Android上的startActivityForResult

Question

I'm trying to develope some very basic code using startActivityForResult and I am always getting an annoying problem : from the main activity (contains only a "hello word" editText) I call a new activity which contains only a TextView, an empty listView and an ImageButton. When I click on the ImageButton it supposes to return "ok" inside an intent to my mainActivity and print it into the "hello word" editText but nothing happens. I already have read all the threads on how to use "StartActivity for result" but I found nothing helpful.Please help me.

My Code below is:

MainActivity

   public class MainActivity extends AppCompatActivity {

    TextView hw;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        hw = (TextView) findViewById(R.id.hw);
        hw.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(getApplicationContext(),DeviceListActivity.class);
                int resultCode = -1;
                startActivityForResult(intent,resultCode);
            }
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {

        if (requestCode == 1) {
            if(resultCode == Activity.RESULT_OK){
                String result=data.getStringExtra("result");
                hw.setText(result);

            }
            if (resultCode == Activity.RESULT_CANCELED) {
                //Write your code if there's no result
            }
        }
    }
    }

DeviceListActivity:

public class DeviceListActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.device_list);

    final ImageButton nextBtn = (ImageButton) findViewById(R.id.nextBtn);
    nextBtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent returnIntent = new Intent();
            String result = "Tout va bien!";
            returnIntent.putExtra("result",result);
            onActivityResult(1,1,returnIntent);
            setResult(Activity.RESULT_OK, returnIntent);
            finish();
        }
    });
}
}

Answer 1

in your MainActivity change:

Intent intent = new Intent(getApplicationContext(),DeviceListActivity.class);
int resultCode = -1;
startActivityForResult(intent,resultCode);

to

Intent intent = new Intent(getApplicationContext(),DeviceListActivity.class);
int resultCode = 1;
startActivityForResult(intent,resultCode);

and in your DeviceListActivity replace your code with:

Intent returnIntent = new Intent();
        String result = "Tout va bien!";
        returnIntent.putExtra("result",result);
        setResult(Activity.RESULT_OK, returnIntent);
        finish();

Hope it will help you out.