I'm newbies in Java and Android Studio also. I'm studying the both of the first answers of this question : Stack Overflow Question : Display the current Times
I reproduced the fist answer so no problem until the second answer with this code :
        import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.Gravity;
    import android.widget.TextView;
    import android.widget.Toast;
    import java.util.Calendar;
public class MainActivity extends AppCompatActivity {
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            //setContentView(R.layout.main);
            Calendar c = Calendar.getInstance();
            System.out.println("Current time => "+c.getTime());
            SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            String formattedDate = df.format(c.getTime());
            // formattedDate have current date/time
            Toast.makeText(this, formattedDate, Toast.LENGTH_SHORT).show();
            // Now we display formattedDate value in TextView
            TextView txtView = new TextView(this);
            txtView.setText("Current Date and Time : "+formattedDate);
            txtView.setGravity(Gravity.CENTER);
            txtView.setTextSize(20);
            setContentView(txtView);
        }
    }
When I'm trying to make the project, I have got the following error :
Error:(21, 9) error: cannot find symbol class SimpleDateFormat 
I don't how know how to declare the symbol as Android Studio is proposing several issue that are not working for me. Thanks.
 
    