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My app cannot launch because of my Homepage [duplicate]

This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 9 months ago.
My Homepage has a problem, the app failed to start when i run it. but, when i comment out the code on .Homepage in the AndroidManifest the app can run.
Error at Logcat:
2022-05-31 13:28:30.991 5606-5606/com.example.limbangfoodhuntfortourism E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.limbangfoodhuntfortourism, PID: 5606
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.limbangfoodhuntfortourism/com.example.limbangfoodhuntfortourism.Homepage}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageView.setImageResource(int)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2951)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3016)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1716)
at android.os.Handler.dispatchMessage(Handler.java:110)
at android.os.Looper.loop(Looper.java:232)
at android.app.ActivityThread.main(ActivityThread.java:6806)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1103)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:964)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageView.setImageResource(int)' on a null object reference
at com.example.limbangfoodhuntfortourism.Homepage.onCreate(Homepage.java:24)
at android.app.Activity.performCreate(Activity.java:6974)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2904)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3016) 
at android.app.ActivityThread.-wrap12(ActivityThread.java) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1716) 
at android.os.Handler.dispatchMessage(Handler.java:110) 
at android.os.Looper.loop(Looper.java:232) 
at android.app.ActivityThread.main(ActivityThread.java:6806) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1103) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:964) 
this is the error:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.limbangfoodhuntfortourism, PID: 27159
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.limbangfoodhuntfortourism/com.example.limbangfoodhuntfortourism.Homepage}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageView.setImageResource(int)' on a null object reference
This is my Log in code:
package com.example.limbangfoodhuntfortourism;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.AuthResult;
import com.google.firebase.auth.FirebaseAuth;
public class Login extends AppCompatActivity {
EditText mEmail, mPassword;
Button mLoginButton;
TextView mCreateLinkSignUp, mForgotPassword;
FirebaseAuth fAuth;
ProgressBar progressBar;
ImageView mLogo;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
mEmail = findViewById(R.id.email);
mPassword = findViewById(R.id.password);
progressBar = findViewById(R.id.progressBarLogin);
mLoginButton = findViewById(R.id.loginButton);
mCreateLinkSignUp = findViewById(R.id.signUpNow);
mForgotPassword = findViewById(R.id.forgotPassword);
fAuth = FirebaseAuth.getInstance();
mLoginButton.setOnClickListener((view) -> {
String email = mEmail.getText().toString().trim();
String password = mPassword.getText().toString().trim();
if(TextUtils.isEmpty(email)) {
mEmail.setError("Email is Required.");
return;
}
if(TextUtils.isEmpty(password)) {
mPassword.setError("Password is Required.");
return;
}
if(password.length() < 6) {
