package com.reactnativenavigation.views.collapsingToolbar; import android.content.Context; import android.support.v4.view.ViewPager; import android.view.View; public class CollapsingViewPager extends ViewPager implements CollapsingView { CollapsingViewMeasurer viewMeasurer; ViewCollapser viewCollapser; public CollapsingViewPager(Context context) { super(context); viewCollapser = new ViewCollapser(this); } public void setViewMeasurer(CollapsingViewMeasurer viewMeasurer) { this.viewMeasurer = viewMeasurer; } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); setMeasuredDimension(viewMeasurer.getMeasuredWidth(widthMeasureSpec), viewMeasurer.getMeasuredHeight(heightMeasureSpec)); } @Override public float getFinalCollapseValue() { return viewMeasurer.getFinalCollapseValue(); } @Override public float getCurrentCollapseValue() { return getTranslationY(); } @Override public View asView() { return this; } @Override public void collapse(CollapseAmount amount) { viewCollapser.collapse(amount); } }