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Trying To Open Up A New Screen/Activity In Android

I am trying to switch to a new screen when the user clicks on one of the options. This code is nested in the main activity.
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.about_settings:
Log.d("tcc", "This is getting to the about fragment");
startActivity(new Intent(MainActivity.this, HelpFragment.class));
return true;
case R.id.help_settings:
Log.d("tcc", "This is getting to the help fragment");
startActivity(new Intent(MainActivity.this, SettingsFragment.class));
return true;
default:
return super.onOptionsItemSelected(item);
}
}
I am then trying to get it to switch to one of the fragments that I have created. When I do this though I am getting an error:
Unable to instantiate activity ComponentInfo{info.hccis.bookingapplication/info.hccis.bookingapplication.SettingsFragment}: java.lang.ClassCastException: info.hccis.bookingapplication.SettingsFragment cannot be cast to android.app.Activity

You want to do Fragment Transactions not startActivity :
#Override
public boolean onOptionsItemSelected(MenuItem item) {
FragmentManager fragmentManager = getSupportFragmentManager();
switch (item.getItemId()) {
case R.id.about_settings:
Log.d("tcc", "This is getting to the about fragment");
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.fragment_container, new HelpFragment());
fragmentTransaction.addToBackStack(null); // to provided navigation when back is clicked
fragmentTransaction.commit();
return true;
case R.id.help_settings:
Log.d("tcc", "This is getting to the help fragment");
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.fragment_container, new SettingsFragment());
fragmentTransaction.addToBackStack(null); // to provided navigation when back is clicked
fragmentTransaction.commit();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
And define a fragment coinainer/which will be replaced by your
fragments: in your Activity's View:
<FrameLayout
android:id="#+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent">

Attempt to read from field 'int android.support.v4.app.Fragment.mContainerId' on a null object reference when using Navigation Drawer

Below is my StackTrace of the error that I am getting in Android Studio when navigation using my navigation drawer. This is a new error as it hasn't happened me before. So I am not sure what if anything I've changed.
08-11 23:16:37.823 15951-15951/com.example.aids.a09application
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.aids.a09application, PID: 15951
java.lang.NullPointerException: Attempt to read from field 'int android.support.v4.app.Fragment.mContainerId' on a null object reference
at android.support.v4.app.FragmentTransition.addToFirstInLastOut(FragmentTransition.java:1017)
at android.support.v4.app.FragmentTransition.calculateFragments(FragmentTransition.java:976)
at android.support.v4.app.FragmentTransition.startTransitions(FragmentTransition.java:95)
at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2146)
at android.support.v4.app.FragmentManagerImpl.optimizeAndExecuteOps(FragmentManager.java:2103)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2013)
at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:710)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6692)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1468)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1358)
Below is the Java Class where I have my Fragment Transactions for my Navigation Drawer.
public class MainActivity extends AppCompatActivity {
DrawerLayout drawerLayout;
Toolbar toolbar;
ActionBarDrawerToggle actionBarDrawerToggle;
FragmentTransaction fragmentTransaction;
NavigationView navigationView;
Intent intent;
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
actionBarDrawerToggle = new ActionBarDrawerToggle(this, drawerLayout, toolbar, R.string.drawer_open, R.string.drawer_close);
drawerLayout.addDrawerListener(actionBarDrawerToggle);
fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.add(R.id.main_container, new HomeFragment());
fragmentTransaction.commit();
getSupportActionBar().setTitle("Drift Fan");
navigationView = (NavigationView) findViewById(R.id.navigation_view);
navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.Home:
fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.main_container, new HomeFragment());
fragmentTransaction.commit();
getSupportActionBar().setTitle("Home Fragment");
item.setCheckable(true);
drawerLayout.closeDrawers();
break;
case R.id.my_account:
fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.main_container, new myAccountFragment());
fragmentTransaction.commit();
getSupportActionBar().setTitle("My Account");
item.setCheckable(true);
drawerLayout.closeDrawers();
break;
case R.id.nav_about:
fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.main_container, new AboutDriftingFragment());
fragmentTransaction.commit();
getSupportActionBar().setTitle("About Drifting");
item.setCheckable(true);
drawerLayout.closeDrawers();
break;
case R.id.nav_shop:
fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.main_container, new ShopFragment());
fragmentTransaction.commit();
getSupportActionBar().setTitle("Shop");
item.setCheckable(true);
drawerLayout.closeDrawers();
break;
case R.id.nav_news:
fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.main_container, new NewsFragment());
fragmentTransaction.commit();
getSupportActionBar().setTitle("News");
item.setCheckable(true);
drawerLayout.closeDrawers();
break;
case R.id.nav_media:
intent = new Intent(MainActivity.this, media_main.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
MainActivity.this.startActivity(intent);
break;
case R.id.nav_results:
fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.main_container, new ResultsFragment());
fragmentTransaction.commit();
getSupportActionBar().setTitle("Results");
item.setCheckable(true);
drawerLayout.closeDrawers();
break;
}
return false;
}
});
}
#Override
protected void onPostCreate(#Nullable Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
actionBarDrawerToggle.syncState();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater menuInflater = getMenuInflater();
menuInflater.inflate(R.menu.drawer_menu, menu);
return true;
}
}