mPassword.setError("Password must be >= 6 characters");
return;
}
progressBar.setVisibility(View.VISIBLE);
// authenticate the user
fAuth.signInWithEmailAndPassword(email,password).addOnCompleteListener((task) -> {
if(task.isSuccessful()) {
Toast.makeText(Login.this, "Logged in Successfully!", Toast.LENGTH_SHORT).show();
startActivity(new Intent(getApplicationContext(),Homepage.class));
} else {
Toast.makeText(Login.this, "Error!" + task.getException().getMessage(), Toast.LENGTH_SHORT).show();
progressBar.setVisibility(View.GONE);
}
});
});
mCreateLinkSignUp.setOnClickListener((view) -> {
startActivity(new Intent(getApplicationContext(), Register.class));
});
mLogo = findViewById(R.id.imageView);
mLogo.setImageResource(R.drawable.main_logo);
mForgotPassword.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
final EditText resetMail = new EditText(view.getContext());
final AlertDialog.Builder passwordResetDialog = new AlertDialog.Builder(view.getContext());
passwordResetDialog.setTitle("Reset Password?");
passwordResetDialog.setMessage("Enter Your Email To Received Reset Link.");
passwordResetDialog.setView(resetMail);
passwordResetDialog.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
// extract the mail and send reset link
String mail = resetMail.getText().toString();
fAuth.sendPasswordResetEmail(mail).addOnSuccessListener(new OnSuccessListener<Void>() {
#Override
public void onSuccess(Void unused) {
Toast.makeText(Login.this, "Reset Link Sent To Your Email.", Toast.LENGTH_SHORT).show();
}
}).addOnFailureListener(new OnFailureListener() {
#Override
public void onFailure(#NonNull Exception e) {
Toast.makeText(Login.this, "Error! Reset Link is Not Sent." + e.getMessage(), Toast.LENGTH_SHORT).show();
}
});
}
});
passwordResetDialog.setNegativeButton("No", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
// close the dialog
}
});
passwordResetDialog.create().show();
}
});
}
}
this is my Homepage:
package com.example.limbangfoodhuntfortourism;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.ImageView;
import android.widget.TextView;
import com.google.firebase.auth.FirebaseAuth;
public class Homepage extends AppCompatActivity {
ImageView mLogo;
TextView mLogoutLink;
FirebaseAuth fAuth;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_homepage);
mLogoutLink = findViewById(R.id.Logout);
mLogo = findViewById(R.id.imageView);
mLogo.setImageResource(R.drawable.main_logo);
fAuth = FirebaseAuth.getInstance();
mLogoutLink.setOnClickListener((view) -> {
startActivity(new Intent(getApplicationContext(), Logout.class));
});
}
}
This is my AndroidManifest code:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="com.example.limbangfoodhuntfortourism">
<application
android:allowBackup="true"
android:dataExtractionRules="#xml/data_extraction_rules"
android:fullBackupContent="#xml/backup_rules"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/Theme.LimbangFoodHuntForTourism"
tools:targetApi="31">
<activity
android:name=".Logout"
android:exported="true" />
<activity
android:name=".RestaurantDetails"
android:exported="true" />
<activity
android:name=".Homepage"
android:exported="true">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".Login"
android:exported="true" />
<activity
android:name=".Register"
android:exported="true">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".MainActivity"
android:exported="true" />
</application>
</manifest>

