I'm very new to Android. I did read many Tutorials, and also the Google example about building first app. 

I was able to correctly run the app only once! The problem is as written in the title of this question. I checked every question and answer provided here on the forum, but I can't figure what's going on. 

The problem is simple. I started a new project with Eclipse and added a id to the `TextView`. When I try to get the view I receive a null pointer. 

This is the XML

```
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  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="com.cguida1978it.prova.MainActivity$PlaceholderFragment" >

  <TextView
      android:id="@+id/text_view"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="@string/hello_world" />
</RelativeLayout> 

```

And this is the `MainActivity.java`

```
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main );

    TextView t = (TextView)findViewById( R.id.text_view );

    if (savedInstanceState == null) {
        getFragmentManager().beginTransaction()
                .add(R.id.container, new PlaceholderFragment()).commit();
    }
}

```

I checked also in the `R.java` and the `text_view` is in the id class 

I try to post the error log:

```
05-03 16:04:22.729: E/AndroidRuntime(2123): FATAL EXCEPTION: main
05-03 16:04:22.729: E/AndroidRuntime(2123): Process: com.cguida1978it.prova, PID:2123
05-03 16:04:22.729: E/AndroidRuntime(2123): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.cguida1978it.prova/com.cguida1978it.prova.MainActivity}: java.lang.NullPointerException
05-03 16:04:22.729: E/AndroidRuntime(2123):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
05-03 16:04:22.729: E/AndroidRuntime(2123):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
05-03 16:04:22.729: E/AndroidRuntime(2123):     at android.app.ActivityThread.access$800(ActivityThread.java:135)
05-03 16:04:22.729: E/AndroidRuntime(2123):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
05-03 16:04:22.729: E/AndroidRuntime(2123):     at android.os.Handler.dispatchMessage(Handler.java:102)
05-03 16:04:22.729: E/AndroidRuntime(2123):     at android.os.Looper.loop(Looper.java:136)
05-03 16:04:22.729: E/AndroidRuntime(2123):     at android.app.ActivityThread.main(ActivityThread.java:5017)
05-03 16:04:22.729: E/AndroidRuntime(2123):     at java.lang.reflect.Method.invokeNative(Native Method)
05-03 16:04:22.729: E/AndroidRuntime(2123):     at java.lang.reflect.Method.invoke(Method.java:515)
05-03 16:04:22.729: E/AndroidRuntime(2123):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
05-03 16:04:22.729: E/AndroidRuntime(2123):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
05-03 16:04:22.729: E/AndroidRuntime(2123):     at dalvik.system.NativeStart.main(Native Method)
05-03 16:04:22.729: E/AndroidRuntime(2123): Caused by: java.lang.NullPointerException
05-03 16:04:22.729: E/AndroidRuntime(2123):     at com.cguida1978it.prova.MainActivity.onCreate(MainActivity.java:23)
05-03 16:04:22.729: E/AndroidRuntime(2123):     at android.app.Activity.performCreate(Activity.java:5231)
05-03 16:04:22.729: E/AndroidRuntime(2123):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
05-03 16:04:22.729: E/AndroidRuntime(2123):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
05-03 16:04:22.729: E/AndroidRuntime(2123):     ... 11 more
05-03 16:04:24.989: I/Process(2123): Sending signal. PID: 2123 SIG: 9

```

Can anyone of you explain me what could be the problem? 

Is it an Eclipse issue/bug? May I reset Eclipse to default settings? When I started studying Android it worked a few times... why?? I'm a little bit confused... 

Thank you very much!

**EDIT**
TheFRedFox here are my imports

```
import android.app.Activity;
import android.widget.*;
import android.app.ActionBar;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.os.Build;
import android.view.View.OnClickListener;

```

**EDIT 2**
This is a piace of the `R.java` 

```
public static final class id {
    public static final int action_settings=0x7f080002;
    public static final int container=0x7f080000;
    public static final int text_view=0x7f080001;
}
public static final class layout {
    public static final int activity_main=0x7f030000;
    public static final int fragment_main=0x7f030001;
}

```

And this is the `AndroidManifest.java`

```
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.cguida1978it.prova"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="14"
        android:targetSdkVersion="19" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.cguida1978it.prova.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>

```

I also tried to retrieve the fragment in the `onCreate()` method using the `getFragmentManager().findFragmentById()` but also the fragment results in a null pointer!

I also tried to delete the content of `R.java` as written in one of your answer here in the forum to force Eclipse to regenerate it, but the problem persists!

I really can't figure what is going wrong here. This is a near blank-porject, created from scratch! The only edits are the addition of the `TextView` id and the lines to retrieve it in the Java code!

Oh... Maybe I did not mention (or it is not clear), I started many new projects from scratch and not modified, but the id and relative codes. Each new project has this issue! 

Do you think is an Eclipse issue or ADT/AVD (virtual device) issue? Is there any other IDE I could use? 

Really I'm a visually-impaired developer so, even in Eclipse I do not use the graphics designer. I always edit XML files, so I was wondering if it is easy to compile from command line and debug. I read about that in the "Getting started" Google guida. Before starting to read more deep I ask you if you would suggest it!

***EDIT 3***
The laalto answer seems to fix the problem. Inside the `MainActivity` class I found a `PlaceHolder` class that extends `Fragment` class and moving the `TextView` stuff inside the `onCreateView()` using `rootView.findViewById()` I can set the text property of the `TextView`. 

Why Eclipse does not create a separate class for the fragment `fragment_main`? Instead it creates a generic class inside the `MainActivity.java`? 

Do you think I should create a separate class for fragments? or use the activity class as suggested in the answer 2? 

In the Google's sample they extends the `MainActivity` class using the activity bar that is a subclass of `Fragment`, but, really, I was not able to retrieve resources inside the simple `onCreate()` of the `MainActivity` class... 

This is causing me a little confusion... 

Thank you for all of your answer and for your further explanation... I really appreciate your effort...