I have had the same issue but when i extend from v4.app.Fragment class. instead of android.app.Fragment it is working fine without crashes.
also see this it has some solutions that you can try.

In your second case, try changing:
new myAccountFragment()
to
new MyAccountFragment()

How can I create sections on my app?

I want to improve my new app so I have question for you. How can I make sections in my app, in Navigation Drawer?
There's a photo if you don't understand what's in my mind. This photo is from Google Play
There's my activity_main_drawer.xml
<?xml version="1.0" encoding="utf-8"?>
<group android:checkableBehavior="single">
<item
android:id="#+id/nav_pagrindinis"
android:icon="#drawable/ic_menu_pagrindinis"
android:title="Pagrindinis" />
<item
android:id="#+id/nav_soctinklai"
android:icon="#drawable/ic_menu_soctinklai"
android:title="Gimnazijos socialiniai tinklai" />
<item
android:id="#+id/nav_dienynas"
android:icon="#drawable/ic_menu_dienynas"
android:title="El. dienynas" />
<item
android:id="#+id/nav_naudingosnuor"
android:icon="#drawable/ic_menu_naudingosnuor"
android:title="Naudingos nuorodos"/>
<item
android:id="#+id/nav_kontaktai"
android:icon="#drawable/ic_menu_kontaktai"
android:title="Kontaktinė informacija" />
</group>
And there's an excerpt from MainActivity.java
#Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.nav_pagrindinis) {
//Set the fragment initially
PagrindinisFragment fragment = new PagrindinisFragment();
android.support.v4.app.FragmentTransaction fragmentTransaction =
getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.fragment_container, fragment);
fragmentTransaction.commit();
// Handle the camera action
} else if (id == R.id.nav_soctinklai) {
//Set the fragment initially
SocTinklaiFragment fragment = new SocTinklaiFragment();
android.support.v4.app.FragmentTransaction fragmentTransaction =
getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.fragment_container, fragment);
fragmentTransaction.commit();
} else if (id == R.id.nav_dienynas) {
Intent i = new Intent(Intent.ACTION_VIEW);
i.setData(Uri.parse("https://sistema.tamo.lt"));
startActivity(i);
} else if (id == R.id.nav_naudingosnuor) {
} else if (id == R.id.nav_kontaktai) {
KontaktaiFragment fragment = new KontaktaiFragment();
android.support.v4.app.FragmentTransaction fragmentTransaction =
getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.fragment_container, fragment);
fragmentTransaction.commit();
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
I want to make section in this place. And if I press on it, it opens more sections in Navigation Drawer.
android:id="#+id/nav_naudingosnuor"

There are available libs try one like that: https://github.com/PrashamTrivedi/DrawerLayoutTest
otherwise you need to create your own expandable list view.

How can I edit the header view element in Navigation Drawer programatically? [duplicate]

