[英]How do I return a value from onResponse
基本上,這就是代碼結構,我想知道如何修改代碼,以便可以在onResponse中獲取值並返回它。 到目前為止,我的mainReply變量返回“(blank)”,但我希望它在我的onResponse段中的名為details的arraylist中傳遞數據。 請放心,我檢查時有返回值,但我只是無法獲取要傳遞給onResponse段的值。
我檢查了替代品,他們提到要使用接口。 但是,我不知道如何修改我的代碼以使用提到的接口和callBacks的解決方案。
public class MainActivity extends AppCompatActivity {
EditText et_message;
FloatingActionButton fab_send;
API api;
ListView list_view_conversation;
List<ChatModel> list_chat = new ArrayList<>();
RevealDetailsCallbacks callback;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
et_message = (EditText) findViewById(R.id.et_message);
fab_send = (FloatingActionButton) findViewById(R.id.fab_send);
list_view_conversation = (ListView) findViewById(R.id.list_view_conversation);
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(API.BASE_URL)
.addConverterFactory(GsonConverterFactory.create())
.build();
api = retrofit.create(API.class);
fab_send.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//this method ultimately is to get response and send back to user
String s = et_message.getText().toString();
ChatModel model = new ChatModel(s, true);
list_chat.add(model);
new retrieveDetails().execute(list_chat);
et_message.setText("'");
}
});
}
public class retrieveDetails extends AsyncTask<List<ChatModel>, Void, String> {
String text = et_message.getText().toString();
String mainReply = "";
List<ChatModel> models;
List<String> details = new ArrayList<String>();
@Override
public String doInBackground(List<ChatModel>[] lists) {
Call<List<Patient>> call = api.getPatients();
models = lists[0];
call.enqueue(new Callback<List<Patient>>() {
public String reply;
@Override
public void onResponse(Call<List<Patient>> call, Response<List<Patient>> response) {
List<Patient> patients = response.body();
for (int i = 0; i < patients.size(); i++) {
if (patients.get(i).getNric().equals(text)) {
details.add("Name: " + patients.get(i).getName() + "\nNRIC: " + patients.get(i).getNric()
+ "\nDOB: " + patients.get(i).getDob() + "\nContact No: " + patients.get(i).getContactno());
}
}
this.mainReply = details.get(0);
Log.i("Here Log i", reply);
}
@Override
public void onFailure(Call<List<Patient>> call, Throwable t) {
Toast.makeText(getApplicationContext(), t.getMessage(), Toast.LENGTH_SHORT).show();
}
});
return mainReply;//I want to reply with the data added into the details arraylist in the onResponse segment
}
@Override
public void onPostExecute(String s) {
ChatModel chatModel = new ChatModel(s, false);
models.add(chatModel);
CustomAdapter adapter = new CustomAdapter(models, getApplicationContext());
list_view_conversation.setAdapter(adapter);
}
}
}
如果要修改現有代碼,則可以添加一個接口,就像我在頂部添加的接口(RevealDetailsCallbacks)一樣,將其傳遞給asynctask構造函數,然后運行它。 代碼如下所示:
public class MainActivity extends AppCompatActivity {
//Interface callback here
interface RevealDetailsCallbacks {
public void getDataFromResult(List<String> details);
}
EditText et_message;
FloatingActionButton fab_send;
API api;
ListView list_view_conversation;
List<ChatModel> list_chat = new ArrayList<>();
RevealDetailsCallbacks callback;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
et_message = (EditText) findViewById(R.id.et_message);
fab_send = (FloatingActionButton) findViewById(R.id.fab_send);
list_view_conversation = (ListView) findViewById(R.id.list_view_conversation);
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(API.BASE_URL)
.addConverterFactory(GsonConverterFactory.create())
.build();
this.callback = new RevealDetailsCallbacks() {
@Override
public void getDataFromResult(List<String> details) {
//Do stuff here with the returned list of Strings
}
};
api = retrofit.create(API.class);
fab_send.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//this method ultimately is to get response and send back to user
String s = et_message.getText().toString();
ChatModel model = new ChatModel(s, true);
list_chat.add(model);
new retrieveDetails(callback).execute(list_chat);
et_message.setText("'");
}
});
}
public class retrieveDetails extends AsyncTask<List<ChatModel>, Void, String> {
String text = et_message.getText().toString();
String mainReply = "";
List<ChatModel> models;
List<String> details = new ArrayList<String>();
private RevealDetailsCallbacks listener;
retrieveDetails(RevealDetailsCallbacks listener){
this.listener = listener;
}
@Override
public String doInBackground(final List<ChatModel>[] lists) {
Call<List<Patient>> call = api.getPatients();
models = lists[0];
call.enqueue(new Callback<List<Patient>>() {
public String reply;
@Override
public void onResponse(Call<List<Patient>> call, Response<List<Patient>> response) {
List<Patient> patients = response.body();
for (int i = 0; i < patients.size(); i++) {
if (patients.get(i).getNric().equals(text)) {
details.add("Name: " + patients.get(i).getName() + "\nNRIC: " + patients.get(i).getNric()
+ "\nDOB: " + patients.get(i).getDob() + "\nContact No: " + patients.get(i).getContactno());
}
}
this.mainReply = details.get(0);
Log.i("Here Log i", reply);
if(listener != null) {
listener.getDataFromResult(details);
}
}
@Override
public void onFailure(Call<List<Patient>> call, Throwable t) {
//Don't make a toast here, it will throw an exception due to it being in doInBackground
//Toast.makeText(getApplicationContext(), t.getMessage(), Toast.LENGTH_SHORT).show();
}
});
return mainReply;//I want to reply with the data added into the details arraylist in the onResponse segment
}
@Override
public void onPostExecute(String s) {
ChatModel chatModel = new ChatModel(s, false);
models.add(chatModel);
CustomAdapter adapter = new CustomAdapter(models, getApplicationContext());
list_view_conversation.setAdapter(adapter);
}
}
}
但是,這里不需要asynctask,因為您正在運行Retrofit並調用在后台線程上運行的.enqueue。 一個更簡單的版本如下所示:
public class MainActivity extends AppCompatActivity {
//Interface callback here
interface RevealDetailsCallbacks {
public void getDataFromResult(List<String> details);
}
//Keep your same variables here
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Same setup here
this.callback = new RevealDetailsCallbacks() {
@Override
public void getDataFromResult(List<String> details) {
//Do stuff here with the returned list of Strings
}
};
fab_send.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//Same setup here, then call the method
makeWebCalls();
}
});
}
private void makeWebCalls(){
Call<List<Patient>> call = api.getPatients();
models = lists[0];
call.enqueue(new Callback<List<Patient>>() {
@Override
public void onResponse(Call<List<Patient>> call, Response<List<Patient>> response) {
//Run your response code here. When done, pass to the callback
}
@Override
public void onFailure(Call<List<Patient>> call, Throwable t) {
Toast.makeText(getApplicationContext(), t.getMessage(), Toast.LENGTH_SHORT).show();
}
});
}
}
您可以立即在OnClick中加入Retrofit調用並在那里處理響應
fab_send.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
final String text = et_message.getText().toString();
// if you're trying to filter data, add a parameter to getPatients()
api.getPatients().enqueue(new Callback<List<Patient>>() {
@Override
public void onResponse(Call<List<Patient>> call, Response<List<Patient>> response) {
// Here you have a full list of patients
final List<Patient> patients = response.body();
// adapter = new PatientAdapter(MainActivity.this, patients);
// mListView.setAdapter(adapter);
}
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