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user.getUsername() crashes the application

I have recently created a chatting application, which gets crash due to these lines :-
reference.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
User user = dataSnapshot.getValue(User.class);
t_username.setText(user.getUsername());
if (user.getImageURL().equals("No image")){
profile_image.setImageResource(R.drawable.profile_img);
} else {
//change this
Glide.with(getApplicationContext()).load(user.getImageURL()).into(profile_image);
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
I don't understand why this crashes my application.
MainActivity.java :-
package com.dccodes.chugli;
import android.app.ProgressDialog;
import android.content.Intent;
import android.graphics.Typeface;
import android.os.Bundle;
import android.os.Handler;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentPagerAdapter;
import androidx.viewpager.widget.ViewPager;
import com.bumptech.glide.Glide;
import com.dccodes.chugli.Adapter.OnItemClick;
import com.dccodes.chugli.Fragments.ChatsFragment;
import com.dccodes.chugli.Fragments.ProfileFragment;
import com.dccodes.chugli.Fragments.UsersFragment;
import com.dccodes.chugli.Model.Chat;
import com.dccodes.chugli.Model.User;
import com.google.android.material.tabs.TabLayout;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;
import java.util.ArrayList;
import java.util.HashMap;
import de.hdodenhof.circleimageview.CircleImageView;
public class MainActivity extends AppCompatActivity implements OnItemClick {
boolean doubleBackToExitPressedOnce = false;
CircleImageView profile_image;
TextView t_username;
ProgressDialog dialog;
Typeface MR,MRR;
FirebaseUser firebaseUser;
DatabaseReference reference;
OnItemClick onItemClick;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.onItemClick = this;
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setTitle("");
profile_image = findViewById(R.id.profile_image);
final TabLayout tabLayout = findViewById(R.id.tab_layout);
final ViewPager viewPager = findViewById(R.id.view_pager);
profile_image.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
TabLayout.Tab tab = tabLayout.getTabAt(2);
tab.select();
}
});
t_username = findViewById(R.id.t_username);
t_username.setTypeface(MR);
firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
reference = FirebaseDatabase.getInstance().getReference("Users").child(firebaseUser.getUid());
reference.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
User user = dataSnapshot.getValue(User.class);
t_username.setText(user.getUsername());
if (user.getImageURL().equals("No image")){
profile_image.setImageResource(R.drawable.profile_img);
} else {
//change this
Glide.with(getApplicationContext()).load(user.getImageURL()).into(profile_image);
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
reference = FirebaseDatabase.getInstance().getReference("Chats");
dialog = com.dccodes.chugli.Utils.showLoader(MainActivity.this);
reference.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
ViewPagerAdapter viewPagerAdapter = new ViewPagerAdapter(getSupportFragmentManager());
int unread = 0;
for (DataSnapshot snapshot : dataSnapshot.getChildren()){
Chat chat = snapshot.getValue(Chat.class);
if (chat.getReceiver().equals(firebaseUser.getUid()) && !chat.isIsseen()){
unread++;
}
}
if (unread == 0){
viewPagerAdapter.addFragment(ChatsFragment.newInstance(onItemClick), "Chats");
} else {
viewPagerAdapter.addFragment(ChatsFragment.newInstance(onItemClick), "("+unread+") Chats");
}
viewPagerAdapter.addFragment(UsersFragment.newInstance(onItemClick), "Users");
