Setting textview text in a method

Question

I am trying to create a method to determine the winner of the game, not worried about the logic of the finding the winner.

In the code I was attempting to add a getWinner() method that would determine the winner when the counter hit 10 moves. In the getWinner() method I took my textview object tv and wrote tv.setText("worked");. The app would crash. If i skip adding the getWinner() method and just toss in the tv.setText() straight into the code it works though.

Since I am not sure how well I explained what's going on maybe my comments throughout the code can give a better understanding.

public class MainActivity extends AppCompatActivity {

    public int counter = 1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final Button button1 = (Button) findViewById(R.id.button1);
        final Button button2 = (Button) findViewById(R.id.button2);
        final Button button3 = (Button) findViewById(R.id.button3);
        final Button button4 = (Button) findViewById(R.id.button4);
        final Button button5 = (Button) findViewById(R.id.button5);
        final Button button6 = (Button) findViewById(R.id.button6);
        final Button button7 = (Button) findViewById(R.id.button7);
        final Button button8 = (Button) findViewById(R.id.button8);
        final Button button9 = (Button) findViewById(R.id.button9);
        final TextView tv = (TextView) findViewById(R.id.winnerTextView);


        button1.setOnClickListener(new View.OnClickListener()    {
            public void onClick(View v) {
                if (counter % 2 == 0)   {
                    button1.setText("O");
                }
                else
                {
                    button1.setText("X");
                }
                counter++;
                if (counter == 10)
                {
                    //getWinner();         ---this does not work
                    //tv.setText("works"); ---this works
                }
            }
        });

        button2.setOnClickListener(new View.OnClickListener()   {
            public void onClick(View v) {
                if (counter % 2 == 0)   {
                    button2.setText("O");
                }
                else
                {
                    button2.setText("X");
                }
                counter++;
                if (counter == 10)
                {
                    //getWinner();         ---this does not work
                    //tv.setText("works"); ---this works
                }
            }
        });

        button3.setOnClickListener(new View.OnClickListener()   {
            public void onClick(View v) {
                if (counter % 2 == 0)   {
                    button3.setText("O");
                }
                else
                {
                    button3.setText("X");
                }
                counter++;
                if (counter == 10)
                {
                    //getWinner();         ---this does not work
                    //tv.setText("works"); ---this works
                }
            }
        });

        button4.setOnClickListener(new View.OnClickListener()   {
            public void onClick(View v) {
                if (counter % 2 == 0)   {
                    button4.setText("O");
                }
                else
                {
                    button4.setText("X");
                }
                counter++;
                if (counter == 10)
                {
                    //getWinner();         ---this does not work
                    //tv.setText("works"); ---this works
                }
            }
        });

        button5.setOnClickListener(new View.OnClickListener()   {
            public void onClick(View v) {
                if (counter % 2 == 0)   {
                    button5.setText("O");
                }
                else
                {
                    button5.setText("X");
                }
                counter++;
                if (counter == 10)
                {
                    //getWinner();         ---this does not work
                    //tv.setText("works"); ---this works
                }
            }
        });

        button6.setOnClickListener(new View.OnClickListener()   {
            public void onClick(View v) {
                if (counter % 2 == 0)   {
                    button6.setText("O");
                }
                else
                {
                    button6.setText("X");
                }
                counter++;
                if (counter == 10)
                {
                    //getWinner();         ---this does not work
                    //tv.setText("works"); ---this works
                }
            }
        });

        button7.setOnClickListener(new View.OnClickListener()   {
            public void onClick(View v) {
                if (counter % 2 == 0)   {
                    button7.setText("O");
                }
                else
                {
                    button7.setText("X");
                }
                counter++;
                if (counter == 10)
                {
                    //getWinner();         ---this does not work
                    //tv.setText("works"); ---this works
                }
            }
        });

        button8.setOnClickListener(new View.OnClickListener()   {
            public void onClick(View v) {
                if (counter % 2 == 0)   {
                    button8.setText("O");
                }
                else
                {
                    button8.setText("X");
                }
                counter++;
                if (counter == 10)
                {
                    //getWinner();
                }
            }
        });

        button9.setOnClickListener(new View.OnClickListener()   {
            public void onClick(View v) {
                if (counter % 2 == 0)   {
                    button9.setText("O");
                }
                else
                {
                    button9.setText("X");
                }
                counter++;
                if (counter == 10)
                {
                    //getWinner();         ---this does not work
                    //tv.setText("works"); ---this works
                }
            }
        });

       /**
        public void getWinner() {
        tv.setText("does not work");
        }
        **/

