To this day I'm facing a slight problem, I've been working on the subject for several weeks and I still can't find out why it doesn't work, I can explain.
For a personal project I need to create EditText dynamically, more precisely an array of EditText, so I managed to do that but I can't get the text from them and display it.
At first I asked
P1.setText(playerName[id].getText().toString());
except I forgot that my id variable had a ++ which was in place so the id I was asking for in the list didn't exist yet so the error Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.jenaijamais, PID: 6450
java.lang.IllegalStateException: Could not execute method for android:onClick
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:390)
at android.view.View.performClick(View.java:7161)
at android.view.View.performClickInternal(View.java:7138)
at android.view.View.access$3500(View.java:811)
at android.view.View$PerformClick.run(View.java:27419)
at android.os.Handler.handleCallback(Handler.java:883)
at android.os.Handler.dispatchMessage(Handler.java:100)
at android.os.Looper.loop(Looper.java:224)
at android.app.ActivityThread.main(ActivityThread.java:7520)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:539)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:385)
at android.view.View.performClick(View.java:7161)
at android.view.View.performClickInternal(View.java:7138)
at android.view.View.access$3500(View.java:811)
at android.view.View$PerformClick.run(View.java:27419)
at android.os.Handler.handleCallback(Handler.java:883)
at android.os.Handler.dispatchMessage(Handler.java:100)
at android.os.Looper.loop(Looper.java:224)
at android.app.ActivityThread.main(ActivityThread.java:7520)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:539)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference
at com.example.jenaijamais.NumberOfPlayers.play(NumberOfPlayers.java:98)
at java.lang.reflect.Method.invoke(Native Method)
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:385)
at android.view.View.performClick(View.java:7161)
at android.view.View.performClickInternal(View.java:7138)
at android.view.View.access$3500(View.java:811)
at android.view.View$PerformClick.run(View.java:27419)
at android.os.Handler.handleCallback(Handler.java:883)
at android.os.Handler.dispatchMessage(Handler.java:100)
at android.os.Looper.loop(Looper.java:224)
at android.app.ActivityThread.main(ActivityThread.java:7520)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:539)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)
so to make a test I asked for 0 in the list and there always the same error even when filling the EditText (I specify that I fill the fields each time so they are not null in theory), then I tried with 1 the same same error it doesn't want to get the text back.
I specify that the final goal is to loop all the text of the fields and insert them in a SQLite database but for the moment I just want to do some tests without a database to make sure it works but I can't get the text from ONE EditText so many at the moment it's not even worth thinking about it.
package com.example.jenaijamais;
import androidx.appcompat.app.AppCompatActivity;
import android.annotation.SuppressLint;
import android.database.Cursor;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;
import java.io.Console;
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Arrays;
public class NumberOfPlayers extends AppCompatActivity {
public Button btnAdd;
public DatabasePlayers databasePlayers;
public ViewGroup layoutAddPlayer;
public ViewGroup main;
public int id = 1;
public int id2 = 1;
public EditText[] playerName;
public TextView P1;
#SuppressLint("ResourceType")
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_number_of_players);
databasePlayers = new DatabasePlayers(this);
layoutAddPlayer = findViewById(R.id.addPlayerLayout);
main = findViewById(R.id.addPlayerLayout2);
btnAdd = findViewById(R.id.btnAdd);
P1 = (TextView) findViewById(R.id.P1);
for (int i = 1; i < 5; i++){
playerName = new EditText[100];
playerName[i] = new EditText(this);
playerName[i].setId(id);
playerName[i].setHint("Joueur n°"+playerName[i].getId());
RelativeLayout.LayoutParams config = new RelativeLayout.LayoutParams(
RelativeLayout.LayoutParams.WRAP_CONTENT,
RelativeLayout.LayoutParams.WRAP_CONTENT);
config.setMargins(0,8,0,8);
config.addRule(RelativeLayout.BELOW, playerName[i].getId());
layoutAddPlayer.addView(playerName[i],config);
playerName[i] = (EditText) findViewById(i);
id++;
}
//playerName[0] = (EditText) findViewById(1);
}
public void addPlayer(View view) {
/*id++;
playerName = new EditText[id--];
playerName[id] = new EditText(this);
playerName[id].setId(id);
playerName[id].setHint("Joueur n°"+this.playerName[id].getId());
RelativeLayout.LayoutParams config = new RelativeLayout.LayoutParams(
RelativeLayout.LayoutParams.WRAP_CONTENT,
RelativeLayout.LayoutParams.WRAP_CONTENT);
config.setMargins(0,8,0,8);
config.addRule(RelativeLayout.BELOW, playerName[id].getId());
