Java Unable to start activity NullPointerException similar questions don't solve this

Question

Hello I am trying to start activity from one to activity to other one but i get error

FATAL EXCEPTION: main java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.bsine_000.baseinas/com.example.bsine_000.baseinas.registracija}: java.lang.NullPointerException

here is the code:

        public class MainActivity extends AppCompatActivity implements View.OnClickListener {

Button etprisijungti;
EditText etelpastas, etslaptazodis;
TextView reglink;
saugykla saugykla;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    etprisijungti = (Button) findViewById(R.id.etprisijungti);
    etelpastas = (EditText) findViewById(R.id.etelpastas);
    etslaptazodis = (EditText) findViewById(R.id.etslaptazodis);
    reglink = (TextView) findViewById(R.id.reglink);
    reglink.setOnClickListener(this);
    etprisijungti.setOnClickListener(this);
    saugykla = new saugykla(this);
}

@Override
public void onClick(View v) {
    switch(v.getId()){

        case R.id.etprisijungti:
            vartotojas vartotojas = new vartotojas(null,null);
            saugykla.saugoti(vartotojas);
            saugykla.vartotojas_prisijunges(true);
            startActivity(new Intent(this, pagrindinis.class));
            break;

        case R.id.reglink:
            startActivity(new Intent(this, registracija.class));
            break;
    }

}
}

code where app crashes is

case R.id.reglink:

startActivity(new Intent(this, registracija.class));

break;

first case works fine code is exactly the same here is registracija class:

public class registracija extends AppCompatActivity implements View.OnClickListener {

Button etregistruotis;
EditText etelpastas, etslaptazodis;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_registracija);
    etregistruotis = (Button) findViewById(R.id.reglink)
    etelpastas = (EditText) findViewById(R.id.etelpastas);
    etslaptazodis = (EditText) findViewById(R.id.etslaptazodis);
    etregistruotis.setOnClickListener(this);

}

@Override
public void onClick(View v) {
    switch(v.getId()){

        case R.id.etregistruotis:
            String elpastas = etelpastas.getText().toString();
            String slaptazdodis = etslaptazodis.getText().toString();
            break;

    }

}
}

Logcat :

    05-25 10:45:36.401  23721-23721/com.example.bsine_000.baseinas W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x41241438)
05-25 10:45:36.411  23721-23721/com.example.bsine_000.baseinas E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.bsine_000.baseinas/com.example.bsine_000.baseinas.registracija}: java.lang.NullPointerException
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2114)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2139)
            at android.app.ActivityThread.access$700(ActivityThread.java:143)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1241)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:4960)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:511)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: java.lang.NullPointerException
            at com.example.bsine_000.baseinas.registracija.onCreate(registracija.java:23)
            at android.app.Activity.performCreate(Activity.java:5203)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2078)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2139)
            at android.app.ActivityThread.access$700(ActivityThread.java:143)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1241)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:4960)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:511)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
            at dalvik.system.NativeStart.main(Native Method)

activity main

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical"
android:layout_height="match_parent"
android:layout_width="match_parent">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    android:padding="10dp"
    android:text="El.pastas"/>

<EditText
    android:id="@+id/etelpastas"
    android:layout_width="match_parent"
    android:layout_marginBottom="10dp"
    android:layout_height="wrap_content" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    android:padding="10dp"
    android:text="slaptazodis"/>
<EditText
    android:id="@+id/etslaptazodis"
    android:inputType="textPassword"
    android:layout_marginBottom="10dp"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" />
<Button
    android:id="@+id/etprisijungti"
    android:text="Prisijungti"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:clickable="true"
    android:enabled="true" />
<TextView
    android:id="@+id/reglink"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textSize="20dp"
    android:textStyle="bold"
    android:padding="10dp"
    android:layout_gravity="center_horizontal"
    android:text="Registruotis"
    android:clickable="true"
    android:linksClickable="true" />

Activity registracija

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_height="match_parent"
    android:layout_width="match_parent">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:padding="10dp"
        android:text="El.pastas"/>

    <EditText
        android:id="@+id/etelpastas"
        android:layout_width="match_parent"
        android:layout_marginBottom="10dp"
        android:layout_height="wrap_content" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:padding="10dp"
        android:text="slaptazodis"/>
    <EditText
        android:id="@+id/etslaptazodis"
        android:inputType="textPassword"
        android:layout_marginBottom="10dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <Button
        android:id="@+id/etregistruotis"
        android:text="Registruotis"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</LinearLayout>

