Spinner items lost on navigate change in Android Studio - java

I have created an Android Studio project and i have MainActivity, FirstFragment and SecondFragment. On the FirstFragment I have an spinner element. When the app starts the spinner is filled with values, when I switch from the First to the second Fragment and back, the values are gone.
MainActivity
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = 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.
PublicCameras Cameras = new PublicCameras();
//get the spinner from the xml.
Spinner dropdown = findViewById(R.id.cameraList); // This element loses his values when navigating to SecondFragment and back
ArrayAdapter<String> adapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_dropdown_item, Cameras.GetNamesEn());
dropdown.setAdapter(adapter);
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);
}
}
FirstFragment
public class FirstFragment extends Fragment {
#Override
public View onCreateView(
LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState
) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_first, container, false);
}
public void onViewCreated(#NonNull View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
view.findViewById(R.id.button_first).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
NavHostFragment.findNavController(FirstFragment.this)
.navigate(R.id.action_FirstFragment_to_SecondFragment);
}
});
}
}
SecondFragment
public class SecondFragment extends Fragment {
#Override
public View onCreateView(
LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState
) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_second, container, false);
}
public void onViewCreated(#NonNull View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
view.findViewById(R.id.button_second).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
NavHostFragment.findNavController(SecondFragment.this)
.navigate(R.id.action_SecondFragment_to_FirstFragment);
}
});
}
}
I would like to point out that on rotating the values are being set again because of re-entering the function onCreateOptionsMenu. What is the best practice to keep values on a layout change?
Thank you for your time !

You're getting this issue cause when you move from one fragment to other android destorys the fragment and recreates that fragment when returned back this happens in the screen orientation case too. In order to handle this override OnSavedInstance method in you're code
There is a little hack you can make it work.
first override
#Override
public void onSaveInstanceState(#NonNull Bundle outState) {
super.onSaveInstanceState(outState);
outState.putStringArray("YOUR_KEY", "YOUR_OBJECT");//chnage this with you're object name
}
Now in you're onViewCreated use the SavedInstance variable and get that stringArray using the key and pass this to the spinner.
Try this and if you faced any issue do comment.

Related

Calling an activity via navigation drawer in android-studio

I am designing an android app and have created an activity which cannot extend to a fragment as I am using a gridview. The problem is, when I try to navigate to the activity within the navigational drawer it does not work. Is there a way I can extend to fragment while still using the gridview?
Activity I am trying to navigate to
public class GalleryActivity extends FragmentActivity {
private GridView gridView;
private GridViewAdapter gridAdapter;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_gallery);
gridView = (GridView) findViewById(R.id.gridView);
gridAdapter = new GridViewAdapter(this, R.layout.grid_item_layout, getData());
gridView.setAdapter(gridAdapter);
gridView.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
ImageItem item = (ImageItem) parent.getItemAtPosition(position);
//Create intent
Intent intent = new Intent(GalleryActivity.this, DetailsActivity.class);
intent.putExtra("title", item.getTitle());
intent.putExtra("image", item.getImage());
//Start details activity
startActivity(intent);
}
});
}
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_gallery, container, false);
}
/**
* Prepare some dummy data for gridview
*/
private ArrayList<ImageItem> getData() {
final ArrayList<ImageItem> imageItems = new ArrayList<>();
TypedArray imgs = getResources().obtainTypedArray(R.array.image_ids);
for (int i = 0; i < imgs.length(); i++) {
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), imgs.getResourceId(i, -1));
imageItems.add(new ImageItem(bitmap, "Image#" + i));
}
return imageItems;
}
}
Below is the code for the navigational drawer, I am trying to navigate to GalleryActivity
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);
}
#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);
}
//Function to switch screens by passing the navigation ID
private void displaySelectedScreen(int id) {
Fragment fragment = null;
switch (id) {
case R.id.nav_Home:
fragment = new HomeActivity();
break;
case R.id.nav_About:
fragment = new AboutActivity();
break;
case R.id.nav_Gallery:
fragment = new GalleryActivity();
break;
case R.id.nav_locationMap:
fragment = new LocationActivity();
break;
case R.id.nav_products:
fragment = new ProductsActivity();
break;
}
if (fragment != null) {
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.content_main, fragment);
ft.commit();
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
}
}
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
displaySelectedScreen(item.getItemId());
return true;
}
}
Refer to Android switch Fragments in the new design support navigation drawer
You need to set a setNavigationItemSelectedListener on the navigationView
you should cast the fragment activity to only fragment.like this use this code..
public class GalleryActivity extends Fragment {
private GridView gridView;
private GridViewAdapter gridAdapter;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_gallery, null);
gridView = (GridView) view.findViewById(R.id.gridView);
gridAdapter = new GridViewAdapter(this, R.layout.grid_item_layout, getData());
gridView.setAdapter(gridAdapter);
gridView.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
ImageItem item = (ImageItem) parent.getItemAtPosition(position);
//Create intent
Intent intent = new Intent(GalleryActivity.this, DetailsActivity.class);
intent.putExtra("title", item.getTitle());
intent.putExtra("image", item.getImage());
//Start details activity
startActivity(intent);
}
});
}
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_gallery, container, false);
}
}
First of all, how you imagined creating fragment by passing activity type?
Fragment fragment = null;
switch (id) {
case R.id.nav_Home:
fragment = new HomeActivity();
break;

