如何在Android中使用Activity将arraylist从一个片段传递到另一个片段？ [复制]

Question

请给我好的解决方案，我需要你的帮助！

我想使用接口类传递参数

从B Fragment到Activity，从Activity到C Fragment。

但是 Service asynctask 我不知道 C 在等待 B 吗？

请解释一下这个 Fragments 做了什么？

编辑：

public class FeedDetailActivity extends AppCompatActivity implements TabFragment_DetailFeed.ArrayPasser {

private Toolbar toolbar;
private TabLayout tabLayout;
private ViewPager viewPager;

String nameSurname;
int feedId;
public ArrayList<String> pathimg;

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

    // toolbar = (Toolbar) findViewById(R.id.toolbar);
    // setSupportActionBar(toolbar);

    // getSupportActionBar().setDisplayHomeAsUpEnabled(true);

    nameSurname = getIntent().getStringExtra("nameSurname");

    Intent i = getIntent();
    feedId = i.getIntExtra("feedId",0); // 20  for default value
   // feedId = getIntent().getStringExtra("feedId"); // Hata burda

    viewPager = (ViewPager) findViewById(R.id.pager);
    setupViewPager(viewPager);

    tabLayout = (TabLayout) findViewById(R.id.tab_layout);
    tabLayout.setupWithViewPager(viewPager);

    /* TabFragment_DetailComment EditTextinden otomatik klavye açtırmasını kapatmasını sağlıyor.  */
    getWindow().setSoftInputMode(
            WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN
    );




}
public String getNameSurname() {
    return nameSurname;
}


public int getFeedId() {
    return feedId;
}

private void setupViewPager(ViewPager viewPager) {
    FeedDetailActivity.ViewPagerAdapter adapter = new FeedDetailActivity.ViewPagerAdapter(getSupportFragmentManager());
    adapter.addFragment(new TabFragment_DetailFeed(), "DETAIL");
    adapter.addFragment(new TabFragment_DetailComment(), "COMMENT");
    adapter.addFragment(new TabFragment_DetailImage(), "IMAGE");
    adapter.addFragment(new TabFragment_DetailSurvey(), "SURVEY");
    viewPager.setAdapter(adapter);
}


@Override
public void sendArray(ArrayList<String> strings) {
    TabFragment_DetailImage frag = (TabFragment_DetailImage)
            getSupportFragmentManager().findFragmentById();
    frag.method(strings);
}

class ViewPagerAdapter extends FragmentPagerAdapter {
    private final List<Fragment> mFragmentList = new ArrayList<>();
    private final List<String> mFragmentTitleList = new ArrayList<>();

    public ViewPagerAdapter(FragmentManager manager) {
        super(manager);
    }

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

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

    public void addFragment(Fragment fragment, String title) {
        mFragmentList.add(fragment);
        mFragmentTitleList.add(title);
    }

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

}

Answer 1

您应该尝试使用EventBus。有了它，您可以在片段中注册接收器并从代码的任何部分发布事件。

这是您的片段的一个小例子：

在 C 片段 中重写 onResume() 和 onPause() 像这样

@Override
public void onResume() {
    super.onResume();
    EventBus.getDefault().register(this);
}

@Override
public void onPause() {
    super.onPause();
    EventBus.getDefault().unregister(this);
}

并且还订阅你的活动（你需要为它创建类）

@Subscribe(threadMode = ThreadMode.MAIN)
public void onResult(OnResultEvent event) {
    //do stuff in event
}

然后在B片段这样做

public void doStuff(){
   //do stuff here
   EventBus.getDefault().post(new OnResultEvent(result));
}

Answer 2

在这种情况下，您的 Activity 实现了您在 FragmentA 中定义的接口（ArrayPasser）

public class YourActivity implements FragmentA.ArrayPasser{
    @Override
    public void sendArray(ArrayList<String> strings){
        // Get instance of Fragment B using FragmentManager
        FraB frag = (FragB)
            getSupportFragmentManager().findFragmentById(R.id.fragment_b);
        frag.someMethod(strings);  //passing arraylist to Fragment B from 
                                         Activity
    }
}


// Fragment A defines an Interface, and calls the method when needed
public class FragA extends Fragment{

    ArrayPasser mCallback; //interface reference

    public interface ArrayPasser{
        public void sendArray(ArrayList<String> strings);
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);

        // This makes sure that the container activity has implemented
        // the callback interface. If not, it throws an exception
        try {
            mCallback = (ArrayPasser) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException(activity.toString()
                + " must implement ArrayPasser");
        }
    }

    public void someMethod(ArrayList<String>strings){
        mCallback.sendArray(strings); //passing array list to fragment
    }

    @Override
    public void onDetach() {
        mCallback = null; // => avoid leaking
        super.onDetach();
    }
}

// Fragment B has a public method to do something with the Array 
public class FragB extends Fragment{

    public void method(ArrayList<String> strings){
        // Here you have it
    }
}