Develop Reference

getSupportFragmentManager().findFragmentById() returns null even though fragment exists

I have a fragment_main.xml inside an activity_main.xml.
The fragment is added inside a Tabbed Activity created from an Android Studio template.
I want to do a change in the Fragment's view from within the Activity. That's why I created an Interface that allows the Fragment to call the Activity during the Fragment's onStart, when I know that the Fragment's view is available for modifications.
I did get this to work if I pass the actual Fragment instance using my interface callback. But I'm still frustrated because I don't understand why this function returns null. Does this have anything to do with reusing fragments in different screen orientations?
I've looked over similar questions here on SO reported with this function returning null. Somebody mentioned that there might be an issue with using import android.support.v4.app.Fragment; as opposed to just android.app.Fragment. I don't think this is my case because getsupportFragmentManager seems to return the correct type of Fragment (v4.app). I have no idea why the v4.app is there, I'm kinda new to all this.
Anyway here's the code, all of it, including imports, because they might be relevant.
package org.axonnsd.musicnexus;
import android.app.Activity;
import android.content.Context;
import android.media.MediaPlayer;
import android.os.Environment;
import android.os.Handler;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.MediaController;
import android.widget.TextView;
import java.io.FileInputStream;
import java.io.IOException;
public class MainActivity extends AppCompatActivity implements OnFragmentReadyListener {
/**
* The {#link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {#link FragmentPagerAdapter} derivative, which will keep every
* loaded fragment in memory. If this becomes too memory intensive, it
* may be best to switch to a
* {#link android.support.v4.app.FragmentStatePagerAdapter}.
*/
private SectionsPagerAdapter mSectionsPagerAdapter;
private static final String TAG = "MyTabbedApplication";
private Handler handler = new Handler();
/**
* The {#link ViewPager} that will host the section contents.
*/
private ViewPager mViewPager;
#Override
protected void onStop() {
super.onStop();
mediaController.hide();
mediaPlayer.stop();
mediaPlayer.release();
}
#Override
public boolean onTouchEvent(MotionEvent event) {
//the MediaController will hide after 3 seconds - tap the screen to make it appear again
mediaController.show();
return false;
}
public void onFragmentReady(PlaceholderFragment fragment)
{
this.getIntent().putExtra(AUDIO_FILE_NAME,AUDIO_FILE_NAME);
audioFile = this.getIntent().getStringExtra(AUDIO_FILE_NAME);
PlaceholderFragment fragment = (PlaceholderFragment)(getSupportFragmentManager().findFragmentById(R.id.main_audio_view));
//FRAGMENT IS NULL!
fragment.setNowPlayingText(audioFile);
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
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();
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A 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";
private TextView _txtNowPlaying;
private MainActivity _parentActivity;
public PlaceholderFragment() {
}
/**
* 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;
}
#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);
_txtNowPlaying = (TextView)rootView.findViewById(R.id.now_playing_text);
textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER)));
//notifyActivity(_parentActivity);
return rootView;
}
#Override
public void onAttach(Activity activity)
{
super.onAttach(activity);
_parentActivity = (MainActivity)activity;
}
#Override
public void onAttach(Context context)
{
super.onAttach(context);
if (context instanceof Activity){
_parentActivity = (MainActivity)context;
}
}
#Override
public void onStart()
{
super.onStart();
notifyActivity(_parentActivity);
}
private void notifyActivity(MainActivity activity)
{
activity.onFragmentReady(this);
}
public void setNowPlayingText(String value)
{
_txtNowPlaying.setText(value);
}
}
/**
* A {#link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a PlaceholderFragment (defined as a static inner class below).
return PlaceholderFragment.newInstance(position + 1);
}
#Override
public int getCount() {
// Show 3 total pages.
return 3;
}
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return "SECTION 1";
case 1:
return "SECTION 2";
case 2:
return "SECTION 3";
}
return null;
}
}
}
I'm pasting the XMLs too, even though they are fine (as I said, it works if I pass the actual fragment).
activity_main.xml
<?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:id="#+id/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="org.axonnsd.musicnexus.MainActivity">
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="#dimen/appbar_padding_top"
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:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="#style/AppTheme.PopupOverlay">
</android.support.v7.widget.Toolbar>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
<android.support.design.widget.FloatingActionButton
android:id="#+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="end|bottom"
android:layout_margin="#dimen/fab_margin"
app:srcCompat="#android:drawable/ic_dialog_email" />
</android.support.design.widget.CoordinatorLayout>
fragment_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:id="#+id/main_audio_view"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="org.axonnsd.musicnexus.MainActivity$PlaceholderFragment">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="Now playing:"
android:textSize="25sp"
android:textStyle="bold"
/>
<TextView
android:id="#+id/now_playing_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="20dip"
android:layout_marginLeft="10dip"
android:layout_marginRight="10dip"
android:layout_gravity="center"
android:text="Now playing.."
android:textSize="16sp"
android:textStyle="italic"
/>
<TextView
android:id="#+id/section_label"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</RelativeLayout>

