// 儲存之前的介面，否則會重新呼叫onCreateView
    viewPager.setOffscreenPageLimit(fragmentList.size());

fragment程式碼：

public class MyFragment extends Fragment {
    private boolean isViewCreate;//view是否已建立
    private boolean isViewVisible;//fragment是否可見
    private int index;

    public static MyFragment newInstance
 
(int index) {
        Bundle args = new Bundle();
        args.putInt("index", index);
        MyFragment fragment = new MyFragment();
        fragment.setArguments(args);
        return fragment;
    }

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View inflate = inflater.inflate(R.layout.fragment_my, container, false
 
);
        index = getArguments().getInt("index");
        Log.d("test", "onCreateView===================================" + index);
        ((TextView) inflate.findViewById(R.id.tv_info)).setText("fragment" + index);
        return inflate;
    }

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super
 
.onViewCreated(view, savedInstanceState);
        Log.d("test", "onViewCreated===================================" + index);
        isViewCreate = true;
        lazyLoad();
    }

    @Override
    public void setUserVisibleHint(boolean isVisibleToUser) {
        super.setUserVisibleHint(isVisibleToUser);
        Log.d("test", "setUserVisibleHint===================================" + index);
        if (isVisibleToUser) {
            isViewVisible = true;
            lazyLoad();
        } else {
            isViewVisible = false;
        }
    }

    private void lazyLoad() {
        if (isViewCreate && isViewVisible) {
            Log.d("test", "lazyLoad===================================" + index);
        }
    }
}