Add dynamic data to spinner in Android application

In this post, I will explain to you how we can set dynamic options into our spinner. We load data from API using OKHTTP if you don’t know how to load data from Web API please check out this post Load data from Web Services using OKHTTP. So let get started.

Prerequisites

Before we start I hope you have good knowledge of Web APIs how we can load them and display their data in our Android Application.

Steps to Create Dynamic Spinner options in Android

Step 1. Create a new Android project using Android Studio.

Step 2. Give Internet Access permission in manifest.xml file and also add usesCleartextTraffic in the application as shown in the below code.

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<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:usesCleartextTraffic="true"
    android:theme="@style/AppTheme">
    /...../
</application>

Step 3. Now we need to add the Okhttp3 library in our project to get data from REST API. Open your MainActivity.java class and add the below method to get data from the server and call that method in your onCreate method.

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public void getHttpResponse() {

    String url = "https://cakeapi.trinitytuts.com/api/listuser";

    OkHttpClient client = new OkHttpClient();

    Request request = new Request.Builder()
            .url(url)
            .header("Accept", "application/json")
            .header("Content-Type", "application/json")
            .build();

    client.newCall(request).enqueue(new Callback() {

        @Override
        public void onFailure(Call call, IOException e) {
            String mMessage = e.getMessage().toString();
            Log.w("failure Response", mMessage);
            //call.cancel();
        }

        @Override
        public void onResponse(Call call, Response response) throws IOException {

            final String mMessage = response.body().string();

            MainActivity.this.runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    Log.e("Response", mMessage);
                }
            });
        }
    });
}

Step 4. Now add Spinner in your Layout file actiity_main.xml

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<Spinner
    android:id="@+id/spinner"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center"></Spinner>

Step 5. Now in this final step, we find spinner in layout in our MainActivity.java class and also create an array adapter and initialize our Spinner and later in our method we set data in the spinner as shown in the below code.

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public class MainActivity extends AppCompatActivity {

    Spinner spinner;
    List<String> usersList;
    ArrayAdapter<String> catAdapter;

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

        spinner = (Spinner)findViewById(R.id.spinner);
        usersList = new ArrayList<String>();

        catAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, usersList);
        spinner.setAdapter(catAdapter);

        getHttpResponse();

    }

    public void getHttpResponse() {

        String url = "https://cakeapi.trinitytuts.com/api/listuser";

        OkHttpClient client = new OkHttpClient();

        Request request = new Request.Builder()
                .url(url)
                .header("Accept", "application/json")
                .header("Content-Type", "application/json")
                .build();

        client.newCall(request).enqueue(new Callback() {

            @Override
            public void onFailure(Call call, IOException e) {
                String mMessage = e.getMessage().toString();
                Log.w("failure Response", mMessage);
                //call.cancel();
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {

                final String mMessage = response.body().string();

                MainActivity.this.runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        Log.e("Response", mMessage);
                        try {
                            JSONObject users = new JSONObject(mMessage);
                            JSONArray usersArr = users.getJSONArray("users");

                            for(int i =0; i < usersArr.length(); i++){
                                JSONObject user = usersArr.getJSONObject(i);
                                Log.e("user", user.getString("username"));
                                usersList.add(user.getString("username"));
                            }

                            catAdapter.notifyDataSetChanged();


                        } catch (JSONException e) {
                            e.printStackTrace();
                        }

                    }
                });
            }
        });
    }
}