First of all, you're using findFragmentById wrong, passing id of root layout of your fragment as a parameter, when it expects an id of a layout that contains your fragment (not layout inside a fragment!)
FragmentPagerAdapter is kinda tricky and getting current fragment is not straightforward. Check this answer:
Getting the current Fragment instance in the viewpager
Replace your:
PlaceholderFragment fragment = (PlaceholderFragment)(getSupportFragmentManager().findFragmentById(R.id.main_audio_view));
//FRAGMENT IS NULL!
with
PlaceholderFragment page = (PlaceholderFragment)
getSupportFragmentManager().findFragmentByTag("android:switcher:" +
R.id.container + ":" + mViewPager.getCurrentItem());

I would try the following, but I'm sure it's not the nicest solution.
I would pass the value of section_number instead of the PlaceholderFragment and get the fragment from the SectionPageAdapter. Something like this:
public void onFragmentReady(int position)
{
this.getIntent().putExtra(AUDIO_FILE_NAME,AUDIO_FILE_NAME);
audioFile = this.getIntent().getStringExtra(AUDIO_FILE_NAME);
PlaceholderFragment fragment = (PlaceholderFragment)mSectionsPagerAdapter.getItem(position);
fragment.setNowPlayingText(audioFile);
}

Starting new fragment from mainactivity

I read a lot of questions here, but I didn't get a proper solution for my problem. I have a MainActivity java class, and I have several activities in for my app. Now, I created a "Tabbed activity" automatically in Android Studio. I do have a Imagebutton which I use for opening a new fragment. This new fragment is called "Generaldiscription". I learned, that a fragment can't be started like an activity, I need to use FragmentManagener to get a fragment open. My app starts, but when I click on the imagebutton, where actually my fragment should start, the app crashes.
In the following, you can see my mainactivity.java, and the fragments as java and as xml. Thank you in anticipation.
MainActivity.java
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);
final ImageButton generaldiscriptionbutton = (ImageButton) findViewById(R.id.imageButton);
setSupportActionBar(toolbar);
checkFirstRun();
generaldiscriptionbutton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
FragmentManager fm = getSupportFragmentManager();
Generaldiscription fragment = new Generaldiscription();
fm.beginTransaction().add(R.id.main_content, ); // don't know what to write here.
}
});
My activity_generaldiscription.xml which was created automatically
<?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:id="#+id/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
>
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="#dimen/appbar_padding_top"
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:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="#style/AppTheme.PopupOverlay">
</android.support.v7.widget.Toolbar>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
My fragment_generaldiscription.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"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="com.example.user.myapp.Generaldiscription$PlaceholderFragment">
<TextView
android:id="#+id/section_label"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:text="fffff" />
EDIT my generaldiscription.java
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
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.widget.TextView;
public class Generaldiscription extends AppCompatActivity {
/**
* The {#link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {#link FragmentPagerAdapter} derivative, which will keep every
* loaded fragment in memory. If this becomes too memory intensive, it
* may be best to switch to a
* {#link android.support.v4.app.FragmentStatePagerAdapter}.
*/
private SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {#link ViewPager} that will host the section contents.
*/
private ViewPager mViewPager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_generaldiscription);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
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();
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_generaldiscription, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A 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";
public PlaceholderFragment() {
}
/**
* 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;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_generaldiscription, container, false);
TextView textView = (TextView) rootView.findViewById(R.id.section_label);
textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER)));
return rootView;
}
}
/**
* A {#link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a PlaceholderFragment (defined as a static inner class below).
return PlaceholderFragment.newInstance(position + 1);
}
#Override
public int getCount() {
// Show 3 total pages.
return 3;
}
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return "SECTION 1";
case 1:
return "SECTION 2";
case 2:
return "SECTION 3";
}
return null;
}
}
}

