viewpager setonpagechangelistener已弃用

Question

今天，我试图设置viewpager.setonpagechangelistener，但我发现它不推荐使用。

Answer 1

>

如果需要，创建接口；

public interface FragmentLifecycle {
public void onPauseFragment();
public void onResumeFragment();

}

在viewpager中的每个片段中实现接口，如图所示

 public class FragmentCast extends Fragment implements FragmentLifecycle {
  @Override
    public void onPauseFragment() {
        Log.i(TAG, "onPauseFragment()");
        Toast.makeText(getActivity(), "onPauseFragment():" + TAG, Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onResumeFragment() {
        Log.i(TAG, "onResumeFragment()");
        Toast.makeText(getActivity(), "onResumeFragment():" + TAG, Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

    }

    @Override
    public void onPageSelected(int position) {


        FragmentLifecycle   fragmentLifecycleToShow =(FragmentLifecycle) viewPager.getAdapter().instantiateItem(viewPager, viewPager.getCurrentItem());
        fragmentLifecycleToShow.onResumeFragment();

        FragmentLifecycle   fragmentLifecycleToHide =(FragmentLifecycle) viewPager.getAdapter().instantiateItem(viewPager, currentPosition);
        fragmentLifecycleToHide.onPauseFragment();

        currentPosition = position;
    }

    @Override
    public void onPageScrollStateChanged(int state) {

    }
});