try this in your login activity
mLogo = findViewById(R.id.imageView);
mLogo.setImageDrawable(ContextCompat.getDrawable(getActivity(),
R.drawable.main_logo));
lemme know if it works out for you

How to start android app as service after booting

I am trying to start up an android app as background service after initial run. At first run, the app should start as normal android app, then after, that it should be a background service which still runs even after booting. I wrote the following code. The service class is verified as standalone android app. But this app is not running as expected. No error code, but when debug, service class is not working.
Manifest file:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.tulga.nar.mytrack">
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<receiver android:name=".MyBroadcastReceiver">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED" />
</intent-filter>
</receiver>
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity
android:name=".MainActivity"
android:label="#string/title_activity_main"
android:theme="#style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
Initial one time running activity class:
package com.tulga.nar.mytrack;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.content_main);
}
public void starterHandler(View v)
{
new MyBroadcastReceiver();
}
}
Initial one time running activity class's xml:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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="com.tulga.nar.mytrack.MainActivity">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/starter"
android:text="start service"
android:onClick="starterHandler"/>
</android.support.constraint.ConstraintLayout>
Broadcast receiver class. It is called from MainActivity after start service button is clicked. It is supposed to start background MyService class.
package com.tulga.nar.mytrack;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
public class MyBroadcastReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context aContext, Intent aIntent) {
// This is where you start your service
aContext.startService(new Intent(aContext, MyService.class));
}
}
This is background MyService class. The class is verified and works as standalone app. But here, code execution is not reaching to here when debug.
package com.tulga.nar.mytrack;
import android.Manifest;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.AsyncTask;
import android.os.Bundle;
import android.provider.Settings;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
/**
* Created by Home on 8/27/2017.
*/
public class MyService extends AppCompatActivity implements
LocationListener
{
private class SendDeviceDetails extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... params) {
String data = "";
HttpURLConnection connection = null;
try {
URL url=new URL(params[0]);
connection = (HttpURLConnection) url.openConnection();
connection.setRequestProperty("Content-Type",
"application/json");
connection.setDoOutput(true);
connection.setRequestMethod("POST");
connection.connect();
DataOutputStream wr = new
DataOutputStream(connection.getOutputStream());
wr.writeBytes(params[1]);
wr.flush();
wr.close();
InputStream in = connection.getInputStream();
InputStreamReader inputStreamReader = new InputStreamReader(in);
int inputStreamData = inputStreamReader.read();
while (inputStreamData != -1) {
char current = (char) inputStreamData;
inputStreamData = inputStreamReader.read();
data += current;
}
} //catch (Exception e) {
//e.printStackTrace();
//}
catch (MalformedURLException e) {
e.printStackTrace();}
catch (IOException e) {
e.printStackTrace();
}
finally {
if (connection != null) {
connection.disconnect();
}
}
return data;
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
Log.e("TAG", result); // this is expecting a response code to be
sent from your server upon receiving the POST data
}
}
public static final int RequestPermissionCode = 1 ;
static public double myLong=151;
static public double myLat=-34;
static public String _id=null;
static public String _rev=null;
Button buttonEnable, buttonGet ;
TextView textViewLongitude, textViewLatitude ;
Context context;
Intent intent1 ;
Location location;
LocationManager locationManager ;
boolean GpsStatus = false ;
Criteria criteria ;
String Holder;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.activity_main);
EnableRuntimePermission();
locationManager = (LocationManager)
getSystemService(Context.LOCATION_SERVICE);
criteria = new Criteria();
Holder = locationManager.getBestProvider(criteria, false);
context = getApplicationContext();
CheckGpsStatus();
JSONObject postData = new JSONObject();
try {
postData.put("_id",String.valueOf("9876543210"));
postData.put("Lat",
String.valueOf(String.valueOf(MyService.myLat)));
postData.put("Long",
String.valueOf(String.valueOf(MyService.myLong)));
postData.put("_rev",String.valueOf("1-
62076042d87cacd2711268d4a396129b"));
new SendDeviceDetails().execute("my-server-name/mydatabase",
postData.toString());
}
catch (JSONException e) {
e.printStackTrace();
}
}
#Override
public void onLocationChanged(Location location) {
textViewLongitude.setText("Longitude:" + location.getLongitude());
textViewLatitude.setText("Latitude:" + location.getLatitude());
myLong=location.getLongitude();
myLat=location.getLatitude();
}
#Override
public void onStatusChanged(String s, int i, Bundle bundle) {
}
#Override
public void onProviderEnabled(String s) {
}
#Override
public void onProviderDisabled(String s) {
}
public void CheckGpsStatus(){
locationManager =
(LocationManager)context.getSystemService(Context.LOCATION_SERVICE);
GpsStatus =
locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
}
public void EnableRuntimePermission(){
if (ActivityCompat.shouldShowRequestPermissionRationale(MyService.this,
Manifest.permission.ACCESS_FINE_LOCATION))
{
Toast.makeText(MyService.this,"ACCESS_FINE_LOCATION permission
allows us to Access GPS in app", Toast.LENGTH_LONG).show();
} else {
ActivityCompat.requestPermissions(MyService.this,new String[]{
Manifest.permission.ACCESS_FINE_LOCATION},
RequestPermissionCode);
}
}
#Override
public void onRequestPermissionsResult(int RC, String per[], int[] PResult)
{
switch (RC) {
case RequestPermissionCode:
if (PResult.length > 0 && PResult[0] ==
PackageManager.PERMISSION_GRANTED) {
Toast.makeText(MyService.this,"Permission Granted, Now your
application can access GPS.", Toast.LENGTH_LONG).show();
} else {
Toast.makeText(MyService.this,"Permission Canceled, Now your
application cannot access GPS.", Toast.LENGTH_LONG).show();
}
break;
}
}

