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Handle Retrofit todo response safely #270

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Merged
merged 1 commit into from
Sep 23, 2025
Merged

Handle Retrofit todo response safely #270

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39 changes: 34 additions & 5 deletions ...ndroidtutorials/java/ui/screens/android/lessons/networking/retrofit/RetrofitActivity.java
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Original file line number Diff line number Diff line change
Expand Up @@ -5,13 +5,17 @@
import android.os.Handler;
import android.os.Looper;

import androidx.annotation.Keep;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

import com.d4rk.androidtutorials.java.R;
import com.d4rk.androidtutorials.java.databinding.ActivityRetrofitBinding;
import com.d4rk.androidtutorials.java.ui.components.navigation.UpNavigationActivity;
import com.d4rk.androidtutorials.java.utils.EdgeToEdgeDelegate;
import com.google.gson.annotations.SerializedName;

import java.util.Map;

import retrofit2.Call;
import retrofit2.Callback;
Expand Down Expand Up @@ -47,17 +51,17 @@ protected void onCreate(@Nullable Bundle savedInstanceState) {
api.getTodo().enqueue(new Callback<>() {
@Override
public void onResponse(@NonNull Call<Todo> call, @NonNull Response<Todo> response) {
if (response.isSuccessful() && response.body() != null) {
binding.textViewResult.setText(response.body().title);
if (response.isSuccessful()) {
displayTodoTitle(response);
} else {
binding.textViewResult.setText(R.string.snack_general_error);
showGeneralErrorMessage();
}
binding.buttonFetch.setEnabled(true);
}

@Override
public void onFailure(@NonNull Call<Todo> call, @NonNull Throwable t) {
binding.textViewResult.setText(R.string.snack_general_error);
showGeneralErrorMessage();
binding.buttonFetch.setEnabled(true);
}
});
Expand All @@ -74,12 +78,37 @@ protected void onDestroy() {
handler.removeCallbacksAndMessages(null);
}

private void displayTodoTitle(@NonNull Response<Todo> response) {
Object body = response.body();
if (body instanceof Todo) {
Todo todo = (Todo) body;
if (todo.title != null && !todo.title.isEmpty()) {
binding.textViewResult.setText(todo.title);
return;
}
} else if (body instanceof Map<?, ?> map) {
Object title = map.get("title");
if (title != null) {
binding.textViewResult.setText(String.valueOf(title));
return;
}
}
showGeneralErrorMessage();
}

private void showGeneralErrorMessage() {
binding.textViewResult.setText(R.string.snack_general_error);
}

interface JsonPlaceholderApi {
@GET("todos/1")
Call<Todo> getTodo();
}

static class Todo {
@Keep
public static final class Todo {
@SerializedName("title")
@Nullable
public String title;
}
}
65 changes: 47 additions & 18 deletions app/src/main/res/raw/text_retrofit_java.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -5,13 +5,17 @@ import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;

import androidx.annotation.Keep;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

import com.d4rk.androidtutorials.java.R;
import com.d4rk.androidtutorials.java.databinding.ActivityRetrofitBinding;
import com.d4rk.androidtutorials.java.ui.components.navigation.UpNavigationActivity;
import com.d4rk.androidtutorials.java.utils.EdgeToEdgeDelegate;
import com.google.gson.annotations.SerializedName;

import com.d4rk.androidtutorials.java.R;
import java.util.Map;

import retrofit2.Call;
import retrofit2.Callback;
Expand All @@ -21,19 +25,10 @@ import retrofit2.converter.gson.GsonConverterFactory;
import retrofit2.http.GET;

public class RetrofitActivity extends UpNavigationActivity {
private ActivityRetrofitBinding binding;
private final Handler handler = new Handler(Looper.getMainLooper());
private ActivityRetrofitBinding binding;
private JsonPlaceholderApi api;

interface JsonPlaceholderApi {
@GET("todos/1")
Call<Todo> getTodo();
}

static class Todo {
public String title;
}

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Expand All @@ -50,20 +45,20 @@ public class RetrofitActivity extends UpNavigationActivity {

binding.buttonFetch.setOnClickListener(v -> {
binding.buttonFetch.setEnabled(false);
api.getTodo().enqueue(new Callback<Todo>() {
api.getTodo().enqueue(new Callback<>() {
@Override
public void onResponse(Call<Todo> call, Response<Todo> response) {
if (response.isSuccessful() && response.body() != null) {
binding.textViewResult.setText(response.body().title);
public void onResponse(@NonNull Call<Todo> call, @NonNull Response<Todo> response) {
if (response.isSuccessful()) {
displayTodoTitle(response);
} else {
binding.textViewResult.setText(R.string.snack_general_error);
showGeneralErrorMessage();
}
binding.buttonFetch.setEnabled(true);
}

@Override
public void onFailure(Call<Todo> call, Throwable t) {
binding.textViewResult.setText(R.string.snack_general_error);
public void onFailure(@NonNull Call<Todo> call, @NonNull Throwable t) {
showGeneralErrorMessage();
binding.buttonFetch.setEnabled(true);
}
});
Expand All @@ -79,4 +74,38 @@ public class RetrofitActivity extends UpNavigationActivity {
super.onDestroy();
handler.removeCallbacksAndMessages(null);
}

private void displayTodoTitle(@NonNull Response<Todo> response) {
Object body = response.body();
if (body instanceof Todo) {
Todo todo = (Todo) body;
if (todo.title != null && !todo.title.isEmpty()) {
binding.textViewResult.setText(todo.title);
return;
}
} else if (body instanceof Map<?, ?> map) {
Object title = map.get("title");
if (title != null) {
binding.textViewResult.setText(String.valueOf(title));
return;
}
}
showGeneralErrorMessage();
}

private void showGeneralErrorMessage() {
binding.textViewResult.setText(R.string.snack_general_error);
}

interface JsonPlaceholderApi {
@GET("todos/1")
Call<Todo> getTodo();
}

@Keep
public static final class Todo {
@SerializedName("title")
@Nullable
public String title;
}
}