViewPager;
import android.support.v7.app.ActionBar;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.megliosolutions.bitsnbytes.MainActivity;
import com.megliosolutions.bitsnbytes.R;
import com.megliosolutions.bitsnbytes.ViewPagerClasses.TabsPagerAdapter;
/**
* Created by Jarvis on 6/21/15.
*/
public class FragmentContact extends Fragment {
private ViewPager viewPager;
TabsPagerAdapter mAdapter;
private ActionBar actionBar;
private String[] tabs = {"Contact", "Social Media"};
public static FragmentContact newInstance(){
FragmentContact fragment = new FragmentContact();
return fragment;
}
public FragmentContact(){};
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_contact, container, false);
LoadTabs(rootView);
return rootView;
}
private void LoadTabs(View rootView) {
FragmentManager fragmentManager = getSupportFragmentManager();
// Initilization
viewPager = (ViewPager) rootView.findViewById(R.id.pager);
actionBar = getActionBar();
mAdapter = new TabsPagerAdapter(fragmentManager);
viewPager.setAdapter(mAdapter);
actionBar.setHomeButtonEnabled(false);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// Adding Tabs
for (String tab_name : tabs) {
actionBar.addTab(actionBar.newTab().setText(tab_name)
.setTabListener((ActionBar.TabListener) this));
}
}
#Override
public void onAttach(FragmentActivity activity) {
super.onAttach(activity);
((MainActivity) activity).onSectionAttached(5);
}
}
TabsPagerAdapter
package com.megliosolutions.bitsnbytes.ViewPagerClasses;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.view.View;
/**
* Created by Jarvis on 6/28/15.
*/
public class TabsPagerAdapter extends FragmentPagerAdapter {
public TabsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int index) {
switch (index) {
case 0:
// Contact fragment activity
return new ContactFragment();
case 1:
// Social Media fragment activity
return new SocialMediaFragment();
}
return null;
}
#Override
public int getCount() {
// get item count - equal to number of tabs
return 2;
}
#Override
public boolean isViewFromObject(View view, Object object) {
return false;
}
}
MAINACTIVITY
package com.megliosolutions.bitsnbytes;
import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarActivity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import com.megliosolutions.bitsnbytes.Fragments.FragmentAbout;
import com.megliosolutions.bitsnbytes.Fragments.FragmentContact;
import com.megliosolutions.bitsnbytes.Fragments.FragmentHome;
import com.megliosolutions.bitsnbytes.Fragments.FragmentProducts;
import com.megliosolutions.bitsnbytes.Fragments.FragmentServices;
import com.megliosolutions.bitsnbytes.Fragments.FragmentWarranties;
public class MainActivity extends ActionBarActivity
implements NavigationDrawerFragment.NavigationDrawerCallbacks {
/**
* Fragment managing the behaviors, interactions and presentation of the navigation drawer.
*/
private NavigationDrawerFragment mNavigationDrawerFragment;
/**
* Used to store the last screen title. For use in {#link #restoreActionBar()}.
*/
private CharSequence mTitle;
private ActionBarDrawerToggle mDrawerToggle;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
mTitle = getTitle();
// Set up the drawer.
mNavigationDrawerFragment.setUp(
R.id.navigation_drawer,
(DrawerLayout) findViewById(R.id.drawer_layout));
}
#Override
public void onNavigationDrawerItemSelected(int position) {
// update the main content by replacing fragments
FragmentManager fragmentManager = getSupportFragmentManager();
if(position == 0) {
fragmentManager.beginTransaction()
.replace(R.id.container, FragmentHome.newInstance())
.commit();
}
else if(position == 1){
fragmentManager.beginTransaction()
.replace(R.id.container, FragmentServices.newInstance())
.commit();
}
else if(position == 2){
fragmentManager.beginTransaction()
.replace(R.id.container, FragmentProducts.newInstance())
.commit();
}
else if(position == 3){
fragmentManager.beginTransaction()
.replace(R.id.container, FragmentWarranties.newInstance())
.commit();
}
else if(position == 4){
fragmentManager.beginTransaction()
.replace(R.id.container, FragmentContact.newInstance())
.commit();
}
else if(position == 5){
fragmentManager.beginTransaction()
.replace(R.id.container, FragmentAbout.newInstance())
.commit();
}
}
public void onSectionAttached(int number) {
switch (number) {
case 1:
mTitle = getString(R.string.title_section1);
break;
case 2:
mTitle = getString(R.string.title_section2);
break;
case 3:
mTitle = getString(R.string.title_section3);
break;
case 4:
mTitle = getString(R.string.title_section4);
break;
case 5:
mTitle = getString(R.string.title_section5);
break;
case 6:
mTitle = getString(R.string.title_section6);
}
}
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 (!mNavigationDrawerFragment.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.main, 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);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
return rootView;
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
((MainActivity) activity).onSectionAttached(
getArguments().getInt(ARG_SECTION_NUMBER));
}
}
}
Now there is an issue with the FragmentContact.newInstance() in onNavigationDrawerItemSelected()
06-28 15:35:24.695 11744-11744/com.megliosolutions.bitsnbytes E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.megliosolutions.bitsnbytes, PID: 11744
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
at com.megliosolutions.bitsnbytes.Fragments.FragmentContact.LoadTabs(FragmentContact.java:55)
at com.megliosolutions.bitsnbytes.Fragments.FragmentContact.onCreateView(FragmentContact.java:43)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1789)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:955)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1138)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:740)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1501)
at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:458)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