You didn't regest your serice in mainifest,and your broadcastReceiver is not at the right place.It should like this:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.tulga.nar.mytrack">
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<application android:allowBackup="true" android:icon="#mipmap/ic_launcher"
android:label="#string/app_name" android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true" android:theme="#style/AppTheme">
<activity android:name=".MainActivity" android:label="#string/title_activity_main"
android:theme="#style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver android:name=".MyBroadcastReceiver">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED" />
</intent-filter>
</receiver>
<service android:name=".service.MyService">
<intent-filter>
<action android:name="write your action name" />
</intent-filter>
</service>
</application>
</manifest>

Get Long/Lat from last know location Android Studio

package com.example.sander.app;
import android.app.Fragment;
import android.location.Location;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.LocationServices;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.List;
/**
* Created by Sander on 6-4-2017.
*/
public class BlankFragment extends Fragment implements GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener{
public BlankFragment() {
// Required empty public constructor
}
GoogleApiClient mGoogleApiClient;
Location mLastLocation;
TextView mLatitudeText;
TextView mLongitudeText;
#Override
public void onCreate(Bundle bundle){
mGoogleApiClient = new GoogleApiClient.Builder(getActivity())
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
super.onCreate(bundle);
}
#Override
public void onConnectionFailed(ConnectionResult result) {
}
#Override
public void onStart(){
mGoogleApiClient.connect();
super.onStart();
}
#Override
public void onStop(){
mGoogleApiClient.disconnect();
super.onStop();
}
#Override
public void onConnectionSuspended(int arg0) {
}
#Override
public void onConnected(Bundle connectionHint) {
mLastLocation = LocationServices.FusedLocationApi.getLastLocation(
mGoogleApiClient);
if (mLastLocation != null) {
mLatitudeText.setText(String.valueOf(mLastLocation.getLatitude()));
//mLongitudeText.setText(String.valueOf(mLastLocation.getLongitude()));
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_blank, container, false);
final TextView txt= (TextView)view.findViewById(R.id.onzin);
//txt.setText(String.valueOf(mLastLocation.getLatitude()));
// Inflate the layout for this fragment
return view;
}
}
ANDROIDMANIFEST
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.sander.app">
<uses-sdk
android:minSdkVersion="17"
android:targetSdkVersion="17" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<meta-data
android:name="com.google.android.geo.API_KEY"
android:value="#string/google_maps_key" />
<activity
android:name=".MainActivity"
android:label="#string/app_name"
android:theme="#style/AppTheme.NoActionBar"
android:configChanges="orientation|screenSize|keyboardHidden">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".SettingsActivity"
android:label="#string/title_activity_settings"></activity>
</application>
</manifest>
LOGCAT
Process: com.example.sander.app, PID: 22804
java.lang.NullPointerException: Attempt to invoke virtual method 'double android.location.Location.getLatitude()' on a null object reference
at com.example.sander.app.BlankFragment.onCreateView(BlankFragment.java:85)
at android.app.Fragment.performCreateView(Fragment.java:2353)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:995)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1171)
at android.app.BackStackRecord.run(BackStackRecord.java:816)
at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1578)
at android.app.FragmentManagerImpl$1.run(FragmentManager.java:483)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
This is the code I have so far, when I launch my "Graph" tab the app crashes. I don't know what I'm doing wrong could anyone help me to fix this issue. What I want is to get the Long & Lat from my last know location.

