Java for android in android studio : Assalam-O-Alaikum guys.I'm beginner in android development just a novice.But i'm facing problems in my first attempt to use log files in a program.See this...

    package com.example.mrunique.myapplicationforexmaple;

    import android.os.Bundle;
    import android.support.v7.app.AppCompatActivity;

    //THIS HERE
    import android.util.Log;


    import android.view.View;
    import android.widget.TextView;

    public class MainActivity extends AppCompatActivity
    {
        TextView mTextView;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {

        super.onCreate(savedInstanceState);
        setupUI();

    }

    private void setupUI()
    {

        setContentView( R.layout.activity_main  );
        mTextView =  ( TextView ) findViewById( R.id.textView );

    }


    //Create a local variable for identifying the class where the log statements 
    come from
    private final static String LOG_TAG = MainActivity.class.getSimpleName();

    /** This method is called when the on screen button is passed.
     * @param view
     */


    public void buttonPressed( View view )
    {

        //An  'info'  log statement
        Log.i( LOG_TAG , "buttonPressed( View ) called" );

        //The string we wish to be displayed
        String stringValue = "Hello World!";

        //Change the text of the TextView on the screen
        mTextView.setText( stringValue );
        Log.v( LOG_TAG , "text changed to: " +stringValue ) ;

        //A debug log statement
        Log.d( LOG_TAG , "buttonPrssed( View ) finished" );

    }

    }

But the problem is [In this image that textView in the red cannot be resolved why?? & TextView highlights as gray why?][1]


  [1]: https://i.stack.imgur.com/pH2vp.png