Building an image gallery/slider app

Create a new project in Android Studio called Image Pager. Use the Empty Activity template and leave all the rest of the settings at their defaults.

The images are in the download bundle in the Chapter 25/Image Pager/drawable folder. This next screenshot shows them in Windows File Explorer:

Figure 25.2 – Add images

Add the images to the drawable folder in the Project Explorer in Android Studio or you could add more interesting images, perhaps some photos you have taken.

Implementing the layout

For a simple image paging app, we use the PagerAdapter class. We can think of this as being like RecyclerAdapter but for images as it will handle the display of an array of images in a ViewPager widget. This is much like how RecyclerAdapter handles the display of the contents of an ArrayList in a ListView. All we need to do is override the appropriate methods.

To implement an image gallery with PagerAdapter, we first...