android简单轮播器代码,简单实现android轮播图

以下是一个简单的Android轮播器的实现代码：

1. 在布局文件中添加ViewPager和指示器（Indicator）：

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="200dp">

    <android.support.v4.view.ViewPager
        android:id="@+id/viewPager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

    <LinearLayout
        android:id="@+id/indicator"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:orientation="horizontal"/>

</RelativeLayout>

2. 创建Adapter和ViewHolder：

public class MyPagerAdapter extends PagerAdapter {

    private Context context;
    private List<Integer> imageList;

    public MyPagerAdapter(Context context, List<Integer> imageList) {
        this.context = context;
        this.imageList = imageList;
    }

    @Override
    public int getCount() {
        return imageList.size();
    }

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

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        View view = LayoutInflater.from(context).inflate(R.layout.item_pager, null);
        ImageView imageView = view.findViewById(R.id.imageView);
        imageView.setImageResource(imageList.get(position));
        container.addView(view);
        return view;
    }

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

}

public class MyViewHolder extends RecyclerView.ViewHolder {

    public ImageView imageView;

    public MyViewHolder(View itemView) {
        super(itemView);
        imageView = itemView.findViewById(R.id.imageView);
    }

}

3. 在Activity中初始化ViewPager和指示器：

private ViewPager viewPager;
private LinearLayout indicator;

private List<Integer> imageList;
private List<ImageView> indicatorList;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    viewPager = findViewById(R.id.viewPager);
    indicator = findViewById(R.id.indicator);

    imageList = new ArrayList<>();
    imageList.add(R.drawable.image1);
    imageList.add(R.drawable.image2);
    imageList.add(R.drawable.image3);

    indicatorList = new ArrayList<>();
    for (int i = 0; i < imageList.size(); i++) {
        ImageView imageView = new ImageView(this);
        imageView.setImageResource(R.drawable.indicator_selector);
        LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,
                LinearLayout.LayoutParams.WRAP_CONTENT);
        params.setMargins(10, 0, 10, 0);
        indicator.addView(imageView, params);
        indicatorList.add(imageView);
    }

    MyPagerAdapter adapter = new MyPagerAdapter(this, imageList);
    viewPager.setAdapter(adapter);
    viewPager.setCurrentItem(0);
    indicatorList.get(0).setSelected(true);

    viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

        }

        @Override
        public void onPageSelected(int position) {
            for (int i = 0; i < indicatorList.size(); i++) {
                indicatorList.get(i).setSelected(false);
            }
            indicatorList.get(position).setSelected(true);
        }

        @Override
        public void onPageScrollStateChanged(int state) {

        }
    });
}

这是一个简单的轮播器实现，但是它还有很多可以改进的地方，比如使用ViewPager2、使用更加灵活的Indicator等。