我必须显示 JSON 数组中的对象列表。但我似乎无法打印出来

Question

// 我已经在这里声明了所有内容，从这里看起来一切正常。我不认为我在这里有问题

public class MainActivity 扩展 AppCompatActivity {

private TextView mTextViewResult;
private RequestQueue mQueue;

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

    mTextViewResult = findViewById(R.id.text_view_result);
    Button buttonParse = findViewById(R.id.button_parse);

    mQueue = Volley.newRequestQueue(this);

    buttonParse.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            jsonParse();
        }
    });
}


private void jsonParse(){
    String url = "https://fetch-hiring.s3.amazonaws.com/hiring.json";

// 我不知道我的问题出在哪里，我已经声明了所有内容但没有任何显示，我在想我应该声明一个数组而不是一个对象，但我仍然有困难

    JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, url, null, new Response.Listener<JSONObject>() {
        @Override
        public void onResponse(JSONObject response) {
            try {
                JSONArray jsonArray = response.getJSONArray("");
                for (int i = 0; i < jsonArray.length(); i++){
                    JSONObject list = jsonArray.getJSONObject(i);

                    int id = list.getInt("id");
                    int listId = list.getInt("listId");
                    String name = list.getString("name");

                    mTextViewResult.append(String.valueOf(id) + ", " + String.valueOf(listId) + ", " + name + "\n\n");
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }
    }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            error.printStackTrace();
        }
    });

    mQueue.add(request);
}

}

Answer 1

尝试使用以下代码。

JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, url, null, new Response.Listener<JSONArray>() {
    @Override
    public void onResponse(JSONArray response) {
        try {
            for (int i = 0; i < response.length(); i++){
                JSONObject list = jsonArray.getJSONObject(i);
                int id = list.getInt("id");
                int listId = list.getInt("listId");
                String name = list.getString("name");
                mTextViewResult.append(String.valueOf(id) + ", " + String.valueOf(listId) + ", " + name + "\n\n");
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }
}, new Response.ErrorListener() {
    @Override
    public void onErrorResponse(VolleyError error) {
        error.printStackTrace();
    }
  });

mQueue.add(request);
}
}

Answer 2

由于响应是一个Json数组，你需要使用JsonArrayRequest而不是JsonObjectRequest，并在onResponse中接收一个JSONArray。

JsonArrayRequest request = new JsonArrayRequest(Request.Method.GET, url, null, new Response.Listener<org.json.JSONArray>() {
    @Override
    public void onResponse(org.json.JSONArray response) {
        try {
            for (int i = 0; i < response.length(); i++){
        ..... etc.

见https://javadoc.io/static/com.android.volley/volley/1.1.1/com/android/volley/toolbox/JsonArrayRequest.html

我必须显示 JSON 数组中的对象列表。但我似乎无法打印出来

I have to show a list of Objects from a JSON array. But i cant seem to print it out

java

android

json

android-volley