android 后台恢复,如何在恢复时更新后台 fragment？_android-fragments_开发99编程知识库...

MainActivity.javaFragmentA fragmentA = null;

FragmentB fragmentB = null;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main_activity);

}

public void replaceFragment(Fragment newFragment){

FragmentTransaction ft = getFragmentManager().beginTransaction();

ft.replace(R.id.right_container, newFragment);

ft.addToBackStack(null);

ft.commit();

}

public void removeFromActivity(Fragment oldFrag){

FragmentManager manager = getFragmentManager();

FragmentTransaction ft = manager.beginTransaction();

manager.popBackStack();

manager.executePendingTransactions();

ft.remove(oldFrag);

ft.commit();

}

FragmentA.javapublic class FragmentA extends Fragment implements OnClickListener{

public View contentView;

@Override

public View onCreateView(LayoutInflater inflater, ViewGroup container,

Bundle savedInstanceState) {

if(null == contentView){

contentView = inflater.inflate(R.layout.fragment_a, null);

EditText editTxt = (EditText) contentView.findViewById(R.id.right_frag_edit_txt);

editTxt.setOnClickListener(this);

}

//--------------------------------------------------//

//Here If I am printing

EditText editTxt = (EditText) contentView.findViewById(R.id.right_frag_edit_txt);

System.out.println(editTxt.getText());//Output -- Now Button has Clicked --New value as expected

return contentView;

}

public void setValues(String newVal){

EditText editTxt = (EditText) contentView.findViewById(R.id.right_frag_edit_txt);

editTxt.setText(newVal);

}

@Override

public void onClick(View v) {

FragmentB newFrag = new FragmentB();

((MainActivity)getActivity()).fragmentB = newFrag;

((MainActivity)getActivity()).replaceFragment(newFrag);

}

}

FragmentB.javapublic class ReplacedFragment extends Fragment implements OnItemClickListener{

public View contentView;

@Override

public View onCreateView(LayoutInflater inflater, ViewGroup container,

Bundle savedInstanceState) {

if(null == contentView){

contentView = inflater.inflate(R.layout.fragment_b, null);

}

return contentView;

}

@Override

public void onClick(View v) {

FragmentA previousFrag = ((MainActivity)getActivity()).fragmentA;

previousFrag.setValues("Now Button has Clicked");

((MainActivity)getActivity()).removeFromActivity(this);

}

}

我在點擊按鈕"背面"時，只是從後面的堆棧中刪除這個。 結果FragmentB恢復了。 但是edittext值沒有用新值更新。

我應該在FragmentA恢復時更新它的某些視圖。 請幫助。