viewPagerAdapter.addFragment(new ProfileFragment(), "Profile");
viewPager.setAdapter(viewPagerAdapter);
tabLayout.setupWithViewPager(viewPager);
if(dialog!=null){
dialog.dismiss();
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()){
case R.id.logout:
FirebaseAuth.getInstance().signOut();
// change this code beacuse your app will crash
startActivity(new Intent(MainActivity.this, StartActivity.class).setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP));
return true;
}
return false;
}
#Override
public void onItemCLick(String uid, View view) {
ViewProfileActivity viewProfileActivity =
ViewProfileActivity.newInstance(uid,this);
viewProfileActivity.show(getSupportFragmentManager(),
"view_profile");
}
class ViewPagerAdapter extends FragmentPagerAdapter {
private ArrayList<Fragment> fragments;
private ArrayList<String> titles;
ViewPagerAdapter(FragmentManager fm){
super(fm);
this.fragments = new ArrayList<>();
this.titles = new ArrayList<>();
}
#Override
public Fragment getItem(int position) {
return fragments.get(position);
}
#Override
public int getCount() {
return fragments.size();
}
public void addFragment(Fragment fragment, String title){
fragments.add(fragment);
titles.add(title);
}
// Ctrl + O
#Nullable
#Override
public CharSequence getPageTitle(int position) {
return titles.get(position);
}
}
private void status(String status){
reference = FirebaseDatabase.getInstance().getReference("User").child(firebaseUser.getUid());
HashMap<String, Object> hashMap = new HashMap<>();
hashMap.put("status", status);
reference.updateChildren(hashMap);
}
#Override
protected void onResume() {
super.onResume();
status("online");
}
#Override
protected void onPause() {
super.onPause();
status("offline");
}
#Override
public void onBackPressed() {
if (doubleBackToExitPressedOnce) {
super.onBackPressed();
return;
}
this.doubleBackToExitPressedOnce = true;
Toast.makeText(this, "Tap again to exit", Toast.LENGTH_SHORT).show();
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
doubleBackToExitPressedOnce=false;
}
}, 2000); }
}
MainActivity.xml :-
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#color/white"
android:orientation="vertical"
tools:context="com.dccodes.chugli.MainActivity">
<com.google.android.material.appbar.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<androidx.appcompat.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#color/dgreen"
android:padding="#dimen/padding_10_dp"
android:theme="#style/Base.ThemeOverlay.AppCompat.Dark.ActionBar"
app:popupTheme="#style/MenuStyle">
<de.hdodenhof.circleimageview.CircleImageView
android:layout_width="50dp"
android:layout_height="50dp"
android:src="#drawable/profile_img"
android:id="#+id/profile_image"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/t_username"
android:textSize="22sp"
android:layout_marginLeft="25dp"
android:textColor="#fff"
android:textStyle="bold"
android:layout_marginStart="25dp" />
</androidx.appcompat.widget.Toolbar>
<com.google.android.material.tabs.TabLayout
android:id="#+id/tab_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#color/dgreen"
app:tabIndicatorColor="#fff"
app:tabSelectedTextColor="#fff"
app:tabTextColor="#fff"
tools:ignore="SpeakableTextPresentCheck,SpeakableTextPresentCheck" />
</com.google.android.material.appbar.AppBarLayout>
<androidx.viewpager.widget.ViewPager
android:id="#+id/view_pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:ignore="SpeakableTextPresentCheck,SpeakableTextPresentCheck" />
</LinearLayout>
I don't understand why I get this error, I have searched it everywhere, but I couldn't find the answer. I hope anyone will help me!

