Android - Set text to TextView

Question

I'm currently learning some android for a school project and I can't figure out the way to set text dynamically to a TextView.

Here is my code:

protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_enviar_mensaje);     err = (TextView)findViewById(R.id.texto);     err.setText("Escriba su mensaje y luego seleccione el canal."); } 

This is currently not working and I can't find a way to make it work...

Any help will be much appreciated... Thank you for the time, José.

EDIT: Here is the activity_enviar_mensaje.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="wrap_content"     ...     tools:context=".EnviarMensaje" >     ...     <TextView         android:id="@+id/texto"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_alignLeft="@+id/listaVista"         android:layout_alignParentBottom="true"         android:layout_alignRight="@+id/listaVista"         android:text="TextView" />     ... </RelativeLayout> 

By not working I mean the text shown does not change at any moment...

Answer 1

In your layout XML:

<TextView         android:id="@+id/myAwesomeTextView"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_alignParentTop="true"         android:text="Escriba el mensaje y luego clickee el canal a ser enviado"         android:textSize="20sp" /> 

Then, in your activity class:

// globally  TextView myAwesomeTextView = (TextView)findViewById(R.id.myAwesomeTextView);  //in your OnCreate() method myAwesomeTextView.setText("My Awesome Text");