layoutAddPlayer.addView(playerName[id],config);
id++;
nameView = new TextView[id--];
nameView[id] = new TextView(this);
nameView[id].setId(id);
nameView[id].setText("Player"+id);
RelativeLayout.LayoutParams config2 = new RelativeLayout.LayoutParams(
RelativeLayout.LayoutParams.WRAP_CONTENT,
RelativeLayout.LayoutParams.WRAP_CONTENT);
config2.setMargins(0, 8, 0, 8);
config2.addRule(RelativeLayout.BELOW, nameView[id].getId());
main.addView(nameView[id],config2);
id++;
//nameView[0].setText(String.valueOf(id));*/
}
public void play(View view) {
P1.setText(playerName[0].getText().toString());
}
private void viewAll(){
/*Cursor data = databasePlayers.getAllData();
if (data.getCount() == 0){
P1.setText("ERROR, NO DATA");
return;
}
StringBuffer buffer = new StringBuffer();
while (data.moveToNext()){
buffer.append("playerID :" +data.getString(0)+"\n");
buffer.append("playerName : "+data.getString(1)+"\n");
buffer.append("playerScore : "+data.getString(2)+"\n");
}
P1.setText(buffer.toString());*/
}
}
Related
This question already has answers here:
Null pointer Exception - findViewById()
(12 answers)
Closed 4 months ago.
i'm a begginner developer and the app in question is a test app for an api, from jkutner's tutorial on github. it is crashing as soon as it opens, which is weird, because i've used this exact same code at least thrice and it used to work. i'll leave the code and the logcat below, thank you in advance for your help!
MainActivity
package com.example.myapplication;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import java.util.List;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;
public class MainActivity extends AppCompatActivity
{
final EditText isbnInput = (EditText) findViewById(R.id.isbnInput);
final TextView textView = (TextView) findViewById(R.id.textView);
final Button button = (Button) findViewById(R.id.button);
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("https://venusdove.herokuapp.com")
.addConverterFactory(GsonConverterFactory.create())
.build();
final BookService service = retrofit.create(BookService.class);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Book book = new Book(isbnInput.getText().toString());
Call<Book> createCall = service.create(book);
createCall.enqueue(new Callback<Book>() {
#Override
public void onResponse(Call<Book> _, Response<Book> resp) {
Book newBook = resp.body();
textView.setText("Created Book with ISBN: " + newBook.isbn);
}
#Override
public void onFailure(Call<Book> _, Throwable t) {
t.printStackTrace();
textView.setText(t.getMessage());
}
});
}
});
}
}
Book class
package com.example.myapplication;
import com.google.gson.annotations.SerializedName;
public class Book
{
#SerializedName("id")
int id;
#SerializedName("isbn")
String isbn;
public Book(int id, String isbn) {
this.id = id;
this.isbn = isbn;
}
public Book(String isbn) {
this.isbn = isbn;
}
}
BookService class
package com.example.myapplication;
import java.util.List;
import retrofit2.Call;
import retrofit2.http.Body;
import retrofit2.http.GET;
import retrofit2.http.POST;
import retrofit2.http.Path;
public interface BookService
{
#GET("books")
Call<List<Book>> all();
#GET("books/{isbn}")
Call<Book> get(#Path("isbn") String isbn);
#POST("books/new")
Call<Book> create(#Body Book book);
}
logcat
2022-10-19 08:56:03.651 8041-8041/com.example.myapplication E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.myapplication, PID: 8041
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.myapplication/com.example.myapplication.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.pm.ApplicationInfo android.content.Context.getApplicationInfo()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2679)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2856)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1589)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.pm.ApplicationInfo android.content.Context.getApplicationInfo()' on a null object reference
at android.content.ContextWrapper.getApplicationInfo(ContextWrapper.java:152)
at android.view.ContextThemeWrapper.getTheme(ContextThemeWrapper.java:157)
at android.content.Context.obtainStyledAttributes(Context.java:655)
at androidx.appcompat.app.AppCompatDelegateImpl.createSubDecor(AppCompatDelegateImpl.java:852)
at androidx.appcompat.app.AppCompatDelegateImpl.ensureSubDecor(AppCompatDelegateImpl.java:819)
at androidx.appcompat.app.AppCompatDelegateImpl.findViewById(AppCompatDelegateImpl.java:640)
at androidx.appcompat.app.AppCompatActivity.findViewById(AppCompatActivity.java:261)
at com.example.myapplication.MainActivity.<init>(MainActivity.java:22)
at java.lang.Class.newInstance(Native Method)
at android.app.Instrumentation.newActivity(Instrumentation.java:1174)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2669)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2856)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1589)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
You need to "find" view after they are created.