Start your fragment this way:
FragmentManager fragmentmanager = getFragmentManager();
fragmentmanager.beginTransaction()
.replace(R.id.main_content
, new Generaldiscription())
.commit();
EDIT
In your case you should start you Generaldiscription like this:
Intent myIntent = new Intent(MainActivity.this, Generaldiscription.class);
MainActivity.this.startActivity(myIntent);
What is more, your GeneralDiscription should import android.support.v4.app.Fragment; instead of android.app.Fragment;

From the Documentation
FragmentTransaction add (int containerViewId,
Fragment fragment,
String tag)
Add a fragment to the activity state. This fragment may optionally
also have its view (if Fragment.onCreateView returns non-null)
inserted into a container view of the activity.
Parameters
containerViewId int: Optional identifier of the container this fragment is to be placed in. If 0, it will not be placed in a
container.
fragment Fragment: The fragment to be added. This fragment must not already be added to the activity.
tag String: Optional tag name for the fragment, to later retrieve the fragment with
FragmentManager.findFragmentByTag(String).
so in your code write:
FragmentManager manager = getSupportFragmentManager();
Generaldiscription fragment = new Generaldiscription();
FragmentTransaction transaction = manager.beginTransaction();
transaction.add(R.id.main_content,fragment,"Tag");
transaction.addToBackStack(null);
transaction.commit();
And in your Generaldiscription Fragment:
import android.support.v4.app.Fragment; //make sure you import the support package
public class Generaldiscription extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.Your_layout, container, false);
return view;
}
}

Declare in your fragment like this
public interface OnClickListener {
void onClick();
}
private final OnClickListener listener;
In your button click listener add this
if(listener!=null){
listener.onclick();
}
In your Activity, implements this listener and add this to the fragment
than you can hide current fragment and show second fragment in onClick method in Activity

Android Error - Inconvertible types required: NavigationDrawerFragment found: Fragment

