Question

    public class screen2 extends Activity {

        @Override
        public void onCreate(Bundle savedInstanceState) {

            super.onCreate(savedInstanceState);
            setContentView(R.layout.screen2);

            final Button button1 = (Button)findViewById(R.id.button1);        
            button1.setOnClickListener(new View.OnClickListener() {
                 public void onClick(View v) {

                    //AInteger.parseInt(string)
                    System.out.println("1");
                    EditText et = (EditText)findViewById(R.id.editText1);
                    System.out.println("2");
                    int zipCode =  Integer.parseInt(et.getText().toString());
                    System.out.println("3");
                    System.out.println(zipCode);

                    System.out.println("dude...5");
                 }
            });
        }        
   }

This code shows the errror in the logcat :

    11-13 19:58:06.806: W/KeyCharacterMap(281): Using default keymap: /system/usr/keychars/qwerty.kcm.bin
11-13 19:58:09.471: I/System.out(281): 1
11-13 19:58:09.471: I/System.out(281): 2
11-13 19:58:09.477: D/AndroidRuntime(281): Shutting down VM
11-13 19:58:09.477: W/dalvikvm(281): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
11-13 19:58:09.527: E/AndroidRuntime(281): FATAL EXCEPTION: main
11-13 19:58:09.527: E/AndroidRuntime(281): java.lang.NullPointerException
11-13 19:58:09.527: E/AndroidRuntime(281):  at com.example.andtwi.screen2$1.onClick(screen2.java:23)
11-13 19:58:09.527: E/AndroidRuntime(281):  at android.view.View.performClick(View.java:2408)
11-13 19:58:09.527: E/AndroidRuntime(281):  at android.view.View$PerformClick.run(View.java:8816)
11-13 19:58:09.527: E/AndroidRuntime(281):  at android.os.Handler.handleCallback(Handler.java:587)
11-13 19:58:09.527: E/AndroidRuntime(281):  at android.os.Handler.dispatchMessage(Handler.java:92)
11-13 19:58:09.527: E/AndroidRuntime(281):  at android.os.Looper.loop(Looper.java:123)
11-13 19:58:09.527: E/AndroidRuntime(281):  at android.app.ActivityThread.main(ActivityThread.java:4627)
11-13 19:58:09.527: E/AndroidRuntime(281):  at java.lang.reflect.Method.invokeNative(Native Method)
11-13 19:58:09.527: E/AndroidRuntime(281):  at java.lang.reflect.Method.invoke(Method.java:521)
11-13 19:58:09.527: E/AndroidRuntime(281):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
11-13 19:58:09.527: E/AndroidRuntime(281):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
11-13 19:58:09.527: E/AndroidRuntime(281):  at dalvik.system.NativeStart.main(Native Method)

Though it looks like an Null Pointer exception , i think i am doing it things exactly i found on forums. Here is code of my related xml file as well. Can anyone suggest where am i doing it wrong?

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Enter Zipcode" />

    <EditText
        android:id="@+id/editText1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="number"
        android:maxLength="5" >

        <requestFocus />
    </EditText>

    <Button
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/button1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Get movies from Flixster" />

</LinearLayout>

The code breaks at this as well :

int zipCode =  Integer.parseInt(et.getText().toString());

Answer 1

Could you post your onCreate method, as well as line 23 on its own? The most likely problem is that you neglect to call setContentView and that is why findViewById returns null.