How to close the navigation drawer when an Item of ListView is selected?

I know that this question is asked many times but we have different situation. Regarding the project I downloaded the project navigation drawer demo from GitHub.com. Provided the code below:
this is the main activity:
package edu.ejapp.dotalegitstore;
#SuppressLint("NewApi")
public class MainActivity extends BaseActivity {
FragmentStackManager fm,sliding_menu;
private Context context;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
context=this;
setUpView();
menuToggeleSetUp(savedInstanceState);
}
void setUpView(){
fm = new FragmentStackManager(this);
sliding_menu = new FragmentStackManager(this);
drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
fm.addFragment(new MainFragment(), R.id.main_frame, false, FragmentTransaction.TRANSIT_NONE, false);
sliding_menu.addFragment(new SlidingMenuFragment(), R.id.slide_fragment, false, FragmentTransaction.TRANSIT_NONE, false);
}
void menuToggeleSetUp(Bundle savedInstanceState){
mDrawerToggle = new ActionBarDrawerToggle(this, drawer,
R.drawable.ic_drawer, // nav menu toggle icon
R.string.app_name
) {
#SuppressLint("NewApi")
public void onDrawerClosed(View view) {
getSupportActionBar().setTitle(mTitle);
// calling onPrepareOptionsMenu() to show action bar icons
invalidateOptionsMenu();
}
public void onDrawerOpened(View drawerView) {
getSupportActionBar().setTitle(mDrawerTitle);
// calling onPrepareOptionsMenu() to hide action bar icons
invalidateOptionsMenu();
}
};
drawer.setDrawerListener(mDrawerToggle);
if (savedInstanceState == null) {
// on first time display view for first nav item
}
}
#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
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
// Sync the toggle state after onRestoreInstanceState has occurred.
mDrawerToggle.syncState();
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
if (id == R.id.action_settings) {
return true;
}
else if (id == R.id.action_exit) {
final AlertDialog.Builder dialog = new AlertDialog.Builder(context);
dialog.setTitle("COnfirm exit");
dialog.setMessage("Are you sure you want to exit?");
dialog.setPositiveButton("No", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
dialog.dismiss();
}
});
dialog.setNegativeButton("Yes", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
finish();
}
});
AlertDialog alertDialog = dialog.create();
alertDialog.show();
}
else if (id == R.id.action_login) {
startActivity(new Intent(MainActivity.this, LoginActivity.class));
}
else {
}
return super.onOptionsItemSelected(item);
}
#Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
// Pass any configuration change to the drawer toggls
mDrawerToggle.onConfigurationChanged(newConfig);
}
}
The base activity extended by MainActivity:
package edu.ejapp.dotalegitstore;
import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBarDrawerToggle;
#SuppressWarnings("deprecation")
public class BaseActivity extends ActionBarActivity{
public ActionBarDrawerToggle mDrawerToggle;
public DrawerLayout drawer;
CharSequence mDrawerTitle;
CharSequence mTitle;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setActionBar();