I am new to android and working on navigationdrawer and fragment application. I was using
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
earlier, but due to some reasons changed to below:
import android.app.Fragment;
import android.app.FragmentManager;
Now I am getting error: Error:(56, 61) error: inconvertible types
required: NavigationDrawerFragment
found: Fragment
on below line
mNavigationDrawerFragment.setUp(
R.id.navigation_drawer,
(DrawerLayout) findViewById(R.id.drawer_layout));
I think I have changed the Fragment and FragmentManager import everywhere, unable to figure out - why is happening.
Any suggestions are most welcome. Thanks in advance.
package com.androidatc.customviewindrawer;
import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.app.Fragment;
//import android.support.v4.app.Fragment;
//import android.support.v4.app.FragmentManager;
import android.app.FragmentManager;
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.widget.Toast;
public class MainActivity extends ActionBarActivity
implements NavigationDrawerFragment.NavigationDrawerCallbacks,
SearchCatFragment.OnFragmentInteractionListener,
AndroidBarcodeQrExample.OnFragmentInteractionListener,
BarCodeFrag.OnFragmentInteractionListener,
MainViewFragment.OnFragmentInteractionListener {
/**
* 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 = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.container, PlaceholderFragment.newInstance(position + 1))
.commit();
}
public void onActivityResult(int requestCode, int resultCode, Intent intent) {
if (requestCode == 0) {
if (resultCode == RESULT_OK) {
String contents = intent.getStringExtra("SCAN_RESULT");
String format = intent.getStringExtra("SCAN_RESULT_FORMAT");
Toast toast = Toast.makeText(this, "Content:" + contents + " Format:" + format, Toast.LENGTH_LONG);
toast.show();
}
}
}
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 = 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.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);
}
#Override
public void onFragmentInteraction(Uri uri) {
}
/**
* 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));
}
}
}
Activity_main.xml
<!-- As the main content view, the view below consumes the entire
space available using match_parent in both dimensions. -->
<FrameLayout android:id="#+id/container" android:layout_width="match_parent"
android:layout_height="match_parent" >
<ImageView
android:layout_width="match_parent"
android:layout_height="611dp"
android:id="#+id/imageView2"
android:layout_gravity="right|center_vertical"
android:background="#drawable/energybook" />
</FrameLayout>
<!-- android:layout_gravity="start" tells DrawerLayout to treat
this as a sliding drawer on the left side for left-to-right
languages and on the right side for right-to-left languages.
If you're not building against API 17 or higher, use
android:layout_gravity="left" instead. -->
<!-- The drawer is given a fixed width in dp and extends the full height of
the container. -->
<fragment android:id="#+id/navigation_drawer"
android:layout_width="#dimen/navigation_drawer_width" android:layout_height="match_parent"
android:layout_gravity="start"
android:name="com.androidatc.customviewindrawer.NavigationDrawerFragment"
tools:layout="#layout/fragment_navigation_drawer" />

Your NavigationDrawer Fragment Class should extend android.support.v4.app.Fragment and not the regular Fragment Class
public class NavigationDrawerFragment extends android.support.v4.app.Fragment

how to create 2 swipe tabs in fragment?