from logcat Error its clear ViewPager not exist in R.layout.fragment_contact. Please verify that.

Since I need to refer to the viewPager in which it exists on activity_main.xml not the current fragment, I manage to solve this error:
I added a declaration for a new view referring to the activity where the ViewPager exists as following:
View viewNext = inflater.inflate(R.layout.activity_main, container, false);
Then, I declared the viewPager with regards the above declaration:
viewPager = (ViewPager) viewNext.findViewById(R.id.viewPager);
After that, I set up the adaptor.

obj Fragment wrong 2nd argument type found 'Android.support.V4.app.Fragment.' required 'Android.app.Fragment'

I can't work out why my objFragment is giving me issues with the support manager, I'm getting this error:
Error:(101, 17) error: no suitable method found for replace(int,android.support.v4.app.Fragment)
method FragmentTransaction.replace(int,android.app.Fragment,String) is not applicable
(actual and formal argument lists differ in length)
method FragmentTransaction.replace(int,android.app.Fragment) is not applicable
(actual argument android.support.v4.app.Fragment cannot be converted to android.app.Fragment by method invocation conversion)
And it's happening on this on objFragment on this line: .replace(R.id.container, objFragment)
Here's my full code:
import android.app.ActionBar;
import android.app.Activity;
import android.app.FragmentManager;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.widget.DrawerLayout;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.support.v4.app.Fragment;
/* public class MainActivity extends FragmentActivity {
public static FragmentManager fragmentManager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// initialising the object of the FragmentManager. Here I'm passing getSupportFragmentManager(). You can pass getFragmentManager() if you are coding for Android 3.0 or above.
fragmentManager = getSupportFragmentManager();
}
} */
public class MainActivity2Activity extends FragmentActivity
implements NavigationDrawerFragment.NavigationDrawerCallbacks {
/**
* Fragment managing the behaviors, interactions and presentation of the navigation drawer.
*/
private NavigationDrawerFragment mNavigationDrawerFragment;
/**
* Used to store the last screen title. For use in {#link #restoreActionBar()}.
*/
private CharSequence mTitle;
public static android.support.v4.app.FragmentManager fragmentManager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_activity2);
// initialising the object of the FragmentManager. Here I'm passing getSupportFragmentManager(). You can pass getFragmentManager() if you are coding for Android 3.0 or above.
fragmentManager = getSupportFragmentManager();
mNavigationDrawerFragment = (NavigationDrawerFragment)
getFragmentManager().findFragmentById(R.id.navigation_drawer);
mTitle = getTitle();
// Set up the drawer.
mNavigationDrawerFragment.setUp(
R.id.navigation_drawer,
(DrawerLayout) findViewById(R.id.drawer_layout));
// initialising the object of the FragmentManager. Here I'm passing getSupportFragmentManager(). You can pass getFragmentManager() if you are coding for Android 3.0 or above.
fragmentManager = getSupportFragmentManager();
}
#Override
public void onNavigationDrawerItemSelected(int position) {
// This method controls the navigation drawer
Fragment objFragment = null;
switch (position) {
case 0:
objFragment = new menu_1_fragment();
break;
case 1:
objFragment = new menu_2_fragment();
break;
case 2:
objFragment = new menu_3_fragment();
break;
case 3:
objFragment = new menu_4_fragment();
break;
case 4:
objFragment = new menu_5_fragment();
break;
}
// update the main content by replacing fragments
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.container, objFragment)
.commit();
}
public void onSectionAttached(int number) {
switch (number) {
case 1:
mTitle = getString(R.string.title_section1);
break;
case 2:
mTitle = getString(R.string.title_section2);
break;
case 3:
mTitle = getString(R.string.title_section3);
break;
case 4:
mTitle = getString(R.string.title_section4);
break;
case 5:
mTitle = getString(R.string.title_section5);
break;
}
}
public void restoreActionBar() {
ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
actionBar.setDisplayShowTitleEnabled(true);
// actionBar.setTitle(mTitle);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
if (!mNavigationDrawerFragment.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.main_activity2, 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();
// Link to settings in the main menu or create google maps options
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main_activity2, container, false);
return rootView;
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
((MainActivity2Activity) activity).onSectionAttached(
getArguments().getInt(ARG_SECTION_NUMBER));
}
}
}