This question already has answers here:
NavigationView get/find header layout
(9 answers)
Closed 7 years ago.
I have a image and a text in my Header layout which is included through android.support.design.widget.NavigationView. The picture will be user's profile picture and text will be name which I'll get from Session Manager Class.
How can I access and edit the text and image programmatically, since it's only included in the definition of NavigationView.
Here's the code:
<android.support.design.widget.NavigationView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:id="#+id/shitstuff"
app:itemTextColor="#color/grey"
app:menu="#menu/drawermenu"
app:headerLayout="#layout/headerlayout"
app:itemIconTint="#color/colorPrimary"
android:layout_marginTop="0dp"
/>
And in activity class:
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawerLayout);
mNavigationView = (NavigationView) findViewById(R.id.shitstuff) ;
/**
* Lets inflate the very first fragment
* Here , we are inflating the TabFragment as the first Fragment
*/
mFragmentManager = getSupportFragmentManager();
mFragmentTransaction = mFragmentManager.beginTransaction();
mFragmentTransaction.replace(R.id.containerView,new helpfragment()).commit();
/**
* Setup click events on the Navigation View Items.
*/
mNavigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
mDrawerLayout.closeDrawers();
if (menuItem.getItemId() == R.id.nav_item_home) {
Intent i = new Intent(help.this, home.class);
startActivity(i);
}
if (menuItem.getItemId() == R.id.nav_item_tenant) {
Intent i = new Intent(help.this, rentertabview.class);
startActivity(i);
}
if (menuItem.getItemId() == R.id.nav_item_profile) {
Intent i = new Intent(help.this, profile.class);
startActivity(i);
}
if (menuItem.getItemId() == R.id.nav_item_owner) {
Intent i = new Intent(help.this, ownertabview.class);
startActivity(i);
}
if (menuItem.getItemId() == R.id.nav_item_services) {
Intent i = new Intent(help.this, services.class);
startActivity(i);
}
return false;
}
});
/**
* Setup Drawer Toggle of the Toolbar
*/
android.support.v7.widget.Toolbar toolbar = (android.support.v7.widget.Toolbar) findViewById(R.id.toolbar);
ActionBarDrawerToggle mDrawerToggle = new ActionBarDrawerToggle(this,mDrawerLayout, toolbar,R.string.app_name,
R.string.app_name);
mDrawerLayout.setDrawerListener(mDrawerToggle);
mDrawerToggle.syncState();
Please explain in details. Will be really thankful to you.

You can simply retrieve your View using
mNavigationView.findViewById(R.id.IDVIEWTOUPDATE)

Display fragments with Navigation Drawer

I'm confused how to open my different fragments by clicking on one Item in my navigation drawer.
In MainActivity I use the following Code:
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
Fragment fragment;
int id = item.getItemId();
if (id == R.id.nav_listview) {
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.fragment, new ListFragment());
ft.commit();
} else if (id == R.id.nav_add_data) {
} else if (id == R.id.nav_settings) {
} else if (id == R.id.nav_legal_information) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
First of all I want to try to open my ListFragment:
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class ListFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_list, container, false);
}
}
In my content main.xml I created the following fragment which should be replaced when clicking on the specific Items in the Navigation Drawer.
<fragment
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/fragment" />
But it isnt working...
Can anyone help me?
Rastaman