}
public void setActionBar(){
getSupportActionBar().setTitle("");
getSupportActionBar().setBackgroundDrawable(new ColorDrawable(this.getResources().getColor(R.color.app_main)));
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setHomeButtonEnabled(true);
}
}
and lastly the sliding fragment activity, here the on item click is implemented not in baseactivity or main which is the reason of my problem: i cant close the drawer when i clicked item on the drawer:
public class SlidingMenuFragment extends Fragment {
List<String> data;
ListView list_view;
SlidingMenuListAdapter adapter;
#SuppressLint("InflateParams")
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
ViewGroup root = (ViewGroup) inflater.inflate(R.layout.fragment_sliding_menu, null);
setUpView(root);
return root;
}
void setUpView(ViewGroup root){
list_view = (ListView)root.findViewById(R.id.list_view);
initList();
setUpClick();
}
void initList(){
data = new ArrayList<String>();
data.add("Home");
data.add("Arcana");
data.add("Courrier");
data.add("Hero Sets");
data.add("Immortals");
adapter = new SlidingMenuListAdapter(getActivity(),data);
list_view.setAdapter(adapter);
}
void setUpClick(){
list_view.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Toast.makeText(getActivity(),"Hi "+position,Toast.LENGTH_SHORT).show();
}
});
}
}
I didnt include the other files such as the xmls. My question is:
How can I close the drawer when I clicked item of the list view provided that the onitemclick is defined in SlidingMenuFragment class and the mDrawerlayout is located in BaseActivity class which is extended by MainActivity class?
create a method to close drawer in your main activity and call it from fragment.
public static void closeDrawer(){
if(drawerLayout.isDrawerOpen(leftDrawerList)){
drawerLayout.closeDrawer(leftDrawerList);
}
}
Inside Fragment
MainActivity.closeDrawer();
here is my suggestion:
provide an interface in SlidingMenuFragment like:
public class SlidingMenuFragment extends Fragment {
private OnListItemClickListener mOnListItemClickListener;
//here is mOnListItemClickListener getter and setter method
public *** set(get)OnListItemClickListener(){};
//define a interface here
public interface OnListItemClickListener{
public void onListenItemClick();
}
.
.
.
void setUpClick(){
list_view.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
if(mOnListItemClickListener != null){
mOnListItemClickListener.onListenItemClick();
}
}
});
}
}
and then you should implement this interface in your MainActivity class like:
public class MainActivity extends BaseActivity {
void setUpView(){
fm = new FragmentStackManager(this);
sliding_menu = new FragmentStackManager(this);
drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
fm.addFragment(new MainFragment(), R.id.main_frame, false, FragmentTransaction.TRANSIT_NONE, false);
SlidingMenuFragment smFragment = new SlidingMenuFragment()
smFragment.setMonListItemClickListener(new OnListItemClickListener(){
public void onListenItemClick(){
drawer.close();
}
});
sliding_menu.addFragment(smFragment, R.id.slide_fragment, false, FragmentTransaction.TRANSIT_NONE, false);
}
}`

