android: ViewPager Indicator like Tinders pictures

So, I have a ViewPager and I want to realize a simple Page-Indicator like Tinder does with its pics:

I thought it would be easy to find a library, but for the life of me, I can't find any.

I don't care if the bar is realized by manipulating the width of a dot or with a drawable, the only thing the library should do is stretching the bars, so that they always take 100% of the width of the ViewPager.

Anyone know a library like that, or is it easy to realize this without help of a library?

Let's solve this problem step by step.

First, Add Jake Wharton's ViewPager Library in your project. Go to your build.gradle (Module:app) and add this line and sync your project.

implementation 'com.github.JakeWharton:ViewPagerIndicator:2.4.1'

Second, Add LinePageIndicator in your xml file where your viewPager is.

<com.viewpagerindicator.LinePageIndicator
        android:id="@+id/indicator"
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        app:strokeWidth="4dp"
        app:unselectedColor="#FF888888"
        app:selectedColor="#FF880000"/>

Third and final step, after attaching a adapter to your viewpager, add this code to get your desired output.

LinePageIndicator linePageIndicator = view.findViewById(R.id.indicator);
    linePageIndicator.setViewPager(viewPager);

    //As we are measuring screen width, you should put the calculation inside onGlobalLayoutListener to get the correct screen width
    linePageIndicator.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
        @Override
        public void onGlobalLayout() {
            int numberOfItems = viewPager.getChildCount();
            DisplayMetrics displayMetrics = getContext().getResources().getDisplayMetrics();
            float widthPixel = displayMetrics.widthPixels;

            float itemWidth = widthPixel/numberOfItems;
            linePageIndicator.setLineWidth(itemWidth);
        }
    });

And that's it, you've got a full screen wide lineindicator.