Android-ViewPager switching animation, PageTransformer, and androidviewpager

Android-ViewPager switching animation, PageTransformer, and androidviewpager
TransformPage (View view, float position)

View is the view in the slide. position is float type and represents the current slide status. For example, when sliding to the full screen, the position is 0, if the previous page and next page are usually half of the screen, the position of the previous page is-0.5, and the posiotn of the next page is 0.5 (Whether it is-0.5 or 0.5. Check whether the current view is the view on the previous page or the view on the next page.), So we can set the required alpha, x/y information based on the position value, that is, we can use setAlpha (), setTranslationX () or setSaleY () to customize the switching animation.

Animation effects officially provided by Google

public class DepthPageTransformer implements PageTransformer {    private static float MIN_SCALE = 0.75f;     @SuppressLint("NewApi")    @Override    public void transformPage(View view, float position) {        int pageWidth = view.getWidth();        if (position < -1) { // [-Infinity,-1)                                // This page is way off-screen to the left.            view.setAlpha(0);        } else if (position <= 0) { // [-1,0]                                    // Use the default slide transition when                                    // moving to the left page            view.setAlpha(1);            view.setTranslationX(0);            view.setScaleX(1);            view.setScaleY(1);        } else if (position <= 1) { // (0,1]                                    // Fade the page out.            view.setAlpha(1 - position);            // Counteract the default slide transition            view.setTranslationX(pageWidth * -position);            // Scale the page down (between MIN_SCALE and 1)            float scaleFactor = MIN_SCALE + (1 - MIN_SCALE)                    * (1 - Math.abs(position));            view.setScaleX(scaleFactor);            view.setScaleY(scaleFactor);        } else { // (1,+Infinity]                    // This page is way off-screen to the right.            view.setAlpha(0);         }    }}

public class ZoomOutPageTransformer implements PageTransformer {    private static float MIN_SCALE = 0.85f;     private static float MIN_ALPHA = 0.5f;     @Override    public void transformPage(View view, float position) {        int pageWidth = view.getWidth();        int pageHeight = view.getHeight();         if (position < -1) { // [-Infinity,-1)                                // This page is way off-screen to the left.            view.setAlpha(0);        } else if (position <= 1) { // [-1,1]                                    // Modify the default slide transition to                                    // shrink the page as well            float scaleFactor = Math.max(MIN_SCALE, 1 - Math.abs(position));            float vertMargin = pageHeight * (1 - scaleFactor) / 2;            float horzMargin = pageWidth * (1 - scaleFactor) / 2;            if (position < 0) {                view.setTranslationX(horzMargin - vertMargin / 2);            } else {                view.setTranslationX(-horzMargin + vertMargin / 2);            }            // Scale the page down (between MIN_SCALE and 1)            view.setScaleX(scaleFactor);            view.setScaleY(scaleFactor);            // Fade the page relative to its size.            view.setAlpha(MIN_ALPHA + (scaleFactor - MIN_SCALE)                    / (1 - MIN_SCALE) * (1 - MIN_ALPHA));        } else { // (1,+Infinity]                    // This page is way off-screen to the right.            view.setAlpha(0);        }    }

Use

ViewPager mPager = (ViewPager) findViewById(R.id.pager);  mPager.setPageTransformer(true, new DepthPageTransformer());

I am the dividing line of tiantiao

Viewpager series:

Gradient effect of viewpager background image: Android -- ViewPager sliding background gradient

Viewpager + fragment: Android -- ViewPager, Fragment, status saving, Communication