Android studio 里实现轮播图具体代码

实现轮播图的具体代码可以参考以下步骤：

1. 在布局文件中添加ViewPager和指示器Indicator：

<RelativeLayout
    android:id="@+id/rl_banner"
    android:layout_width="match_parent"
    android:layout_height="200dp">

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

    <LinearLayout
        android:id="@+id/ll_indicator"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="10dp"
        android:orientation="horizontal"/>

</RelativeLayout>

2. 创建一个适配器BannerPagerAdapter继承自PagerAdapter，在其中实现轮播图的数据绑定：

public class BannerPagerAdapter extends PagerAdapter {

    private List<String> mDataList;
    private Context mContext;
    private OnBannerItemClickListener mListener;

    public BannerPagerAdapter(Context context, List<String> dataList, OnBannerItemClickListener listener) {
        mContext = context;
        mDataList = dataList;
        mListener = listener;
    }

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

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

    @NonNull
    @Override
    public Object instantiateItem(@NonNull ViewGroup container, final int position) {
        ImageView imageView = new ImageView(mContext);
        imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
        Glide.with(mContext).load(mDataList.get(position)).into(imageView);
        container.addView(imageView);

        imageView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mListener != null) {
                    mListener.onBannerItemClick(position);
                }
            }
        });

        return imageView;
    }

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

    public interface OnBannerItemClickListener {
        void onBannerItemClick(int position);
    }
}

3. 在Activity或Fragment中初始化ViewPager和Indicator，并设置适配器：

private ViewPager mViewPager;
private LinearLayout mIndicatorLayout;
private List<String> mDataList = new ArrayList<>();
private BannerPagerAdapter mBannerPagerAdapter;
private int mCurrentPosition = 0;

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

    mViewPager = findViewById(R.id.vp_banner);
    mIndicatorLayout = findViewById(R.id.ll_indicator);

    initDataList();
    initIndicator();
    initViewPager();
}

private void initDataList() {
    mDataList.add("http://xxx/1.jpg");
    mDataList.add("http://xxx/2.jpg");
    mDataList.add("http://xxx/3.jpg");
    mDataList.add("http://xxx/4.jpg");
    mDataList.add("http://xxx/5.jpg");
}

private void initIndicator() {
    for (int i = 0; i < mDataList.size(); i++) {
        ImageView imageView = new ImageView(this);
        LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
                LinearLayout.LayoutParams.WRAP_CONTENT,
                LinearLayout.LayoutParams.WRAP_CONTENT);
        params.leftMargin = 10;
        params.rightMargin = 10;
        imageView.setLayoutParams(params);
        imageView.setImageResource(R.drawable.ic_indicator_normal);
        mIndicatorLayout.addView(imageView);
    }
}

private void initViewPager() {
    mBannerPagerAdapter = new BannerPagerAdapter(this, mDataList, new BannerPagerAdapter.OnBannerItemClickListener() {
        @Override
        public void onBannerItemClick(int position) {
            // 轮播图点击事件处理
        }
    });
    mViewPager.setAdapter(mBannerPagerAdapter);
    mViewPager.setCurrentItem(mDataList.size() * 1000);

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

        }

        @Override
        public void onPageSelected(int position) {
            int realPosition = position % mDataList.size();
            mIndicatorLayout.getChildAt(mCurrentPosition).setImageResource(R.drawable.ic_indicator_normal);
            mIndicatorLayout.getChildAt(realPosition).setImageResource(R.drawable.ic_indicator_selected);
            mCurrentPosition = realPosition;
        }

        @Override
        public void onPageScrollStateChanged(int state) {

        }
    });

    mHandler.sendEmptyMessageDelayed(0, 3000);
}

private Handler mHandler = new Handler(new Handler.Callback() {
    @Override
    public boolean handleMessage(Message msg) {
        mViewPager.setCurrentItem(mViewPager.getCurrentItem() + 1);
        mHandler.sendEmptyMessageDelayed(0, 3000);
        return true;
    }
});

通过以上代码，即可在Android Studio里实现轮播图。