To get what you want try this ,I was also held up with this somewhat complex looking code but its more of a easy way to use
Here's detailed explanation and walk through to this issue:
(Its seems Long But You can easily relate your work asap)
When you first create the Navigation Drawer Activity, there are 5 files we’ll look at:
MainActivity.java - this is the code behind for everything in our app.
activity_main.xml - this is the layout for the app including the nav drawer and an include for the app_bar_main.
app_bar_main.xml - this is the layout with the toolbar (at the top), a floating action button (at the bottom right), and an include for content_main.
content_main.xml - this is the layout for the content of the main page.
nav_header_main.xml - this is the UI for the top part of the nav drawer.
Step 1:
open up the app_bar_main.xml, comment out the include and add a new FrameLayout:
<!--<include layout="#layout/content_main" />-->
<FrameLayout
android:id="#+id/Fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="?attr/actionBarSize"/>
This FrameLayout is what we’ll use to load our fragments into.
Step 2:
Next, you’ll want to add a few fragments
To do so, right click on your project, or go to File –> New and from the Fragment list choose Fragment (Blank) or others
Step 3:
The next step is to load a fragment when the app first launches. Go to the MainActivity’s onCreate method and put the following in after the call to setSupportActionBar:
Fragment fragment = null;
Class fragmentClass = null;
fragmentClass = FragmentOne.class;
try {
fragment = (Fragment) fragmentClass.newInstance();
} catch (Exception e) {
e.printStackTrace();
}
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction().replace(R.id.Fragment_container, fragment).commit();
Step 4:
You’ll then need to add OnFragmentInteractionListener to the interfaces your MainActivity implements and also implement the onFragmentInteraction method.Like this
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener, FragmentOne.OnFragmentInteractionListener ,FragmentTwo.OnFragmentInteractionListener,FragmentThree.OnFragmentInteractionListener {
Step 5:
Finally, in the onNavigationItemSelected method, you can add the ability to load different fragments when menu items are tapped:
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
Fragment fragment = null;
Class fragmentClass = null;
if (id == R.id.nav_camera) {
fragmentClass = FragmentOne.class;
} else if (id == R.id.nav_gallery) {
fragmentClass = FragmentTwo.class;
} else if (id == R.id.nav_slideshow) {
fragmentClass = FragmentThree.class;
} else if (id == R.id.nav_manage) {
} else if (id == R.id.nav_share) {
} else if (id == R.id.nav_send) {
}
try {
fragment = (Fragment) fragmentClass.newInstance();
} catch (Exception e) {
e.printStackTrace();
}
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction().replace(R.id.flContent, fragment).commit();
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
Here I’m just loading one of the two fragments I’ve added to my app. Note that because I have two different fragments, I had to implement the interfaces for both FragmentOne.OnFragmentInteractionListener and FragmentTwo.OnFragmentInteractionListener.
That’s all you need to do to implement fragment loading in your Navigation Drawer.
What the user taps a menu item, the drawer will slide back in smoothly and the new fragment will have already started / finished loading. This also prevents any possible jankiness that you could see when launching a new activity.
EXTRA
One last thing to note is that if you switch to a different fragment and then rotate the device or cause another recreation of the activity, the code above will cause the first fragment to be reloaded. One easy way to deal with that is to wrap the fragment block in the onCreate method in a check to see if the savedInstanceState is not null like this:
protected void onCreate(Bundle savedInstanceState) {
...
if (savedInstanceState == null) {
//Fragment load code
}
...
}

Try this Code
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
Fragment fragment=null;
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
int id = item.getItemId();
if (id == R.id.nav_listview) {
fragment= new ListFragment();
} else if (id == R.id.nav_add_data) {
} else if (id == R.id.nav_settings) {
} else if (id == R.id.nav_legal_information) {
}
ft.replace(R.id.container, fragment);
ft.addToBackStack(null);
ft.commit();
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
<FrameLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/container" />

Please Change The name of your fragment class ListFragment Because ListFragment is already Sub Class of Fragments in android.app package android OS

Mhmm I found an answer. But I am confused.
If I use:
if (id == R.id.nav_listview) {
fragment= new com.thomas.testapp.ListFragment();
It works. But I only have to use the package name if I want to open my ListFragment. Why?

I suggest to Create codes More Dynamic
first of all, if you have custom class to create Navigation Drawer, use listener to call methods from your activity
there is class call HomeFragment extends Fragment, so we have :
if(condition){
fragment = new HomeFragment();
// if there is Listener
if(mListener != null){
mListener.someMethod
}
// Other Settings And Codes
}

public class MainActivity extends AppCompatActivity {
// ...
#Override
protected void onCreate(Bundle savedInstanceState) {
// ...From section above...
// Find our drawer view
nvDrawer = (NavigationView) findViewById(R.id.nvView);
// Setup drawer view
setupDrawerContent(nvDrawer);
}
private void setupDrawerContent(NavigationView navigationView) {
navigationView.setNavigationItemSelectedListener(
new NavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
selectDrawerItem(menuItem);
return true;
}
});
}
public void selectDrawerItem(MenuItem menuItem) {
// Create a new fragment and specify the fragment to show based on nav item clicked
Fragment fragment = null;
Class fragmentClass;
switch(menuItem.getItemId()) {
case R.id.nav_first_fragment:
fragmentClass = FirstFragment.class;
break;
case R.id.nav_second_fragment:
fragmentClass = SecondFragment.class;
break;
case R.id.nav_third_fragment:
fragmentClass = ThirdFragment.class;
break;
default:
fragmentClass = FirstFragment.class;
}
try {
fragment = (Fragment) fragmentClass.newInstance();
} catch (Exception e) {
e.printStackTrace();
}
// Insert the fragment by replacing any existing fragment
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction().replace(R.id.flContent, fragment).commit();
// Highlight the selected item has been done by NavigationView
menuItem.setChecked(true);
// Set action bar title
setTitle(menuItem.getTitle());
// Close the navigation drawer
mDrawer.closeDrawers();
}
// ...
}