조각에서 onCreateView 전에 setUserVisibleHint 호출

조각에서 onCreateView 전에 setUserVisibleHint 호출

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나는 거기 에서 일하고 ViewPager사용하고 Fragment있습니다.

조각의 onCreateView () 전에 setUserVisibleHint () 호출

Fragment지원 라이브러리에서 사용 하고 있습니다.android.support.v4.app.Fragment

이것이 도서관의 문제입니까?

어떻게 제거 할 수 있습니까?

편집하다

나는 setUserVisibleHint ()를 재정의하고 그것을 제거하기 위해 super를 호출하지 않습니다.

@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
    //FIXED: setUserVisibleHint() called before onCreateView() in Fragment causes NullPointerException
    //super.setUserVisibleHint(isVisibleToUser);
}

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// create boolean for fetching data
private boolean isViewShown = false;

@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
    super.setUserVisibleHint(isVisibleToUser);
    if (getView() != null) {
        isViewShown = true;
        // fetchdata() contains logic to show data when page is selected mostly asynctask to fill the data
        fetchData();
    } else {
        isViewShown = false;
    }
} 

isViewShown인스턴스 변수를 사용 하여에서 onCreateView()또는에서 데이터를 가져올 지 여부를 결정합니다 setUserVisibleHint().

아래 코드에는 다음에 대한 논리가 포함되어 있습니다 onCreateView().

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.main_layout, container, false);

   // view initialization steps.......

   if (!isViewShown) {
        fetchData();
   } 
   // do other stuff
}

이 코드는 문제를 해결할 것입니다. 내 문제가 해결되면서. :)

이 트릭은 onCreateView()한 페이지에서 다른 페이지로 직접 점프하기 위해 데이터를 가져 오는 반면,보기를 스 와이프하면 setUserVisibleHint()메소드 에서 데이터를 가져옵니다 . :)

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이 로직을 사용할 수 있습니다. 또한 viewDidAppear설정 하여 언제든지 끌 수 있습니다.isVisible = false

public class MyFragment extends Fragment {
    private Boolean isStarted = false;
    private Boolean isVisible = false;

    @Override
    public void onStart() {
        super.onStart();
        isStarted = true;
        if (isVisible && isStarted){
            viewDidAppear();
        }
    }

    @Override
    public void setUserVisibleHint(boolean isVisibleToUser) {
        super.setUserVisibleHint(isVisibleToUser);
        isVisible = isVisibleToUser;
        if (isStarted && isVisible) {
            viewDidAppear();
        }
    }

    public void viewDidAppear() {
       // your logic
    }
}

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최고의 솔루션을 찾았습니다

private boolean isVisible;
private boolean isStarted;

@Override
public void onStart() {
    super.onStart();
    isStarted = true;
    if (isVisible)
        sendRequest(); //your request method
}

@Override
public void onStop() {
    super.onStop();
    isStarted = false;
}

@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
    super.setUserVisibleHint(isVisibleToUser);
    isVisible = isVisibleToUser;
    if (isVisible && isStarted)
        sendRequest(); //your request method
}

fareed namrouti 의 답변 의 개선 된 버전입니다 . 나는 이것을 여러 조건에서 테스트했습니다. 안전합니다.

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@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment, container, false);

    if (getUserVisibleHint()) {
         sendRequest();
    }

    return view;
}

@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
    super.setUserVisibleHint(isVisibleToUser);
    if (isVisibleToUser) {
        if (isResumed()){ 
             sendRequest();
          }
    }
}

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아래는 나를 위해 일했습니다 ....

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState)
{
    //// create class member variable to store view
    viewFrag =inflater.inflate(R.layout.fragment_main_favorite, container, false);

    // Inflate the layout for this fragment
    return viewFrag;
}

그리고 이것을 사용하십시오

 @Override
    public void setUserVisibleHint(boolean visible)
    {
        super.setUserVisibleHint(visible);


            if (visible)
            {

                View v =  viewFrag ;
                if (v == null) {
                    Toast.makeText(getActivity(), "ERROR ", Toast.LENGTH_LONG ).show();
                    return;
                }
            }

    }

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내 SightFragment.java 여기 에 플래그를 다시 설정해야합니다onDestroyView() :

package cc.cubone.turbo.core.app;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.View;