Hi guys, I have a very big problem and I really don't know where I were wrong.
my app contains Navigation Drawer menu and i need to create swipe tabs in fragments_accounts.xml
Navigation Drawer Menu contains "Accounts" when it's clicked fragments_accounts.xml will show and i wanna create 2 swipe tabs in it.
I changed import android.support.v4.app.Fragment; to import android.app.Fragment; in both of the AccountsFtagmets.java and MainActivity.java
This error will show:
Error:(88, 28) error: incompatible types: AccountsFragment cannot be
converted to Fragment
How can i rescue from this error??
it's killing me!!!
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"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<LinearLayout
android:id="#+id/container_toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<include
android:id="#+id/toolbar"
layout="#layout/toolbar" />
</LinearLayout>
<FrameLayout
android:id="#+id/container_body"
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_weight="1" />
</LinearLayout>
<fragment
android:id="#+id/fragment_navigation_drawer"
android:name="com.rastari.salar.mymetarialbank.adapter.FragmentDrawer"
android:layout_width="#dimen/nav_drawer_width"
android:layout_height="match_parent"
android:layout_gravity="start"
app:layout="#layout/fragment_navigation_drawer"
tools:layout="#layout/fragment_navigation_drawer" />
</android.support.v4.widget.DrawerLayout>
fragments_accounts.xml
<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent">
</android.support.v4.view.ViewPager>
there is AccountsFtagmets.java:
import com.rastari.salar.mymetarialbank.R;
import android.app.ActionBar;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
/**
* Created by Salar on 24/4/2015.
*/
public class AccountsFragment extends FragmentActivity implements ActionBar.TabListener {
AppSectionsPagerAdapter mAppSectionsPagerAdapter;
ViewPager mViewPager;
public static AccountsFragment newInstance() {
return new AccountsFragment();
}
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_accounts, container, false);
// Create the adapter that will return a fragment for each of the three primary sections
// of the app.
mAppSectionsPagerAdapter = new AppSectionsPagerAdapter(getSupportFragmentManager());
// Set up the action bar.
final ActionBar actionBar = getActionBar();
// Specify that the Home/Up button should not be enabled, since there is no hierarchical
// parent.
actionBar.setHomeButtonEnabled(false);
// Specify that we will be displaying tabs in the action bar.
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// Set up the ViewPager, attaching the adapter and setting up a listener for when the
// user swipes between sections.
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mAppSectionsPagerAdapter);
mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
#Override
public void onPageSelected(int position) {
// When swiping between different app sections, select the corresponding tab.
// We can also use ActionBar.Tab#select() to do this if we have a reference to the
// Tab.
actionBar.setSelectedNavigationItem(position);
}
});
// For each of the sections in the app, add a tab to the action bar.
for (int i = 0; i < mAppSectionsPagerAdapter.getCount(); i++) {
// Create a tab with text corresponding to the page title defined by the adapter.
// Also specify this Activity object, which implements the TabListener interface, as the
// listener for when this tab is selected.
actionBar.addTab(
actionBar.newTab()
.setText(mAppSectionsPagerAdapter.getPageTitle(i))
.setTabListener(this));
}
// Inflate the layout for this fragment
return rootView;
}
#Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
#Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
// When the given tab is selected, switch to the corresponding page in the ViewPager.
mViewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
/**
* A {#link android.support.v4.app.FragmentPagerAdapter} that returns a fragment corresponding to one of the primary
* sections of the app.
*/
public static class AppSectionsPagerAdapter extends FragmentPagerAdapter {
public AppSectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int i) {
switch (i) {
case 0:
// The first section of the app is the most interesting -- it offers
// a launchpad into the other demonstrations in this example application.
return new LaunchpadSectionFragment();
default:
// The other sections of the app are dummy placeholders.
Fragment fragment = new DummySectionFragment();
Bundle args = new Bundle();
args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, i + 1);
fragment.setArguments(args);
return fragment;
}
}
#Override
public int getCount() {
return 2;
}
#Override
public CharSequence getPageTitle(int position) {
return "Section " + (position + 1);
}
}
/**
* A fragment that launches other parts of the demo application.
*/
public static class LaunchpadSectionFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_accounts_activity, container, false);
return rootView;
}
}
/**
* A dummy fragment representing a section of the app, but that simply displays dummy text.
*/
public static class DummySectionFragment extends Fragment {
public static final String ARG_SECTION_NUMBER = "section_number";
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_chart_activity, container, false);
Bundle args = getArguments();
return rootView;
}
}
public AccountsFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
}
MainActivity.java:
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
import java.text.DateFormat;
import java.util.Date;
public class MainActivity extends ActionBarActivity implements FragmentDrawer.FragmentDrawerListener {
private static String TAG = MainActivity.class.getSimpleName();
private Toolbar mToolbar;
private FragmentDrawer drawerFragment;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mToolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(mToolbar);
getSupportActionBar().setDisplayShowHomeEnabled(true);
String currentDateTimeString = DateFormat.getDateTimeInstance().format(new Date());
TextView date= (TextView) findViewById(R.id.dateAndTime);
date.setText(currentDateTimeString);
drawerFragment = (FragmentDrawer)
getSupportFragmentManager().findFragmentById(R.id.fragment_navigation_drawer);
drawerFragment.setUp(R.id.fragment_navigation_drawer, (DrawerLayout) findViewById(R.id.drawer_layout), mToolbar);
drawerFragment.setDrawerListener(this);
// display the first navigation drawer view on app launch
displayView(0);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, 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;
}
if(id == R.id.action_search){
Toast.makeText(getApplicationContext(), "Search action is selected!", Toast.LENGTH_SHORT).show();
return true;
}
return super.onOptionsItemSelected(item);
}
#Override
public void onDrawerItemSelected(View view, int position) {
displayView(position);
}
private void displayView(int position) {
Fragment fragment = null;
String title = getString(R.string.app_name);
switch (position) {
case 0:
fragment = new AccountsFragment();
title = getString(R.string.title_accounts);
break;
default:
break;
}
if (fragment != null) {
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.container_body, fragment);
fragmentTransaction.commit();
// set the toolbar title
getSupportActionBar().setTitle(title);
}
}
}
Thank You.