How can I show the places suggestions below text box?

I am using mapbox for my apllication where I want to to show the suggestions of places below the textbox...
Below is my code,
In my code what was happening is after clicking on the search button which is a floatingaction button, a search bar opens and it allow us to search for places...
and after that a marker is placed to that location
It looks like this
package com.example.mapboxwithmarker;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import android.app.Activity;
import android.content.Intent;
import android.graphics.BitmapFactory;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import com.google.gson.JsonObject;
import com.mapbox.api.geocoding.v5.models.CarmenFeature;
import com.mapbox.geojson.Feature;
import com.mapbox.geojson.FeatureCollection;
import com.mapbox.geojson.Point;
import com.mapbox.mapboxsdk.Mapbox;
import com.mapbox.mapboxsdk.camera.CameraPosition;
import com.mapbox.mapboxsdk.camera.CameraUpdateFactory;
import com.mapbox.mapboxsdk.geometry.LatLng;
import com.mapbox.mapboxsdk.maps.MapView;
import com.mapbox.mapboxsdk.maps.MapboxMap;
import com.mapbox.mapboxsdk.maps.OnMapReadyCallback;
import com.mapbox.mapboxsdk.maps.Style;
import com.mapbox.mapboxsdk.plugins.places.autocomplete.PlaceAutocomplete;
import com.mapbox.mapboxsdk.plugins.places.autocomplete.model.PlaceOptions;
import com.mapbox.mapboxsdk.style.layers.SymbolLayer;
import com.mapbox.mapboxsdk.style.sources.GeoJsonSource;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.iconImage;
import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.iconOffset;
public class Locationsearch extends AppCompatActivity implements OnMapReadyCallback {
private static final int REQUEST_CODE_AUTOCOMPLETE = 1;
private MapView mapView;
private MapboxMap mapboxMap;
private CarmenFeature home;
private CarmenFeature work;
private String geojsonSourceLayerId = "geojsonSourceLayerId";
private String symbolIconId = "symbolIconId";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Mapbox access token is configured here. This needs to be called either in your application
// object or in the same activity which contains the mapview.
Mapbox.getInstance(this, getString(R.string.mapbox_access_token));
// This contains the MapView in XML and needs to be called after the access token is configured.
setContentView(R.layout.activity_locationsearch);
mapView = findViewById(R.id.mapView);
mapView.onCreate(savedInstanceState);
mapView.getMapAsync(this);
}
#Override
public void onMapReady(#NonNull final MapboxMap mapboxMap) {
this.mapboxMap = mapboxMap;
mapboxMap.setStyle(Style.MAPBOX_STREETS, new Style.OnStyleLoaded() {
#Override
public void onStyleLoaded(#NonNull Style style) {
initSearchFab();
addUserLocations();
// Add the symbol layer icon to map for future use
style.addImage(symbolIconId, BitmapFactory.decodeResource(
Locationsearch.this.getResources(), R.drawable.ic_location_on));
// Create an empty GeoJSON source using the empty feature collection
setUpSource(style);
// Set up a new symbol layer for displaying the searched location's feature coordinates
setupLayer(style);
}
});
}
private void initSearchFab() {
findViewById(R.id.fab_location_search).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new PlaceAutocomplete.IntentBuilder()
.accessToken(Mapbox.getAccessToken() != null ? Mapbox.getAccessToken() : getString(R.string.mapbox_access_token))
.placeOptions(PlaceOptions.builder()
.backgroundColor(Color.parseColor("#EEEEEE"))
.limit(10)
.addInjectedFeature(home)
.addInjectedFeature(work)
.build(PlaceOptions.MODE_CARDS))
.build(Locationsearch.this);
startActivityForResult(intent, REQUEST_CODE_AUTOCOMPLETE);
}
});
}
private void addUserLocations() {
home = CarmenFeature.builder().text("Mapbox SF Office")
.geometry(Point.fromLngLat(-122.3964485, 37.7912561))
.placeName("50 Beale St, San Francisco, CA")
.id("mapbox-sf")
.properties(new JsonObject())
.build();
work = CarmenFeature.builder().text("Mapbox DC Office")
.placeName("740 15th Street NW, Washington DC")
.geometry(Point.fromLngLat(-77.0338348, 38.899750))
.id("mapbox-dc")
.properties(new JsonObject())
.build();
}
private void setUpSource(#NonNull Style loadedMapStyle) {
loadedMapStyle.addSource(new GeoJsonSource(geojsonSourceLayerId));
}
private void setupLayer(#NonNull Style loadedMapStyle) {
loadedMapStyle.addLayer(new SymbolLayer("SYMBOL_LAYER_ID", geojsonSourceLayerId).withProperties(
iconImage(symbolIconId),
iconOffset(new Float[] {0f, -8f})
));
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == Activity.RESULT_OK && requestCode == REQUEST_CODE_AUTOCOMPLETE) {
// Retrieve selected location's CarmenFeature
CarmenFeature selectedCarmenFeature = PlaceAutocomplete.getPlace(data);
// Create a new FeatureCollection and add a new Feature to it using selectedCarmenFeature above.
// Then retrieve and update the source designated for showing a selected location's symbol layer icon
if (mapboxMap != null) {
Style style = mapboxMap.getStyle();
if (style != null) {
GeoJsonSource source = style.getSourceAs(geojsonSourceLayerId);
if (source != null) {
source.setGeoJson(FeatureCollection.fromFeatures(
new Feature[] {Feature.fromJson(selectedCarmenFeature.toJson())}));
}
// Move map camera to the selected location
mapboxMap.animateCamera(CameraUpdateFactory.newCameraPosition(
new CameraPosition.Builder()
.target(new LatLng(((Point) selectedCarmenFeature.geometry()).latitude(),
((Point) selectedCarmenFeature.geometry()).longitude()))
.zoom(14)
.build()), 4000);
}
}
}
}
// Add the mapView lifecycle to the activity's lifecycle methods
#Override
public void onResume() {
super.onResume();
mapView.onResume();
}
#Override
protected void onStart() {
super.onStart();
mapView.onStart();
}
#Override
protected void onStop() {
super.onStop();
mapView.onStop();
}
#Override
public void onPause() {
super.onPause();
mapView.onPause();
}
#Override
public void onLowMemory() {
super.onLowMemory();
mapView.onLowMemory();
}
#Override
protected void onDestroy() {
super.onDestroy();
mapView.onDestroy();
}
#Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
mapView.onSaveInstanceState(outState);
}
}
But what I want to achieve is I want to use one EditText as a search box and show the result(suggestions) below the edittext...
How can I achieve this?

