This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 6 years ago.
I want to call another fragment from the current fragment on the click of the button in the current fragment.Based on answers I got here, calling a fragment from fragment.
My revised code is as follows :
Here is my Mainactivity :
package com.kibitz4college.k4c;
import android.app.FragmentManager;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import com.asd.fragments.RecommendationsFragment;
import com.asd.fragments.SearchCoachingFragment;
import com.asd.fragments.SearchCollegesFragment;
import com.asd.fragments.MainFragment;
import com.asd.fragments.SearchConsultanciesFragment;
import com.asd.fragments.SearchResultsFragment;
import com.asd.fragments.TrendingFragment;
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener, SearchCoachingFragment.searchbtnclickedlistner {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
FragmentManager fm = getFragmentManager();
fm.beginTransaction().replace(R.id.content_frame,new MainFragment()).commit();
}
#Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
FragmentManager fm = getFragmentManager();
fm.beginTransaction().replace(R.id.content_frame,new MainFragment()).commit();
if (id == R.id.search_colleges) {
// Handle the Search Colleges action
fm.beginTransaction().replace(R.id.content_frame,new SearchCollegesFragment()).commit();
}
else if (id == R.id.search_consultancies) {
fm.beginTransaction().replace(R.id.content_frame,new SearchConsultanciesFragment()).commit();
}
else if (id == R.id.search_coaching) {
fm.beginTransaction().replace(R.id.content_frame,new SearchCoachingFragment()).commit();
}
else if (id == R.id.my_recommendations) {
fm.beginTransaction().replace(R.id.content_frame, new RecommendationsFragment()).commit();
}
else if (id == R.id.trending) {
fm.beginTransaction().replace(R.id.content_frame, new TrendingFragment()).commit();
} else if (id == R.id.profile) {
} else if (id == R.id.logout) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
#Override
public void showresults() {
FragmentManager fm = getFragmentManager();
fm.beginTransaction().replace(R.id.content_frame,new SearchResultsFragment()).commit();
}
}
Here is one of my fragment from which I'm trying to call another :
import android.app.Activity;
import android.app.Fragment;
import android.content.Context;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import com.kibitz4college.k4c.R;
public class SearchCoachingFragment extends Fragment {
Button search_coll_btn;
searchbtnclickedlistner searchbtnclickedlistner_var;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
final View rootview = inflater.inflate(R.layout.fragment_search_coaching, container, false);
search_coll_btn = (Button) rootview.findViewById(R.id.Search_coaching_btn );
search_coll_btn.setOnClickListener(new View.OnClickListener() {
TextView lite=(TextView) rootview.findViewById(R.id.textView3);
#Override
public void onClick(View v) {
searchbtnclickedlistner_var.showresults();
}
});
return rootview;
}
public interface searchbtnclickedlistner
{
public void showresults();
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
try{
searchbtnclickedlistner_var=(searchbtnclickedlistner)context;
}
catch(Exception e){
throw new RuntimeException(context.toString()+ " must implement OnMyFragmentInteractionListener");
}
}
}
I've implemented interface & Overridden in the mainactivity, now I get a nullpointer exception as follows:
java.lang.NullPointerException: Attempt to invoke interface method
void com.asd.fragments.SearchCoachingFragment$searchbtnclickedlistner.showresults() on a null object reference.
can someone please tell me what I'm doing wrong?
You are calling a method from the interface and that interface is null. You should implement that interface in another class for the callback. Also you should create the interface outside the fragment for a better structure.
The problem could be caused from the fact, you don't put replaced/removed Fragment in the backstack, calling the method addToBackStack().
If you do not call addToBackStack() when you perform a transaction that removes a fragment, then that fragment is destroyed when the transaction is committed and the user cannot navigate back to it. Whereas, if you do call addToBackStack() when removing a fragment, then the fragment is stopped and will be resumed if the user navigates back.
So when you try to use a method of a replaced/removed Fragment you have NullPointerException. This is the link.
Related
I developed a app using fragments and a Navigation Drawer.
On the whole it works perfect. The only thing that I would like to add is a welcome screen on the startup.
At the moment the app shows a empty screen with the Navigation Drawer after starting up because the content_main.xml contains only the 'FrameLayout' that not looks very nice.
I have already a fragment Welcome so that I just need to show it on startup of the app.
