Declaring variables outside onCreate - Android

Question

My application stops when I declare the TextView outside the onCreate method, I'm doing this because I need do access the TextView variable from other methods as well. I'll be grateful for any kind of help.

public class MainActivity extends ActionBarActivity {
    TextView textView = (TextView)findViewById(R.id.defaultText);

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.activity_main);

        textView.setText("Hello");
    }
}

Just define your TextView as a class scoped variable (ie, place it at the top of your class outside of any method scope. — Booger, Sep 02 '14 at 22:02
Look in Logcat for the actual error message. When you ask a question like this, include the Logcat info with your question. — Dale Wilson, Sep 02 '14 at 22:05
@TehCoder True, but if the OP had looked at Logcat he wouldn't have needed to ask the question, and this question is not likely to help future SO users. — Dale Wilson, Sep 02 '14 at 22:07

Rod_Algonquin · Answer 1 · 2014-09-02T22:07:45.783

My application stops when I declare the TextView outside the onCreate method

That is because the Layout is not yet inflated in your activity thus crashing you app and I am 100% sure the error is NPE when you set the text here : textView.setText("Hello");.

Solution:

always initialized your TextView inside your Oncreate after setContentView and having your textView object as a global instance.

public class MainActivity extends ActionBarActivity {
   TextView textView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.activity_main);

        textView = (TextView)findViewById(R.id.defaultText);
        textView.setText("Hello");
    }
}

TehCoder · Answer 2 · 2014-10-07T16:10:59.113

3

You can't declare a View outside a function.

TextView tv; and in OnCreate do: tv = (TextView)findViewById(...)

edited Oct 07 '14 at 16:10

answered Sep 02 '14 at 22:02

TehCoder

209
1
8

score 0 · Answer 3 · answered Sep 02 '14 at 22:36

As others pointed out, the error you are getting is because the view containing the TextView as a child as not yet been inflated. You should declare the strong reference and then instantiate the variable on the onCreate() method. If you insist on using such a code then I recommend you to take a look at Dependency injection.

score 0 · Answer 4 · edited Sep 05 '19 at 05:47

0

To do this:

TextView textView = (TextView)findViewById(R.id.defaultText);

You first set the content view to the Activity if not will not work.

edited Sep 05 '19 at 05:47

Android

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answered Sep 02 '14 at 22:46

Carlos Piñán

79
1
4

score -1 · Answer 5 · answered Jun 19 '20 at 20:48

I faced this problem and i solved it by using (tag) for my view (myTextView.tag) you can lean more about this property from here:

What is the main purpose of setTag() getTag() methods of View?

I mean I declare a variable called (counter) outside onCreate method, then i find my view wherever i need using his tag.

hope this helping

Declaring variables outside onCreate - Android

5 Answers5