Question

我正在尝试从JSON读取数据。我将Firebase添加到我的Android应用程序中，并且一切正常，但是我不明白如何读取数组字段。

例如，我需要获取"correctAnswers":["Var1","Var4"]字段，但Google无法回答如何做到。

请解释。谢谢。

我的JSON文件的一部分

 {
    "answA" : "Var1",
    "answB" : "Var2",
    "answC" : "Var3",
    "answD" : "Var4",
    "categoryId" : 1,
    "correctAnswers":["Var1","Var4"],
    "id" : 104,
  }

我得到了光标

Cursor cursor = sqlLiteDataBaseInstance.rawQuery(String.format("SELECT * FROM Question WHERE CategoryID = %d ORDER BY RANDOM() LIMIT 30", category), null);

并可以使用

读取answA, answB, answC, answD

cursor.getString(cursor.getColumnIndex(String columnName))和

categoryId, id using cursor.getInt(cursor.getColumnIndex(String columnName))

Answer 1

检查。

  private void readJson() {
        try {
            JSONObject jsonObject = new JSONObject("{\n" +
                    "\t\"answA\": \"Var1\",\n" +
                    "\t\"answB\": \"Var2\",\n" +
                    "\t\"answC\": \"Var3\",\n" +
                    "\t\"answD\": \"Var4\",\n" +
                    "\t\"categoryId\": 1,\n" +
                    "\t\"correctAnswers\": [\"Var1\", \"Var4\"],\n" +
                    "\t\"id\": 104\n" +
                    "}");

            JSONArray jsonArray = jsonObject.getJSONArray("correctAnswers");
            Log.e("Array Size is ", jsonArray.length() + "");

            for (int i = 0; i < jsonArray.length(); i++) {
                Log.e("Array Values", jsonArray.getString(i) + "");
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }

如何从JSON文件读取数组？

1 个答案: