Java 安卓系统：；onCreatedView“；每次回去时都会打电话，并且；setUserVisibleHint"；不叫

在我的android应用程序中，我有一个ViewPager和5个片段。我以前使用过

viewPager.setCurrentItem（）

导航，但是导航动画的要求已经改变；例如，在一些片段中，当调用前一个片段时，我们被要求不要显示返回（从左到右动画），而是向用户显示他们移动到下一个片段（从右到左动画）。例如，在某些情况下，用户必须一次又一次地插入相同的数据，因此我们没有为这些数据创建新的Fragmnet，而是重新使用我们创建的现有Fragmnet-因此当

viewPager.setCurrentItem（）

调用后面的片段时（例如：我们现在在第20个片段中，我们调用第10个片段）它返回并显示从左到右的动画

现在我们不使用

viewPager.setCurrentItem（）

方法导航，而是使用

FragmentTransaction

。然而，我们并没有从ViewPager中删除这些片段，希望用最少的工作量来完成这项工作（当这个需求出现时，我们正处于项目的末尾）

但是当我们使用

FragmentTransaction

时，我们现在有了一个新问题。当我们回来时，Fragmnet的

onCreateView

总是被调用！当我们使用

viewPager.setCurrentItem（）

时，没有发生这种情况。我们的许多代码应该只运行一次，它们都在这个

onCreateView

中

另一个问题是

setUserVisibleHint（）

仅在第一个片段中调用，而且也仅在初始运行时调用！每次显示fragmnet时应该运行的所有代码都位于此方法中

下面是一个示例代码，它演示了我们的问题

MainActivity.java

public class MainActivity extends FragmentActivity {

    private ViewPager viewPager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        viewPager=(ViewPager)findViewById(R.id.viewPager);
        viewPager.setAdapter(new MyPagerAdapter2(getSupportFragmentManager()));
        viewPager.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                if (viewPager.getCurrentItem() == 0) {
                    return true;
                }

                if (viewPager.getCurrentItem() == 1) {
                    return true;
                }

                if (viewPager.getCurrentItem() == 2) {
                    return true;
                }

                if (viewPager.getCurrentItem() == 3) {
                    return true;
                }

                if (viewPager.getCurrentItem() == 4) {
                    return true;
                }

                return false;
            }
        });



    }

    private class MyPagerAdapter2 extends FragmentPagerAdapter {

        public MyPagerAdapter2(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int pos) {
            switch(pos) {

                case 0: return FirstFragment1.newInstance("FirstFragment_1");
                case 1: return SecondFragment1.newInstance("SecondFragment_1");
                case 2: return ThirdFragment1.newInstance("ThirdFragment_1");
                case 3: return FourthFragment1.newInstance("FourthFragment_1");
                case 4: return FifthFragment1.newInstance("FifthFragment_1");
                default: return FirstFragment1.newInstance("DefaultFragment_1");
            }
        }

        @Override
        public int getCount() {
            return 1;
        }
    }

    public void setCurrentItem(int which) {
        if(viewPager != null && which >= 0 && which <= 4) {
            viewPager.setCurrentItem(which);
        }
    }
}

public class FirstFragment1 extends Fragment {

    TextView textView;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.first_frag_1, container, false);

        TextView tv = (TextView) v.findViewById(R.id.tvFragFirst);
        tv.setText("FRAGMENT 01");

        textView=(TextView)v.findViewById(R.id.textView1);
        textView.setText("Fragment Name : - 01");

        Log.d("FRAGMENT_01", "ON_CREATE");

        Button button1 = (Button) v.findViewById(R.id.nextButton);
        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (getActivity() != null) {

                    FragmentManager fragmentManager=getFragmentManager();
                    FragmentTransaction transaction = fragmentManager.beginTransaction();
                    transaction.setCustomAnimations(R.anim.from_right, R.anim.to_left);
                    transaction.replace(R.id.firstFragment, new SecondFragment1());
                    transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
                    transaction.addToBackStack(null);
                    transaction.commit();
                }
            }
        });

        return v;
    }

    public static FirstFragment1 newInstance(String text) {

        FirstFragment1 f = new FirstFragment1();
        Bundle b = new Bundle();
        b.putString("msg", text);

        f.setArguments(b);

        return f;
    }

    @Override
    public void setUserVisibleHint(boolean isVisibleToUser) {
        super.setUserVisibleHint(isVisibleToUser);
        if (isVisibleToUser) {
            Activity a = getActivity();
            if (a != null) a.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LOCKED);

        //    textView.setText("Fragment Name : - 01");
            Log.d("FRAGMENT_01", "VISIBLE_HINT");

        }
    }

}

public class SecondFragment1 extends Fragment {

    TextView textView;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.second_frag_1, container, false);

        TextView tv = (TextView) v.findViewById(R.id.tvFragSecond);
        tv.setText("FRAGMENT 03");

        textView=(TextView)v.findViewById(R.id.textView2);
        textView.setText("Fragment Name : - 02");

        Log.d("FRAGMENT_02", "ON_CREATE");

        Button button=(Button)v.findViewById(R.id.printButton);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                if(getActivity() != null) {

                    FragmentManager fragmentManager=getFragmentManager();
                    FragmentTransaction transaction = fragmentManager.beginTransaction();
                    transaction.setCustomAnimations(R.anim.from_right, R.anim.to_left);
                    transaction.replace(R.id.secondFrag, new FirstFragment1());
                    transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
                    transaction.addToBackStack(null);
                    transaction.commit();
                }

            }
        });

        Button button1=(Button)v.findViewById(R.id.nextButton);
        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (getActivity() != null) {

                    FragmentManager fragmentManager=getFragmentManager();
                    FragmentTransaction transaction = fragmentManager.beginTransaction();
                    transaction.setCustomAnimations(R.anim.from_right, R.anim.to_left);
                    transaction.replace(R.id.secondFrag, new ThirdFragment1());
                    transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
                    transaction.addToBackStack(null);
                    transaction.commit();
                }
            }
        });

        return v;
    }

    public static SecondFragment1 newInstance(String text) {

        SecondFragment1 f = new SecondFragment1();
        Bundle b = new Bundle();
        b.putString("msg", text);

        f.setArguments(b);

        return f;
    }

    @Override
    public void setUserVisibleHint(boolean isVisibleToUser) {
        super.setUserVisibleHint(isVisibleToUser);
        if(isVisibleToUser) {
            Activity a = getActivity();
            if(a != null) a.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LOCKED);

            Log.d("FRAGMENT_02","VISIBLE_HINT");


        }
    }

}

SecondFragment1.java

public class MainActivity extends FragmentActivity {

    private ViewPager viewPager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        viewPager=(ViewPager)findViewById(R.id.viewPager);
        viewPager.setAdapter(new MyPagerAdapter2(getSupportFragmentManager()));
        viewPager.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                if (viewPager.getCurrentItem() == 0) {
                    return true;
                }

                if (viewPager.getCurrentItem() == 1) {
                    return true;
                }

                if (viewPager.getCurrentItem() == 2) {
                    return true;
                }

                if (viewPager.getCurrentItem() == 3) {
                    return true;
                }

                if (viewPager.getCurrentItem() == 4) {
                    return true;
                }

                return false;
            }
        });



    }

    private class MyPagerAdapter2 extends FragmentPagerAdapter {

        public MyPagerAdapter2(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int pos) {
            switch(pos) {

                case 0: return FirstFragment1.newInstance("FirstFragment_1");
                case 1: return SecondFragment1.newInstance("SecondFragment_1");
                case 2: return ThirdFragment1.newInstance("ThirdFragment_1");
                case 3: return FourthFragment1.newInstance("FourthFragment_1");
                case 4: return FifthFragment1.newInstance("FifthFragment_1");
                default: return FirstFragment1.newInstance("DefaultFragment_1");
            }
        }

        @Override
        public int getCount() {
            return 1;
        }
    }

    public void setCurrentItem(int which) {
        if(viewPager != null && which >= 0 && which <= 4) {
            viewPager.setCurrentItem(which);
        }
    }
}

public class FirstFragment1 extends Fragment {

    TextView textView;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.first_frag_1, container, false);

        TextView tv = (TextView) v.findViewById(R.id.tvFragFirst);
        tv.setText("FRAGMENT 01");

        textView=(TextView)v.findViewById(R.id.textView1);
        textView.setText("Fragment Name : - 01");