The problem is that there is a mismatch in fragments types between objFragment and fragmentManager. The first is from package android.support.v4.app while the second is from the android.app package.
See this answer here to know the difference between the two types of Fragments.
Now to fix the issue you have to handle your imports.
Either use import android.app.Fragment instead of import android.support.v4.app.Fragment
Or do as Modge suggested; Update the main content of your app with a support Fragment manager like this: FragmentManager fragmentManager = getSupportFragmentManager(). But then you also have to change the type of the FragmentManager itself; import android.app.FragmentManager to import android.support.v4.app.FragmentManager;

You tried to use the non support FragmentManager for your transaction. Change it to get the support one.
// update the main content by replacing fragments
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.container, objFragment)
.commit();

Just change getFragmentManager() to getSupportFragmentManager()

Below is the answer to a similar question I found while searching the internet. This worked for me, so I hope it will help you.
Menu_Fragment is not inheriting from
android.support.v4.app.Fragment. Presumably, it is inheriting from
android.app.Fragment.
There are two fragment implementations: the native one (e.g.,
android.app.Fragment) and the backport (e.g.,
android.support.v4.app.Fragment). You need to be consistent. Your
activity is a FragmentActivity, which is part of the backport, so
you need your fragments to inherit from
android.support.v4.app.Fragment.