EditText isbnInput;
TextView textView;
Button button;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
isbnInput = (EditText) findViewById(R.id.isbnInput);
textView = (TextView) findViewById(R.id.textView);
button = (Button) findViewById(R.id.button);
}
It is because of findViewById. You should call it inside OnCreate. Because it needs View that it is being called from to be initialized.
private EditText isbnInput;
private TextView textView;
private Button button;
#Override
protected void onCreate(Bundle savedInstanceState)
{
isbnInput = (EditText) findViewById(R.id.isbnInput);
textView = (TextView) findViewById(R.id.textView);
button = (Button) findViewById(R.id.button);
Im new to android and they(some people :) ) gave me an half developed app and im still confused about some things.
Im getting an error which i can't understand what it means. So the error is what i wrote in the title : java.lang.IllegalStateException: FragmentManager has not been attached to a host, and is hapening when this activity runs:
package com.example.loginregistodb;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Spinner;
import android.widget.Toast;
public class ClienteActivity extends AppCompatActivity {
Spinner tipo_intervencao;
Button bt_cliente_seguinte;
EditText et_inserir_cliente;
ImageView icon1;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_cliente);
bt_cliente_seguinte = (Button) findViewById(R.id.bt_cliente_seguinte);
et_inserir_cliente = findViewById(R.id.et_inserir_cliente);
tipo_intervencao = findViewById(R.id.tipo_intervencao);
icon1 = findViewById(R.id.icon2);
bt_cliente_seguinte.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String cliente = et_inserir_cliente.getText().toString();
String tipoIntervencao = "" + tipo_intervencao.getSelectedItem().toString();
preencherExcel Excel = new preencherExcel();
Excel.entradaWhatsapp(cliente, tipoIntervencao);
if (cliente.equalsIgnoreCase("")) {
Toast.makeText(ClienteActivity.this, "Preencha o campo Cliente!", Toast.LENGTH_SHORT).show();
} else {
Intent i = new Intent(ClienteActivity.this, EmpresaActivity.class);
startActivity(i);
}
}
});
}
}
EDIT :
the error message i get is this :
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.loginregistodb, PID: 15275
java.lang.IllegalStateException: FragmentManager has not been attached to a host.
at androidx.fragment.app.FragmentManager.ensureExecReady(FragmentManager.java:1938)
at androidx.fragment.app.FragmentManager.execPendingActions(FragmentManager.java:1996)
at androidx.fragment.app.FragmentManager.executePendingTransactions(FragmentManager.java:600)
at com.google.firebase.firestore.core.ActivityScope.lambda$onFragmentActivityStopCallOnce$1(ActivityScope.java:180)
at com.google.firebase.firestore.core.ActivityScope$$ExternalSyntheticLambda1.run(Unknown Source:4)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
I am learning how to develop for Android (and development in general). I am trying to create a Quiz App, so I can learn the basics.
While trying to use an Intent to go to another class with an extra variable on it, I found this problem (which I think is pretty usual): My app crashes when I go to the next Activity.
This is the code in the activity that gets the username ("usuario and nomeUsuario"):
package com.isa56.quiz2;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import androidx.appcompat.app.AppCompatActivity;
public class HomeActivity extends AppCompatActivity {
public EditText usuario;
public EditText senha;
public Button botaoLogin;
public String nomeUsuario;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
botaoLogin = findViewById(R.id.botaoLogin);
senha = findViewById(R.id.senha);
usuario = findViewById(R.id.usuario);
nomeUsuario = usuario.getText().toString();
Log.d("nome de usuario", nomeUsuario);
botaoLogin.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v) {
Intent i = new Intent(HomeActivity.this, FirstQuestionActivity.class);
i.putExtra("nome", nomeUsuario);
startActivity(i);
}});
}
}
And this is the code on the SecondQuestionActivity:
package com.isa56.quiz2;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
public class FirstQuestionActivity extends AppCompatActivity {
public Button prox1;
public Button respUm1;
public Button respUm2;
public TextView texto1;
public int pontuacao = 0;
Intent i = getIntent();
String nome = i.getStringExtra("nome");
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_firstquestion);
prox1 = findViewById(R.id.prox1);
respUm1 = findViewById(R.id.botao1a);
respUm2 = findViewById(R.id.botao1b);
texto1 = findViewById(R.id.texto1);
respUm1.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v) {
texto1.setText("Resposta errada!");
respUm1.setEnabled(false);
respUm2.setEnabled(false);
prox1.setEnabled(true);
}});
respUm2.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v) {
texto1.setText("Resposta certa!");
respUm2.setEnabled(false);
respUm1.setEnabled(false);
pontuacao += 1;
prox1.setEnabled(true);
}});
prox1.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v) {
Intent i = new Intent(FirstQuestionActivity.this, SecondQuestionActivity.class);
i.putExtra("pontos", pontuacao);
i.putExtra("nome", nome);
startActivity(i);
}
});
}
}
What is wrong with it? How can I prevent it?