        Log.d("FRAGMENT_01", "ON_CREATE");

        Button button1 = (Button) v.findViewById(R.id.nextButton);
        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (getActivity() != null) {

                    FragmentManager fragmentManager=getFragmentManager();
                    FragmentTransaction transaction = fragmentManager.beginTransaction();
                    transaction.setCustomAnimations(R.anim.from_right, R.anim.to_left);
                    transaction.replace(R.id.firstFragment, new SecondFragment1());
                    transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
                    transaction.addToBackStack(null);
                    transaction.commit();
                }
            }
        });

        return v;
    }

    public static FirstFragment1 newInstance(String text) {

        FirstFragment1 f = new FirstFragment1();
        Bundle b = new Bundle();
        b.putString("msg", text);

        f.setArguments(b);

        return f;
    }

    @Override
    public void setUserVisibleHint(boolean isVisibleToUser) {
        super.setUserVisibleHint(isVisibleToUser);
        if (isVisibleToUser) {
            Activity a = getActivity();
            if (a != null) a.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LOCKED);

        //    textView.setText("Fragment Name : - 01");
            Log.d("FRAGMENT_01", "VISIBLE_HINT");

        }
    }

}

public class SecondFragment1 extends Fragment {

    TextView textView;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.second_frag_1, container, false);

        TextView tv = (TextView) v.findViewById(R.id.tvFragSecond);
        tv.setText("FRAGMENT 03");

        textView=(TextView)v.findViewById(R.id.textView2);
        textView.setText("Fragment Name : - 02");

        Log.d("FRAGMENT_02", "ON_CREATE");

        Button button=(Button)v.findViewById(R.id.printButton);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                if(getActivity() != null) {

                    FragmentManager fragmentManager=getFragmentManager();
                    FragmentTransaction transaction = fragmentManager.beginTransaction();
                    transaction.setCustomAnimations(R.anim.from_right, R.anim.to_left);
                    transaction.replace(R.id.secondFrag, new FirstFragment1());
                    transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
                    transaction.addToBackStack(null);
                    transaction.commit();
                }

            }
        });

        Button button1=(Button)v.findViewById(R.id.nextButton);
        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (getActivity() != null) {

                    FragmentManager fragmentManager=getFragmentManager();
                    FragmentTransaction transaction = fragmentManager.beginTransaction();
                    transaction.setCustomAnimations(R.anim.from_right, R.anim.to_left);
                    transaction.replace(R.id.secondFrag, new ThirdFragment1());
                    transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
                    transaction.addToBackStack(null);
                    transaction.commit();
                }
            }
        });

        return v;
    }

    public static SecondFragment1 newInstance(String text) {

        SecondFragment1 f = new SecondFragment1();
        Bundle b = new Bundle();
        b.putString("msg", text);

        f.setArguments(b);

        return f;
    }

    @Override
    public void setUserVisibleHint(boolean isVisibleToUser) {
        super.setUserVisibleHint(isVisibleToUser);
        if(isVisibleToUser) {
            Activity a = getActivity();
            if(a != null) a.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LOCKED);

            Log.d("FRAGMENT_02","VISIBLE_HINT");


        }
    }

}

正如您在代码中看到的，我们使用下面的代码在片段之间导航。（下面的代码显示从第一个fragmnet导航到第二个fragmnet）

---

查看我们的代码，并考虑到我们也添加了

ViewPager

，我们如何确保

onCreateView

只调用一次，并且每次显示片段时都调用

setUserVisibleHint

方法和您想要的代码应该每次在onCreateView（）中调用

调用setUserVisibleHint时会遇到挑战。请尝试viewPager.setOffscreenPageLimit（5）；并使用setMenuVisibility方法，如果您通过通知在任何片段上启动应用程序

@Override
public void setMenuVisibility(boolean menuVisible) {
    super.setMenuVisibility(menuVisible);
    if(menuVisible &&  isResumed()){
       // do  your work here
    }
    if(!isResumed()){
       // do your work when Activity is created 
    }
}

---

onCreate（）在每次看到片段时都会被调用当您滑动viewpager时，它不会被一次又一次调用。我没有滑动viewpager，我使用按钮单击来更改片段流。