My code in the MainActivity.java looks like this.
package com.example.petra.accessibilitydemonstration;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
FragmentTransaction fragmentTransaction;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
DrawerLayout drawer = (DrawerLayout)
findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open,
R.string.navigation_drawer_close);
drawer.addDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView)
findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
}
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
Fragment fragment = null;
int id = item.getItemId();
if (id == R.id.nav_welcome) {
fragment = new WelcomeFragment();
} else if (id == R.id.nav_table) {
fragment = new TableFragment();
} else if (id == R.id.nav_table_accessible) {
fragment = new TableAccessibleFragment();
} else if (id == R.id.nav_about_us) {
fragment = new AboutFragment();
}
if (fragment != null){
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction ft = fragmentManager.beginTransaction();
ft.replace(R.id.screen_area, fragment );
ft.commit();
}
DrawerLayout drawer = (DrawerLayout)
findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
Can some one explain what I have to do in order to solve this problem, please,
Petra
That startup screen is commonly known as Splash screen. Take a new activity with a layout having ImageView or you can also set the welcome image to the layout background.
Declare this Welcome activity as launcher activity in AndroidManifest.xml file.
It seems you are new to the android development world, if it's true then there are multiple online courses available, I would suggest you to start with completing or learning from one course https://in.udacity.com/courses/android
i had problem that my string-array not showing in listview at ListFragment, i didn't get any error, just the data of string-array not display. i create a navigation drawer that show data form another fragment
here my ListFragment
import android.os.Bundle;
import android.app.ListFragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
public class FragmentFood extends ListFragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_food,container,false);
String[] food = getResources().getStringArray(R.array.food_array);
ArrayAdapter adapter = new ArrayAdapter(getActivity(),android.R.layout.simple_list_item_1,food);
setListAdapter(adapter);
return rootView;
}
}
MainActivity.java
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.app.ListFragment;
import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v4.app.FragmentActivity;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
public class MainActivity extends FragmentActivity
implements NavigationView.OnNavigationItemSelectedListener {
String nama;
FragmentManager fragmentManager;
FragmentTransaction fragmentTransaction;
Fragment fragment = null ;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
// setSupportActionBar(toolbar);
Intent intent = getIntent();
nama = intent.getStringExtra("Nama");
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
View headerView = navigationView.getHeaderView(0);
TextView tvNama = (TextView) headerView.findViewById(R.id.tv_name);
tvNama.setText(nama);
fragmentManager = getFragmentManager();
if (savedInstanceState == null) {
fragment = new FragmentFood();
callFragment(fragment);
}
/*FragmentFood fragmentFood = (FragmentFood) getSupportFragmentManager().findFragmentByTag("fragmentfood");
if (fragmentFood == null) {
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.add(R.id.frame_content,null,"fragmentfood");
transaction.commit();
}*/
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
}
#Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
ListFragment listFragment=null;
int id = item.getItemId();
if (id == R.id.nav_food) {
listFragment = new FragmentFood();
callFragment(listFragment);
} else if (id == R.id.nav_dessert) {
} else if (id == R.id.nav_drink) {
/*fragment = new FragmentDrink();
callFragment(fragment);*/
} else if (id == R.id.nav_chartpayment) {
} else if (id == R.id.nav_status) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
private void callFragment(Fragment fragment) {
fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.remove(fragment);
fragmentTransaction.replace(R.id.frame_content, fragment);
fragmentTransaction.commit();
}
}
fragment_food.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="8dp"
android:paddingRight="8dp">
<ListView android:id="#id/android:list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
/>
</LinearLayout>
i dont have any idea to show data in ListFragment at NavigationDrawer
I'm creating a Navigation Drawer like this
MainActivity.java
import android.support.v4.app.FragmentManager;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.NavigationView;
import android.support.design.widget.Snackbar;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import com.paperwrrk.videos.FragmentVideo;
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
}
#Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
FragmentManager fragmentManager = getSupportFragmentManager();
if (id == R.id.nav_home) {
// Handle the camera action
} else if (id == R.id.nav_articles) {
} else if (id == R.id.nav_videos) {
fragmentManager.beginTransaction()
.replace(R.id.content_frame, new FragmentVideo())
.addToBackStack(null)
.commit();
} else if (id == R.id.fb_posts) {
} else if (id == R.id.nav_share) {
} else if (id == R.id.nav_send) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
My FragmentVideo
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.paperwrrk.R;
public class FragmentVideo extends Fragment {
View myView;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
myView = inflater.inflate(R.layout.fragment_video, container, false);
return myView;
}
}
But when I click on the item from Navigation Drawer second fragment doesn't replace or hide the first one, it is overlapping like this
Please see the screenshot
Use a container instead of using fragment tag
<FrameLayout
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="Hello World!" />
Now in activity
if(condition)
getSupportFragmentManager().beginTransaction().replace(R.id.container,new FirstFragment()).commit();
else
getSupportFragmentManager().beginTransaction().replace(R.id.container, new SecondFragment()).commit();
if this not works try to get the fragment container view ID..Here's the code:
transaction.replace(((ViewGroup)(getView().getParent())).getId(), fragment);
It works for me...
