一、使用com.youth.banner报错

报错：llegalStateException: Pages must fill the whole ViewPager2 (use match_parent)

292dd935fbd1b3e3fcbb4583c8e7592.png

二、解决：

1、解决：必须指定view 的宽和高是MATCH_PARENT

   View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.layout_custom_banner_view, null, false);
    //注意，必须设置为match_parent，这个是viewpager2强制要求的
   ViewGroup.LayoutParams params = (ViewGroup.LayoutParams) new ViewGroup.LayoutParams(
                ViewGroup.LayoutParams.MATCH_PARENT,
                ViewGroup.LayoutParams.MATCH_PARENT);
        view.setLayoutParams(params);

注意，必须设置为match_parent，这个是viewpager2强制要求的.

2、完整代码

/**
 * 自定义布局，图片
 */
public class ImageAdapter extends BannerAdapter<BannerBean, ImageHolder> {
    MyChangeInterface myChangeInterface;

    public ImageAdapter(Context context, List<BannerBean> mDatas) {

        //设置数据，也可以调用banner提供的方法,或者自己在adapter中实现
        super(mDatas);
    }


    /**
     * 创建ViewHolder，可以用viewType这个字段来区分不同的ViewHolder
     *
     * @param parent
     * @param viewType
     * @return
     */
    @Override
    public ImageHolder onCreateHolder(ViewGroup parent, int viewType) {
//        ImageView imageView = new ImageView(parent.getContext());
//        //注意，必须设置为match_parent，这个是viewpager2强制要求的
//        ViewGroup.LayoutParams params = (ViewGroup.LayoutParams) new ViewGroup.LayoutParams(
//                ViewGroup.LayoutParams.MATCH_PARENT,
//                ViewGroup.LayoutParams.MATCH_PARENT);
//        imageView.setLayoutParams(params);
//        //设置左右间距
//        imageView.setPadding(15, 0, 15, 0);
//        imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
//        return new ImageHolder(imageView);
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.layout_custom_banner_view, null, false);
        ViewGroup.LayoutParams params = (ViewGroup.LayoutParams) new ViewGroup.LayoutParams(
                ViewGroup.LayoutParams.MATCH_PARENT,
                ViewGroup.LayoutParams.MATCH_PARENT);
        view.setLayoutParams(params);
        return new ImageHolder(view);
    }


    @Override
    public void onBindView(ImageHolder holder, BannerBean data, int position, int size) {
        ImageView ivPic = holder.view.findViewById(R.id.iv_pic);
        GlideUtils.INSTANCE.loadRoundedRectangAllUrl(holder.view.getContext(), data.getUrl(), ivPic, 6);
    }


    public interface MyChangeInterface {
        public void MyChangeInterface(int position);
    }
}

三、com.youth.banner.Banner的下方替换图片的指示器有bug，自己重写了一个

效果图.png

//依赖的版本
implementation 'io.github.youth5201314:banner:2.2.1'

1、指示器的xml

    <com.youth.banner.Banner
                android:id="@+id/banner"
                android:layout_width="match_parent"
                android:layout_height="@dimen/ui_dp_308"
                android:layout_marginTop="@dimen/ui_dp_20"
                app:banner_indicator_normal_color="@android:color/white"
                app:banner_indicator_selected_color="@color/colorPrimary"
                app:banner_radius="5dp"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toBottomOf="@+id/tv_banner_title"
                app:layout_goneMarginTop="@dimen/ui_dp_40" />

            <androidx.recyclerview.widget.RecyclerView
                android:id="@+id/rv_indicator"
                android:layout_width="wrap_content"
                android:layout_height="@dimen/ui_dp_10"
                android:layout_marginTop="@dimen/ui_dp_15"
                app:layout_constraintEnd_toEndOf="@+id/banner"
                app:layout_constraintStart_toStartOf="@+id/banner"
                app:layout_constraintTop_toBottomOf="@+id/banner" />

2、指示器的代码

  /**
     * 初始化banner
     */
    private fun initBanner() {
        var url1 = "https://pic.lvmama.com/uploads/pc/place2/2017-11-24/19e96e3c-ba34-4dc4-8b17-62b3aa595cf9.jpg"
        var url2 = "https://img0.baidu.com/it/u=3358848204,1936258606&fm=253&fmt=auto&app=120&f=JPEG?w=1421&h=800"
        var list = mutableListOf<BannerBean>()
        list.add(BannerBean(url1,true))
        list.add(BannerBean(url2,false))
        list.add(BannerBean(url1,false))
        list.add(BannerBean(url2,false))
        list.add(BannerBean(url1,false))
        mViewBind.banner.setAdapter(ImageAdapter(context, list))

        //添加魅族效果
        mViewBind.banner.setBannerGalleryMZ(70)
        mViewBind.banner.setOnBannerListener { any, position ->
            MyToash.Log("lyy", "-----点击事件:" + position)
        }

        //banner的事件监听
        mViewBind.banner.addOnPageChangeListener(object : OnPageChangeListener {
            override fun onPageScrolled(
                position: Int,
                positionOffset: Float,
                positionOffsetPixels: Int
            ) {
            }

            override fun onPageSelected(position: Int) {
                //更新下方指示器的状态
                list?.forEach {
                    it.isSelect = false
                }
                val bean = list.get(position)
                bean.isSelect = true
                //更新下方指示器
                indicatorAdapter.notifyDataSetChanged()
            }
            override fun onPageScrollStateChanged(state: Int) {
                //MyToash.Log("lyy", "-----onPageScrollStateChanged:" + state)
            }
        })

        //指示器的adapter
        mViewBind.rvIndicator.apply {
            var linearLayoutManager = LinearLayoutManager(context)
            linearLayoutManager.orientation = LinearLayoutManager.HORIZONTAL
            layoutManager = linearLayoutManager
            adapter = indicatorAdapter
        }
        indicatorAdapter.setList(list)
    }

3、IndicatorAdapter的代码：

class IndicatorAdapter:BaseQuickAdapter<BannerBean,BaseDataBindingHolder<ItemIndicatorBinding>>(R.layout.item_indicator) {
    override fun convert(holder: BaseDataBindingHolder<ItemIndicatorBinding>, item: BannerBean) {


        holder.dataBinding?.apply{
            if (item.isSelect){
                ivDot.setImageResource(R.drawable.white_radius_new)
            }else{
                ivDot.setImageResource(R.drawable.gray_radius_new)
            }

        }

    }
}