Requires permission before using this line of code even after i use the dexter library to specifically ask permissions

@Override
public void onClick(View v) {
    Dexter.withActivity(this)
            .withPermission(Manifest.permission.CALL_PHONE)
            .withListener(new PermissionListener() {
                @Override public void onPermissionGranted(PermissionGrantedResponse response) {
                    Intent callIntent = new Intent(Intent.ACTION_CALL);
                    callIntent.setData(Uri.parse("tel:123456789"));


                    mcontext.startActivity(callIntent);}
                @Override public void onPermissionDenied(PermissionDeniedResponse response) {/* ... */}
                @Override public void onPermissionRationaleShouldBeShown(PermissionRequest permission, PermissionToken token) {/* ... */}
            }).check();
}

The context 'this' shows as an error. And also the line of code that calls someone is still showing as an error even after i put it in the OnPermissionGranted() method. What should i change to make this work?

The link for the dexter library is given below:

https://github.com/Karumi/Dexter

I used Activity act = (Activity)(holder.call.getContext()); to get the activity and then used act inside Dexter.withActivity(). None of the other solutions worked. I had to get the context through one of the views and then convert it into an activity as shown above.