Question

我尝试为我的应用程序制作选项卡式片段，但是存在问题。从Android Studio创建选项卡式片段。制作SectionsPagerAdapter。所有好的和我的XML文件都能正常工作，但是当涉及片段源代码时，我的ArchiveALL和ArchiveINS会在同一时间输出。我将标签更改为ArchiveOUT它没有显示任何内容等等。我无法理解，如果我在第一个（ArchiveALL）选项卡上，为什么活动会调用第二个ArchiveINS（）。

这是我的SectionPagerAdapter

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by amrah on 2/28/18.
 */

class SectionsPagerAdapter extends FragmentPagerAdapter {
    private final List<Fragment> ArchiveList = new ArrayList<>();
    private final List<String> titles = new ArrayList<>();
    public void addFragment(Fragment fragment, String title){
        ArchiveList.add(fragment);
        titles.add(title);
    }
    public SectionsPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return titles.get(position);
    }

    @Override
    public Fragment getItem(int position) {
        return ArchiveList.get(position);
    }

    @Override
    public int getCount() {
        return ArchiveList.size();
    }
}

这是我的标签片段

import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

public class ArchiveInfoFragment extends Fragment {
    private SectionsPagerAdapter mSectionsPagerAdapter;


    private ViewPager mViewPager;
    public ArchiveInfoFragment() {
        // Required empty public constructor
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_archive_info, container, false);

    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        mSectionsPagerAdapter = new SectionsPagerAdapter(getActivity().getSupportFragmentManager());
        mViewPager = (ViewPager) view.findViewById(R.id.ArchivePages);
        setupViewAdapter(mViewPager);
        TabLayout tabLayout = (TabLayout) view.findViewById(R.id.user_archives);
        tabLayout.setupWithViewPager(mViewPager);
    }
    private void setupViewAdapter(ViewPager viewPager){
        SectionsPagerAdapter adapter = new SectionsPagerAdapter(getActivity().getSupportFragmentManager());
        adapter.addFragment(new ArchiveAll(), "ALL");
        adapter.addFragment(new ArchiveINS(), "INS");
        adapter.addFragment(new ArchiveOUTS(), "OUTS");
        viewPager.setAdapter(adapter);

    }

}

这些是我的片段：

ArchiveALL片段：

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class ArchiveAll extends Fragment {

    public ArchiveAll() {
        // Required empty public constructor
    }


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View v= inflater.inflate(R.layout.fragment_archive_all, container, false);
        System.out.println("it is ALL fragment ");

        return v;


    }

    @SuppressLint("StaticFieldLeak")
    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

    }
}

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

这是ArchiveINS片段：

public class ArchiveINS extends Fragment {

    public ArchiveINS() {
        // Required empty public constructor
    }


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View v = inflater.inflate(R.layout.fragment_arhcive_in, container, false);
        System.out.println("it is INS fragment ");
        return v;
    }

    @SuppressLint("StaticFieldLeak")
    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
    }
}

和ArchiveOUTS片段：

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class ArchiveOUTS extends Fragment {

    public ArchiveOUTS() {
        // Required empty public constructor
    }


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View v= inflater.inflate(R.layout.fragment_archive_out, container, false);
        System.out.println("It is OUTS fragment");
        return v;
    }

    @SuppressLint("StaticFieldLeak")
    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

    }
}

最后，当我从NavigationDrawer菜单中打开ArchiveInfoFragment时，它会出局： I / System.out：它是所有片段 I / System.out：它是INS片段

Answer 1

我找到了解决方案。实际上它不是问题，因为ViewPager本身加载了位于+和 - 位置的类。因此，他们没有使程序工作到很晚。而不是FragmentPagerAdapter使用FragmentStatePagerAdapter会有所不同。在FragmentStatePagerAdapter类中，在更改之前没有加载类，它只加载用户使用的类。

虽然没有调用，但碎片可以在选项卡式活动上工作

1 个答案: