Apps Issue with setText changing the wrong text

[ceogreen]

I'm new to Android so hope this is a simple issue, I've searched using a couple of the above keywords and found nothing.
Basically I have a layout with a few textview elements a few edittext elements and a few buttons. In the java any incorrect entries by the user in the edittext elements should change a textview element which acts as user instructions to prompt the user to make corrections, the problem is it actually changes one of the button texts. Here is the code for the layout (activity_main.xml):

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_below="@+id/button4"
        android:layout_marginTop="26dp"
        android:background="@color/yellow"
        android:gravity="center_horizontal"
        android:text="@string/hello_world"
        android:textColor="@color/red" />

    <Button
        android:id="@+id/button5"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/textView1"
        android:layout_alignLeft="@+id/button2"
        android:layout_alignParentRight="true"
        android:onClick="onButton5Click"
        android:text="@string/stringminusfeed" />

    <Button
        android:id="@+id/button4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignRight="@+id/button3"
        android:layout_below="@+id/button3"
        android:onClick="onButton4Click"
        android:text="@string/stringminusspeed" />

And here is the code for the Java (MainActivity.java):

        TextView testView;
        testView = (TextView) findViewById(R.id.textView1);
        testView.setText("");

I know this worked as intended when I only had buttons 1-3, but adding 4 and 5 seems to have started something odd, I can't see anything wrong so am guessing this is a stupid mistake on my part. For reference it is button4 which has it's text changed by the java code. My only thought was that this was something more complicated caused by relative layout and inheritence.
Thanks in advance.

 

[jonbonazza]

What you have given us is correct. The error must reside somewhere else in your code.

 

[ceogreen]

Thanks, that has atleast confirmed I wasn't doing something stupid. The issue has been resolved by changing textView1 to textVw1, I have no idea why this would work however it does.