问题

I want to implement Carousel using View Pager2 with preview of left and right page like this:

Initially I was using view pager1 which supported. Now I think it's removed

    viewPagerhost.setPageMargin(20);

Any idea how we can achieve this using View Pager 2

回答1:

Now we need to use setPageTransformer() in Version 1.0.0-alpha05

New features

ItemDecorator introduced with a behaviour consistent with RecyclerView.
MarginPageTransformer introduced to provide an ability to create space between pages (outside of page inset).
CompositePageTransformer introduced to provide an ability to combine multiple PageTransformers.

SAMPLE CODE

myViewPager2.setPageTransformer(new MarginPageTransformer(1500));

Check out my previous answer if you want to implement Carousel using View Pager2

回答2:

MarginPageTransformer cannot help your need.

You must use custom setPageTrarnsformer.

Step 1

Here is my Extension Method for this.

you can check detail in this article Medium article

fun ViewPager2.setShowSideItems(pageMarginPx : Int, offsetPx : Int) {

    clipToPadding = false
    clipChildren = false
    offscreenPageLimit = 3

    setPageTransformer { page, position ->

        val offset = position * -(2 * offsetPx + pageMarginPx)
        if (this.orientation == ViewPager2.ORIENTATION_HORIZONTAL) {
            if (ViewCompat.getLayoutDirection(this) == ViewCompat.LAYOUT_DIRECTION_RTL) {
                page.translationX = -offset
            } else {
                page.translationX = offset
            }
        } else {
            page.translationY = offset
        }
    }

}

Step 2

set pageMarginPx and offsetPx with your use case.

<resources>
    <dimen name="pageMargin">20dp</dimen>
    <dimen name="pagerOffset">30dp</dimen>
    <dimen name="pageMarginAndoffset">50dp</dimen>
</resources>

Step 3

set your side margin of layout item in your xml.

like this

    <androidx.cardview.widget.CardView
            app:cardCornerRadius="12dp"

            android:layout_marginTop="16dp"
            android:layout_marginBottom="16dp"

            android:layout_marginLeft="@dimen/pageMarginAndoffset"
            android:layout_marginRight="@dimen/pageMarginAndoffset"

            android:layout_width="match_parent"
            android:layout_height="match_parent">

回答3:

you can use this code

   viewPager.setPageTransformer(new MarginPageTransformer(margin as PX));

but if you want to use DP you can use the below function for convert PX to DP

 private  int pxToDp(int px) {
    return (int) (px / Resources.getSystem().getDisplayMetrics().density);
}

来源：https://stackoverflow.com/questions/56114430/android-viewpager2-setpagemargin-unresolved

标签

android

carousel

android-viewpager2

Android ViewPager2 setPageMargin unresolved