LoginButton Facebook with appcompat-v7:22.1.1

Has anyone try using appcompat-v7:22.1.1 with facebook login sdk version 4.0.0 I tried that but Failed,and I dont know how to fix it, when I try using different layout it works, but when using layout that contain LoginBUtton From facebook it does not work, here is my code :
my Activity looks like this :
import android.content.Intent;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.Signature;
import android.os.Bundle;
import android.os.PersistableBundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Base64;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import com.facebook.AccessToken;
import com.facebook.CallbackManager;
import com.facebook.FacebookCallback;
import com.facebook.FacebookException;
import com.facebook.FacebookSdk;
import com.facebook.GraphRequest;
import com.facebook.GraphResponse;
import com.facebook.appevents.AppEventsLogger;
import com.facebook.login.LoginResult;
import com.facebook.login.widget.LoginButton;
import org.json.JSONException;
import org.json.JSONObject;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import java.util.List;
import santana.gujarat.chatmeet.R;
/**
* Created by root on 14/05/15.
*/
public class LoginActivity extends AppCompatActivity implements GraphRequest.GraphJSONObjectCallback {
private static final List<String> permissionNeeds= Arrays.asList("user_photos", "friends_photos", "email", "user_birthday", "user_friends");
private LoginButton loginButton;
private CallbackManager callbackManager;
private GraphRequest request;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_login_activity);
try {
PackageInfo info = getPackageManager().getPackageInfo(
"com.facebook.samples.loginhowto",
PackageManager.GET_SIGNATURES);
for (Signature signature : info.signatures) {
MessageDigest md = MessageDigest.getInstance("SHA");
md.update(signature.toByteArray());
Log.d("KeyHash:", Base64.encodeToString(md.digest(), Base64.DEFAULT));
}
} catch (PackageManager.NameNotFoundException e) {
} catch (NoSuchAlgorithmException e) {
}
loginButton = (LoginButton) findViewById(R.id.login_button);
loginButton.setReadPermissions(permissionNeeds);
FacebookSdk.sdkInitialize(getApplicationContext());
callbackManager = CallbackManager.Factory.create();
loginButton.registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
#Override
public void onSuccess(LoginResult loginResult) {
loginResult.getAccessToken();
request = GraphRequest.newMeRequest(loginResult.getAccessToken(), LoginActivity.this);
request.executeAsync();
Log.d("FB Granted", loginResult.getRecentlyGrantedPermissions().toString());
Log.d("FB Denied", loginResult.getRecentlyDeniedPermissions().toString());
AccessToken.getCurrentAccessToken();
}
#Override
public void onCancel() {
}
#Override
public void onError(FacebookException e) {
Log.d("Error Login",e.getMessage());
}
});
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
callbackManager.onActivityResult(requestCode, resultCode, data);
}
#Override
protected void onResume() {
super.onResume();
// Logs 'install' and 'app activate' App Events.
AppEventsLogger.activateApp(this);
}
#Override
public void onCompleted(JSONObject user, GraphResponse response) {
Log.d("resultFB", user.toString());
try {
Log.d("resultFB",user.getString("username"));
} catch (JSONException e) {
}
}
}
My Manifest :
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<application
android:name=".AppController"
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:theme="#style/Theme.AppCompat" >
<activity
android:name=".activity.RegisterActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".activity.LoginActivity" />
<activity
android:name="com.facebook.FacebookActivity"
android:configChanges=
"keyboard|keyboardHidden|screenLayout|screenSize|orientation"
android:theme="#android:style/Theme.Translucent.NoTitleBar"
android:label="#string/app_name" />
<meta-data
android:name="com.facebook.sdk.ApplicationId"
android:value="#string/facebook_app_id" />
</application>
</manifest>
My layout :
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<com.facebook.login.widget.LoginButton
android:id="#+id/login_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" />
</RelativeLayout>
And the Logcat Error :
java.lang.ExceptionInInitializerError
at java.lang.reflect.Constructor.constructNative(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:417)
at android.view.LayoutInflater.createView(LayoutInflater.java:587)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:687)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:746)
at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
at android.view.LayoutInflater.inflate(LayoutInflater.java:352)
at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:249)
..
Caused by: null
            at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:106)
            at santana.gujarat.chatmeet.activity.ListPeopleActivity.onCreate(ListPeopleActivity.java:18)
...

