如何制作新的 Fragment onTabSelected 来刷新我的内容？

Question

我正在尝试刷新我的片段，以便我可以向用户提供新信息。基本上我在做一个应用程序来制作锦标赛。我的应用程序上有 3 个选项卡，第一个选项卡允许用户添加人员，第二个选项卡允许用户创建锦标赛，最后一个选项卡向用户显示分数。

但是我遇到了一个问题，当我从第一个选项卡中删除用户并转到第二个选项卡时，我的内容没有更新，我真的希望它更新，我很难创建一个新的片段它被选中或在被选中时尝试刷新它，但我是 android 的新手，我真的不知道该怎么做。

有什么想法吗？

这是我的 MainActivity 代码：

public class MainActivity extends AppCompatActivity{
    // Declaring Your View and Variables
    Toolbar toolbar;
    ViewPager viewPager;
    ViewPagerAdapter adapter;
    TabLayout tabLayout;
    CharSequence Titles[]={"Participantes","Torneio","Classificação"};
    int Numboftabs =3;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        toolbar = (Toolbar) findViewById(R.id.tool_bar);
        viewPager = (ViewPager) findViewById(R.id.viewPager);
        tabLayout = (TabLayout)findViewById(R.id.tabLayout);


        // Creating The Toolbar and setting it as the Toolbar for the activity
        setSupportActionBar(toolbar);
        // Creating The ViewPagerAdapter and Passing Fragment Manager, Titles fot the Tabs and Number Of Tabs.
        adapter =  new ViewPagerAdapter(getSupportFragmentManager(),Titles,Numboftabs);
        // Assigning ViewPager View and setting the adapter
        viewPager.setAdapter(adapter);


        tabLayout.setupWithViewPager(viewPager);
        tabLayout.setSelectedTabIndicatorColor(getResources().getColor(R.color.colorTextIcons));
        tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                //should i refresh my tab here?
                // how do i do that ?
            }


            @Override
            public void onTabUnselected(TabLayout.Tab tab) {

            }

            @Override
            public void onTabReselected(TabLayout.Tab tab) {

            }
        });
    }



    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }
        if (id == R.id.action_info) {
            Toast.makeText(getApplicationContext(), "Contacto: Juniortalisson16@gmail.com", Toast.LENGTH_LONG).show();
            return true;
        }
        return super.onOptionsItemSelected(item);
    }


}

这是我的 ViewPageAdapter 代码：

public class ViewPagerAdapter extends FragmentStatePagerAdapter {

    CharSequence Titles[]; // This will Store the Titles of the Tabs which are Going to be passed when ViewPagerAdapter is created
    int NumbOfTabs; // Store the number of tabs, this will also be passed when the ViewPagerAdapter is created


    // Build a Constructor and assign the passed Values to appropriate values in the class
    public ViewPagerAdapter(FragmentManager fm,CharSequence mTitles[], int mNumbOfTabsumb) {
        super(fm);

        this.Titles = mTitles;
        this.NumbOfTabs = mNumbOfTabsumb;

    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        super.destroyItem(container, position, object);
        FragmentManager manager = ((Fragment) object).getFragmentManager();
        FragmentTransaction trans = manager.beginTransaction();
        trans.remove((Fragment) object);
        trans.commit();
    }


    //This method return the fragment for the every position in the View Pager
    @Override
    public Fragment getItem(int position) {

        switch(position) {// if the position is 0 we are returning the First tab
            case 0:
            Tab1 tab1 = new Tab1();
            return tab1;
            case 1:
            Tab2 tab2 = new Tab2();
            return tab2;
            case 2:
            Tab3 tab3 = new Tab3();
            return tab3;
            default:
                return null;
        }


    }

    // This method return the titles for the Tabs in the Tab Strip

    @Override
    public CharSequence getPageTitle(int position) {
        return Titles[position];
    }

    // This method return the Number of tabs for the tabs Strip

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

Answer 1

根据答案和一些测试，我也面临同样的问题。

我有三分之一的选择（quite similar to the second method）：

相反，您调用 notifyDataSetChanged()（这在我的 TabLayout 中导致了奇怪的行为），创建类型 ViewPager.OnPageChangeListener 的侦听器，然后直接调用片段更新方法。看代码：

public interface Updateable {
   public void update();
}


public class MyFragment extends Fragment implements Updateable {

   ...

   public void update() {
     // do your stuff on fragment became visible
   }
}

在Activity 主持人：

mAdapter = new DashboardPagerAdapter(DashboardActivity.this,
        getSupportFragmentManager(), mTabs);
mAdapter.configure(mViewPager);
mViewPager.addOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener(){
    @Override
    public void onPageSelected(int position) {
        if (mAdapter != null) {
            Updateable fragment = (Updateable)mAdapter.getItem(position);
            if (fragment != null) {
                fragment. update();
            }
        }
    }
});

这样就不会重新创建片段，只是运行更新方法。对我来说已经足够了。

如何制作新的 Fragment onTabSelected 来刷新我的内容？

How do i make new Fragment onTabSelected to refresh my content?

tabs

android

refresh

fragment