The other answers did not work for me. I have implemented this instead:
SnackBar.class
public  class SnackBar{  
Context context;
Snackbar getSnackbar(View v, String s, View.OnClickListener listener, String action){
    Snackbar sn = Snackbar.make(v, "" + s, Snackbar.LENGTH_LONG);
    sn.setAction("" + action, listener);
    sn.setActionTextColor(Color.CYAN);
    sn.show();
 sn.getView().setBackground(ContextCompat.getDrawable(context,R.drawable.snackbar_shape));
    return sn;
}
in MainActivity.class include
MainActivity.class:
  // Snackbar.make(v,"Notification for pressing button",Snackbar.LENGTH_LONG).show();
            final SnackBar snackBar=new SnackBar();
           snackBar.context=MainActivity.this;
           snackBar.getSnackbar(v, "Notification for pressing ", new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Log.e(TAG,"cancelled");
                    snackBar.onClick=true;
                    
                }
            }, "cancel");
in drawable directory
snackbar_shape.xml
<item
    android:left="20dp"
    android:right="20dp"
    android:bottom="10dp"
    android:top="10dp">     
    <shape android:shape="rectangle"  >
        <solid android:color="#F31E1E1E" />    
        <padding android:left="25dp"android:right="25dp" android:bottom="10dp"android:top="10dp" />
        <corners android:radius="7dp" />
    </shape>
</item>