当试图在第二个Fragment上获取值时，该值将消失

Question

当片段B关闭时，我从用startActivityForResult打开碎片B当EditText到片断A时，我得到字符串值，一切都很好，但现在我从

片段Aragment B我在这里存储editText中的objectiveTextvalue，但不保存到json，但我希望在退出FragmentA时保存它

public class Cloud {

private static final String JSON_ID = "id";
private static final String JSON_PURPOSE = "purpose";
private UUID mId;
private String purposeText = "";

public Cloud() {
mId = UUID.randomUUID();
}

public Cloud(JSONObject json) throws JSONException {
mId = UUID.fromString(json.getString(JSON_ID));
if (json.has(JSON_PURPOSE)){
purposeText = json.getString(JSON_PURPOSE);
}
}
public JSONObject toJSON() throws JSONException{
JSONObject json = new JSONObject();
json.put(JSON_ID, mId.toString());
json.put(JSON_PURPOSE, purposeText);
return json;
}

@Override
//Using get and set methods to get it in private String
public String getPurposeText(){return purposeText;}
public void setPurposeText(String purpose){purposeText = purpose;}

public UUID getId() {return mId;};
}

在片段A中，我获取文本并将其设置为文本视图，它可以工作，然后将其设置回云类中的setter

public class AddFragment extends Fragment {
private static final String TAG = "Cload";
public static final String EXTRA_DREAM_ID = "com.example.tadas.dreamcload1.dream_id";
private static final  int REQUEST_DATE = 0;
private static final int REQUEST_TEXT =1;
private Cloud dCloud;
private TextView purposeView;
private String comeBackPurpose;

@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
dCloud = new Cloud();
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
getActivity().setTitle("Add new dream");
}
@Override
public View onCreateView(LayoutInflater inflater,
ViewGroup parent, Bundle savedInstanceState){
View v = inflater.inflate(R.layout.fragment_add,parent,false);
purposeView = (TextView)v.findViewById(R.id.dream_purpose);
purposeView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent i = new Intent(getActivity(),DreamPurposeActivity.class);
startActivityForResult(i,REQUEST_TEXT);
}
});
return v;
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == REQUEST_TEXT){
comeBackPurpose = data.getStringExtra("comeBackPurpose");
// Log.e(TAG,"SHITFACE " + comeBackPurpose);
purposeView.setText(comeBackPurpose);
dCloud.setPurposeText(comeBackPurpose);
Log.e(TAG,"SHITFACE " + dCloud.getPurposeText());
}
}

public static AddFragment newInstance(UUID dreamId) {
Bundle args = new Bundle();
args.putSerializable(EXTRA_DREAM_ID, dreamId);
AddFragment fragment = new AddFragment();
fragment.setArguments(args);
return  fragment;
}
}

现在，在Fragment B中，我正试图在onCreateView方法中将该文本设置回EditText，但它得到了默认值，我应该怎么做才能修复它？

public class PurposeFragment extends Fragment {
public static final String EXTRA_D = "com.dropstudio.drea.dr_ids";
private static final String TAG = "Cload";
private EditText purposeEText;
private String purposeEditText;
private Cloud mCloud;
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mCloud = new Cloud();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.dream_purpose_edit,container,false);
purposeEText = (EditText)v.findViewById(R.id.purpose_edit);

purposeEText.setText(mCloud.getPurposeText());
return v;
}

public void savePurpose(){
purposeEditText = purposeEText.getText().toString();
mCloud.setPurposeText(purposeEditText);
Intent returnIntent = new Intent();
returnIntent.putExtra("comeBackPurpose",purposeEditText);
getActivity().setResult(Activity.RESULT_OK,returnIntent);
getActivity().finish();

}
public static PurposeFragment newInstance(UUID dreaIds) {
Bundle args = new Bundle();
args.putSerializable(EXTRA_D, dreaIds);
PurposeFragment fragment = new PurposeFragment();
fragment.setArguments(args);
return fragment;
}
}

Answer 1

在Fragment B中，您正在onCreate()中创建一个新的Cloud对象，并试图从onCreateView()中的该对象中获取值，该对象将始终为null。

@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mCloud = new Cloud(); //New instance will be created
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.dream_purpose_edit,container,false);
purposeEText = (EditText)v.findViewById(R.id.purpose_edit);

purposeEText.setText(mCloud.getPurposeText()); // 'mCloud' is a new object everytime and hence will not have your saved value
return v;
}

对于您的任务，使用SharedPreferences或在实例化Fragment B时传递保存的值。