Mapbox SDK Android Studio

I got to put the map in my app and running in my mobile, but I don't get to put the overlay file GeoJson from Assets Folder in the my locate folder in PC. I want to overlay the points from GeoJson and show popups of points' id. How could I do this?
Below the code that I made from tutorials in Mapbox site in Android Studio
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import com.mapbox.mapboxsdk.Mapbox;
import com.mapbox.mapboxsdk.maps.MapView;
import com.mapbox.mapboxsdk.maps.MapboxMap;
import com.mapbox.mapboxsdk.maps.OnMapReadyCallback;
import com.mapbox.mapboxsdk.maps.Style;
import com.mapbox.mapboxsdk.style.sources.GeoJsonSource;
import java.net.URI;
import java.net.URISyntaxException;
public class MainActivity extends AppCompatActivity {
private MapView mapView;
private final String SOURCE_ID = "SOURCE_ID";
private final String ICON_ID = "ICON_ID";
private final String LAYER_ID = "LAYER_ID";
private final String TAG = "TAG";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Mapbox.getInstance(this, getString(R.string.access_token));
setContentView(R.layout.activity_main);
mapView = (MapView) findViewById(R.id.mapView);
mapView.onCreate(savedInstanceState);
mapView.getMapAsync(new OnMapReadyCallback() {
#Override
public void onMapReady(#NonNull MapboxMap mapboxMap) {
mapboxMap.setStyle(Style.DARK, new Style.OnStyleLoaded() {
#Override
public void onStyleLoaded(#NonNull Style style) {
try {
GeoJsonSource layer = new GeoJsonSource("mapView", new URI("assets://covid_unidades.geojson"));
style.addSource(layer);
} catch (URISyntaxException excepcion) {
Log.d(TAG, String.valueOf(excepcion));
}
}
});
}
});
}
#Override
public void onResume() {
super.onResume();
mapView.onResume();
}
#Override
protected void onStart() {
super.onStart();
mapView.onStart();
}
#Override
protected void onStop() {
super.onStop();
mapView.onStop();
}
#Override
public void onPause() {
super.onPause();
mapView.onPause();
}
#Override
public void onLowMemory() {
super.onLowMemory();
mapView.onLowMemory();
}
#Override
protected void onDestroy() {
super.onDestroy();
mapView.onDestroy();
}
#Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
mapView.onSaveInstanceState(outState);
}
} ```

Exoplayer activity not playing video instead it's showing an empty screen

I am newbie to the android studio, with the help of the developer guide I created this exoplayer activity but it's not playing video instead it's showing an empty screen. I created a button in my MainActivity, when I click that button it should open this player activity and play my hls streaming. Please help
MY Player activity.java
package com.example.mystream;
import androidx.appcompat.app.AppCompatActivity;
import android.net.Uri;
import android.os.Bundle;
import android.view.WindowManager;
import com.google.android.exoplayer2.ExoPlayerFactory;
import com.google.android.exoplayer2.SimpleExoPlayer;
import com.google.android.exoplayer2.source.hls.HlsMediaSource;
import com.google.android.exoplayer2.ui.PlayerView;
import com.google.android.exoplayer2.upstream.DataSource;
import com.google.android.exoplayer2.upstream.DefaultHttpDataSourceFactory;
import com.google.android.exoplayer2.util.Util;
public class playlive extends AppCompatActivity {
private SimpleExoPlayer player;
private PlayerView playerView;
private Uri uri;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_playlive);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON, WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
try {
this.getSupportActionBar().hide();
} catch (Exception e) {
}
}
private void play() {
SimpleExoPlayer player = ExoPlayerFactory.newSimpleInstance(this);
playerView = findViewById(R.id.player_view);
playerView.setPlayer(player);
uri = Uri.parse("http://localhost:1935/live/mystream/index.m3u8");
DataSource.Factory dataSourceFactory =
new DefaultHttpDataSourceFactory(Util.getUserAgent(this, "app-name"));
// Create a HLS media source pointing to a playlist uri.
HlsMediaSource hlsMediaSource =
new HlsMediaSource.Factory(dataSourceFactory).createMediaSource(uri);
player.prepare(hlsMediaSource);
player.setPlayWhenReady(true);
}
public void onStart(){
super.onStart();
play();
}
public void onStop(){
super.onStop();
onBackPressed();
player.release();
}
public void onDestroy(){
super.onDestroy();
onBackPressed();
player.release();
}
}
My playlive .xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".playlive">
<com.google.android.exoplayer2.ui.PlayerView
android:id="#+id/exo_buffering"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:focusable="true"
app:resize_mode="fill"
/>
</androidx.constraintlayout.widget.ConstraintLayout>
Main activity
package com.example.mystream;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
try {
this.getSupportActionBar().hide();
}catch (Exception e){
}
Button button = findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent activity2Intent = new Intent(getApplicationContext(), playlive.class);
startActivity(activity2Intent);
}
});
}
}

