在微调器中选择项目后，在textview中显示相应的json数据

因此，您想从选定的标准中获取所有学生的详细信息。 这是将解决您的问题的代码。

用getter和setter创建价值项目类

public class StudentVO implements Serializable{

    private String name;
    private String surname;
    private String age;
    private String div;
    private String standard;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSurname() {
        return surname;
    }

    public void setSurname(String surname) {
        this.surname = surname;
    }

    public String getAge() {
        return age;
    }

    public void setAge(String age) {
        this.age = age;
    }

    public String getDiv() {
        return div;
    }

    public void setDiv(String div) {
        this.div = div;
    }

    public String getStandard() {
        return standard;
    }

    public void setStandard(String standard) {
        this.standard = standard;
    }
}

现在在您要从微调器中选择标准的主类中，将代码替换为：

//Add this
public class MainActivity extends AppCompatActivity {

ArrayList<String> AllStandards = new ArrayList<>();
private ArrayList<StudentVO> studentVOList = new ArrayList<>();
ArrayAdapter<String> adapter;
JSONArray jsonArray;
Spinner spinner;

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

    final List<String> items = getCountries("data.json");

    spinner = (Spinner) findViewById(R.id.spinnerStandard);
    adapter = new ArrayAdapter<String>(this, R.layout.second_layout, R.id.txtStandard, items);

    spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {

        public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
            try {

                String standard = AllStandards.get(i);

                if (studentVOList.size() > 0)
                    studentVOList.clear();
                for (int j = 0; j < jsonArray.length(); j++) {
                    JSONObject jsonObject = jsonArray.getJSONObject(j);
                    String stand = jsonObject.getString("standard");
                    if (stand.equalsIgnoreCase(standard)) {
                        StudentVO studentVO = new StudentVO();
                        studentVO.setAge(jsonObject.getString("age"));
                        studentVO.setName(jsonObject.getString("name"));
                        studentVO.setDiv(jsonObject.getString("div"));
                        studentVO.setStandard(stand);
                        studentVOList.add(studentVO);
                    }
                }

                Log.d("TAG", "List With All Students in selected standard: "+studentVOList.size());

                Intent intent = new Intent(getApplicationContext(), StudentsInfo.class);
                Bundle b = new Bundle();
                b.putSerializable("list",studentVOList);

                intent.putExtra("bundle",b);

                startActivity(intent);
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }
        public void onNothingSelected(AdapterView<?> arg0) {
        }
    });
    spinner.setAdapter(adapter);

}//onCreate Method

private List<String> getCountries(String fileName) {
    jsonArray = null;


    //ArrayList<String> cList = new ArrayList<String>();
    try {
        InputStream is = getResources().getAssets().open(fileName);
        int size = is.available();
        byte[] data = new byte[size];
        is.read(data);
        is.close();
        String json = new String(data, "UTF-8");

        AllStandards.clear();
        try {
            jsonArray = new JSONArray(json);

            for (int i = 0; i < jsonArray.length(); i++) {
                JSONObject jsonObject = jsonArray.getJSONObject(i);
                String stand = jsonObject.getString("standard");
                if (!AllStandards.contains(stand)) {
                    AllStandards.add(stand);
                }
            }
        }
        catch (JSONException je) {
            je.printStackTrace();
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }catch (IOException e) {
        e.printStackTrace();
    }
    return AllStandards;
}
}

之后，您可以在StudentsInfo类中获得此列表，例如：

Bundle b = getIntent().getBundleExtra("bundle");
ArrayList<StudentVO> studentVOList = (ArrayList<StudentVO>) b.getSerializable("list");

Log.d("TAG", "List Size; "+studentVOList.size());

而且您不需要从json数组中获取标准列表。 您可以准备具有标准1,2,3 ....的学生的静态列表，依此类推，然后将其传递给阵列适配器。

查看我的调试结果：

我只是检查您的代码删除

intent.putExtra("name", jsonArray.optJSONObject(i).getString("name"));
                    intent.putExtra("surname", jsonArray.optJSONObject(i).getString("surname"));
                    intent.putExtra("age", jsonArray.optJSONObject(i).getString("age"));
                    intent.putExtra("div", jsonArray.optJSONObject(i).getString("div"));

来自MainActivity的代码，以及StudentInfo活动类的onCreate（）方法中的代码，您可以获取以下学生的列表：

Bundle b = getIntent().getBundleExtra("bundle");
    ArrayList<StudentVO> studentVOList = (ArrayList<StudentVO>) b.getSerializable("list");