CODEWITHSUNDEEP
javaandroidtextviewandroid-view
AtlasOnEarth
AtlasOnEarth

Reputation: 83

Changing the textview in a different view

I'm trying to prepare a view to be shown by update the text in the textview before I ever switch over to that view.

I've declared the textview variable as public, initialized it in the OnCreate

 Info = (TextView) findViewById(R.id.BackDialogText);

And then when it comes time to change the text, I get a nullpointerException

Info.setText(TheString);
setContentView(R.layout.mydialog_layout);

I've run the app without the setText and it runs fine, showing me my view with the predefined text. Is there some trick I'm missing to update the text of the view?

Upvotes: 0

Views: 120

Answers (3)

Abhay Kumar
Abhay Kumar

Reputation: 1618

Basically before you set the view 

 setContentView(R.layout.mydialog_layout);

to your activity you cannot use the elements inside the view in your code. So you must have something like this in your code

setContentView(R.layout.mydialog_layout);
 Info = (TextView) findViewById(R.id.BackDialogText); // you cannot initialize your view before  setcontentview
 Info.setText(TheString);  //this line must be always called after setContentView

Upvotes: 1

ajacian81
ajacian81

Reputation: 7569

findViewById() finds Views in the View you're calling it from.

edit: sorry my Mac was crashing and I couldn't expand further. Basically, in Android only the foreground Activity is living at any one point. So even modifying one View from another Activity is not a good idea. If it's just the text you want to modify, then you have a couple of options, the easiest is to have a public static variable in one of the Activities, and calling setText with that variable.

So for instance:

public class Activity1 extends Activity {
    private static theString = "";

    public static void setString(String s) { 
         theString = s;
     }

    public void onCreate(Bundle b) {
        super.onCreate(b);
      setContentView(R.layout.mydialog_layout);
    Info = (TextView) findViewById(R.id.BackDialogText);



      Info.setText(TheString);
    }
}

and then in Activity2 you can call:

Activity1.setString("New String");

Upvotes: 0

Vipul
Vipul

Reputation: 28093

Just interchange the line positions.

Below is the working snippet.

setContentView(R.layout.mydialog_layout);
Info.setText(TheString);

Upvotes: 1

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