Question

I created a (very simple) class wich gets a string value from an intent. If i create a Toast with the result, it’s oké. But when i try to set the text of the TextView the program stops with a NullPointerException. Eclipse gives a warning on:

TextView debugView = (TextView) findViewById(R.id.debugView);

The local variable debugView is never read

I hope someone has an idea.

public class Main extends Activity {

TextView debugView;
Button chooseOne;

Intent myIntent;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    TextView debugView = (TextView) findViewById(R.id.debugView);
    //debugView.setText("Hola supermercado!");

    Button ChooseOne = (Button) findViewById(R.id.chooseOne);

    ChooseOne.setOnClickListener(new OnClickListener() {

        public void onClick(View arg0) {

            myIntent = new Intent(Main.this, ResultFromSelection.class);
            myIntent.putExtra("sampleData", "This is Sample Data");
            startActivityForResult(myIntent, 1);

        }
    });

}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (resultCode == RESULT_OK && requestCode == 1) {

        String msg = data.getStringExtra("returnedData");

        //Toast.makeText(Main.this, ""+msg, Toast.LENGTH_LONG).show();
        debugView.setText(""+msg);

    }
}

}

Where i get the result from:

public class ResultFromSelection extends Activity {

 Intent intent;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.selection);

    Intent intent= getIntent();
      intent.putExtra("returnedData", "A Value");
      setResult(RESULT_OK, intent);
    finish();
}

 }

XML From Main:

Logcat doesn’t give me any info at all, just the nullPointer. I can’t post a logcat right now because the emulator gives me some more trouble (after this briljant update >:(). Will try again when needed.

Answer 1

You are creating the debugView inside your oncreate which makes it a variable that only can be used there. Change

TextView debugView = (TextView) findViewById(R.id.debugView);

to

this.debugView = (TextView) findViewById(R.id.debugView);