Thank you!
P.S.: I am not used to forum or development in general, so I might have done this wrongly. I'm sorry.
Edit: Also, if anyone wanna take a look at the whole project, it's here.
Edit2: This is the Logcat output:
2020-11-13 21:05:18.531 7517-7517/com.isa56.quiz2 E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.isa56.quiz2, PID: 7517
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.isa56.quiz2/com.isa56.quiz2.FirstQuestionActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Intent.getStringExtra(java.lang.String)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3365)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Intent.getStringExtra(java.lang.String)' on a null object reference
at com.isa56.quiz2.FirstQuestionActivity.<init>(FirstQuestionActivity.java:18)
at java.lang.Class.newInstance(Native Method)
at android.app.AppComponentFactory.instantiateActivity(AppComponentFactory.java:95)
at androidx.core.app.CoreComponentFactory.instantiateActivity(CoreComponentFactory.java:45)
at android.app.Instrumentation.newActivity(Instrumentation.java:1253)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3353)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
Keep these lines inside onCreate() method.
Intent i = getIntent();
String nome = i.getStringExtra("nome");
This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 3 years ago.
I just got done one part of my code and went to launch the app and everything went fine. The build was successful and no issues were found. I then go to the emulator and the app doesn't launch and the log shows a lot of error.
Anyone know where I messed up and how I can fix it.Below is the errors from the log that I receive and I also pasted in the code that I was working on.
2019-05-07 13:06:14.358 22792-22792/com.example.drunktankfix E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.drunktankfix, PID: 22792
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.drunktankfix/com.example.drunktankfix.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.EditText.setText(int)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2913)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.EditText.setText(int)' on a null object reference
at com.example.drunktankfix.MainActivity.onCreate(MainActivity.java:55)
at android.app.Activity.performCreate(Activity.java:7136)
at android.app.Activity.performCreate(Activity.java:7127)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2893)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
2019-05-07 13:06:16.368 22792-22792/com.example.drunktankfix I/Process: Sending signal. PID: 22792 SIG: 9
Also here is the code:
package com.example.drunktankfix;
import android.content.Intent;
import android.content.SharedPreferences;
import android.net.Uri;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v4.app.Fragment;
import android.support.v7.app.AppCompatActivity;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import com.example.drunktankfix.AppFragment;
import com.example.drunktankfix.BlacklistFragment;
import com.example.drunktankfix.HelpFragment;
import com.example.drunktankfix.HomeFragment;
//implement the interface OnNavigationItemSelectedListener in your activity class
public class MainActivity extends AppCompatActivity implements BottomNavigationView.OnNavigationItemSelectedListener {
Button Save;
EditText edt1, edt2, edt3;
int in;
Float fl;
String st;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//loading the default fragment
loadFragment(new HomeFragment());
//getting bottom navigation view and attaching the listener
BottomNavigationView navigation = findViewById(R.id.navigation);
navigation.setOnNavigationItemSelectedListener(this);
Save = (Button) findViewById(R.id.BtnSave);
edt1 = (EditText) findViewById(R.id.editText1);
edt2 = (EditText) findViewById(R.id.editText2);
edt3 = (EditText) findViewById(R.id.editText3);
// to Retrieve the Data from the SharedPref
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
int in1= prefs.getInt("in",0);
edt1.setText(in1);
float fl1 = prefs.getFloat("fl", 0);
edt2.setText(""+fl1);
String st1 = prefs.getString("st","");
edt3.setText(st1);
Save.setOnClickListener (new View.OnClickListener() {
#Override
public void onClick(View v) {
in = Integer.parseInt(edt1.getText().toString());
fl = Float.parseFloat(edt2.getText().toString());
st = edt3.getText().toString();
// To save the data that is entered
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(MainActivity.this);
SharedPreferences.Editor editor = prefs.edit();
editor.putInt("in", in);
editor.putFloat("fl", fl);
editor.putString("st", st);
editor.apply();
}
});
}
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
Fragment fragment = null;
switch (item.getItemId()) {
case R.id.navigation_home:
fragment = new HomeFragment();
break;
case R.id.navigation_Apps:
fragment = new AppFragment();
break;
case R.id.navigation_Blacklist:
fragment = new BlacklistFragment();
break;
case R.id.navigation_Help:
fragment = new HelpFragment();
break;
}
return loadFragment(fragment);
}
private boolean loadFragment(Fragment fragment) {
//switching fragment
if (fragment != null) {
getSupportFragmentManager()
.beginTransaction()
.replace(R.id.fragment_container, fragment)
.commit();
return true;
}
return false;
}
}
You can not enter int value inside the edit text . Try to make it string.
