Android programming - trying to change TextView's text using Java code - error in launch

Question

I'm a beginner with both Java and Android programing. I'm trying to create a TextView and then edit its content within Java code. This is the TextView definition:

<TextView android:id="@+id/NewTV"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/NewTVS"
    android:textSize="20sp" />

And this is the Java code (the needed part, everything else is default):

@Override
protected void onCreate(Bundle savedInstanceState) {    
    TextView mNewTV = (TextView)findViewById(R.id.NewTV);
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    String newstr = "hello";
    mNewTV.setText(newstr);
}

Launching this code causes a problem - the app closing itself. I believe that the problem occurs during the findViewById command.

Hopefully I was clear enough despite my bad English. Thanks in advance.

Answer 1

you are trying to get reference of TextView mNewTV before setting setContentView(R.layout.activity_main);

the order must be like this :

 @Override
    protected void onCreate(Bundle savedInstanceState) {    

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        TextView mNewTV = (TextView)findViewById(R.id.NewTV);
        String newstr = "hello";
        mNewTV.setText(newstr);
    }