如何确定Fragment在ViewPager中变得可见？

ViewPager2 + FragmentStateAdapter + onResume() (in Fragment) solve the problem

Old Answer (deprecated)

要检测 Fragment 中的 ViewPager 可见，我很确定 only using setUserVisibleHint is not enough.
这是我检查一个片段是否可见或不可见的方案。首先，当启动viewpager时，在页面之间切换，转到另一个活动/片段/背景/前景`。

public class BaseFragmentHelpLoadDataWhenVisible extends Fragment {
    protected boolean mIsVisibleToUser; // you can see this variable may absolutely <=> getUserVisibleHint() but it not. Currently, after many test I find that
     * This method will be called when viewpager creates fragment and when we go to this fragment background or another activity or fragment
     * NOT called when we switch between each page in ViewPager
    @Override
    public void onStart() {
        super.onStart();
        if (mIsVisibleToUser) {
            onVisible();
    @Override
    public void onStop() {
        super.onStop();
        if (mIsVisibleToUser) {
            onInVisible();
     * This method will called at first time viewpager created and when we switch between each page
     * NOT called when we go to background or another activity (fragment) when we go back
    @Override
    public void setUserVisibleHint(boolean isVisibleToUser) {
        super.setUserVisibleHint(isVisibleToUser);
        mIsVisibleToUser = isVisibleToUser;
        if (isResumed()) { // fragment have created
            if (mIsVisibleToUser) {
                onVisible();
            } else {
                onInVisible();
    public void onVisible() {
        Toast.makeText(getActivity(), TAG + "visible", Toast.LENGTH_SHORT).show();
    public void onInVisible() {
        Toast.makeText(getActivity(), TAG + "invisible", Toast.LENGTH_SHORT).show();
你可以仔细检查下面的logcat，然后我想你可能会知道为什么这个解决方案会有效

第一次发射
Fragment1: setUserVisibleHint: isVisibleToUser=false isResumed=false
Fragment2: setUserVisibleHint: isVisibleToUser=false isResumed=false
Fragment3: setUserVisibleHint: isVisibleToUser=false isResumed=false
Fragment1: setUserVisibleHint: isVisibleToUser=true isResumed=false // AT THIS TIME isVisibleToUser=true but fragment still not created. If you do something with View here, you will receive exception
Fragment1: onCreateView
Fragment1: onStart mIsVisibleToUser=true
Fragment2: onCreateView
Fragment3: onCreateView
Fragment2: onStart mIsVisibleToUser=false
Fragment3: onStart mIsVisibleToUser=false
转到第2页
Fragment1: setUserVisibleHint: isVisibleToUser=false isResumed=true
Fragment2: setUserVisibleHint: isVisibleToUser=true isResumed=true
转到第3页
Fragment2: setUserVisibleHint: isVisibleToUser=false isResumed=true
Fragment3: setUserVisibleHint: isVisibleToUser=true isResumed=true
转到背景。
Fragment1: onStop mIsVisibleToUser=false
Fragment2: onStop mIsVisibleToUser=false
Fragment3: onStop mIsVisibleToUser=true
Go to foreground
Fragment1: onStart mIsVisibleToUser=false
Fragment2: onStart mIsVisibleToUser=false
Fragment3: onStart mIsVisibleToUser=true
DEMO project here
Hope it help