Why I can't connect XML layout file to source code in Android?

[bikerjeg]

I only begin to learn android development and can't perform a simple thing. I have an activity_login.xml which defines couples of widgets (TextViews, buttons, etc.) and I want to change textview size programmatically. I' m trying to use R.id but Eclipse don't see my text view. Here what i've tried. TextView in res/layout/activity_login.xml file:\[code\]<TextView android:id="@+id/textView1" android:layout_width="23" android:layout_height="wrap_content" android:layout_alignLeft="@+id/button1" android:layout_alignParentTop="true" android:layout_alignRight="@+id/button1" android:layout_marginTop="34dp" android:text="TextView" />\[/code\]And here I'm trying to connect to it in my LoginActivity.java:\[code\]public void ClickLogin (View view){ TextView t_view = (TextView) findViewById(R.id.textView1);\[/code\]The problem Eclipse don't see neither textview nor other widgets in xml file.Then question what am I doing wrong?And how to implement this correctly?