如何让两个片段在viewpager中相互沟通android

Question

假设我在viewpager中有两个片段FragmentA和FragmentB。当我单击fragmentA中的按钮时，它应该能够在另一个fragmentB.so中添加textview，怎么可能......请帮助我。

class Myadpter extends FragmentPagerAdapter { 
    Fragment fragment =null; 
    public Myadpter(FragmentManager fm) { 
     super(fm); 
    } 

    @Override 
    public Fragment getItem(int position) { 
     if(position==0){ 
      fragment = new Post(); 
     } 
     if(position==1){ 
      fragment = new ActiveChat(); 
     } 
     if(position==2){ 
      fragment = new LastUsers(); 
     } 
     if(position==3){ 
      fragment = new Noname(); 
     } 

     return fragment; 
    } 

    @Override 
    public int getCount() { 
     return 4; 
    } 
} 

Answer 1

实现一个接口，两个片段之间的通信，所在班级的观点寻呼机是将是一个中间人

Answer 2

如其他用户已经指出，实现一个接口是要走的路。此链接Communicating with Other Fragments将更详细地解释如何实现您正在尝试执行的操作。希望这能解决你的问题。

Answer 3

如下操作：

片段A

public class FragmentA extends Fragment implements View.OnClickListener { 

OnButtonPressed mCallback; 
Button yourButton; 
TextView textViewFragA; 

@Nullable 
@Override 
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { 

    return inflater.inflate(R.layout.your_layout, container, false); 
} 

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

    yourButton = findViewById(R.id.yourBtn); 
    textViewFragA = findViewById(R.id.textViewFragA); 

    yourButton.setOnClickListener(this); 

} 

@Override 
public void onClick(View view) { 

switch(view.getId()){ 
     case R.id.yourBtn: 
      mCallback.onButtonPressed(textViewFragA); 
      break; 
} 

@Override 
public void onAttach(Context context) { 
    super.onAttach(context); 
    // This makes sure that the container activity has implemented 
    // the callback interface. If not, it throws an exception 
    try { 
     mCallback = (OnButtonPressed) getActivity(); 
    } catch (ClassCastException e) { 
     throw new ClassCastException(getActivity().toString() 
       + " must implement OnButtonPressed"); 
    } 
} 

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

/** 
* Interface called whenever the user has clicked on the Button 
* @param textView The TextView to add in FragmentB 
*/ 
public interface OnButtonPressed{ 
    void onButtonPressed(TextView textView); 
} 
} 

FragmentB

public class FragmentB extends Fragment{ 

TextView textViewFragB; 

@Nullable 
@Override 
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { 

    return inflater.inflate(R.layout.your_layout, container, false); 
} 

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

    textViewFragB= findViewById(R.id.textViewFragB); 

} 

public TextView getTextViewFragB(){ 

return textViewFragB; 
} 

活动

public class TabControllerActivity extends AppCompatActivity implements FragmentA.OnButtonPressed{ 

MyAdapter adapter; 

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

// Your Stuff 

} 

// Everytime the user clicks on the Button in FragmentA, this interface method gets triggered 
@Override 
public void onButtonPressed(TextView textViewFragA) { 

FragmentB fragmentB = (FragmentB) adapter.getItem(1)/* Be careful here and get the right fragment, 

otherwise the App will crash*/ 

// Since you got the TextView and not only the text inside of it, 
// you can do whatever you want. Here for example we set the text like the textViewFragA. 
//In a few words you turn the textViewFragB to the other one 
fragmentB.getTextViewFragB().setText(textViewFragA.getText().toString()); 

} 

} 

希望这将有助于