Your AccountsFragment needs to extend Fragment not FragmentActivity.

ListFragment with Navigation Drawer

Bit of a noob at android, but made it this far.
Trying to get a ListView with navigation drawer...
The following doesn't work unless I uncomment the setContentView line. Throws a null ptr exception. When I uncomment it, the ListView works, but the nav drawer quits showing up.
Also, the onListItemClick doesn't trigger, but that's a later problem for me to learn.
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.ListFragment;
import android.util.Log;
import android.view.View;
import android.widget.ListView;
import android.widget.Toast;
public class All_Listview extends ListFragment {
#Override
public void onListItemClick(ListView l, View v, int position, long id) {
super.onListItemClick(l, v, position, id);
Log.d("onClick", String.valueOf(position));
Activity a = getActivity();
String item = (String) getListAdapter().getItem(position);
Toast.makeText(a, item + " selected", Toast.LENGTH_LONG).show();
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
ArrayList<WeekItem> wkList = new ArrayList<>();
Activity a = getActivity();
// a.setContentView(R.layout.all_listview);
WeekAdapter adapter = new WeekAdapter(a.getBaseContext(), wkList);
ListView lv = (ListView)a.findViewById(R.id.all_list_view);
lv.setAdapter(adapter);
SQLiteHelper db = new SQLiteHelper(getActivity());
List<Week> weeks = db.getAll();
ArrayList<WeekItem> wkItem = WeekItem.fromList(weeks);
adapter.addAll(wkItem);
}
}
I'm sure there's more to this problem than I can see at the moment, but any help is welcomed.
MainActivity
package com.hourtracker;
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.pm.ActivityInfo;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toast;
import android.support.v4.widget.DrawerLayout;
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);
Log.e("hours","creating session filter");
setContentView(R.layout.activity_main);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
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
Log.d("onNavDrawerSelected", String.valueOf(position));
FragmentManager fragmentManager = getSupportFragmentManager();
switch(position) {
case 0:
fragmentManager
.beginTransaction()
.replace(R.id.frame_container,
((Fragment)new Entry_Fragment())).commit();
break;
case 1:
fragmentManager
.beginTransaction()
.replace(R.id.frame_container,
((Fragment)new Week_Fragment())).commit();
break;
case 2:
fragmentManager
.beginTransaction()
.replace(R.id.frame_container,
((Fragment)new All_Listview())).commit();
break;
}
}
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();
if (id == R.id.action_settings) {
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager
.beginTransaction()
.replace(R.id.frame_container,
((Fragment)new Settings_Fragment())).commit();
return true;
}
Toast.makeText(this, "Not settings", Toast.LENGTH_SHORT).show();;
return super.onOptionsItemSelected(item);
}
}
activity_main.xml
<!--
As the main content view, the view below consumes the entire
space available using match_parent in both dimensions.
-->
<FrameLayout
android:id="#+id/frame_container"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<!--
android:layout_gravity="start" tells DrawerLayout to treat
this as a sliding drawer on the left side for left-to-right
languages and on the right side for right-to-left languages.
If you're not building against API 17 or higher, use
android:layout_gravity="left" instead.
-->
<!--
The drawer is given a fixed width in dp and extends the full height of
the container.
-->
<fragment
android:id="#+id/navigation_drawer"
android:name="com.hourtracker.NavigationDrawerFragment"
android:layout_width="#dimen/navigation_drawer_width"
android:layout_height="match_parent"
android:layout_gravity="start" />
</android.support.v4.widget.DrawerLayout>
all_listview.xml
<?xml version="1.0" encoding="utf-8"?>
<ListView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/all_list_view"
android:layout_width="match_parent"
android:layout_height="match_parent" >
</ListView>

I think the main error is when you create All_Listview that extends ListFragment, i suggest that you follow this example that helps you create Simple ListFragment
After you do it right i think the list fragment will work and even the navigation drawer too, thats because when you setContentView from ListFragment you do it wrong