    }
}

@IntelliJAmiya 1:32 AM Gradle build finished with 4 error(s) in 1s 123ms 1:32 AM PSI and index do not match: PSI and index do not match — Chris
– Chris, Commented Nov 10, 2017 at 6:33
@IntelliJAmiya dont think that is what you wanted, when i hover mouse over getWinner(); it says method cannot be resolved. — Chris
– Chris, Commented Nov 10, 2017 at 6:34

Vishnu Nair · Accepted Answer · 2017-11-10 06:33:14Z

2

Try passing textview obj to the method getWinner and then try to set it.getWinner should be outside oncreate method.

answered Nov 10, 2017 at 6:33

Vishnu Nair

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1 Comment

gStephin Over a year ago

onne podoooooooo

ישו אוהב אותך · Accepted Answer · 2017-11-10 06:50:54Z

As other answer has pointing out, you're creating a method inside a method which is a code error and you're trying to access a variable inside of another method which is a method scope.

First, we need to resolve the first problem.

If we simplify your code, it will be something like this

public class MainActivity extends AppCompatActivity {

    public int counter = 1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final Button button1 = (Button) findViewById(R.id.button1);
        // get all the view.

        final TextView tv = (TextView) findViewById(R.id.winnerTextView);


        button1.setOnClickListener(listener);

        button2.setOnClickListener(listener);

        button3.setOnClickListener(listener);

        button4.setOnClickListener(listener);

        button5.setOnClickListener(listener);

        button6.setOnClickListener(listener);

        button7.setOnClickListener(listener);

        button8.setOnClickListener(listener);

        button9.setOnClickListener(listener);

       /**
        public void getWinner() {
        tv.setText("does not work");
        }
        **/

    }
}

From the above code, you can see that you're trying to create getWinner() inside of onCreate() which is wrong.

It should be:

public class MainActivity extends AppCompatActivity {

    protected void onCreate(Bundle savedInstanceState) {

      final TextView tv = (TextView) findViewById(R.id.winnerTextView);
    }

    public void getWinner() {
        tv.setText("does not work");
    }
}

Now the code is working but it will giving you an error because getWinner() can't found the tv variable which is only inside the onCreate() method. So, you need to make it a class scope like this:

public class MainActivity extends AppCompatActivity {

    // make it class scope.
    private TextView tv;

    protected void onCreate(Bundle savedInstanceState) {
      ...

      TextView tv = (TextView) findViewById(R.id.winnerTextView);

      ...
    }

    public void getWinner() {
        tv.setText("does not work");
    }
}

Both of the problems happen because you're creating a method with a too much line of code. You should always make your method not more than 15 line. This is the best practice to make your code more maintainable in the future.

Don't do too much logic in a single method. Focus only solving one problem in a method. Always use a Divide et impera principal to separate a bigger problem to many smaller problems.

Surya Soma · Accepted Answer · 2017-11-10 06:32:40Z

1

Try it by putting the getWinner() method outside your onCreate() function and pass the textView reference to it.

I guess it should work.

answered Nov 10, 2017 at 6:32

Surya Soma

999 bronze badges

Comments

noman404 · Accepted Answer · 2017-11-10 06:33:31Z

0

What you may do is the,

Declare the TextView objects globally.
you can not use the background thread to set text so be careful if you uses any background thread.

answered Nov 10, 2017 at 6:33

noman404

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Comments

Upendra Shah · Accepted Answer · 2017-11-10 06:38:13Z

Define tv at globally and no need to put getWinner() into on create so pickup it out

public class MainActivity extends AppCompatActivity {

public int counter = 1;
private TextView tv;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    final Button button1 = (Button) findViewById(R.id.button1);
    final Button button2 = (Button) findViewById(R.id.button2);
    final Button button3 = (Button) findViewById(R.id.button3);
    final Button button4 = (Button) findViewById(R.id.button4);
    final Button button5 = (Button) findViewById(R.id.button5);
    final Button button6 = (Button) findViewById(R.id.button6);
    final Button button7 = (Button) findViewById(R.id.button7);
    final Button button8 = (Button) findViewById(R.id.button8);
    final Button button9 = (Button) findViewById(R.id.button9);
    tv = (TextView) findViewById(R.id.winnerTextView);


    button1.setOnClickListener(new View.OnClickListener()    {
        public void onClick(View v) {
            if (counter % 2 == 0)   {
                button1.setText("O");
            }
            else
            {
                button1.setText("X");
            }
            counter++;
            if (counter == 10)
            {
                getWinner();        

            }
        }
    });

}
public void getWinner() {
    tv.setText("does not work");
    }
}

SHA · Accepted Answer · 2017-11-10 06:39:39Z

0

make getWinner() method outside of onCreate() and make tv global variable. it should work.

answered Nov 10, 2017 at 6:39

SHA

574 bronze badges

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