XML scope in Android

Question

Is there anywhere that I can find documentation on the scope of the XML files? I have an app I am currently working on and have been struggling with getting a feature to work and it seems that the problem I am having is that I am trying to access an element in an XML file that must be out of scope. To simplify the layout, my project has main.xml, sub.xml, main.java, and sub.java files in it. As you can probably guess, main.java works with main.xml and sub.java is working with the elements in sub.xml. Here's where the issue comes in, I have a TextView element that is created in main.xml that I would like to modify the text in, but the action that would trigger it will occur in sub.java. I can't figure out how to change it from sub.java, and I can't figure out how to move the element into sub.xml. The code I am using is pretty simple:

TextView titleText = (TextView) findViewById(R.id.myTitle);
titleText.setText(filePath);

I get a FC every time I run the app, but if I move the code into main.java, it runs flawlessly. If anyone can offer any ideas, or point me in the direction of some documentation that would explain what java files can access what elements in which xml files, that would be awesome! Sorry for the novel, but I'm just struggling to get the point across. Thanks.

Answer 1

Activity.findViewById(int) only works if that view is in the activity's layout. So no, you can't refer to a view in main.xml because that layout doesn't apply to sub.

Do you have any TextViews in sub.xml called myTitle?

Answer 2

Hai Bryan, U can access the the textview of main.java(main.xml) in submain.java as follows In main.java write the following code

  static TextView titleText = (TextView) findViewById(R.id.myTitle);
titleText.setText(filePath);

and u can access this submain.java as

   Main.titleText.setText(filePath);

Answer 3

try like this Bryan in Main.xml file it works with no issue...........Declare first & then Initialize it...



  public class Main extends Activity {

        static TextView tv;
        static Button submit;

        /** Called when the activity is first created. */
        @Override
        public void onCreate(Bundle savedInstanceState) {

            tv = (TextView) findViewById(R.id.header_text1);
            }
}