int id = item.getItemId();
android.app.Fragment fragment = null;
if (id == R.id.nav_profile) {
fragment = new ProfileActivity();
if (fragment != null) {
android.app.FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.content_frame, fragment).commit();
}
How do I access a button that is on a fragment and program click events. I know there are similar questions to this, however I have tried the solutions they have given and they did not work for me. I always get the unreachable error.
Requirement; Basically I have two buttons in the XML, one is visible the other is not. I am trying to click on the visible button, making it invisible, then making the previously invisible one, visible.
Please note, the fragments are being made by editing Android Studios default navaigation drawer activity
I am trying to have a universal navigation drawer. Easier to edit the default class.
Activity Code
package co.timetrax.drawer;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import butterknife.Bind;
import butterknife.ButterKnife;
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
NavigationView navigationView = null;
Toolbar toolbar = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//setting fragments
MainFragment fragment = new MainFragment();
android.support.v4.app.FragmentTransaction fragmentTransaction =
getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.fragment_container, fragment);
fragmentTransaction.commit();
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
}
#Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.nav_camera) {
// Handle the camera action
MainFragment fragment = new MainFragment();
android.support.v4.app.FragmentTransaction fragmentTransaction =
getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.fragment_container, fragment);
fragmentTransaction.commit();
} else if (id == R.id.nav_gallery) {
} else if (id == R.id.nav_slideshow) {
} else if (id == R.id.nav_manage) {
} else if (id == R.id.nav_share) {
} else if (id == R.id.nav_send) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
Fragment Code
package co.timetrax.drawer;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import butterknife.Bind;
import butterknife.ButterKnife;
/**
* A simple {#link Fragment} subclass.
*/
public class MainFragment extends Fragment implements View.OnClickListener {
public MainFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_main, container, false);
}
#Override
public void onClick(View v) {
}
}
Here is the fragment xml;
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="co.timetrax.drawer.MainFragment">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="MAIN"
android:padding="8dp"
android:textColor="#fff"
android:background="#color/colorPrimary"
android:textSize="28sp"
android:id="#+id/main_button"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="second"
android:visibility="gone"
android:padding="8dp"
android:textColor="#fff"
android:background="#color/colorPrimary"
android:textSize="28sp"
android:id="#+id/second_button"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" />
</RelativeLayout>
Change this method to this:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_main, container, false);
Button mainButton = (Button) view.findViewById(R.id.main_button);
//proceed to add the listener in a regular way
//I will not write that code here; mainButton.setOnClickListener ......
return view;
}
And do this for every Button or any other UI element you need.
You can call getView() anywhere in the fragment to get the root view. Then you can call:
View root = getView();
Button myButton = (Button) root.findViewById(R.id./*id*/);
myButton.setVisibility(View.INVISIBLE);
I want to call another fragment from the current fragment on the click of the button in the current fragment.
