Implementing multiple interfaces in android studio

Question

I am trying to use a spinner and a button in my app. I want to know if my syntax for implementing multiple interfaces is correct. This is how it is currently set up:

public class MainActivity extends AppCompatActivity
    implements View.OnClickListener, AdapterView.OnItemSelectedListener

My @Override for the onItemSelectedListener is also not being accepted. I'll post what I have but i will leave out the part that handles what happens after the button is clicked, as I there are no errors there and i believe it has no bearing on this problem:

public class MainActivity extends AppCompatActivity
    implements View.OnClickListener, AdapterView.OnItemSelectedListener {

Button setCountdown;
Spinner higestNotification;
EditText countdownTime;
int countdownConversion; //convert contents of countdownTime to an integer
int clockStart = 1;
int[] notificationTimes = new int[7];
String convertNotificationTimeToString;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    setCountdown = (Button) findViewById(R.id.setCountdown);
    higestNotification = (Spinner) findViewById(R.id.highestNotification);
    countdownTime = (EditText) findViewById(R.id.countdownTime);


    setCountdown.setEnabled(false);//disable button at the start of the app
    higestNotification.setEnabled(false);// disable spinner at the start of the app


    countdownTime.setOnClickListener(this);
    setCountdown.setOnClickListener(this);

    higestNotification.setOnItemSelectedListener(this);
}

@Override
public void OnItemSelected(AdapterView<?> arg0, View arg1, int position, long id )

{

}

@Override
public void OnNothingSelected(AdapterView<?> arg0)
{

}

as i said, the errors are when i try to implement View.OnClickListener and AdapterView.OnItemSelectedListener, as well as the overrides for OnItemSelected

Your overridden methods should start with a lower-case letter. As it's specified now in your code, the method signatures don't match the interface. — Michael Krause
– Michael Krause, Commented Aug 1, 2017 at 3:38

Michael Krause · Accepted Answer · 2017-08-01 07:34:07Z

1

Your overridden methods should start with a lower-case letter.

As it's specified now in your code, the method signatures don't match the interface contract.

Try instead something like:

@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
}

@Override
public void onNothingSelected(AdapterView<?> parent) {
}

@Override
public void onClick(View view) {
}

As an aside, Android Studio provides a shortcut for overriding interface methods on your behalf: Control + O

edited Aug 1, 2017 at 7:34

answered Aug 1, 2017 at 3:42

Michael Krause

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Comments

JRG · Accepted Answer · 2017-08-01 03:41:45Z

Your method OnItemSelected is having upper case letter O which is not same as onItemSelected.

I tried this in my android-studio and it works.

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;

public class MainActivity extends AppCompatActivity implements View.OnClickListener, AdapterView.OnItemSelectedListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Log.d("TEST", "onCreate");
    }

    @Override
    public void onClick(View view) {
        // handle onClick        
    }

    @Override
    public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
        // handle onItemSelected
    }

    @Override
    public void onNothingSelected(AdapterView<?> adapterView) {
        // handle onNothingSelected

    }
}

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