star = (ImageView) rootView.findViewById(R.id.heart);
    star.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            Toast.makeText(getActivity(),"the star was clicked",
                   Toast.LENGTH_LONG).show();
        }
    });

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

<ImageView
    android:id="@+id/lesson_video"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:contentDescription="Video"
    android:scaleType="centerCrop"
    />

</LinearLayout>


public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {

    View v = inflater.inflate(R.layout.lesson_video_fragment, container, false);

    videoImage = (ImageView)v.findViewById(R.id.lesson_video);

    videoImage.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {

            //do your thing
        }
    });