Unable to instantiate activity ComponentInfo .. java.lang.NullPointerException

I'm trying to run a simple app using volley and a custom header, it builds with no error, I'm running it directly in my smartphone, but when the app start I get the following log:
06-24 16:35:35.653 1380-1380/com.rep E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.rep, PID: 1380
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.rep/com.rep.app.principal.InicioActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2135)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2269)
at android.app.ActivityThread.access$800(ActivityThread.java:139)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5102)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at android.content.ContextWrapper.getCacheDir(ContextWrapper.java:230)
at com.android.volley.toolbox.Volley.newRequestQueue(Volley.java:43)
at com.android.volley.toolbox.Volley.newRequestQueue(Volley.java:78)
at com.representemais.app.principal.InicioActivity.<init>(InicioActivity.java:86)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1208)
at android.app.Instrumentation.newActivity(Instrumentation.java:1084)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2126)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2269)
            at android.app.ActivityThread.access$800(ActivityThread.java:139)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5102)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
            at dalvik.system.NativeStart.main(Native Method)
that's the InicioActivity:
package com.rep.app.principal;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.TextView;
import com.actionbarsherlock.app.SherlockFragmentActivity;
import com.android.volley.AuthFailureError;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.VolleyLog;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.Volley;
import com.rep.R;
import org.json.JSONObject;
import java.util.HashMap;
import java.util.Map;
public class InicioActivity extends SherlockFragmentActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
AutenticacaoLocalTask mAutenticacaoLocalTask = new AutenticacaoLocalTask();
mAutenticacaoLocalTask.execute((Void) null);
}
private TextView txtDisplay;
RequestQueue queue = Volley.newRequestQueue(this);
public class AutenticacaoLocalTask extends AsyncTask<Void, Void, Boolean> {
#Override
protected Boolean doInBackground(Void... params) {
try {
txtDisplay = (TextView) findViewById(R.id.txtDisplay);
String url = "http://192.168.1.15/rep-api/api/clients";
JsonObjectRequest jsonObjReq = new JsonObjectRequest(Request.Method.GET,
url, null,
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
txtDisplay.setText("Response => "+response.toString());
findViewById(R.id.progressBar1).setVisibility(View.GONE);
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d("Error: " + error.getMessage());
}
})
{
#Override
public Map<String, String> getHeaders() throws AuthFailureError {
HashMap<String, String> headers = new HashMap<String, String>();
headers.put("X-API-TOKEN", "99KI9Gj68CgCf70deM22Ka64chef2C40Gm2lFJ2J0G9JkD0bDAcbFfd19MfacGf3FFm8CM1hG0eDiIk8");
return headers;
}
};
queue.add(jsonObjReq);
return true;
} catch (Exception e) {
Log.e("RM", e.getMessage());
return false;
}
}
#Override
protected void onPostExecute(final Boolean success) {
}
#Override
protected void onCancelled() {
}
}
}
and the Manifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.rep"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk
android:minSdkVersion="7"
android:targetSdkVersion="19" />
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission>
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"></uses-permission>
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme">
<activity
android:name=".app.principal.InicioActivity"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".app.login.LoginActivity"
android:configChanges="keyboardHidden"
android:label="#string/app_name">
</activity>
<activity
android:name=".app.principal.MainActivity"
android:label="#string/app_name"></activity>
<activity android:name=".app.cliente.ClienteDetalheActivity"
android:label="#string/app_name"></activity>
<activity android:name=".app.login.LoginTelaBloqueada"
android:label="#string/app_name"></activity>
</application>
</manifest>

Initialize your RequestQueue, using Volley.newRequestQueue(this);, in onCreate() after the super.onCreate() call. You are trying to use your Activity from an initializer, which frequently causes problems like this.
Step #1: Replace:
RequestQueue queue = Volley.newRequestQueue(this);
with:
RequestQueue queue = null;
Step #2: Change your onCreate() to be:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
queue=Volley.newRequestQueue(this);
AutenticacaoLocalTask mAutenticacaoLocalTask = new AutenticacaoLocalTask();
mAutenticacaoLocalTask.execute((Void) null);
}