/**
 * Fragment for handling view after it has been created and visible to user for the first time.
 *
 * <p>Specially in {@link android.support.v4.view.ViewPager}, the page will be created beforehand
 * but not be visible to user.
 *
 * <p>Call {@link android.support.v4.view.ViewPager#setOffscreenPageLimit(int)} to set the number of
 * pages that should be retained.
 *
 * Reference:
 * <ul>
 * <li><a href="http://stackoverflow.com/questions/10024739/how-to-determine-when-fragment-becomes-visible-in-viewpager">
 * How to determine when Fragment becomes visible in ViewPager</a>
 * </ul>
 */
public class SightFragment extends Fragment {

    private boolean mUserSeen = false;
    private boolean mViewCreated = false;

    public SightFragment() {
    }

    /*public boolean isUserSeen() {
        return mUserSeen;
    }

    public boolean isViewCreated() {
        return mViewCreated;
    }*/

    @Override
    public void setUserVisibleHint(boolean isVisibleToUser) {
        super.setUserVisibleHint(isVisibleToUser);
        if (!mUserSeen && isVisibleToUser) {
            mUserSeen = true;
            onUserFirstSight();
            tryViewCreatedFirstSight();
        }
        onUserVisibleChanged(isVisibleToUser);
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        // Override this if you want to get savedInstanceState.
        mViewCreated = true;
        tryViewCreatedFirstSight();
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        mViewCreated = false;
        mUserSeen = false;
    }

    private void tryViewCreatedFirstSight() {
        if (mUserSeen && mViewCreated) {
            onViewCreatedFirstSight(getView());
        }
    }

    /**
     * Called when the new created view is visible to user for the first time.
     */
    protected void onViewCreatedFirstSight(View view) {
        // handling here
    }

    /**
     * Called when the fragment's UI is visible to user for the first time.
     *
     * <p>However, the view may not be created currently if in {@link android.support.v4.view.ViewPager}.
     */
    protected void onUserFirstSight() {
    }

    /**
     * Called when the visible state to user has been changed.
     */
    protected void onUserVisibleChanged(boolean visible) {
    }

}

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이 솔루션의 대부분이 작동하지만 직접 상태를 추적 할 필요도 없습니다.

지원 라이브러리의 현재 버전 isResumed()에는 isStarted플래그 를 사용하여 대부분의 사용자가 달성하려는 작업을 수행하는 방법이 있습니다 .

조각이 재개 된 상태이면 true를 반환합니다. 이는 onResume () 및 onPause () 기간 동안에도 마찬가지입니다.

그리고 다음과 같이 쉽습니다.

    @Override
    public void setUserVisibleHint(boolean isVisibleToUser) {
        super.setUserVisibleHint(isVisibleToUser);
        if (isResumed()) {
            updateUi(isVisibleToUser);
        }
    }

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That simple variant work in my code:

@Override
public void onStart() {
    super.onStart();

    if (getUserVisibleHint()) {
        updateUI(); // your logic
    }
}

and

@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
    super.setUserVisibleHint(isVisibleToUser);

    if (isResumed() && isVisibleToUser) {
       updateUI(); // your logic
    }
}

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Create this code in your setUserVisibleHint() :

if(isVisibleToUser && getView() != null){
        isActive = true;
        init();
    }else if(isVisibleToUser && getView() == null){
        isActive = false;
    }else{
        isActive = true;
    }

In your onCreateView() :

public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
if(!isActive){
        init();
    }
}

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BELOW WORKED FOR ME

Please create a global view like this

private View view; 

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
    {
        //Inflate view layout
        view =inflater.inflate(R.layout.your_fragment, container, false);

        // return view
        return view;
    }

and use this

@Override
    public void setUserVisibleHint(boolean isUserVisible)
    {
        super.setUserVisibleHint(isUserVisible);
       //When fragment is visible to user and view is not null then enter here.
            if (isUserVisible && view != null)
            {
               // do your stuff here.
            }
    }

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This is the best solution i found.

    @Override
    public void onCreateView() {
        super.onStart();
        if (getUserVisibilityHint()){
            //do stuff
        }
    }

    @Override
    public void setUserVisibleHint(boolean isVisibleToUser) {
        super.setUserVisibleHint(isVisibleToUser);
        if (isResumed() && isVisibleToUser) {
            //do stuff
        }
    }

참고URL : https://stackoverflow.com/questions/24161160/setuservisiblehint-called-before-oncreateview-in-fragment