Activity is not an enclosing class in Android Studio

I am New to Android. I Have Created Tab using android.support.v4.view.ViewPager. When i trying to get data from server using Json Request it give me the Error
AccountActivity is not an enclosing class.
please Any Help will be Appreciated
TAb1.java
public class Tab1 extends Fragment {
private ProgressDialog pDialog;
private UserAddress userAddress;
private TextView txtResponsec;
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
new LoadUserAddress().execute();
}
class LoadUserAddress extends AsyncTask<String,String,String> {
private ProgressDialog progressDialog;
#Override
protected String doInBackground(String... params) {
try {
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
JSONHttpClient jsonHttpClient = new JSONHttpClient();
userAddress = jsonHttpClient.Get(ServiceUrl.UserAddress, nameValuePairs, UserAddress.class);
String id = userAddress.GetId();
}
catch (Exception ex){
String message = ex.getMessage();
}
return null;
}
#Override
protected void onPreExecute() {
super.onPreExecute(); //To change body of overridden methods use File | Settings | File Templates.
progressDialog = new ProgressDialog(AccountActivity.this);
progressDialog.setMessage("Loading products. Please wait...");
progressDialog.show();
}
#Override
protected void onPostExecute(String s) {
progressDialog.dismiss();
getActivity().runOnUiThread(new Runnable() {
#Override
public void run() {
txtResponsec.setText(userAddress.GetCountry());
}
});
}
}
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View v =inflater.inflate(R.layout.tab_1,container,false);
return v;
}
}
AccountActivity.java
public class AccountActivity extends AppCompatActivity {
Toolbar toolbar;
ActionBar actionBar;
ViewPager pager;
ViewPagerAdapter adapter;
SlidingTabLayout tabs;
CharSequence Titles[]={"Info.","Address","Contact","Email"};
int Numboftabs =4;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_account);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
assert getSupportActionBar() != null;
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
if (toolbar != null) {
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
onBackPressed();
}
});
}
adapter = new ViewPagerAdapter(getSupportFragmentManager(),Titles,Numboftabs);
// Assigning ViewPager View and setting the adapter
pager = (ViewPager) findViewById(R.id.pager);
pager.setAdapter(adapter);
// Assiging the Sliding Tab Layout View
tabs = (SlidingTabLayout) findViewById(R.id.tabs);
tabs.setDistributeEvenly(true); // To make the Tabs Fixed set this true, This makes the tabs Space Evenly in Available width
// Setting Custom Color for the Scroll bar indicator of the Tab View
tabs.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
#Override
public int getIndicatorColor(int position) {
return getResources().getColor(R.color.tabsScrollColor);
}
});
// Setting the ViewPager For the SlidingTabsLayout
tabs.setViewPager(pager);
}
#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_account, 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);
}
}
You should change
progressDialog = new ProgressDialog(AccountActivity.this);
to
progressDialog = new ProgressDialog(getActivity());
in Tab1 Fragment also i see txtResponsec=null you forget to initialized it.
Edit:
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View v =inflater.inflate(R.layout.tab_1,container,false);
txtResponsec=(TextView)v.findViewById(R.id.txtResponsecId);
return v;
}

Where to write java code in Android app

I just started learning how to create Android app and I'm stuck with methods in MainActivity.java. I don't know where to write my java code because the app is crashing.
package com.cidecode.loveometer;
public class MainActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment())
.commit();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public static class PlaceholderFragment extends 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;
}
}
}
Things you want to be created when the activity is started should be in the onCreate method (buttons and onClickListeners etc). If for example you have a button you have stated an onClick name for in the xml file (rather than put an onClickListener on it) then you can put that function where you like as long as it is not after the last curly brace that finishes the activity. You should try the new boston tutorials on youtube, I found they explained a lot and helped me understand where I actually needed to put things.

intent is undefined tried a lot , nothing works

I get error with Intent. It says: intent is undefined. I've been searching a lot of other posts and it still doesn't work. Any ideas?
for your knowledge, i develop my own app with the basic of android developpes. Because my own intent didn't work, i used and created the exact same class as in the example, class DisplayMessageActivity but the problem remains the same, Here some of my code.
public class Main extends ActionBarActivity {
public final static String EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE";
#Override
protected void onCreate(Bundle savedInstanceState) {
try{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment()).commit();
}
}
catch(Exception e){
System.out.println("fout zit hier");
}
}
#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();
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 {
public PlaceholderFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container,
false);
return rootView;
}
/** Called when the user clicks the Send button */
public void sendMessage(View view) {
Intent intent = new Intent(this, DisplayMessageActivity.class);
EditText editText = (EditText) findViewById(R.id.edit_message);
String message = editText.getText().toString();
intent.putExtra(EXTRA_MESSAGE, message);
startActivity(intent);
}
}
}
Try replacing the first parameter on the Intent constructor.
Intent intent = new Intent(this, DisplayMessageActivity.class); // wrong
Intent intent = new Intent(getActivity(), DisplayMessageActivity.class); // right
The first parameter is a Context object, and remember that a Fragment does not inherit from Context, so the solution is getting the one from the parent Activity.

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