Error on newInstance() using fragments

I'm trying to use the navigation bar that comes pre-built in Android Studio and found several guides on how to use it but most of them are either outdated or for some reason don't work.
The one I use now seems to "work" but I get an error on newInstance()
Error code:
Error:(58, 59) error: method newInstance in class FirstFragment cannot be applied to given types;
required: String,String
found: no arguments
reason: actual and formal argument lists differ in length
Here is my code:
`package welovecode.se.outfitted;
import android.app.Activity;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.content.Context;
import android.os.Build;
import android.os.Bundle;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.support.v4.widget.DrawerLayout;
import android.widget.ArrayAdapter;
import android.widget.TextView;
public class MainActivity extends ActionBarActivity
implements NavigationDrawerFragment.NavigationDrawerCallbacks {
/**
* Fragment managing the behaviors, interactions and presentation of the navigation drawer.
*/
private NavigationDrawerFragment mNavigationDrawerFragment;
/**
* 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_main);
mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
mTitle = getTitle();
// Set up the drawer.
mNavigationDrawerFragment.setUp(
R.id.navigation_drawer,
(DrawerLayout) findViewById(R.id.drawer_layout));
}
#Override
public void onNavigationDrawerItemSelected(int position) {
// update the main content by replacing fragments
FragmentManager fragmentManager = getSupportFragmentManager();
if (position == 0) {
fragmentManager.beginTransaction()
.replace(R.id.container, FirstFragment.newInstance())
.commit();
} else if (position == 1) {
fragmentManager.beginTransaction()
.replace(R.id.container, SecondFragment.newInstance())
.commit();
} else if (position == 2) {
fragmentManager.beginTransaction()
.replace(R.id.container, ThirdFragment.newInstance())
.commit();
}
}
public void onSectionAttached(int number) {
switch (number) {
case 1:
mTitle = getString(R.string.title_section1);
break;
case 2:
mTitle = getString(R.string.title_section2);
break;
case 3:
mTitle = getString(R.string.title_section3);
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 (!mNavigationDrawerFragment.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.main, 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);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
return rootView;
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
((MainActivity) activity).onSectionAttached(
getArguments().getInt(ARG_SECTION_NUMBER));
}
}
}
`
Thank you so much in advance!

The error is pretty informative. You have classes FirstFragment, SecondFragment etc which define newInstance methods that take arguments, in this case two strings. You are however calling those methods without any arguments.
So the solution should be obvious, either supply the needed arguments, or modify those classes not to require any arguments. It's hard to tell you what exactly you should change in your code because 1) I don't know exactly what you want to accomplish and 2) I don't have the code for your fragments.

It seems to me you want to pass a Section Number for your Fragment, like:
int sectNum = 100;
fragmentManager.beginTransaction()
.replace(R.id.container, FirstFragment.newInstance( sectNum ))
Notes:
newInstance method call requires an int type only.
You need to determine how to get the section number.

Incompatible types: Fragment cannot be converted to NavigationDrawerFragment

I've been working on an app using API 14, but I had to downgrade to API 10. the app has fragments and activity fragments, I have imported the libraries and used the getFragmentSupportManager because it is v4. However, I have following error:
I created a dummy app with Drawer layout and fragments with API 10 from the beginning, it had the same line in MyActivity file and it was not an error. Here is my code:
package az.test2;
import android.app.Activity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.view.Gravity;
public class MyActivity extends ActionBarActivity
implements NavigationDrawerFragment.NavigationDrawerCallbacks {
/**
* Fragment managing the behaviors, interactions and presentation of the navigation drawer.
*/
private NavigationDrawerFragment mNavigationDrawerFragment;
/**
* 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_my);
mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
mTitle = getTitle();
// Set up the drawer.
mNavigationDrawerFragment.setUp(
R.id.navigation_drawer,
(DrawerLayout) findViewById(R.id.drawer_layout));
}
#Override
public void onNavigationDrawerItemSelected(int position) {
// update the main content by replacing fragments
android.support.v4.app.FragmentManager lolo;
FragmentManager FM = getSupportFragmentManager();
FragAV fav = new FragAV();
FragW fw = new FragW();
switch (position){
case 0:
FM.beginTransaction()
.replace(R.id.container, fav).commit();
break;
case 1:
FM.beginTransaction()
.replace(R.id.container, fw).commit();
break;
case 2: break;
}
//FM.beginTransaction().replace(R.id.container, PlaceholderFragment.newInstance(position + 1)).commit();
}
public void onSectionAttached(int number) {
switch (number) {
case 1:
mTitle = getString(R.string.title_section1);
break;
case 2:
mTitle = getString(R.string.title_section2);
break;
case 3:
mTitle = getString(R.string.title_section3);
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 (!mNavigationDrawerFragment.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.my, 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();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_my, container, false);
return rootView;
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
((MyActivity) activity).onSectionAttached(
getArguments().getInt(ARG_SECTION_NUMBER));
}
}
}
I did everything I could but this error seems to be very rare. any help would be much appreciated.

