Simple android class for user input null pointer exception

Question

I am trying to write this simple class which will take user input and display it to a text view but every time I try to run it I am getting a fatal error in my main class. I'm a newbie and I know this is something simple but for the life of me I can't find it!! Any help greatly appreciated. Please see below my code to create the class

 package com.ObComDis.wayne;

import android.app.Activity;
import android.os.Bundle;
import java.util.Date;
import android.app.Activity;
import android.os.Bundle;
import android.text.format.DateFormat;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class ObComDisActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
}

String name;
EditText et = (EditText) findViewById(R.id.edittext);
TextView t = (TextView) findViewById(R.id.textView1);

public String getName()
{
    String name = et.getText().toString();
    return name;
}
public void main (String args [])
{
    ObComDisActivity myocd = new ObComDisActivity();
    t.setText(name);

}
}

And here is the reading I am getting from log cat.....

07-11 18:55:01.149: D/AndroidRuntime(525): Shutting down VM
07-11 18:55:01.149: W/dalvikvm(525): threadid=1: thread exiting with uncaught exception       (group=0x40015560)
07-11 18:55:01.189: E/AndroidRuntime(525): FATAL EXCEPTION: main
07-11 18:55:01.189: E/AndroidRuntime(525): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.ObComDis.wayne/com.ObComDis.wayne.ObComDisActivity}: java.lang.NullPointerException
07-11 18:55:01.189: E/AndroidRuntime(525):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1569)
07-11 18:55:01.189: E/AndroidRuntime(525):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
07-11 18:55:01.189: E/AndroidRuntime(525):  at android.app.ActivityThread.access$1500(ActivityThread.java:117)
07-11 18:55:01.189: E/AndroidRuntime(525):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
07-11 18:55:01.189: E/AndroidRuntime(525):  at android.os.Handler.dispatchMessage(Handler.java:99)
07-11 18:55:01.189: E/AndroidRuntime(525):  at android.os.Looper.loop(Looper.java:123)
07-11 18:55:01.189: E/AndroidRuntime(525):  at android.app.ActivityThread.main(ActivityThread.java:3683)
07-11 18:55:01.189: E/AndroidRuntime(525):  at java.lang.reflect.Method.invokeNative(Native Method)
07-11 18:55:01.189: E/AndroidRuntime(525):  at java.lang.reflect.Method.invoke(Method.java:507)
07-11 18:55:01.189: E/AndroidRuntime(525):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
07-11 18:55:01.189: E/AndroidRuntime(525):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
07-11 18:55:01.189: E/AndroidRuntime(525):  at dalvik.system.NativeStart.main(Native Method)
07-11 18:55:01.189: E/AndroidRuntime(525): Caused by: java.lang.NullPointerException
07-11 18:55:01.189: E/AndroidRuntime(525):  at android.app.Activity.findViewById(Activity.java:1647)
07-11 18:55:01.189: E/AndroidRuntime(525):  at com.ObComDis.wayne.ObComDisActivity.<init>(ObComDisActivity.java:25)
07-11 18:55:01.189: E/AndroidRuntime(525):  at java.lang.Class.newInstanceImpl(Native Method)
07-11 18:55:01.189: E/AndroidRuntime(525):  at java.lang.Class.newInstance(Class.java:1409)
07-11 18:55:01.189: E/AndroidRuntime(525):  at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
07-11 18:55:01.189: E/AndroidRuntime(525):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1561)
07-11 18:55:01.189: E/AndroidRuntime(525):  ... 11 more

Can you format your log cat reading? If possible post to pastebin. It is a pain to read as is. — Mob
– Mob, Commented Jul 11, 2012 at 19:04
Sorry about that! Don't know what you mean by post it to the paste bin? How can I format it? I just pasted what was in my log cat to the question? Thanks./ — meself1000
– meself1000, Commented Jul 12, 2012 at 17:29

Chris Stratton · Accepted Answer · 2012-07-11 19:05:33Z

1

findViewById() returns null until that view is created, which in your case would happen only as a result of your setContentView() in onCreate().

Try something like this:

EditText et;
TextView t;

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    et = (EditText) findViewById(R.id.edittext);
    t = (TextView) findViewById(R.id.textView1);
}

answered Jul 11, 2012 at 19:05

Chris Stratton

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