The issue seems in these two line
HlsMediaSource hlsMediaSource =new HlsMediaSource.Factory(dataSourceFactory).createMediaSource(uri);
uri= Uri.parse("http://localhost:1935/live/mystream/index.m3u8");
You are trying to pass uri before initializing which is causing the issue.
try initializing before as below
uri= Uri.parse("http://localhost:1935/live/mystream/index.m3u8");
and then use it
HlsMediaSource hlsMediaSource =new HlsMediaSource.Factory(dataSourceFactory).createMediaSource(uri);
This should solve your issue.

Here is the detailed desc of your requirement.
Method to Check Net Connection
private boolean checkConnection(Context context)
{
final ConnectivityManager mConnMngr= (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
if (mConnMngr!= null) {
NetworkInfo mNetworkInfo = mConnMngr.getActiveNetworkInfo();
if (mNetworkInfo != null) {
if ((mNetworkInfo .getType() == ConnectivityManager.TYPE_WIFI) {
return true;
} else return mNetworkInfo.getType() == ConnectivityManager.TYPE_MOBILE;
}
}
return false;
}
Permissions
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
Usage
if (checkConnection(context)) {
play();
} else {
Toast.makeText(context,"No internet available!",Toast.LENGTH_LONG).show()
}

Android - Toast button not appearing

After reading about Android's Toast class, I had to try it out.
I added a button to my layout, followed the instructions on this page, and added an OnClickListener to my button that would call the toast.
The problem now is that when I debug the app, the button doesn't appear on the view.
Do I have something where it's not supposed to be? (Additional information available upon request)
Code:
activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/relLayout"
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=".MainActivity" >
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:text="Button" />
</RelativeLayout>
MainActivity.java
package com.joseph.toasttest;
import com.joseph.toasttest.R;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import android.app.Activity;
import android.content.Context;
public class MainActivity extends Activity {
Context context = getApplicationContext();
CharSequence text = "Test";
int duration = Toast.LENGTH_SHORT;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button btnToast = (Button) findViewById(R.id.button1);
btnToast.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
toastMe(v);
}
});
}
private void toastMe(View v) {
Toast.makeText(context, text, duration).show();
}
}

try this :
btnToast.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
Toast msg = Toast.makeText(MainActivity.this, text, duration );
msg.show();

Just guessing here, but I'd start removing those paddings in your RelativeLayout. You may be running the app in a device in which values of
#dimen/activity_vertical_margin
and/or
#dimen/activity_horizontal_margin
are 'moving' your button out of the screen. You can also try aligning the button in the center of the view.-
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:text="Button" />

You must create your context inside onCreate() method:
package com.joseph.toasttest;
import com.joseph.toasttest.R;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import android.app.Activity;
import android.content.Context;
public class MainActivity extends Activity {
Context context = getApplicationContext();
CharSequence text = "Test";
int duration = Toast.LENGTH_SHORT;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button btnToast = (Button) findViewById(R.id.button1);
btnToast.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
toastMe(v);
}
});
}
private void toastMe(View v) {
Toast.makeText(context, text, duration).show();
}
}

You can't use the application context for UI stuff, like creating dialogs, toasts or launching activities. Just use the activity as a context instead.
Different contexts in Android, and what they can and can't be used for.

I got it to work by removing the context and duration variables altogether and setting them manually inside my Toast method.
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button btnToast = (Button) findViewById(R.id.button1);
btnToast.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
toastMe(v);
}
});
}
private void toastMe(View v) {
Toast.makeText(getApplicationContext(), "Test", Toast.LENGTH_SHORT).show();
}
}

This should work:
package com.joseph.toasttest;
import com.joseph.toasttest.R;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import android.app.Activity;
import android.content.Context;
public class MainActivity extends Activity {
CharSequence text = "Test";
int duration = Toast.LENGTH_SHORT;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button btnToast = (Button) findViewById(R.id.button1);
btnToast.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
toastMe(this);
}
});
}
private void toastMe(Context context) {
Toast.makeText(context, text, duration).show();
}
}