android实现轮播图整体代码

以下是 Android 实现轮播图的整体代码示例：

1. 在布局文件中添加 ViewPager 和指示器的布局：

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <android.support.v4.view.ViewPager
        android:id="@+id/viewPager"
        android:layout_width="match_parent"
        android:layout_height="200dp" />

    <LinearLayout
        android:id="@+id/indicatorLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:orientation="horizontal"
        android:padding="10dp" />

</RelativeLayout>

2. 创建 Adapter 类，继承自 PagerAdapter，并实现其中的方法：

public class ImagePagerAdapter extends PagerAdapter {
    private List<Integer> mImageIds;
    private Context mContext;

    public ImagePagerAdapter(Context context, List<Integer> imageIds) {
        mContext = context;
        mImageIds = imageIds;
    }

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

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

    @NonNull
    @Override
    public Object instantiateItem(@NonNull ViewGroup container, int position) {
        ImageView imageView = new ImageView(mContext);
        imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
        imageView.setImageResource(mImageIds.get(position));
        container.addView(imageView);
        return imageView;
    }

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

3. 在 Activity 或 Fragment 中设置 ViewPager 和指示器：

List<Integer> imageIds = new ArrayList<>();
imageIds.add(R.drawable.image1);
imageIds.add(R.drawable.image2);
imageIds.add(R.drawable.image3);

ViewPager viewPager = findViewById(R.id.viewPager);
ImagePagerAdapter adapter = new ImagePagerAdapter(this, imageIds);
viewPager.setAdapter(adapter);

LinearLayout indicatorLayout = findViewById(R.id.indicatorLayout);
for (int i = 0; i < imageIds.size(); i++) {
    ImageView indicator = new ImageView(this);
    LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(
            LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
    lp.setMargins(10, 0, 10, 0);
    indicator.setLayoutParams(lp);
    indicator.setImageResource(R.drawable.indicator_selector);
    indicatorLayout.addView(indicator);
}

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 < indicatorLayout.getChildCount(); i++) {
            ImageView indicator = (ImageView) indicatorLayout.getChildAt(i);
            if (i == position) {
                indicator.setSelected(true);
            } else {
                indicator.setSelected(false);
            }
        }
    }

    @Override
    public void onPageScrollStateChanged(int state) {

    }
});

viewPager.setCurrentItem(0);
((ImageView) indicatorLayout.getChildAt(0)).setSelected(true);

4. 在 res/drawable 文件夹中添加指示器的 Selector 文件，例如 indicator_selector.xml：

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/indicator_selected" android:state_selected="true" />
    <item android:drawable="@drawable/indicator_unselected" />
</selector>

其中，indicator_selected 和 indicator_unselected 分别是选中和未选中状态下的指示器图片。