viewpager实现banner轮播的平滑过渡_android viewpager怎么平滑过渡-优快云博客

本文链接：https://blog.youkuaiyun.com/tiankongcheng6/article/details/78837334

本文介绍了如何使用viewpager在Android应用中实现Banner轮播的效果，包括适配器的编写和在activity中的具体配置，确保轮播的平滑过渡。

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1.适配器代码

public class VPAdapter extends PagerAdapter {

    private List<ImageView> list;
    private Context context;
    private BannerClick bannerClick;

    public VPAdapter(List<ImageView> list, Context context) {
        this.list = list;
        this.context = context;
    }

    @Override
    public int getCount() {
        return Integer.MAX_VALUE;
    }

    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view == object;
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        final int newposition = position % list.size();
        ImageView iv = list.get(newposition);
        iv.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
               bannerClick.onBannerClickListener(newposition);
            }
        });
        container.addView(iv);
        return iv;
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        ImageView imageView = (ImageView) object;
        container.removeView(imageView);
    }

    public interface BannerClick{
        void onBannerClickListener(int psn);
    }

    public void setOnBannerClickListener(BannerClick bannerClickListener){
        bannerClick = bannerClickListener;
    }

}

主要代码在这里

@Override
public int getCount() {
    return Integer.MAX_VALUE;
}

获取总数的时候返回最大

@Override
public Object instantiateItem(ViewGroup container, int position) {
    final int newposition = position % list.size();
    ImageView iv = list.get(newposition);
    iv.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
           bannerClick.onBannerClickListener(newposition);
        }
    });
    container.addView(iv);
    return iv;
}

实例化item的时候用余数来计算

2.activity中

计时器计时轮播

private void autoMove(){
    timer = new Timer();
    timerTask = new TimerTask() {
        @Override
        public void run() {
            if (isSwitchBanner){
                handlerPlus.sendEmptyMessage(0);
            }
        }
    };
    timer.schedule(timerTask , 0 , 3000);
}

handler处理接收

private class HandlerPlus extends WeakHandler{

    public HandlerPlus(Object object) {
        super(object);
    }

    @Override
    public void handleMessage(Message msg) {
        super.handleMessage(msg);
        Fragment fragment = (Fragment) handlerPlus.getObject();
        if (fragment != null){
            switch (msg.what){
                case 0:
                    laundry_vp.setCurrentItem(laundry_vp.getCurrentItem() + 1);
                    break;
            }
        }
    }
}