When using the support pack, your fragments should extend android.support.v4.app.Fragment and not the regular Fragment class.

make sure your drawer fragment class extend
android.support.v4.app.Fragment
not fragment.

change this
NavigationDrawerFragment mNavigationDrawerFragment;
mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
to
Fragment mNavigationDrawerFragment;
mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);

in your mNavigationDrawerFragment class import
"import android.support.v4.app.Fragment;"
instead of "import android.app.Fragment;"

Fragment error in android navigation drawer

Hello I'm getting expression expected error multiple times and I don't know what i'm doing wrong, if someone can help me that will be great.
Thanks.
import android.support.v4.app.Fragment;
import android.app.Activity;
import android.app.ActionBar;
import android.app.FragmentManager;
import android.content.Context;
import android.os.Build;
import android.os.Bundle;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.support.v4.widget.DrawerLayout;
import android.widget.ArrayAdapter;
import android.widget.TextView;
public class MainActivity extends Activity
implements NavigationDrawerFragment.NavigationDrawerCallbacks {
/**
* Fragment managing the behaviors, interactions and presentation of the navigation drawer.
*/
private NavigationDrawerFragment mNavigationDrawerFragment;
/**
* 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_main);
mNavigationDrawerFragment = (NavigationDrawerFragment)
getFragmentManager().findFragmentById(R.id.navigation_drawer);
mTitle = getTitle();
// Set up the drawer.
mNavigationDrawerFragment.setUp(
R.id.navigation_drawer,
(DrawerLayout) findViewById(R.id.drawer_layout));
}
#Override
public void onNavigationDrawerItemSelected(int position) {
// update the main content by replacing fragments
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.container, Fragment) //expression expected error on "Fragment"
.commit();
}
public void onSectionAttached(int position) {
switch (position) {
case 1:
Fragment = new Welcome(); //expression expected error on "Fragment"
break;
case 2:
Fragment = new Tutorials(); //expression expected error on "Fragment"
break;
case 3:
Fragment = new Blueprints(); //expression expected error on "Fragment"
break;
case 4:
Fragment = new Wiki(); //expression expected error on "Fragment"
break;
case 5:
Fragment = new Chat(); //expression expected error on "Fragment"
break;
case 6:
Fragment = new Item_Search(); //expression expected error on "Fragment"
break;
case 7:
Fragment = new Recipes(); //expression expected error on "Fragment"
break;
case 8:
Fragment = new Wallpaper(); //expression expected error on "Fragment"
break;
case 9:
Fragment = new Maps_Mods(); //expression expected error on "Fragment"
break;
default :
break;
}
}
public void restoreActionBar() {
ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setTitle(mTitle);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
if (!mNavigationDrawerFragment.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.main, 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();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
TextView textView = (TextView) rootView.findViewById(R.id.section_label);
textView.setText(Integer.toString(getArguments().getInt(ARG_SECTION_NUMBER)));
return rootView;
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
((MainActivity) activity).onSectionAttached(
getArguments().getInt(ARG_SECTION_NUMBER));
}
}
}
The error is underlining "Fragment". I'm trying to have the navigation drawer stitch to different fragments.

It should be
fragmentManager.beginTransaction()
.replace(R.id.container,new Welcome())
and
Welcome fragment = new Welcome();
Similarly for others.
Since you are using support based Fragment. You need to change this
public class MainActivity extends Activity
to
public class MainActivity extends ActionBarActivity
if you need ActionBar. You also need to use AppCompat.
Check this
Navigation Drawer with backword compatibility android

Fragment is a key word. What you need is a variable of type Fragment. So, for example, put this in the same section as mTitle:
Fragment mFragment = null;
In your switch statement, put, for example:
mFragment = new Welcome();
Then, when you're setting up the transaction, you can put:
fragmentManager.beginTransaction()
.replace(R.id.container, mFragment)
This may not solve all your problems, but should get you past these compilation errors.