`etregistruotis` is null in the `onCreate()` method of `registracija`. The View you're setting the `OnClickListener` on is not the one you initialized in the previous line. — Mike M., May 25 '15 at 07:41
Can u give me more detail about this? Code is exactly the same but one works other does not. — ben, May 25 '15 at 07:43
You need to initialize `etregistruotis` with `findViewById()`, like you did with the `EditText`s, before you call `setOnClickListener()` on it. — Mike M., May 25 '15 at 07:44
Stop downvoting. If u can solve my problem it does not mean u can downvote. — ben, May 25 '15 at 07:57
You've mis-diagnosed which line is giving you the error - your stack trace shows that the null pointer is within the `onCreate()` method : `at com.example.bsine_000.baseinas.registracija.onCreate(registracija.java:23)` Work out what line that is (line 23) and you find what is giving you your error - whatever can be null on that line — J Richard Snape, May 25 '15 at 08:25

Thomas Vos · Accepted Answer · 2015-05-25T08:35:10.470

0

Try this: In your MainActivity replace this code:

startActivity(new Intent(this, registracija.class));

With this code:

startActivity(new Intent(MainActivity.this, registracija.class));

Hope it helps, if it didn't please post the code of activity_registracija.xml.

Edit: Reglink doesn't exist in your activity_registracija.xml.

edited May 25 '15 at 08:35

answered May 25 '15 at 08:15

Thomas Vos

12,271
5
33
71

I don't think that's the problem since the code is reaching the on create of the activity. The poster must post the activity xml – Miguel Ribeiro May 25 '15 at 08:20
1

@MiguelRibeiro that's what I asked in my answer in case it didn't help. – Thomas Vos May 25 '15 at 08:21
1

xml added take a look. – ben May 25 '15 at 08:23
1

@SuperThomasLab did you understand what was fixed, how and why? – Miguel Ribeiro May 25 '15 at 09:31

Miguel Ribeiro · Answer 2 · 2015-05-25T08:31:23.137

-1

As said in one comment, etregistruotis variable is not initialized. You need to do it like you do to the other two variables above and then only call the setOnClickListener.

If it still crashes after that please update your answer with the code you are using.

Bonus : your activity class starts with a lower case letter. By convention it should start with a capital letter.

Update: Reglink doesn't exist in the activity xml

edited May 25 '15 at 08:31

answered May 25 '15 at 08:01

Miguel Ribeiro

8,057
20
51
74

Edited code but it still gives same error. – ben May 25 '15 at 08:05
Please post the activity xml – Miguel Ribeiro May 25 '15 at 08:18
Updated answer. Reglink doesn't exist in the xml if you look closer – Miguel Ribeiro May 25 '15 at 08:26
Sorry I duplicated xmls now it is fixed take a look. – ben May 25 '15 at 08:27
You either change the declaration of your button to @+id/reglink in the xml or your find view by id must be changed and sent the correct R.id. Sorry for not giving all details but on the ios app is hard to copy/paste – Miguel Ribeiro May 25 '15 at 08:30
There is scroll bar so u can scroll to see reglink.. – ben May 25 '15 at 08:33
In registracija xml there is no reglink, look again :-) – Miguel Ribeiro May 25 '15 at 08:37
registracija xml does not need reglink it is different button. Anyway I got fixed it. – ben May 25 '15 at 08:40
Care to explain why you downvoted my answer and describe properly how you solved it? Maybe in a different answer? You accepted SuperThomasLab answer and he basically says the same I do. – Miguel Ribeiro May 25 '15 at 09:26
U both did not answer my question, so I chose randomly. I said how I solved it magicaly. – ben May 25 '15 at 18:14
1

In this case you shouls accept none and answer it yourself – Miguel Ribeiro May 25 '15 at 18:15

score -1 · Answer 3 · answered May 25 '15 at 08:06

     public class registracija extends AppCompatActivity implements

View.OnClickListener {

         Button etregistruotis;
        EditText etelpastas, etslaptazodis;

       @Override
     protected void onCreate(Bundle savedInstanceState) {
              super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_registracija);
      etregistruotis=(Button)findViewById(R.id. etregistruotis);
      etelpastas = (EditText) findViewById(R.id.etelpastas);
     etslaptazodis = (EditText) findViewById(R.id.etslaptazodis);
           etregistruotis.setOnClickListener(this);

                }

    @Override
      public void onClick(View v) {

        String elpastas = etelpastas.getText().toString();
        String slaptazdodis = etslaptazodis.getText().toString();
        break;

    }

 }

please intialise the button on onCreate(). as you are making click on that same button no need to giva the id again in registracija.java.ithink this will resolve your error

Java Unable to start activity NullPointerException similar questions don't solve this

3 Answers3