117笔记问答要实现Android中的无限滚动广告栏，可以使用ViewPager和FragmentPagerAdapter来实现。下面是一个简单的示例代码：
- 创建一个BannerFragment用于显示广告内容：
public class BannerFragment extends Fragment {
private int[] images = {R.drawable.image1, R.drawable.image2, R.drawable.image3};
private int currentPosition = 0;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_banner, container, false);
ImageView imageView = view.findViewById(R.id.banner_image);
imageView.setImageResource(images[currentPosition]);
return view;
}
public void nextBanner() {
currentPosition++;
if (currentPosition >= images.length) {
currentPosition = 0;
}
ImageView imageView = getView().findViewById(R.id.banner_image);
imageView.setImageResource(images[currentPosition]);
}
}
- 创建一个BannerAdapter用于管理BannerFragment：
public class BannerAdapter extends FragmentPagerAdapter {
public BannerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
return new BannerFragment();
}
@Override
public int getCount() {
return Integer.MAX_VALUE;
}
}
- 在MainActivity中设置ViewPager和BannerAdapter：
public class MainActivity extends AppCompatActivity {
private ViewPager viewPager;
private BannerAdapter bannerAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
viewPager = findViewById(R.id.view_pager);
bannerAdapter = new BannerAdapter(getSupportFragmentManager());
viewPager.setAdapter(bannerAdapter);
// 设置一个定时器来轮播广告
Timer timer = new Timer();
timer.schedule(new TimerTask() {
@Override
public void run() {
runOnUiThread(new Runnable() {
@Override
public void run() {
int currentItem = viewPager.getCurrentItem();
viewPager.setCurrentItem(currentItem + 1);
}
});
}
}, 0, 3000);
}
}
这样就可以实现一个简单的无限滚动广告栏，通过不断切换ViewPager的当前项来实现无限滚动效果。