Here is my Mainactivity :
import android.app.FragmentManager;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import com.asd.fragments.RecommendationsFragment;
import com.asd.ibitz4college.fragments.SearchCoachingFragment;
import com.asd.fragments.SearchCollegesFragment;
import com.asd.fragments.MainFragment;
import com.asd.fragments.SearchConsultanciesFragment;
import com.asd.fragments.TrendingFragment;
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
FragmentManager fm = getFragmentManager();
fm.beginTransaction().replace(R.id.content_frame,new MainFragment()).commit();
}
#Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
FragmentManager fm = getFragmentManager();
fm.beginTransaction().replace(R.id.content_frame,new MainFragment()).commit();
if (id == R.id.search_colleges) {
// Handle the Search Colleges action
fm.beginTransaction().replace(R.id.content_frame,new SearchCollegesFragment()).commit();
}
else if (id == R.id.search_consultancies) {
fm.beginTransaction().replace(R.id.content_frame,new SearchConsultanciesFragment()).commit();
}
else if (id == R.id.search_coaching) {
fm.beginTransaction().replace(R.id.content_frame,new SearchCoachingFragment()).commit();
}
else if (id == R.id.my_recommendations) {
fm.beginTransaction().replace(R.id.content_frame, new RecommendationsFragment()).commit();
}
else if (id == R.id.trending) {
fm.beginTransaction().replace(R.id.content_frame, new TrendingFragment()).commit();
} else if (id == R.id.profile) {
} else if (id == R.id.logout) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
Here is one of my fragment :
import android.app.Fragment;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.asd.k4c.R;
public class SearchCoachingFragment extends Fragment {
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootview = inflater.inflate(R.layout.fragment_search_coaching,container,false);
return rootview;
}
} //Update code formatting
Suppose I want to call resultsfragment from the above fragment on the click
of a button whose id is btn_search, then what should I do?
I tried some already existing answers here, no luck!
P.S: I'm a starter to the world of android dev.
For doing a fragment transaction.Please do the following.
Eg..
A and B are fragments.
Currently A is visible to the User. If you want to do a transaction.
Just create as like below
B b = new B();
((YourActivity)getActivity).setnewFragment(b,true);
public void setNewFragment(Fragment fragment,boolean addbackstack) {
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(R.id.fragment_content, fragment);
if (addbackstack)
transaction.addToBackStack(title);
transaction.commit();
}
Use an interface to communicate between fragments. For example
public YourFirstFragment extends Fragment {
public interface FragmentCallBack {
void callBack();
}
private FragmentCallBack fragmentCallBack;
public void setFragmentCallBack(FragmentCallBack fragmentCallBack) {
this.fragmentCallBack = fragmentCallBack;
}
private void callThisWhenYouWantToCallTheOtherFragment(){
fragmentCallBack.callBack();
}
}
Then in You activity
private void setCallToFragment{
yourFirstFragment.setFragmentCallBack(new FragmentCallBack(){
void callBack(){
yourSecondFragment.doWhatEver();
}})
}
First you need to create an interface which defines methods that will be used by your fragment to invoke code from the respective activity it is attached to
public interface OnFragmentInteractionlistener {
// the method that you call from your fragment,
// add whatever parameter you need in the implementation of this
// method.
void onClickOfMyView();
}
once you have created the interface, implement it any and all activities that use this fragment.
public class MainActivity extends AppCompatActivity
implements OnMyFragmentInteractionListener {
#Override
public void onClickOfMyView() {
// DO your on click logic here, like starting the transaction
// to add/replace another fragment.
}
}
Then in the onAttach of your fragment to an activity be sure to check if the attaching activity implements this interface, else throw a RunTimeException like so
#Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnMyFragmentInteractionListener) {
mListener = (OnMyFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnMyFragmentInteractionListener");
}
}
Here mListener is a interface reference you hold in your fragment class through which you invoke the onClickOfMyView() method when actually the click happens
Your fragment class where the view's click code is there.
myView.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v) {
mListener.onClickOfMyview();
}
});
You should create some method in your activity. Supposedly it will look like this :
public void startFragment(Fragment fragment) {
fm.beginTransaction().replace(R.id.content_frame,new fragment).commit();
}
As you already done in youronNavigationItemSelected
Then, from your fragment, you can call
((MainActivity)getActivity()).startFragment(new SearchConsultanciesFragment())
for example
Create a method switchFragment in your MainActivity
FragmentTransaction ft;
public void switchFrag() {
try {
ft = getActivity().getFragmentManager().beginTransaction();
ft.replace(R.id.frame_container, new Your_Fragment.class);
ft.commit();
} else {
Log.e("test", "else part fragment ");
}
} catch (Exception e) {
e.printStackTrace();
}
}
Now from your current Fragment you can call this MainActivity's funciton throught the below code:
((MainActivity)getActivity()).switchFrag();
Let me know if this works for you! :)