code: public void show() {
          androidContentView.addView(this);
  
          // set the translations for the content view
          content.setTranslationX(distanceFromLeft);
          content.setTranslationY(distanceFromTop);
  
          // animate the alpha of the PeekView
          ObjectAnimator animator = ObjectAnimator.ofFloat(this, View.ALPHA, 0.0f, 1.0f);
          animator.addListener(new AnimatorEndListener() {
              @Override
              public void onAnimationEnd(Animator animator) {
                  if (callbacks != null) {
                      callbacks.shown();
                  }
              }
          });
          animator.setDuration(options.useFadeAnimation() ? ANIMATION_TIME : 0);
          animator.setInterpolator(INTERPOLATOR);
          animator.start();
      }
docs: Show the content of the PeekView by adding it to the android.R.id.content FrameLayout.