edt1.setText(in1+"");
To set the integer propertly do the following:
edt1.setText("" + integer);
or better solution:
edt1.setText(String.valueOf(integer));
I am not sure how are you getting Nullpointer Exception But from the I code, I see any issue with your here.
editText.setText(Integer Value)
You are setting integer value to Edit text, So that in turn tries to get String resource based on the integer which you set to EditText.That should throw Resource not found Exception not NPE.
I am facing the problem when I use Intent to send a value to another activity by click a button. I have tried to solve it in many ways but it always show NullPointerException although I declared it clearly.
Here is my code.
Manufacturer.java
package com.example.student.macheckcar;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
public class Manufacturer extends AppCompatActivity {
public String message;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_manufacturer);
Button toyota = (Button) findViewById(R.id.Toyota);
Button subaru = (Button) findViewById(R.id.Subaru);
Button audi = (Button) findViewById(R.id.Audi);
toyota.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
message = "Toyota";
goAnother(message.toString());
}
});
subaru.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
message = "Subaru";
goAnother(message);
}
});
audi.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
message = "Audi";
goAnother(message);
}
});
}
protected void goAnother(String brand){
Intent i = new Intent(Manufacturer.this, ShowCarPrice.class);
i.putExtra("brand", brand);
startActivity(i);
}
}
Showcarprice.java
package com.example.student.macheckcar;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.view.Window;
import java.util.ArrayList;
public class ShowCarPrice extends AppCompatActivity {
private Cursor cursor;
private ArrayList<String> price;
private ArrayAdapter<String> aa;
private DBprice dbPrice;
private Manufacturer maFact;
SQLiteDatabase db;
ListView list;
Intent intent = getIntent();
String brand = intent.getStringExtra("brand");
#Override
protected void onCreate(Bundle savedInstanceState) {
requestWindowFeature(Window.FEATURE_NO_TITLE);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_show_car_price);
list = (ListView) findViewById(R.id.listView);
dbPrice = new DBprice(this);
db = dbPrice.getWritableDatabase();
cursor = db.rawQuery("SELECT " + dbPrice.KEY_TASK + " FROM " + dbPrice.TABLE_NAME + " WHERE Manufacturer = ?", new String[] {brand});
price = new ArrayList<String>();
cursor.moveToFirst();
while ( !cursor.isAfterLast() ){
price.add(cursor.getString(cursor.getColumnIndex(dbPrice.KEY_TASK)));
cursor.moveToNext();
}
aa = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, price);
list.setAdapter(aa);
}
public void onPause() {
super.onPause();
dbPrice.close();
db.close();
}
}
And the error:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.student.macheckcar, PID: 934
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.student.macheckcar/com.example.student.macheckcar.ShowCarPrice}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2110)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
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 com.example.student.macheckcar.ShowCarPrice.<init>(ShowCarPrice.java:22)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1208)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2101)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
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)
Please help.
UPDATE
public class ShowCarPrice extends AppCompatActivity {
// OK, Create the objects, variables here if needed
Intent intent;
String brand;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.your_activity_layout);
// You should assign the intent here (in onCreate method)
intent = getIntent();
// Then, the string variable
brand = intent.getStringExtra("brand");
// You can also check whether or not received a valid value
if (brand != null && !brand.isEmpty())
// do something with brand value
else
// brand value is null or empty
}
}
Well, you call getIntent() at the wrong position. You should call getIntent() in method onCreate() , and I don't know why you keep intent as a member of your activity. If I were you I just do
String brand = getIntent().getStringExtra("brand");
in onCreate() method.
get your intent and extras of intent in onCreate() method of activity just check below link for this
https://stackoverflow.com/a/5265952/5316836