Apps TextView.setText

[Engmex]

Hi I'm very new to Android development so forgive my innocence. Why does this simple program crash on the TextView.setText method ?
package com.example.testsettext;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class TestSetText extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
TextView tv1 = (TextView) findViewById(R.id.TextView01);
tv1.setText("Display This Text in the Text View");
setContentView(R.layout.main);
}
}

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

<TextView android:text="@+id/TextView01" android:id="@+id/TextView01"
android:layout_width="wrap_content" android:layout_height="wrap_content"></TextView>
</LinearLayout>

Regards!

Update: Ok I solved it myself I need to put setText after setContentView like this:
setContentView(R.layout.main);
TextView tv1 = (TextView) findViewById(R.id.TextView01);
tv1.setText("Display This Text in Text View");

 

[hiephm]

You must call
setContentView(R.layout.main);
before
TextView tv1 = (TextView) findViewById(R.id.TextView01);
otherwise tv1 will be null and you will get NullPointerException when calling tv1.setText()

 

[Engmex]

You must call
setContentView(R.layout.main);
before
TextView tv1 = (TextView) findViewById(R.id.TextView01);
otherwise tv1 will be null and you will get NullPointerException when calling tv1.setText()

yes I worked it out myself (see my update), but thanks for the reply
Regards